Principles and Methods of Ecology with Dr. Blay

Ref: Jorge Blay (2020). Principles and Methods of Ecology. JHU MS-ESP COI (420.611.81.SU20). Email: jdarosa@jhu.edu

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Summary

• The study of Ecology through an Environmental Science and Policy lens with Dr. Jorge Blay with accompanying supporting articles. 

• Solar Energy strikes Earth…

• Producers: Autotrophs that convert incoming solar energy to carbohydrates through chemo and photosynthesis. These include green plants and cyanobacteria.

• Primary Consumers: Herbivores (phagotrophs) that feed on producers. 

• Secondary Consumers: Carnivores that feed on herbivores and, sometimes, producers. 

• Tertiary Consumers: Top carnivores (predators).

• Decomposers: Bacteria, Fungi, Detritus, Feeders that breakdown consumers and producers. 

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Ecology

Ecology: The study of the rules that govern the different levels of biological organization; attempts to explain, interpret, and predict natures phenomenon. 

• “Ecology teaches that all life on Earth can be viewed as a competition among species for the solar energy captured by green plants and stored in the form of complex carbon molecules. A food chain is a system for passing those calories on to species that lack the plant’s unique ability to synthesize them from sunlight.”-Pollan.

• Ecological Community: A group of species that live together and interact with each other. Some species eat others, some provide shelter or other services for their neighbors, and some compete with each other for food and/or space. These relationships bind a community together and determine the local community structure: the composition and relative abundance of the different types of organism’s present. 

• A community’s trophic structure begins with plants, the primary producers. The consumers that eat the plants (the herbivores) are primary consumers, predators that eat the herbivores are secondary consumers, big predators that eat smaller predators are tertiary consumers, etc. 

• Community structure is regulated primarily by top predators in this way are said to be under top-down control, as opposed to those regulated by the abundance of producers, which are said to be under bottom-up control.

• Intertidal Community: Consists of all the organisms living in the area covered by water at high tide and exposed to the air at low tide.

• Trophic Cascade: Occurs when the abundance of individuals at one trophic level affects the abundance of individuals several trophic levels removed from them.

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Species Diversity

• Diversity has two important components: 1) richness and 2) evenness. 

• Richness: The number of species in a community. A community that is less even is considered to have high dominance (dominance is the inverse of evenness).

• Intermediate Disturbance Hypothesis: Intermediate levels of disturbance will lead to the greatest species diversity. The rationale behind the intermediate disturbance hypothesis is that in low-disturbance environments, a small number of competitively dominant species will take over, and in high-disturbance environments, only species that tolerate disturbance will survive. With intermediate levels of disturbance, neither type of species will be excluded, allowing for higher species diversity.

• Simpson’s Index: Uses the population size of each species in the study area to generate a single number indicating diversity. This number will be low when diversity is low (minimum of 1), and will be higher as diversity increases; D = 1 / (E pi2, I = l to s). 

• S: # of species. 

• Pi: Population size of species i divided by the total population size of all species (the proportion of individuals that are of species.

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Lake Environments

• Benthic Zone: The mud on the bottom. 

• Pelagic Zone: The zone of water from bottom to surface. 

• Phytoplankton: Single-celled, plant-like organisms that photosynthesize; the base of the food chain in lakes. There are two species of phytoplankton: green algae and cyanobacteria (also known as blue-green algae). Both are pelagic, meaning they primarily float in the water. 

• Zooplankton: The animal components of the planktonic community; aquatic organisms that are unable to swim effectively against currents, they drift or are carried along by currents. 

• Growth in lakes is usually limited by nutrients, often P or N.

• Nitrogen Fixation: The conversion of N2 gas into NH3, a form of N that can be used by plants and bacteria.

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Forest Fires

• For years it was a common policy to put out fires as soon as they started and not to let any forest burn. More recently, managers have started considering fires and other disturbances as part of the natural processes that help to rejuvenate the land and perhaps lead to a greater diversity of life. Some disturbance (but not too much) creates space for colonizers that normally would be out-competed by other species.

• Forest Fire Recovery: FIRE occurs, Grasses first, then annual plants, then Blackberry bushes followed by shrubs, then white pines, sugar maples, oak trees, and Hickory Trees. 

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Colony Collapse Disorder (CCD)

Colony Collapse Disorder: The phenomenon that occurs when the majority of worker bees in a colony disappear and leave behind the queen, plenty of food, and a few nurse bees to care for the remaining immature bees and the queen. Once thought to pose a major long-term threat to bees, reported cases of CCD have declined substantially over the last five years. The number of hives that do not survive over the winter months – the overall indicator for bee health – has maintained an average of about 28.7% since 2006-2007 but dropped to 23.1% for the 2014-2015 winter. While winter losses remain somewhat high, the number of those losses attributed to CCD has dropped from roughly 60% of total hives lost in 2008 to 31.1% in 2013; in initial reports for 2014-2015 losses, CCD is not mentioned (EPA).

• One virus, Israeli acute paralysis virus, which in early stages causes wing-shivering, and which ultimately leads to paralysis and death, was found in 83% of CCD colonies and only 5% of healthy colonies. Other pathogens found significantly more frequently in CCD colonies were Kashmir bee virus, which also causes paralysis and death, and two species of Nosema, a microsporidian fungus that leads to dysentery-like symptoms. 

• There was a higher incidence of three parasites and pathogens out of 20 that were tested. Similar to the Cox-Foster (2007) study, Kashmir bee virus and the microsporidian fungus Nosema were more common in CCD colonies than in control colonies. These and other studies suggest that CCD does not arise from one single causative agent. 

• In one study exposure to low doses of a widely used neonicotinoid increased honeybee susceptibility to Nosema infection (Pettis et al. 2012). A study on bumblebees, Bombus terrestris, showed that low doses of the same neonicotinoid resulted in much slower weight gain, and an 85% reduction in queen production (Whitehorn et al. 2012). Finally, low doses of a related neonicotinoid interfered with the ability of foragers to find their nests.

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Habitats

• Habitat loss is the primary anthropogenic cause of loss of biodiversity. As we humans convert more and more natural habitat for our own uses, we not only reduce the amount of habitat suitable for other species, but we also subdivide remaining habitat into fragments. If individual fragments become too small and/or too isolated, a species may become vulnerable to extinction even if the total amount of its habitat appears sufficient.

• Habitat Corridors: Restoration of continuous strips of habitat between existing patches.

• Depending on the nature of the core habitat and its surroundings, edge effects can include: increased sunlight, temperature, and aridity at the patch’s border; the establishment of predator and/or competitor populations that would otherwise not have access to core habitat; and invasion by exotic species.

• Smaller populations are more likely to succumb to stochastic events such as severe storms, disease outbreaks, and droughts. Inbreeding and loss of genetic diversity can reduce fitness, further threatening species. Small habitat patches also have a relatively high ratio of edge to core habitat, increasing edge effects.

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Terminology

• Anthropogenic: Human induced. 

• Demography: The study of the characteristics of human populations, such as size, growth, density, distribution and vital statistics. 

• Ruderal: Rapid colonizer.

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Chronology

• Mar, 2012: The warmest month-year on record throughout many sections of the north central US. The first milkweeds emerge in early April, about a month earlier than usual (Blay, 2020). 

• 2006: Commercial beekeepers begin noticing that honeybee workers in many of their previously healthy colonies were disappearing over a few-week time period, leaving the colonies with only the queen, her brood, and almost no workers (Blay, 2020). 

• Winter, 2007: Colony Collapse Disorder (CCD) spreads across the USA becoming partially responsible for overwinter mortality rates > 35% (Blay, 2020).  

• 1986: Cyanobacterium Prochlorococcus is found to account for more than half of the photosynthesis of the open ocean (Blay, 2020). 

• 1950s: The WHO sends supplies of DDT to Borneo to fight mosquitoes that spread malaria among the people. The mosquitoes were quickly wiped out. But billions of roaches survived and lived in the villages, and they simply stored the DDT in their bodies. One kind of animal that fed on the roaches was a small lizard. When these lizards ate the roaches, they also ate a lot of DDT. Instead of killing them, DDT only slowed them down. This made it easier for cats to catch the lizards, one of their favorite foods. About the same time, people also found that hordes of caterpillars had moved in to feed on the roofing materials of their homes. They realized that the cats had eaten the lizards that previously had kept the caterpillar population under control. And now, all over North Borneo, cats that ate the lizards died from DDT poisoning. Then rats moved in because there were no cats to control their population. With the rats came a new danger: plague. Officials sent out emergency calls for cats. Cats were sent in by airplane and dropped by parachute to help control the rats (Blay, 2020). 

• 1864: George Marsh publishes “Man and Nature” first asking “To what degree are the processes of nature threatened by human activity?” (Blay, 2020). 

• 2.6 ma: Glacial–interglacial cycles begin (Barnosky, unk). 

• ~400ma: Tetrapod’s first appear (Standen, 2014). 

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---Articles---

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Are There General Laws in Ecology? by Lawton

Ref: John Lawton (Feb, 1999). Are There General Laws in Ecology? Nordic Society Oikos, Vol 84, No. 2.

• Law: Generalized formulation based on a series of events or processes observed to recur regularly under certain conditions; a widely observable tendency. 

• Ecology has numerous laws in this sense of the word, in the form of widespread, repeatable patterns in nature, but hardly any laws that are universally true. 

• What is true: The 1st and 2nd laws of thermodynamics, the rules of stoichiometry, natural selection. 

• Pattern-  Mechanism- Generalization- Hypothesis- Theory- Rule- Law- Model. 

• Community Ecology: The ecology of sets of coexisting species interacting at local scales. 

• Expect unexpected changes in communities when they are manipulated or changed in some way. 

• It remains an open question whether key processes and interactions change and decay over time at different rates in different systems; presumably they do, not least because the generation times of dominant species are very different in different ecosystems. 

• Macroecology: A blend of ecology, biogeography, and evolution; the search for major, statistical patterns in the types, distributions, abundances, and richness of species, from local to global scales, and the development and testing of underlying theoretical explanations for these patterns. 

• Patterns only emerge by ignoring the details. 

• In a clear majority of studies, possibly the great majority, the main driver of local species richness appears to be the size of the regional species pool.

• There are too many species with tiny populations and very small ranges.

• Survival of the fittest + Sexual Selection= natural selection. 

• Related, but distinct, patterns between energy inputs to ecosystems and species richness.

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Sixteen Years of Change in the Global Terrestrial Human Footprint by Venter

Ref: Venter et al (23 Aug, 2016). Sixteen Years of Change in the Global Terrestrial Human Footprint and Implications for Biodiversity Conservation. Nature Communications.

• We use recently available data on infrastructure, land cover and human access into natural areas to construct a globally standardized measure of the cumulative human footprint on the terrestrial environment at 1 km2 resolution from 1993 to 2009. We note that while the human population has increased by 23% and the world economy has grown 153%, the human footprint has increased by just 9%. Still, 75% the planet’s land surface is experiencing measurable human pressures.

• We need to better understand spatial and temporal trends in human pressures and their related consequences, so we can act accordingly.

• We find that lands of no pressures dominate in places that are fully unsuitable for agriculture (for example, deserts), but are then rapidly replaced by moderate- and high-pressure bins in areas even marginally suitable for agriculture. Pressure-free lands are almost totally lacking in locations which are at least 60% suitable.

• The pressures underlying the human footprint are all linked in some way to socio-economic activities. These pressures include our urban centers, which are the powerhouses of the global economy, agricultural lands, transport networks and the people who are ultimately responsible for all economic output.

• It appears as though the global human economy is increasing its efficiency in the use of land resources when measured in terms of human footprint per person or per dollar gross domestic product (GDP), which is in line with findings from other studies.

• We find an inverted-U-shaped relationship for human pressure across income categories, with lower-middle income countries undergoing the greatest increase in human footprint and high-income countries undergoing the least. Moreover, we find that footprint trajectories have actually reversed in the wealthiest nations. This trend is not entirely unexpected considering that environmental Kuznets curve theory posits an inverted-U-shaped relationship between economic growth and environmental degradation.

• We found that some countries, particularly wealthy countries and those associated with high urbanization and low corruption, have been undergoing rapid economic growth while simultaneously reducing their human footprint.

• Importance of improving HDI FIRST! To tackle climate issues. 

• This study used ArcGIS Pro with 1km2 resolution of the Earth as 134.1M pixels. 

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Homage to Santa Rosalia by Hutchinson

Ref: G. E. Hutchinson (1959). Homage to Santa Rosalia or Why are there so many kinds of animals? The American Naturalist, Vol. 93, No. 870.

• Homage to Santa Rosalia: This article was a speech given to the American Society of Naturalists in 1958 (almost 100 years after Darwin's "On the Origin of Species"). The address began with observations on Corixiadae (also known as Water Boatmen which swim on the surface of the water and I'd imagine are essentially fodder for both fish below and birds above) and continued with an interesting yet somewhat difficult to follow scientific tone as to the importance of diversity in healthy food webs and ended with, among others, an interesting question as to when humanity will understand the importance of said diversity. A few takeaways from the article: 

• Beetle: Coleoptera

• “If there is a God, he has an inordinate fondness for beetles.”-JBS Haldene. 

• A major source of terrestrial diversity was introduced by the evolution of almost 200,000 species of flowering plants, and the three quarters of a million insects supposedly known today are in part a product of that diversity. 

• Sometimes an extremely successful invader may oust a species but add little or nothing to stability, at other times the invader by some specialization will be able to compete successfully for the marginal parts of a niche. In all cases it is probable that invasion is most likely when one or more species happen to be fluctuating and are underrepresented at any given moment. As the communities build up, these opportunities get progressively rarer. 

• We may conclude that the reason why there are so many species of animals is at least partly because a complex trophic organization of a community is more stable than a simple one, but that limits are set by the tendency of food chains to shorten or become blurred, by unfavorable physical factors, by space, by the fineness of possible subdivision of niches, and by those characters of the environmental mosaic which permit a greater diversity of small than of large allied species. 

• We may hope for a limited reversal of this process when man becomes aware of the value of diversity no less in an economic than in an esthetic and scientific shape. 

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Ecology of Some Warblers of Northeastern Coniferous by MacArthur

Ref: Robert MacArthur (Oct, 1958). Ecology of Some Warblers of Northeastern Coniferous Forests. Ecology, Vol. 39, No. 4.

• To permit coexistence it seems necessary that each species, when very abundant, should inhibit its own further increase more than it inhibits the others. 

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The Impact of Seasonality in Temperature on Thermal Tolerance and Elevational Range Size by Sheldon

Ref: Sheldon & Tewksbury (Aug, 2014). The Impact of Seasonality in Temperature on thermal tolerance and elevational range size. Ecology, Vol. 95, No. 8.

• The Impact of Seasonality in Temperature on Thermal Tolerance and Elevational Range: I know a lot of people don't like beetles, but this was a rough study for these poor coleopteras. The authors, Sheldon and Tewksbury, collected beetles from Costa Rica (10d N), Ecuador (0d N), the SW USA (~30d N), and Argentina (~30d S). They studied the impact of temperature variation in order to deduce the beetles thermal tolerance levels, which they describe as CTmax-CTmin. They posited and found that species adapted to higher temperature variations (thermal generalists) would outperform beetles adapted to lower temperature variations (thermal specialists)- known as the seasonality hypothesis. This study, was important in understanding species tolerance to climate change. A major fault of the study, which the authors point out, was a lack of assessing adaptation to warming climates over successive generations, which frankly, I'm fine with given the methods section of discerning this data.

• Environmental temperature variation can influence physiology, biogeography, and life history, with large consequences for ecology, evolution, and the impacts of climate change. 

• Greater annual temperature variation at high lats should result in greater thermal tolerance and, consequently, larger elevational ranges in temperate compared to tropical species. 

• All organisms have an optimal temperature for performance. When temperatures are warmer than optimal, performance declines rapidly to the critical thermal maximum (CTmax), the high temperature at which the organism ceases to function. When temperatures are colder than optimal, performance declines more slowly to the critical thermal minimum (CTmin). The temperature range is often referred to as thermal tolerance. 

• Thermal specialists are expected to display narrower elevational ranges compared to thermal generalists. 

• Ectotherms: Rely on heat exchange with their environment to maintain body temperature. 

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Flight of Winter Moths near 0 C by Heinrich

Ref: Heinrich & Mommsen (12 Apr, 1985). Flight of Winter Moths near 0 C. Science, New Series, Vol. 228, No. 4696.

• Some noctuid winter moths fly at near 0 C by maintain an elevated (30-35 C) thoracic muscle temperature. 

• The geometrids that are able to fly with a thoracic temperature near -0 C do so largely because of unusually low wing-loading (large wings relative to body mass), which permits a low energetic cost of flight. 

• Endothermic moths shiver before flight until the power output of the muscles is sufficient for takeoff. 

• Ectotherms show a pronounced increase in enzyme activity associated with decreasing temperature. 

• Enthalpy compensation is a common phenomenon in low temperature adapted ectotherms. 

• Low wing loading that decreases the cost of transport may be a preadaptation in these geometrids that has allowed them to fly at low ambient and muscle temperatures. 

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Baboon Watch by Pennisi

Ref: Elizabeth Pennisi (17 Oct, 2014). Baboon Watch. Science, Vol. 346, Issue 6207.

• Amboseli researchers are probing how baboons age to understand why women outlive men but are apparently sicker over the course of their lives. 

• Methylation: Methyl Groups attach to DNA and silence nearby genes. 

• 1974: Jeanne Altman publishes a method for observing individuals in a predetermined random order for preset lengths of time, in order to greatly reduce bias. 

• No matter what a female baboon’s status, having friends correlates to a longer lifespan. 

• Low social status often dampens immune function. 

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Bats Jamming Food by Corcoran

Ref: Corcoran & Conner (7 Nov, 2014). Bats Jamming Bats: Food Competition through SONAR Interference. Science, Vol. 346, Issue 6210.

• Many active sensing animals, including bats and electric fish, alter the frequency of their emissions to avoid inadvertent jamming from conspecifics. 

• Echolocating bats adaptively jam conspecifics during competitions for food. 

• Bats emitted sinusoidal frequency modulated ultrasonic signals that interfered with the echolocation of conspecifics attacking insect prey. Playbacks of the jamming call, but not control sounds, caused bats to miss insect targets. 

• Bats were less likely to capture insects in the presence of conspecific- produced sinFM calls. 

• An example of interference competition through disruption of a competitor’s senses. 

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How and Why Species Multiply by Grant

Ref: Grant & Grant (unk). How and Why Species Multiply, The Radiation of Darwin’s Finches. Princeton University Press.

• How do you detect and measure the signal of divergence?

• Interacting populations may be subject to natural selection that causes resource- exploiting traits (beaks) to diverge, and it results in diminished competition between them. This is referred to as character displacement. Character displacement in beak morphology is revealed by a comparison of populations of two closely related species in sympatry and allopathy. 

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Developmental Plasticity and the Origin of Tetrapod’s by Standen

Ref: Standen et al (2014). Developmental Plasticity and the Origin of Tetrapod’s. Nature 513, 54–58. https://doi.org/10.1038/nature13708

• ~400ma: Tetrapod’s first appear (Standen, 2014). 

• The evolution of terrestrial locomotion in vertebrates required the appearance of new behaviors and supporting appendicular structures. The skeletal changes included the origin of supporting limbs, the decoupling of the dermal pectoral girdle from the skull and the strengthening of the girdle ventrally for support. The predicted behavioral changes at this transition include the planting of the pectoral fins closer to the midline of the body, thereby increasing the vertical component of the ground reaction force and raising the anterior body off the ground

• Environmentally induced phenotypes and their subsequent incorporation into heritable material may play an important role in macroevolution including in the origin of novel traits. 

• Phenotypic Plasticity: The ability of an organism to react to the environment by changing its morphology, behavior, physiology and biochemistry.

• Phenotypically plastic traits can also eventually become heritable through genetic assimilation, which fixes a reduced range of phenotypic plasticity by decreasing a trait’s environmental sensitivity.

• Examining plasticity in an extant form may therefore shed light on the epigenetic processes in past evolutionary events.

• This Article relates plasticity in an extant fish taxon to a major evolutionary transition: the origin of tetrapod’s. The plasticity of ancient fish might have provided the variation necessary to allow the evolution of the terrestrially functional fins that eventually evolved into limbs.

• By placing this predominantly aquatic animal in an obligatory terrestrial environment, we changed the forces experienced by the animal’s musculoskeletal system. We predicted that the increased gravitational and frictional forces experienced by terrestrialized fish would cause changes in the ‘effectiveness’ of their locomotory behavior when travelling over land, as well as changes in the shape of the skeletal structures used in locomotion.

• There was minimal ‘loss’ of swimming function associated with being raised in a terrestrial environment without the ability to ‘practice’ swimming after gill absorption.

• By precisely controlling fin placement and fin slide timing, the treatment group fish may be streamlining the power that is required by the tail and the body to push the fish forwards by ensuring that the tail and body thrust occur when the body and head are lifted by the fin.

• The treatment group fish kept their fins stationed on the ground for the remainder of the step, allowing the fin to contribute to force production and control during the final phase of the step, and for the initiation of the next contralateral step.

• Terrestrial Changes: Optimized Biomechanical performance on land, conditioned training advantage, minimizing energy expenditure and slip, anatomical plasticity, less- variable walking behavior, less fin slip, higher head position, performance enhancing traits during terrestrial locomotion that may have influenced skeletal growth, neck evolution.

• Our results show that exposure to a novel terrestrial environment can increase the phenotypic variation in the terrestrial locomotory behavior and the pectoral girdle of Polypterus.

• Magnitude of Kinematic Variables show a marked difference between the control group and the treatment group, primarily in velocity/fin beat, path curvature, stroke duration, nose oscillation, tail oscillation, nose elevation, fin elevation, and xy fin motion during terrestrial locomotion (walking), fin slide duration, fin slide distance.

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The Human Footprint and the Last of the Wild by Sanderson

Ref: Sanderson et al (unk). The Human Footprint and the Last of the Wild: The Human Footprint Is a Global Map of Human Influence on the Land Surface, Which Suggests That Human Beings Are Stewards of Nature, Whether We like It or Not. BioScience, vol. 52, no. 10, 2002, pp. 891–904. JSTOR, www.jstor.org/stable/10.1641/0006-3568(2002)052[0891:thfatl]2.0.co;2 

• According to scientists’ reports, we appropriate over 40% of the net primary productivity (the green material) produced on Earth each year (Vitousek et al. 1986,Rojstaczer et al. 2001). We consume 35% of the productivity of the oceanic shelf (Pauly and Christensen 1995), and we use 60% of freshwater run-off (Postel et al. 1996). 

• Despite the broad consensus among biologists about the importance of human influence on nature, this phenomenon and its implications are not fully appreciated by the larger human community, which does not recognize them in its eco-nomic systems (Hall et al. 2001) or in most of its political decisions (Soulé and Terborgh 1999, Chapin et al. 2000). In part, this lack of appreciation may be due to scientists’ propensity to express themselves in terms like “appropriation of net primary productivity” or “exponential population growth,” abstractions that require some training to understand. 

• George Marsh first asked, “To what degree are the processes of nature threatened by human activity?” in his 1864 work, Man and Nature.

• Four types of data as proxies for human influence: population density, land transformation, accessibility, and electrical power infrastructure. 

• To combine the nine datasets, we needed to (1) present them in one map projection, using a consistent set of coastal boundaries and regions; (2) express them as overlaying grids at a resolution of 1 square kilometer (km2); and (3) code each dataset into standardized scores that reflected their estimated contribution to human influence on a scale of 0 to 10 (0 for low human in-fluence, 10 for high). 

• Simple mathematics suggests that the greater the number of people, the more resources that will be required from the land, as mediated by their consumption rate (Malthus 1798). 

• We assume that human influence attributable solely to human population density reaches an asymptote at some level, though at what density that influence evens out is uncertain; we chose 10 persons per km2 as an estimate. 

• We summed the human influence scores for each of the nine datasets to create the human influence index (HII) on the land’s surface (figure 1). Overall, 83% of the land’s surface, and 98% of the area where it is possible to grow rice, wheat, or maize (FAO 2000), is directly influenced by human beings (HII > 0). The theoretical maximum (72) is reached in only one area, Brownsville, Texas, USA, but the top 10% of the highest scoring areas looks like a list of the world’s largest cities: New York, Mexico City, Calcutta, Beijing,Durban, São Paulo,London, and so on. The minimum score (0) is found in large tracts of land in the boreal forests of Canada and Russia, in the desert regions of Africa and Central Australia, in the Arctic tundra, and in the Amazon Basin. The majority of the world (about 60%), however, lies along the continuum between these two extremes, in areas of moderate but variable human influence. 

• The human footprint does not measure impact per se; rather, it suggests areas of influence where humans have more or less responsibility for biological outcomes. 

• It is possible to imagine conservation strategies mapped out for different parts of the human influence continuum, based on the hypothesis that if human influence increases as it has for the last 100 years, conservation strategies will increasingly shift from preservation to restoration—with the concomitant increases in cost, time, and difficulty—much as they already have in the United States and Europe. 

• Conservation organizations and biological scientists have demonstrated surprising solutions that allow people and wildlife to coexist, if people are willing to apply their natural capacity to modify the environment to enhance natural values, not degrade them, while making their living. 

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Human Population Reduction is Not a Quick Fix for Environmental Problems by Bradshaw

Ref: Bradshaw & Brook (unk). Human Population Reduction Is Not a Quick Fix For Environmental Problems. Proceedings of the National Academy of Sciences of the United States of America, vol. 111, no. 46, 2014, pp. 16610–16615. JSTOR, www.jstor.org/stable/43190270. Accessed 24 June 2020.

• Reduction, even a rapid transition to a worldwide one-child policy leads to a population similar to todays by 2100.

• Even a catastrophic mass mortality event of 2B deaths over a hypothetical 5-y window in the mid-21c would still yield around 8.5B people by 2100.

• Humanity's large demographic momentum means that there are no easy policy levers to change the size of the human population substantially over coming decades.

• More immediate results for sustainability would emerge from policies and technologies that reverse rising consumption of natural resources.

• Homo Sapiens is now numerically the dominant large organism on the planet. According to the UN, the world human population reached nearly 7.1B in 2013, with median projections of 9.6B (range: 8.3-11.0 billion) by 2050 and 10.9B (range: 6.8-16.6 billion) by 2100 (12), with more recent refinements placing the range at 9.6 to 12.3B by 2100 (13). So rapid has been the recent rise in the human population (i.e., from 1.6B in 1900), that roughly 14% of all of the human beings that have ever existed are still alive today.

• Worldwide, environmental conditions are threatened primarily because of human-driven processes in the form of land conversion (agriculture, logging, urbanization), direct exploitation (fishing, bushmeat), species introductions, pollution, climate change (emissions), and their synergistic interactions.

• Amoral wars and global pandemics aside, the only humane way to reduce the size of the human population is to encourage lower per capita fertility. This lowering has been happening in general for decades (27, 28), a result mainly of higher levels of education and empowerment of women in the developed world, the rising affluence of developing nations, and the one-child policy of China (29-32). Despite this change, environmental conditions have worsened globally because of the overcompensating effects of rising affluence-linked population and consumption rates (3, 18). One of the problems is that there is still a large unmet need for more expansive and effective family-planning assistance, which has been previously hindered by conservative religious and political opposition, premature claims that rapid population growth has ended, and the reallocation of resources toward other health issues (33). Effective contraception has also been delayed because of poor education regarding its availability, supply, cost, and safety, as well as op-position from family members.

• Using data from 2008, there were 208M pregnancies globally, of which an estimated 86M were unintended (44). Of these 86M, ~11M were miscarried, 41M aborted, and 33M resulted in unplanned births. 

• One child per woman by 2100: peak population of 8.9B declining to ~7B. 

• The most striking aspect of the "hypothetical catastrophe" scenarios was just how little effect even these severe mass mortality events had on the final population size projected for 2100.

• The catastrophic mass mortality of 2B dead within 5 y half-way through the projection interval (Scenario 7) resulted in a population size of 8.4B by 2100, whereas the 6B-dead scenario (Scenario 8) implemented one-third of the way through the projection still led to a population of 5.1B by 2100. 

• Our models clearly demonstrate that the current momentum (28) of the global human population precludes any demographic "quick fixes." That is, even if the human collective were to pull as hard as possible on the total fertility policy lever (via a range of economic, medical, and social interventions), the result would be ineffective in mitigating the immediately looming global sustainability crises (including anthropogenic climate disruption), for which we need to have major solutions well under way by 2050 and essentially solved by 2100. 

• More realistically, if worldwide average fertility could be reduced to two children per female by 2020 (compared with 2.37 today), there would be 111M fewer people to feed planet-wide by 2050.

• Perhaps with a more planned (rather than forced) approach to family planning, substantial reductions in future population size are plausible. Better family planning could be achieved not only by providing greater access to contraception, but through education, health improvements directed at infant mortality rates, and outreach that would assuage some of the negative social and cultural stigmas.

• There are clearly many environmental and societal benefits to ongoing fertility reduction in the human population (3, 48, 58), but here we show that it is a solution long in the making from which our great-great-great-great grandchildren might ultimately benefit, rather than people living today. It therefore cannot be argued to be the elephant in the room for immediate environmental sustainability and climate policy. 

• A corollary of this finding is that society's efforts toward sustainability would be directed more productively toward adapting to the large and increasing human population by rapidly reducing our footprint as much as possible through technological (63, 64) and social innovation (3, 65), de-vising cleverer ways to conserve remaining species and ecosystems, encouraging per capita reductions in consumption of irreplaceable goods (58), and treating population as a long-term planning goal.

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Has the Earth’s Sixth Mass Extinction Already Arrived? By Barnosky

Ref: Barnosky et al (unk). Has the Earth’s sixth mass extinction already arrived? Nature 471, 51–57 (2011). https://doi.org/10.1038/nature09678

• Paleontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540M years or so.

• Observations suggest that humans are now causing the sixth mass extinction, through co-opting resources, fragmenting habitats, introducing non-native species, spreading pathogens, killing species directly, and changing global climate. 

• Extinction involves both rate and magnitude, which are distinct but intimately linked metrics. Rate is essentially the number of extinctions divided by the time over which the extinctions occurred. One can also derive from this a proportional rate—the fraction of species that have gone extinct per unit time. Magnitude is the percentage of species that have gone extinct. Mass extinctions were originally diagnosed by rate: the pace of extinction appeared to become significantly faster than background extinction.

• E/MSY (extinctions per million species-years). 

• A second hypothetical approach asks how many more years it would take for current extinction rates to produce species losses equivalent to Big Five magnitudes. The answer is that if all ‘threatened’ species became extinct within a century, and that rate then continued unabated, terrestrial amphibian, bird and mammal extinction would reach Big Five magnitudes in 240 to 540 years (241.7 years for amphibians, 536.6 years for birds, 334.4 years for mammals). 

• If extinction were limited to ‘critically endangered’ species over the next century and those extinction rates continued, the time until 75% of species were lost per group would be 890 years for amphibians, 2,265 years for birds and 1,519 years for mammals.

• For scenarios that project extinction of ‘threatened’ or ‘critically endangered’ species over 500 years instead of a century, mass extinction magnitudes would be reached in about 1,200 to 2,690 years for the ‘threatened’ scenario (1,209 years for amphibians, 2,683 years for birds and 1,672 years for mammals) or 4,450 to 11,330 years for the ‘critically endangered’ scenario (4,452 years for amphibians, 11,326 years for birds and 7,593 years for mammals).

• This emphasizes that current extinction rates are higher than those that caused Big Five extinctions in geological time; they could be severe enough to carry extinction magnitudes to the Big Five benchmark in as little as three centuries. It also highlights areas for much needed future research. Among major unknowns are (1) whether ‘critically endangered’, ‘endangered’ and ‘vulnerable’ species will go extinct, (2) whether the current rates we used in our calculations will continue, increase or decrease; and (3) how reliably extinction rates in well-studied taxa can be extrapolated to other kinds of species in other places.

• Common features of the Big Five suggest that key synergies may involve unusual climate dynamics, atmospheric composition and abnormally high-intensity ecological stressors that negatively affect many different lineages.

• 2.6 ma: Glacial–interglacial cycles that began (Barnosky, unk). 

• Today, rapidly changing atmospheric conditions and warming above typical interglacial temperatures as CO2 levels continue to rise, habitat fragmentation, pollution, overfishing and overhunting, invasive species and pathogens (like chytrid fungus), and expanding human biomass are all more extreme ecological stressors than most living species have previously experienced. Without concerted mitigation efforts, such stressors will accelerate in the future and thus intensify extinction especially given the feedbacks between individual stressors

• Our examination of existing data in these contexts raises two important points. First, the recent loss of species is dramatic and serious but does not yet qualify as a mass extinction in the paleontological sense of the Big Five.

• Losing species now in the ‘critically endangered’ category would propel the world to a state of mass extinction that has previously been seen only five times in about 540 million years. Additional losses of species in the ‘endangered’ and ‘vulnerable’ categories could accomplish the sixth mass extinction in just a few centuries. It may be of particular concern that this extinction trajectory would play out under conditions that resemble the ‘perfect storm’ that coincided with past mass extinctions: multiple, atypical high-intensity ecological stressors, including rapid, unusual climate change and highly elevated atmospheric CO2.

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Change in Northern Oceans

Ref: Unk. Change in Northern Oceans. 

• Summary: Atlantic Cod and Pacific pollock abundances and distributions shift as climate and ocean conditions change.

• During warming phases, the spawning stock biomass gradually builds up and the cod spawn farther north, whereas in cooling phases, spawning stock biomass decreases and spawning occurs farther south.

• Since the 1980s, increasing ocean temperatures have been accompanied by a steady increase in spawning stock biomass of NEA cod, reaching more than 2M metric tons and a record-high northward distribution in 2012.

• The increase in abundance and the poleward displacement of the cod stock reflects a general pattern in other components of the ecosystem, from zooplankton to plankton-eating and fish-eating fish. 

• Losses due to fishing and natural causes exceeded replenishment from growth and reproduction.

• The response of seafloor fish species in the border regions between the boreal and Arctic domains to climate variability may provide clues to how future anthropogenic climate change will influence fish stocks and marine ecosystems at high latitudes.

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Chemical Warfare Among Any Invaders by Lebrun

Ref: Lebrun et al (28 Feb, 2014). Chemical Warfare Among Invaders: A Detoxification Interaction Facilitates an Ant Invasion. Science, Vol. 343.

• As tawny crazy ants (Nylanderia fulva) invade the southern US, they often displace imported fire ants (Solenopsis invicta). After exposure to S. invicta venom, N. fulva applies abdominal exocrine gland secretions to its cuticle. Bioassays reveal that these secretions detoxify S. invicta venom. Further, formic acid from N. fulva venom is the detoxifying agent. 

• The capacity to detoxify a major competitor’s venom probably contributes substantially to its ability to displace S. invicta populations, making this behavior a causative agent in the ecological transformation of regional arthropod assemblages.

• The native ranges of S. invicta and N. fulva overlap in northern Argentina, Paraguay, and southern Brazil, and within this expansive region, these species compete directly for resources.

• N. fulva populations are displacing S. invicta.

• In contrast, N. fulva workers will charge into masses of S. invicta surrounding food items, spraying venom. In response, S. invicta workers gaster flag (extruding and vibrating a venom droplet from their stinger) and dab venom onto nearby attackers.

• After contacting S. invicta venom, an N. fulva worker immediately engages in a highly stereotyped behavioral sequence. Standing on its hind and middle legs, the worker curls its gaster (the modified abdomen of ants) underneath its body, touching its acidopore (the specialized exocrine gland opening at the tip of the gaster) to its mandibles. The N. fulva worker then runs its front legs through its mandibles and grooms itself vigorously, periodically reapplying its acidopore to its mandibles. Apparently, these ants apply an exocrine gland secretion in what seems to be an attempt to detoxify S. invicta venom. We refer to this sequence of behaviors as “detoxification behavior.” 

• Survivorship differed strongly across treatments (Wilcoxon: c2 = 48.6, df = 2, P < 0.0001), with no mortality in acidopore-sealed controls that were not exposed to S. invicta venom. N. fulva workers with sealed acidopores exposed to S. invicta died at a high rate, with 48% surviving. In contrast, 98% of sham-treated N. fulva workers dabbed by S. invicta with venom survived (Wilcoxon: c2 = 28.0, df = 1, P < 0.0001). These ants employed their detoxification behavior frequently after exposure to venom. Thus, detoxification behavior is an extremely effective countermeasure to S. invicta venom.

• The venom gland of N. fulva contains the detoxifying agent. 

• N. fulva venom consists primarily of concentrated formic acid.

• Formic acid appears to be the compound responsible for detoxifying S. invicta venom.

• How formic acid renders fire ant venom nontoxic is unresolved. Five principal piperidine alkaloids (2,6-dialkylpiperidines) and some of their stereoisomers primarily make up S. invicta venom.

• N. fulva and other formicines use formic acid as a chemical weapon because it is highly caustic. Self-applying formic acid is thus costly, favoring selectivity in the expression of the detoxification behavior.

• We suggest that the behavior of N. fulva of applying toxic formic acid to its own cuticle may constitute an adaptation to competition with S. invicta in South America. 

• The use of defensive compounds to achieve competitive dominance is widespread and amazingly varied in ants.

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Love thy Neighbor? by Statsny

Ref: Statsny, Anurag, Agrawal (Oct, 2014). Love thy neighbor? Reciprocal impacts between plant community structure and insect herbivory in co-occurring Asteraceae. Ecology, Vol. 95, No. 10.

• Insect herbivory consistently reduced overall plant productivity, and promoted colonization by other old-field species. 

• Interspecific and Intraspecific differences in defense effectively present herbivores with a fine-scale assortment of plants of differing attractiveness and palatability. The likelihood as well as the extent of herbivory on a given plant species may therefore depend on its neighbors. This context dependence of attack is best known as associational resistance.

• Herbivory may alter the dynamics of plant competition by suppressing species that are competitively dominant thereby creating opportunities for establishment and proliferation of competitively subordinate species. Through these mechanisms, top-down effects of herbivores may thus lead to increased community evenness and species richness. 

• Mesocosms with herbivory had 10% more plant species than those with insects excluded. 

• Plant spatial structure and herbivory may reciprocally influence each other. 

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Designer Reefs by Mascarelli

Ref: Amanda Mascarelli (24 Apr, 2014). Designer Reefs. Nature, Vol. 508.

• Planting “the smartest future reef we can imagine”. Based on the high temperature resilient (35C) reefs of America Samoa. 

• Some researchers are concerned that human-assisted evolution goes too far down the slippery slope of altering natural systems. 

• 19% of the world’s coral reefs have been lost since 1950 and another 35% are threatened or in critical condition. Some areas have suffered disproportionately: the Caribbean, for example, has lost 80% of its reefs since the 1970s. By the end of this century, researchers expect ocean waters to drop from a pH of 8.1 to 7.9 or lower, and to warm by at least 2 °C, averaged across the globe. 

• Waters with a reduced pH are expected to dissolve coral skeletons — but in Palau in the western Pacific Ocean, researchers have found reefs that are bigger and more diverse in relatively acidic waters than the Pacific average. Another study found that dire predictions about the frequency of future coral-bleaching events — mass die-offs when stressed corals lose their symbiotic algae — are reduced by 20–80% if the models take into account corals’ ability to adapt after previous bleaching events. That delays predicted mass reef deaths by about a decade. 

• Unpublished work by Gates, led by the University of Hawaii’s Hollie Putnam, shows that adult cauliflower corals (Pocillopora damicornis) exposed to stress during brooding produce larvae with increased resilience to heat and ocean acidification. The team hypothesizes that this transgenerational protection is caused by epigenetic changes: the modification of molecular tags on the genome that affect gene expression. 

• An important piece of the puzzle is the corals’ symbiotic algae: these are shorter-lived and faster-evolving than their hosts, and research has shown that they can pass along thermal tolerance.

• “Selective-breeding programmes may effectively reduce the capacity of corals to adapt to future changes in environmental conditions by narrowing genetic variation.

• We stopped selectively breeding dogs. So why would we start with corals? (Eric Bond)

• Some 500 million people depend in some way on coral reefs for food and income, and the livelihoods of another 30 million are entirely dependent on reefs. 

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Species Interactions and a Chain of Indirect Effects Driven by Reduced Precipitation by Barton

Ref: Barton & Ives (Feb, 2014). Species Interactions and a Chain of Indirect Effects Driven by Reduced Precipitation. Ecology, Vol. 95, No. 2.

• Identifying the chains of direct and indirect effects on species to climate change- in this case, the indirect effect of spotted aphids on a decrease in precipitation. Drought= reduced water content for alfalfa plants= lower population growth rate of pea aphids, reducing their density= decreased lady beetle predators (who prefer the pea aphids)= increased spotted aphid populations (up to 3x). 

• Therefore, tracing chains of indirect interactions and anticipating the ultimate outcome of climate change for a community is difficult.

• In a factorial mesocosm field experiment in Madison, Wisconsin, USA, we showed that complex species interactions transmit the indirect effects of short-term drought across four species in a simple agroecosystem. 

• The positive effect of drought on spotted aphid abundance when pea aphids were present is best explained by the low abundance of pea aphids attracting fewer predators.

• Importance of combining top down and bottom up biotic and abiotic factors. 

• First, species that are not directly affected by climate change may nonetheless be indirectly affected. Second, climate change may affect communities simultaneously via bottom-up and top-down processes. 

• It is difficult, but not impossible, to determine the net effect on small communities on climate change.

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Impacts of Biological Invasions by Simberloff

Ref: Simberloff et al (Jan, 2013). Impacts of Biological Invasions: What’s What and the Way Forward. Trends in Ecology and Evolution. Vol. 28. No. 1.

• Need for Invasion Science.

• This article depicts the growing understanding of invasion impacts; (ii) show how scientists have responded to the increased management burden this understanding imposes; (iii) discuss challenges posed by the interaction of the field with society; and (iv) suggest ways to advance the field and enhance its ability to respond to challenges.

• Examples

• Foot and Mouth Disease- Botswana

• Mud/Dirt from E. Africa. 

• Lake Tahoe- Zebra Mussels

• Rate of biological invasions is increasing despite elucidation of their consequences and knowledge about mitigations. 

• Many of the systems in Ecology are based on closed systems. 

• Who determines what is a pro or negative invasive species?

• Often, impacts usually seen as negative from the ecosystem perspective are perceived as positive by some societal segments.

• Invasive Population: Introduced population that spreads and maintains itself without human assistance.

• Eradication: Complete removal of all individuals of a distinct population, not contiguous with other populations.

• Extirpation: Elimination of a local population, but with conspecifics remaining in contiguous populations or nearby.

• Impact: Any significant change (increase or decrease) of an ecological property or process, regardless of perceived value to humans. 

• Solutions

• Public Education.

• Screening for pathways and vectors.

• Prevention as the priority response.

• Detection and Eradication when Prevention fails.

• Prevention (Information, Screening, Regulation, Quarantine).

• Early Detection (Interception, Monitoring/Surveillance, Removal).

• Management (Eradication, Containment, Control).

• Alert the public and policymakers to subtle or non-obvious impacts.

• Invasion science must develop better metrics for quantifying and categorizing impacts to improve prioritization of management and risk assessments. Economists require such quantified information for valuing impacts and courses of action in the cost–benefit analyses of individual species that are a pillar of invasion economics.

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The Biodiversity of Species and their Rates of Extinction by Pimm

Ref: Pimm et al (30 May, 2014). The Biodiversity of Species and their Rates of Extinction. Distribution, and Protection. Science, Vol. 344, Issue 6187.

• We start by asking how many species are known and how many remain undescribed. We then consider by how much human actions inflate extinction rates.

• Current rates of extinction are about 1000 times the background rate of extinction.

• Although there has been rapid progress in developing protected areas, such efforts are not ecologically representative, nor do they optimally protect biodiversity. 

• So how many eukaryote species are there (4)? For land plants, there are 298,900 accepted species’ names, 477,601 synonyms, and 263,925 names unresolved (5). Because the accepted names among those resolved is 38%, it seems reasonable to predict that the same proportion of unresolved names will eventually be accepted. This yields another ~100,000 species for a total estimate of 400,000 species (5). Models predict 15% more to be discovered (6), so the total number of species of land plants should be >450,000 species, many more than are conventionally assumed to exist.

• For animals, recent overviews attest to the question’s difficulty. About 1.9 million species are described (7); the great majority are not. Costello et al. (8) estimate 5 T 3 million species, Mora et al. (9) 8.7 T 1.3 million, and Chapman (7) 11 million. Raven and Yeates (10) estimate 5 to 6 million species of insects alone, whereas Scheffers et al. (11) think uncertainties in insect and fungi numbers make a plausible range impossible. Estimates for marine species include 2.2 T 0.18 million (9), and Appeltans et al. estimate 0.7 to 1.0 million species, with 226,000 described and another 70,000 in collections awaiting description

• We express extinction rates as fractions of species going extinct over time—extinctions per million species-years (E/MSY). 

• This suggests that 0.1 E/MSY is an order-of-magnitude estimate of the background rate of extinction.

• The IUCN in its Red List of Threatened Species, assesses species’ extinction risk as Least Concern, Near-Threatened, three progressively escalating categories of Threatened species (Vulnerable, Endangered, and Critically Endangered), and Extinct.

• In sum, present extinction rates of ~100 E/MSY and the strong suspicion that these rates miss extinctions even for well-known taxa, and certainly for poorer known ones, means present extinction rates are likely a thousand times higher than the background rate of 0.1 E/MSY.

• Globally, species with >50% of the sites of particular importance for them protected are sliding toward extinction only half as rapidly as those with <50% of their important sites protected.

• Ocean protection lags behind that on land. A 2013 assessment (106) reported ~10,000 marine protected areas (MPAs) covering 2.3% of the oceans. As on land, marine protected area coverage is uneven. Reserves are often absent where threats to biodiversity are highest, such as fishing grounds and oil and gas leases.

• Marine protected areas that are no-take, well-enforced, old, large, and isolated by deep water or sand are disproportionately successful in retaining their species 

• We believe that a COI database can be developed within 20 years for the 5–10M animal species on the planet (Hammond 1992; Novotny et al. 2002) for approximately $1B, far less than that directed to other major science initiatives such as the Human Genome project or the International Space Station. Moreover, initial efforts could focus on species of economic, medical or academic importance. Data acquisition is now simple enough for individual laboratories to gather, in a single year, COI profiles for 1000 species, a number greater than that in many major taxonomic groups on a continental scale. Once completed, these profiles will be immediately cost effective in many taxonomic contexts, and innovations in sequencing technology promise future reductions in the cost of DNA-based identifications. If advanced comprehensively, a COI database could serve as the basis for a global bio-identification system (GBS) for animals. Implementation on this scale will require the establishment of a new genomics database. While GenBank aims for comprehensive coverage of genomic diversity, the GBS database would aim for com- prehensive taxonomic coverage of just a single gene. Through web-based delivery, this system could provide easy access to taxonomic information, a particular benefit to developing nations. 

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Invasive Alga Reaches California by Jousoon

Ref: Jousson et al (9 Nov, 2000). Invasive alga reaches California. Nature, Vol. 408.

• Recent discovery of the marine green alga Caulerpa taxifolia on the Californian coast.

• A small colony of C. taxifolia introduced into the Mediterranean in 19843,4 from a public aquarium5 has spread to more than 6,000 hectares today, outcompeting native species and seriously reducing diversity in areas of the northwestern Mediterranean.

• This invasive strain of C. taxifolia differs from tropical populations in that it is much larger, grows more vigorously, does not rely on sexual reproduction, and is resistant to low temperature.

• Evaluate the risk of invasion by Californian C. taxifolia by comparing it genetically with the Mediterranean and aquarium strain, as well as with native tropical populations. Our results show that the Californian alga is the same as the invasive Mediterranean strain, calling for its rapid eradication to prevent a new invasion.

• Reported from Carlsbad and Huntington Harbor. 

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Killer Alga by Hoddle

Ref: Mark Hoddle (unk). Caulerpa Taxifolia or Killer Alga. From: https://cisr.ucr.edu/invasive-species/caulerpa-taxifolia-or-killeralga#:~:text=The%20Situation%3A%20Caulerpa%20taxifolia%20is,from%20southern%20California%20 n%202006.

• Officially eradicated from S. CA in 2006. 

• UC Riverside Dept of Entomology.

• The appearance of Caluerpa in southern California in 2000 was most probably caused by an aquarium owner improperly dumping the contents of a marine fish tank into a storm water system that fed into Agua Hedionda Lagoon in Carlsbad where this weed was first discovered. California has since passed a law forbidding the possession, sale or transport of Caulerpa taxifolia within the state. There is also a federal law under the Noxious Weed Act forbidding interstate sale and transport of the aquarium strain Caulerpa.

• To eradicate underwater populations of Caulerpa, patches were covered with tarpaulins which were held down with sandbags which sealed the edges. Chlorine was poured under the sealed tarpaulins which trapped the chlorine. Chlorine in this instance acted as a pesticide and killed living organisms trapped under the tarpaulins, including Caulerpa.

• Eradication efforts took six years at a cost of >$7M (US).

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Producing More Grain with Lower Environmental Costs by Chen

Ref: Chen et al (23 Oct, 2014). Producing More Grain with Lower Environmental Costs. Nature, Vol. 514. 

• Agriculture faces great challenges to ensure global food security by increasing yields while reducing environmental costs.

• Rice, wheat and maize production in China. A set of integrated soil–crop system management practices based on a modern understanding of crop ecophysiology and soil biogeochemistry increases average yields for rice, wheat and maize from 7.2 million grams per hectare (Mg ha-1), 7.2 Mg ha-1 and 10.5 Mg ha-1 to 8.5 Mg ha-1 , 8.9 Mg ha-1 and 14.2 Mg ha-1.

• Integrated soil–crop system management. If farmers in China could achieve average grain yields equivalent to 80% of this treatment by 2030, over the same planting area as in 2012.

• Agriculture incurs substantial environmental costs, including emissions of greenhouse gases, loss of biodiversity, and degradation of land and freshwater. These challenges may grow in the future, because global food demand is likely to double by 2050 (reflecting both population growth and increased consumption of animal protein).

• In each experiment four treatments were employed: (1) current practice (the farmers’ practice in the region but conducted in experimental plots); (2) improved practice (which modified current practice to offset the major limitations to crop growth); (3) high yielding (which maximized yields without regard to costs); and (4) integrated soil–crop system management (ISSM, which used advanced crop and nutrient management). ISSM redesigned the whole production system based on the local environment, drawing upon appropriate crop varieties, sowing dates, densities and advanced nutrient management. 

• Our experiments demonstrate that substantially increased yields can be produced with lower inputs of nitrogen fertilizer

• Current yields and cropping areas across China combine to produce 204, 121 and 206 Mt of rice, wheat and maize annually, with 74% of maize fed to livestock (with 5 Mt of imported maize, and 58 Mt of imported soybean). With population and economic growth, demand for grain in China is expected to reach 218, 125 and 315 Mt of rice, wheat and maize by 2030, by which time China’s population is expected to have stabilized. If farmers could achieve grain yields of 80% of the yield level in our ISSM treatment by 2030, using the same planting area as in 2012, total production of rice, wheat and maize would reach 216, 174 and 397 Mt; this is enough to meet the demand for direct human consumption and domestically produced animal feed. Such yields would even suffice to offset imports of animal feed, while reducing nitrogen use, reactive nitrogen losses and GHG emissions by 21%, 30% and 11% respectively, compared with current levels. Further, if we simply reach the projected demand in 2030 with 80% of ISSM yields, then reactive nitrogen losses and GHG emission could be reduced by 48% and 26%, and the land and nitrogen fertilizer used for these three crops could also be reduced by 22% and 33%.

• Improved practice, which was based on improving farmers’ practices beginning with an analysis of limiting factors, followed by implementing key new technologies, mostly through using root zone nutrient management to improve nutrient use efficiency, together with known agronomic management practices (that is, increasing planting density) to increase yield. 

• ISSM, which redesigned cropping systems using advanced crop and nutrient management to bring yields closer to their biophysical potential, while optimizing various resource inputs (that is, nutrient and water) and minimizing environmental costs, based on an understanding of crop ecophysiology (for example, crop canopy, solar radiation use and dry matter accumulation), physiological nutrient demands by high-yielding crop and the biogeochemical processes relating to nutrient availability and loss.

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Defaunation in the Anthropocene by Dirzo

Ref: Dirzo et al (25 Jul, 2014). Defaunation in the Anthropocene. Science, Vol. 345, Issue 6195. 

• Among terrestrial vertebrates, 322 species have become extinct since 1500, and populations of the remaining species show 25% average decline in abundance. Invertebrate patterns are equally dire: 67% of monitored populations show 45% mean abundance decline. Such animal declines will cascade onto ecosystem functioning and human well-being. Much remains unknown about this “Anthropocene defaunation”

• Anthropocene Defaunation: This recent pulse of animal loss triggers cascades of extinction.

• Remote sensing technology provides rigorous quantitative information and compelling images of the magnitude, rapidity, and extent of patterns of deforestation, defaunation remains a largely cryptic phenomenon. It can occur even in large protected habitats

• Across vertebrates, 16 to 33% of all species are estimated to be globally threatened or endangered (17, 18), and at least 322 vertebrate species have become extinct since 1500

• Although less than 1% of the 1.4 million described invertebrate species have been assessed for threat by the IUCN, of those assessed, ~40% are considered threatened.

• Lepidoptera (butterflies and moths).

• Size-selective defaunation gradient.

• The long-established major proximate drivers of wildlife population decline and extinction in terrestrial ecosystems- namely, overexploitation, habitat destruction, and impacts from invasive species—remain pervasive.

• Consequences of Defaunation: Impacts on ecosystem functions and services

• Pollination: Insect pollination, needed for 75% of all the world’s food crops, is estimated to be worth ~10% of the economic value of the world’s entire food supply.

• Pest Control: Observational and experimental studies show that declines in small vertebrates frequently lead to multitrophic cascades, affecting herbivore abundance, plant damage, and plant biomass . Arthropod pests are responsible for 8 to 15% of the losses in most major food crops. Without natural biological control, this value could increase up to 37% (57). In the US alone, the value of pest control by native predators is estimated at $4.5B annually.

• Nutrient Cycling and Decomposition: Among large animals, Pleistocene extinctions are thought to have changed influx of the major limiting nutrient, phosphorus, in the Amazon by ~98%, with implications persisting today.

• Water Quality: Defaunation can also affect water quality and dynamics of freshwater systems. For instance, global declines in amphibian populations increase algae and fine detritus biomass, reduce nitrogen uptake, and greatly reduce wholestream respiration

• Human Health: Because defaunation of vertebrates often selects on body size, and smaller individuals are often unable to replace fully the ecological services their larger counterparts provide, there is strong potential for cascading effects that result from changing body-size distributions 

• Evolutionary Patterns.

• Way Forward

• Defaunation is about much more than species loss. Indeed, the effects of defaunation will be much less about the loss of absolute diversity than about local shifts in species compositions and functional groups within a community.

• We must more meaningfully address immediate drivers of defaunation: Mitigation of animal overexploitation and land-use change are two feasible, immediate actions that can be taken.

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Reversing Defaunation by Seddon

Ref: Seddon et al (25 Jul, 2014). Reversing Defaunation: Restoring Species in a Changing World. Science, Vol 345, Issue 6195. 

• Substantial progression reversing defaunation is being achieved through the intentional movement of animals to restore populations. 

• Defaunation: Loss or depletion of animal species from ecological communities. Such losses can reduce the stability of ecological communities with cascading effects.

• In situ conservation measures 

• Creation and management of protected areas

• Increasing connectivity between wildlife populations

• Reduction of the impacts of predation and hunting.

• Bias towards Birds and mammals in Conservation. 

• Bias geographically towards more developed places.

• Main Types of Conservation

• Translocation: Release of animals into their indigenous range. The ultimate objective is the establishment of a self-sustaining population. Generally low success rate at 23% with reintroduced populations going through a period of relatively small population size where the risks of inbreeding and loss go genetic variations is high. The challenge, therefore, is to minimize loss of genetic variation by creating large effective population sizes. The IUCN guidelines advocate that projects make clear definitions of success in relation to three phases of any reintroduction: establishment, growth, and regulations, with future population persistence assessed through population viability analysis. 

• Reinforcements: Release of an organism into an existing population of conspecifics to enhance population viability. 

• Reintroductions: Reestablishment of a population in an area after a local extinction.

• Conservation Introductions: Movement and release of an organism outside its indigenous range. 

• Ecological Replacement: Introduction involving the release of an appropriate substitute species to reestablish an ecological function lost through extinction. 

• Assisted Colonization: Intentional movement of an organism outside its indigenous range to avoid extinction of populations due to current or future threats. 

• For any conservation introduction, the risk of unintended effects must be evaluated and weighed against the expected benefits. The greatest progress will come from carefully designed experimental substitutions using species that can be readily monitored and managed and easily removed should the manifestation of unwanted effects reach some predetermined threshold. 

• Rewilding: Species reintroduction to restore ecosystem functioning. 

• There is a distinction between translocation for species conservation- where the primary objective is to improve the status of the focal species through reinforcements, reintroduction, or assisted colonization, and translocation for rewinding- where the objective is to restore natural ecosystem functions or processes. 

• How best to apply these approaches to maximize conservation benefit while minimizing the risk of unintended consequences. The focus needs to be on development and application of rigorous methods to match species to habitats while evaluating risk. 

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Climate-Induced Range Contract Drives Genetic Erosion in an Alpine Mammal by Rubidge

Ref: Rubidge et al (Apr, 2012). Climate- Induced Range Contraction Drives Genetic Erosion in an Alpine Mammal. Nature Climate Change, Vol. 2. 

• Climate-driven elevational range contraction in the alpine chipmunk, Tamias alpinus, in Yosemite National Park.

• Consistent with a reduced and more fragmented range, we found a decline in overall genetic diversity and increased genetic subdivision in T. alpinus. In contrast, there were no significant genetic changes in T. speciosus over the same time period. This study demonstrates genetic erosion accompanying a climate induced range reduction and points to decreasing size and increasing fragmentation of montane populations as a result of global warming.

• The influence of geologic-scale climate change on morphology, genetic diversity and community assembly.

• Tested for genetic consequences of a recent (20c) climate-induced range contraction.

• Warming induced fragmentation will reduce genetic diversity over time.

• Alpine chipmunk T. alpinus is endemic to the high Sierra Nevada of CA and has retracted its elevational range upwards as a result of a ∼3 ◦C temperature increase in YNP over the past century.

• The relative stability of T. speciosus resulted in no significant changes in genetic diversity or population structure from the past to the present.

• Significant decline in average allelic richness.

• Climate driven range contraction has decreased genetic diversity and increased local isolation for alpine chipmunk populations in YNP.

• This study provides clear evidence of a relationship between climate-driven habitat loss and fragmentation and loss of genetic diversity and gene flow in a terrestrial mammal…A climate-induced distributional shift.

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Anthropogenic Carbon and Ocean pH by Caldeira

Ref: Caldeira and Wickett (25 Sep, 2003). Anthropogenic Carbon and Ocean pH. Nature, Vol. 425.

• We find that oceanic absorption of CO2 from fossil fuels may result in larger pH changes over the next several centuries than any inferred from the geological record of the past 300M years, with the possible exception of those resulting from rare, extreme events such as bolide impacts or catastrophic methane hydrate degassing.

• Coral reefs, calcareous plankton and other organisms whose skeletons or shells contain calcium carbonate may be particularly affected. Most biota reside near the surface, where the greatest pH change would be expected to occur, but deep-ocean biota may be more sensitive to pH changes.

• To investigate the effects of CO2 emissions on ocean pH, we forced the Lawrence Livermore National Laboratory ocean general-circulation model with the pressure of atmospheric CO2 (pCO2) observed from 1975 to 2000, and with CO2 emissions from the IPCC’s IS92a scenario for 2000–2100. Beyond 2100, emissions follow a logistic function for the burning of the remaining fossil-fuel resources (assuming 5,270 GtC) in 1750. Simulated atmospheric CO2 exceeds 1,900 ppm at ~2300. The maximum pH reduction at the ocean surface is 0.77.

• When a CO2 change occurs over a short time interval (that is, less than about 104 yr), ocean pH is relatively sensitive to added CO2. However, when a CO2 change occurs over a long-time interval (longer than about 105 yr), ocean chemistry is buffered by interactions with carbonate minerals, thereby reducing sensitivity to pH changes

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Where Have All the Insects Gone? by Kolbert

Ref: Elizabeth Kolbert (May, 2020). Where Have All the Insects Gone? National Geographic.

• Insecta include millions of species. All, when adults, have six legs, three body segments, and a rigid exoskeleton. 

• Pesticides don’t discriminate between insects that damage crops and those that pollinate them. 

• Insects perform myriad Ecosystem services

• Pollination: 3/4 of all flowering plants rely on insect pollinators. 

• Seed Dispersal: Many plants equip their seeds with little appendages, known as elaiosomes, that are paced with fats and other goodies. Ant’s carry off the seed, eat only the elaisome, and leave the rest to sprout. 

• Pest Control: By feeding on crop-threatening pests, predatory insects perform the role of pesticides without chemicals.

• Providers (Food): Insects are in nearly every food chain.

• Decomposition: Waste eating insects unlock nutrients for use by the ecosystem that would otherwise stagnate in dung, dead plants, and carrion. 

• Soil Engineers.

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Fact or Fiction? The Sixth Mass Extinction Can Be Stopped by Biello

Ref: David Biello (25 Jul, 2014). Fact or Fiction? The Sixth Mass Extinction Can Be Stopped. Scientific American. 

• C is the cause of most extinctions.

• Biologists and Paleo-ecologists estimate that humans have driven roughly 1,000 species extinct in our 200,000 years on the planet. Since 1500 we have killed off at least 322 types of animals, including the passenger pigeon, the Tasmanian tiger and, most recently, the baiji, a freshwater dolphin in China.

• The population of any given animal among the 5M or so species on the planet is, on average, 28% smaller, thanks to humans. And as many as one third of all animals are either threatened or endangered,

• Based on an estimate published in Nature in 2011, we have a century or two at present rates before our depredations assure a mass extinction.

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Climate Change to Disrupt Nutrients Cycles in Global Drylands Soils by Yahia

Ref: Mohammed Yahia (30 Oct, 2013). Climate Change to Disrupt Nutrients Cycles in Global Drylands Soils. doi:10.1038/nmiddleeast.2013.198 

• Increased aridity could adversely impact nutrient cycles in Earth’s dryland ecospheres which cover 41% of the planet and are growing. 

• Study shows that aridity has a negative impact on the concentration of organic carbon and total nitrogen but a positive effect on the concentration of inorganic phosphorus.

• Aridity can reduce plant cover, which may promote physical processes, such as rock weathering, over biological processes, such as litter decomposition. It is physical processes that tend to produce phosphorus and biological processes that provide carbon and nitrogen. The rapid rise in aridity predicted would uncouple these three biogeochemical cycles in drylands, which could have a negative impact on the 38% of the global human population who depend on these ecosystems.

• Other recent studies suggest that the current extinction rate is roughly 1,000 times faster than the average pace in Earth's history.

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Biodiversity Redistribution Under Climate Change by Pecl

Ref: Pecl et al (31 Mar, 2017). Biodiversity Redistribution Under Climate Change: Impacts on Ecosystems and Human Well-being. Science, Vol 355, Issue 6332.

• The success of human societies depends intimately on the living components of natural and managed systems.

• The ability of natural ecosystems to deliver ecosystem services is being challenged by the largest climate-driven global redistribution of species since the Last Glacial Maximum.

• Extraction cannot exceed recharge. 

• Human society has yet to appreciate the implications of unprecedented species redistribution for life on Earth, including for human lives. 

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Extraordinary Pictures Show Animals Heading for Extinction by Lukacs

Ref: Anna Lukacs (22 Oct, 2018). 12 Extraordinary Pictures Show Animals Headed for Extinction. From: https://www.nationalgeographic.com/news/2015/05/150517-endangered-species-pictures-wildlife-animals-science/#/01endangeredspecies.ngsversion.1431779406943.jpg 

• Two big threats are driving some animals toward extinction: habitat loss and poaching.

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Alien Species: To Remove or Not to Remove? by Bonanno

Ref: Giuseppe Bonanno (2016). Alien Species: To Remove or Not to Remove? That is the Question. Journal of Environmental Science and Policy, Vol 59. 

• The functional roles of a species matter more than their origins.

• Species, commonly called alien species, are spread both intentionally, because of their utilitarian value, and unintentionally as a consequence of travel and trade.

• Generally ranked as the second greatest cause of species endangerment and extinction after habitat destruction (Wilcove et al., 1998; IUCN, 2011), IAS can also affect seriously the ecosystem services that are fundamental to human survival and well-being.

• IAS can threaten biological diversity in various ways, from reducing genetic variation and eroding gene pools to the extinction of endemic species, especially in islands and freshwater ecosystems.

• The costs associated with the impacts of IAS are consequently enormous, and amount yearly to hundreds of billion dollars worldwide. Pimentel et al. (2005) estimated that the damage and management of IAS determine an economic impact of $120B yearly in the USA alone.

• The general goal was to provide valuable insights for a paradigm shift from focusing on the negative effects of IAS to recognizing the potential positive contribution of non-native organisms.

• The total restoration of native biodiversity should not be the driving principle in ecological restoration, which should instead rely on species functional roles rather than taxonomic considerations. Yet many conservationists still consider the native-versus-alien species dichotomy a core guiding principle in ecological restoration.

• IAS management can take a significant step forward if all stakeholders realize that IAS cause changes but not necessarily harm. IAS are actually the symptoms of natural environments that are changing forever thanks to drivers such as climate change, nitrogen eutrophication, increased urbanization and other land-use changes. The next challenge is to understand as far as these changes are acceptable. 

• Uses ecosystem services as metrics for assessing IAS impact.

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Multiple Dimensions of Climate Change and their Implications for Biodiversity by Garcia

Ref: Garcia et al (2 May, 2014). Multiple Dimensions of Climate Change and Their Implications for Biodiversity. Science, Vol. 344.

• Anomalies: The difference in climate parameters at a given locality over time.

• Standardized Anomalies: The Euclidean distance between baseline and future climate at a given locality, standardized by historical interannual climate variability

• Change in the Probability of Extremes: The difference over time, at a given locality, in the magnitude of extreme climatic events, or in the probability of occurrence of the most extreme historical climatic event

• Change in Seasonality: The difference over time in the timing of climatic events.

• Change in Area of Analogous Climates: The change over time in area experiencing similar climates [defined with reference to the difference between climates, classification rules, histograms, or clustering analysis.

• Novel Climates: Emergence of future climatic conditions not found at present [future conditions that are most dissimilar to baseline climates (23), that do not overlap with present conditions in environmental space (29), or that lack baseline-analogs as defined above]. Conversely, disappearing climates refer to the disappearance of extant climates.

• Change in Distance to Analogous Climates: The change over time in the distance to similar climates (as defined above for the change in area of analogous climates).

• Climate Change Velocity: The ratio of the temporal climatic gradient at a given locality to the spatial climatic gradient across neighboring cells.

• Phenological change particularly for species with specialized climatic requirements or interacting with climatic events with narrow temporal distributions.

• Potential effect on population demography and on species assemblages.

• Demographic change particularly for species with specialized climatic requirements. Opportunity or threat for species living close to their lower or upper climatic tolerance limits, respectively. Threat greatest for species with lower capacity to adapt in situ.

• Species range displacement where low velocities, within species’ dispersal abilities, provide opportunities for tracking suitable climates over the region's topography, and where habitat structure, intervening climates, and biotic interactions allow connectivity; threat where velocities are high.

• Species range size change, with expanding climate area providing opportunity for range expansion if habitat quality and biotic interactions allow establishment, and with shrinking climate area posing threat of range contraction. Effect greatest for species with specialized climatic requirements.

• Novel species assemblages, with potential for both disrupted and newly formed biotic interactions.

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The Evolution and Future of Earth’s Nitrogen Cycle by Canfield

Ref: Canfield et al (8 Oct, 2010). The Evolution and Future of Earth’s Nitrogen Cycle. Science Vol. 330, No. 6001.

• An active biosphere ultimately requires incorporation of N into biological molecules through N fixation, a process where prokaryotes in the bacterial and archaeal domains reduce N gas (N2) to NH4. 

• Although nitrogenase is widely distributed among prokaryotic lineages, most organisms can- not fix nitrogen but rather obtain their nitrogen directly as NH4+ (or organic nitrogen) from the environment, or from the reduction of NO3~ to NH4+ through assimilatory nitrate reduction.

• In the presence of oxygen, NH4"1" is sequentially oxidized to NO3" by specific groups of bacteria and archaea. In this pathway, known as nitrification, organisms containing the enzyme ammonium monooxygenase first oxidize NH4+ to hydroxylamine, which is subsequently oxidized to NO2~ by hydroxylamine oxidore- ductase, and finally the NO2~ is oxidized to NO3~ by nitrite oxidoreductase. 

• The electrons and protons derived during ammonium and nitrite oxidation are used by the microbes to fix inorganic carbon in the absence of light (i.e., chemoautotrophy). 

• The greenhouse gas N2O is a by- product in this process; indeed, nitrification from both marine and terrestrial environments is an important source of atmospheric N2O 

• Planetary accretion models generally assume that nitrogen was delivered to the protoplanet as solid (ice) NH3, amino acids, and other simple organics. These reduced forms of nitrogen subsequently became oxidized via high-temperature reactions in the upper mantle with iron and other transition elements to form atmospheric N2, which outgassed from volcanoes. 

• Because UV oxidation of atmospheric NH3 (in equilibrium with NH/ in the oceans) would have formed N2, N2 gas remained the dominant form of nitrogen in the atmosphere.

• Nitrification is the critical aerobic process in the nitrogen cycle; once it evolved, the modern nitrogen cycle emerged.

• That molecular O2 and the complete nitrogen cycle were present in the upper ocean for several hundred million years before the widespread oxygenation of the atmosphere.

• Oxygen rose to its modern levels over the last 550M years, aided by the rise of terrestrial plants.

• On the modern Earth, rates of net primary production are nearly equally balanced between the land and sea at about 4e15 mol year each. 

• In the 20c, humans began to have an enormous impact on the global nitrogen cycle by developing industrial processes to reduce N2 to NH4+, by implementing new agricultural practices that boost crop yields, and by burning fossil fuels.

• During 2008 alone, the Haber-Bosch process of NH4+ production supplied 9.5e12 mol, and fossil fuel combustion generated another 1.8 x 1012 mol (45). Together, anthropo- genic sources contribute double the natural rate of terrestrial nitrogen fixation, and they provide around 45% of the total fixed nitrogen produced annually on Earth 

• N- use efficiency is typically below 40%, meaning that most applied fertilizer either washes out of the root zone or is lost to the atmosphere by de- nitrification before it is assimilated into biomass. 

• Worldwide, nearly 90% of nitrogen fertilizer is NH4+, where nitrifying bacteria can convert it to highly mobile NO3~, which in turn can leach into rivers, lakes, and aquifers. This results in nitrogen loss and leads to eutrophication of coastal waters, creating huge hypoxic zones around the world.

• Huge hypoxic zones around the world. Under anoxic conditions (e.g., as found in wet soils), denitrification forms mainly N2 but also forms N2O, a fraction of which is lost to the atmosphere and increasingly contributes to the rise in atmospheric N2O concentrations.

• As a GHG, N2O has 300 times (per molecule) the warming potential of CO2, and it also reacts with and destroys ozone in the stratosphere. 

• One potential consequence of increased fixed nitrogen use will be increased fluxes of riverine nitrogen to coastal zones, leading in turn to enhanced biological productivity, increased coastal anoxia, detrimental impacts on water quality, and increased fluxes of N2O to the atmosphere. 

• Several new approaches and a much wider use of more sustainable time-honored practices, however, can decrease nitrogen use substantially. These include (i) systematic crop rotation [e.g., legume cropping in maize-based systems supplies the nitrogen otherwise provided by synthetic fertilizers (58)], (ii) optimizing the timing and amounts of fertilizer applied to increase the efficiency of their use by crops (59), (iii) breeding or developing genetically engineered varieties for improved nitrogen use efficiency (60), (iv) improving the ability of economically important varieties of wheat, barley, and rye to produce nitrification inhibitors through traditional breeding techniques (60, 61), and (v) further developing cereals and other crops with endosymbiotic nitrogen-fixing bacteria to supply their nitrogen needs. 

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---Discussion Threads---

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 Q1: Photosynthesis

Good afternoon class, 

I have to admit, a bit embarrassingly, that I was not aware of C3, C4, and CAM type photosynthesis until the readings this week. I've always found the photosynthesis process unbelievable beautiful and arguably the basis for Ecology in general, which of course also is not entirely true as autotrophs exist converting chemical energy to complex carbohydrates in the absence of sunlight in order to feed a food web in various places around the Earth, but I digress. Setting the scene for C3, C4, and CAM....

1. Shortwave Radiation (wavelength <4um) from the sun travels ~93,000,000 miles to the Earth striking nearly perpendicular at the poles with decreased irradiance latitudinally North and South. 

2. Sunlight is absorbed by the blade of a leaf, grass, fern, etc. Due to the presence of Clorophyll, the blade generally has a dark green color which has a low albedo and thus, increases absorption of solar energy. 

3. All the meanwhile, the plant extends roots into the soil tapping groundwater which it transpires through the roots, up the xylem of the trunk and into the leaf, where they are stored in mesophyll cells to be used for photosynthesis. 

4. The Stomata (or Stoma), connect the mesophyll spaces with the atmosphere by changing the size of their guard cells open, allowing the photosynthetic process to occur. That is, with Stomata open: Carbon Dioxide is absorbed from the atmosphere with water and mix to create glucose and Oxygen: CO2 (from the atmosphere) + H20 (from transpiration) + Energy (from sunlight) = Glucose (the basis for all of the Carb's/sugars we eat) + O2 (released back into the atmosphere). 

5. Cleaned up and balanced, it looks like this: 6CO2 + 6H2O + Energy = C6H12O6 + 6O2.

6. This process is not without issue and any over or under abundance of these components can complicate matters: Lack of groundwater, for example, leads to dehydrated tree roots which can send a signal (ABA) telling the stoma to close. Simply, open stoma allows photosynthesis to occur while increasing water loss while closed stoma do the opposite. 

Hopefully I did not mess-up the above too badly. Moving onto the differences between C3, C4, and CAM; the primary difference being the stomata. C3 Photosynthesis occurs with the stoma fully open, C4 with the stoma partially open, and CAM with the stoma open at night! The development of these different processes is fundamentally driven by the above stated over or under abundance of compounds on the left side of the balanced Photosynthesis equation. Where solar irradiance is strong and groundwater is abundant, C3 dominates. C3 Photosynthesizing plants readily open stomata fully to the environment losing excess water while maximizing photosynthesis to create sugars the trees use, in part, to grow. C4 plants abound in drier and hotter environments where H2O can become a limiting factor and C4 plants must conserve water to the maximum extent possible, limiting their ability to grow quickly but enabling increased resilience in a drier environment. Similar to C4, CAM photosynthesis maximally conserves water, relative to C3 and C4, by opening stomata to collect CO2 only at night when temperatures are lower and relative humidity higher. The lower temperature and higher relative humidity drastically reduce evapotranspiration from open stomata cells. Stoma close in the morning and CAM plants use stored CO2, H20 in the mesophyll cells, and sunlight via transduction to enable photosynthesis; the trade off being a reduction in overall photosynthesis as CO2 storage is limited. 

I know what you're thinking, so what about the pathways?

Well, the Calvin Cycle turns the one Carbon absorbed from the atmosphere in the form of CO2 into a 6 Carbon Sugar in the form of Glucose. So where are the other 5 carbons coming from? The book does not follow Einstein's rule of explaining things simply, so I found this TED-ED Video to help explain: https://www.youtube.com/watch?v=0UzMaoaXKaM&list=PLB4FF8DAC735BEA50&index=117

The C3 pathway is as follows: 

1. CO2 is captured from the atmosphere. Using the plant enzyme Rubisco, that single Carbon from the atmosphere is combined with RuBP, which is stored in the plant cell and has 5 Carbons. 1 Carbon CO2 + 5 Carbon RuBP = 6 Carbons! Unfortunately, it's not that easy. Were we to stop here, then the plant would quickly run out of its store of RuBP for further sugar creation. 

2. The newly created Carbon chain splits into 2 sets of 3 Carbons, known as Phosphoglycerates (PGAs). Now we have 1 Carbon from the atmosphere that mixed with 5 Carbons provided by the Plant (RuBP) that has split into 2 PGAs with 3 Carbons each. 

3. At this point, ATP adds energy and NADPH adds a single Hydrogen molecule to each PGA, turning them into G3Ps. 

4. This cycle is occurring all throughout the leaf and a minority of G3Ps are combined to form a single sugar molecule while the majority are recombined as RuBP for further sugar synthesis. 

C4 photosynthesis is, as you would expect, fairly similar to C3 with a couple early differences. 

1. The enzyme PEPcase (not Rubisco) is used to combine 3 Carbon PEP (not 5 Carbon RuBP) with CO2 becoming a 4 Carbon Molecule (as opposed to the 6 Carbon from C3). 

2. One CO2 molecule breaks off and combines with RuBP to undergo steps 1-4 of the C3 Process listed above. The remaining 3 Carbon PEP Molecule cycles anew through the mesophyll cell combining with CO2 from the atmosphere.

Finally, the CAM Photosynthesis pathway is very similar to C4 Photosynthesis with the stoma absorbing CO2 at night and undergoing the C4 process listed above. The product from C4 is stored overnight and the C3 process (Calvin Cycle) begins the following day. 

The major trade off in the process itself is the amount of energy required; 3 molecules of C3 vs. 5 for C4 and CAM. 

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 Q2: Learning Objectives

Good evening class, 

The learning objectives for the week are: 

1. Compare how each partner in a mutualistic interaction acts to serve its own ecological and evolutionary interests.

2. Identify conditions where facilitative interactions are likely to evolve and be maintained.

3. Explain community structure and what factors influence it.

Summarizing the articles I read: 

Ch. 15 Article- Designer Reefs: Science Journalist Amanda Mascarelli discusses the increased thermal tolerance of Equatorial Pacific Ocean Corals that are flourishing despite increasing sea surface temperatures, often approaching upwards of 35 degrees Celsius, in this case, in American Samoa. A great deal of ecological research is being undertaken to understand the relationship between the coral and their zooxanthallae at these elevated temperatures that may make them more resilient to climate change, which in the coral reef biosphere is marked by increasing water temperatures and decreasing pH levels. The former causes coral to kick out, in a sense, their zooxanthallae, with the latter causes ocean acidification making it more difficult to form CaCO3 and build reefs. Research into Thermal Tolerance suggests that both coral and their symbiotic algae are producing offspring with increased water heat resistance due to epigenetic changes (gene expression possible due increased stress levels). Coral Farms and selective breeding programs have arisen with experiments designed to construct thermally tolerant artificial reefs; of which many scientists disagree on economic, political, and ethical bounds. 

Ch. 16 Article- Species Interactions and a Chain of Indirect Effects Driven by Reduced Precipitation. This was an interesting read by authors Barton and Ives that studied the indirect effects of a single environmental change- in this case, reduced precipitation, on a microcosm of predator-prey. In normal conditions: 1) Precipitation falls, 2) Alfalfa Plants Grow, 3) Pea Aphids and spotted aphids feed on alfalfa plants, 4) Lady Beetles eat both pea aphids and spotted aphids (but prefer the pea aphids). Under conditions of reduced precipitation, drought in this case: 1) Precipitation decreases, 2) alfalfa plants grow poorly, 3) Pea Aphid population reduces, 4) Lady Beetle populations reduce (think of the moose- wolf relationship from the Isle Royale Lab), 5) the Spotted Aphid population increases. This study reflects the complexity in analyzing the impact of indirect effects from both top down and bottom up simplifications of food web dynamics. 

Both articles nicely touch on all three objectives. Corals and their symbiotic algae must adapt to changing environmental conditions or die, and the naturally selected survivors mutalistic relationship continues. Similarly, the community structure of the aphids, alfalfa, and predator-prey were not only biotic in nature, they were abiotic, with both direct and indirect effects up and down the food web. That is, the factors affecting the small community in both studies were complex- ocean temperatures, pH levels, solar irradiance, coral type, algae type, plant species like alfalfa, arthropods, precipitation, predator-prey relationships, and more. And we haven't even begin discussing the parasitic relationships in any of these studies that will only add a level of additional complexity to the community structure. 

I find, at times, the prospect of re-designing nature...unsettling, and some of my favorite authors on the subject elaborate on how some our best attempts at interfering with nature under the most compassionate of intentions has far reaching consequences up and down the food web; often with a seemingly greater negative impacts than if no treatment had been done at all. I live in Tropical Japan and I see flourishing coral reefs nearly every day despite the warmer water temepratures (the SST yesterday was 31 in the ECS) and I read about studies, such as the "Designer Reefs" which mention how some coral biospheres have rebounded quite nicely following environmental disturbances such as ENSO events that cause massive coral bleaching. The Designer Reef article mentioned the economic impact of losing coral reefs, of which some half billion people rely on as the primary food source (almost all of the 106million people in the Philippines alone, for example), and another 30 million rely on them for their livelihoods. This makes for a perfect discussion on Environmental Science and Policy. We have a biosphere that needs further protection not only against seemingly self-created environmental disturbances, but one in which many people rely on for food and work. A wicked problem (see "Nudge") at its best.

Please pardon the long discussion thread but lastly, the aphid article nicely explains the complexity in the food web that, for me at least, highlights the importance of finding a way to convey to the general public the message that it's not as simple as "higher temperatures melts ice and here's a picture of a starving polar bear swimming," while the designer reefs seem to reintroduce the issues of selective breeding- which seems not to be the best way forward given the about-face we've done on designer dogs and the complexity we've created with designer plants. 

Do you think we should be selectively designing nature? Do you think the ESP face of climate change should be the starving polar bear or the aphid study? 

-Eric 

References

• Barton & Ives. Species interactions and a chan of indirect effects driven by reduced precipitation (Feb, 2014). Ecology, Vol. 95, No. 2. 

• Amanda Mascarelli. Designer Reefs (24 Apr, 2014). Nature, Vol. 508.

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 Q3: Exotic Species

Good evening class, 

I spent 18 months living in the Nevada High Desert in a town called Fallon, about 1hr (100km) East of Reno. Pardon the parallel if you’re from this area, but Fallon was like a mix of “Breaking Bad” and “The Hills have Eyes.” In fact, the first store you’d see when entering town was called “Guns and Liquor” and there would literally be tumbleweeds rolling across the road. But I digress. My first summer there I encountered a massive invasive (to me, invasive) ant population into my house and I tried everything. Lines of Salt- no effect. Bleach- no effect. Vinegar- no effect. Vacuum cleaner- no effect. Kitchen cleaners- no effect. Ant Killer- no effect. A couple weeks went by and I was recommended the small toxic food traps that bate the worker ants into taking a poisonous substance back to the queen. Lo and behold- my chemical warfare experiment entirely decimated the population within 48 hours. My occupation with the DOD follows similar methods; namely, understanding, detecting, and engaging the network as a whole vice the individual as a strategic means paramount to  deterring and controlling undesirable efforts at the individual level. These, albeit tangential, examples, parallel nicely into the world of invasion science, which seeks to a) understand the astoundingly complex interspecific competition and biotic/abiotic interaction amongst invasive and native species, and b) educates, c) prevents, d) detects, and e) manages, through various means, all directed at the network as a whole. 

Exotic Species have the capacity to outdo native species through interspecific competition on numerous levels. Even some plants, like the California Eucalyptus, which although aesthetically pleasing on a social level, may have complicated indirect impacts on the species living within it’s branches and the species fighting for soils and nitrogens in its soils. Similarly, lion fish outcompete native fish around the world, zebra mollusks displace aquatic biota all over the United States, Nile perch have directly contributed to greater than 150 species extinctions (!!!), and much much more. Even subjectively pleasing mammals like the North American Beaver can negatively impact human agriculture and tourist systems on large scales- a problem I have personally dealt with under Memorandums of Agreement with the EPA in Klamath, Oregon. The overarching issue here becomes the difficulty with how and who and when a species is relegated to invasive (aren’t we by definition?). The interactions are complex, the time scales are not well defined, the habitats are poorly discussed, and the population size (the main driver for the term) is not well articulated. Add to that a seemingly poorly educated public who may fight for an invasive mammal while dismissing an invasive arthropod and you have a general mix of social- economic- ecological- biological- political trouble to deal with. 

The article does a fairly good job explaining solutions (Figure 1 on Pg. 61 is worth saving) and in line with the article, I’d recommend the following: 

1. International Scientific Research and Political Oversight on Invasive Species (possibly at the UN level). 

2. National Scientific Research and Political Oversight on Invasive Species (possibly at the EPA Level which reports down to states and up to the UN or international level). 

3. Public Education at the most simplistic scale as possible (infographics &c). 

4. Continual Screening and monitoring for pathways and vectors- which is already done at many lakes, states, ports of entry, airports, etc.

5. Network focused detection and eradication campaigns when prevention fails. 

Pardon the long post- I promise I'm working on making them shorter. There are infinite more items to add to this list. What do you think is most important?

-Eric 

References

• Simberloff et al. Impacts of Biological Invasions: What’s what and the way forward (Jan, 2013). Trends in Ecology and Evolution,. Vol. 28. No. 1. 

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 Q4: Objectives Review

Good afternoon class, 

The Objectives for the week were: 

• Describe how communities are groups of interacting species that occur in the same spatial and temporal areas.

• State the utility and reasoning behind the intermediate disturbance hypothesis.

• Describe niche partitioning is theorized to reduce competition and increase species diversity.

• Explore the relationship between species diversity and community function.

• Explain how stress and interactions can mediate resource availability and drive species diversity.

• Review complex networks of direct and indirect interactions can characterize communities.

• Calculate and explain community diversity indices as descriptors of community structure.

Summarizing the two articles I read: 

The Biodiversity of species and their rates of extinction, distribution, and protection: This article explored predictions into the number of known and unknown species and compared hypothesized background extinction rates to today’s anthropogenically driven extinction rates. Using a blend of statistical analysis, prediction, archaeology, use of ArcGIS, and metadata, the authors found that current rates of extinction are ~1000x the background extinction rate (.1 E/MSY historical vs. ~100 E/MSY today). The article concludes with a discussion on the relevance and utility of terrestrial and maritime protected areas to optimally protect species which, as you would imagine, suggests that protected areas- particularly well regulated, no-take, geographically isolated, and little disturbed areas are slowing species extinctions to less than half- a number I still found high and in which it may be fair to conclude that in even very well protected areas, species are still being lost to indirect impacts such as trophic cascades and abiotic changes. 

This article has the potential to lead you on a number of rabbit holes as it merges several different areas of research in its discussion section, to name a few: 

1. The Aichi Biodiversity Targets: https://www.cbd.int/sp/targets/

2. The iNaturalist Application (which I will definitely be signing up for): https://www.inaturalist.org/ 

3. The Reef Life Survey: https://reeflifesurvey.com/

4. Gen Bank: https://www.ncbi.nlm.nih.gov/genbank/ which is looking at compiling a genetic barcode, of sorts, for all of the Earth’s species.

Invasive Alga reaches Southern CA: This very brief article, written in 2000, confirmed the introduction of the invasive C. Taxifolia alga to the waters of Carlsbad and Huntington Harbor in Southern California. The species was first introduced into the Med in the mid 1980’s and quickly engulfed more than 6000 hA. It grows quickly, asexually, and is more thermally tolerant than other species allowing it to outcompete. 

In a nice twist on ESP,  the article was taken seriously and California undertook a $7 million dollar, six year campaign to eradicate the Invasive alga, which was deemed successful in 2006 (https://cisr.ucr.edu/invasive-species/caulerpa-taxifolia-or-killer-alga#:~:text=The%20Situation%3A%20Caulerpa%20taxifolia%20is,from%20southern%20California%20in%202006. In order to eradicate the species, researchers covered the underwater habitats of the alga with tarps and introduced bleach under the tarp.

Both articles covered a number of the weeks objectives- particularly in describing the “complex networks of direct and indirect interactions that characterize communities.” The invasive alga was able to outcompete native species throughout the Mediterranean vastly changing the community structure and reducing diversity over a broad maritime area. Similarly, the biodiversity of species study, explored the proportion of species according to their geographical ranges (which interestingly found could be approximated using a logarithmic curve across various animal classes) highlighting species richness near the tropics and optimal species range abundance by area showing a reduced community size per species by class both above and below an mean geographical range. 

The articles and the objectives imply that some level of stress, not too little and not too much (intermediate disturbance), allows niche partitioning and species diversity which builds overall community diversity. Unfortunately, we (humanity) seem to be changing the biotic and abiotic factors for innumerable species as we play the metaphorical role of the high disturbance boulders from the Sousa study (ch. 17 of the textbook) which was measured to have less than half the species richness of the intermediate disturbance. 

-Eric 

References

• Pimm et al. The Biodiversity of species and their rates of extinction. Distribution, and protection (30 May, 2014). Science, Vol. 344, Issue 6187. 

• Jousson et al. Invasive alga reaches California (9 Nov, 2000). Nature, Vol. 408. 

• Mark Hoddle. Caulerpa Taxifolia or Killer Alga (date unk). Retrieved from: https://cisr.ucr.edu/invasive-species/caulerpa-taxifolia-or-killer-alga#:~:text=The%20Situation%3A%20Caulerpa%20taxifolia%20is,from%20southern%20California%20in%202006. Accessed on 15 July, 2020.

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 Q5: Ecological Scales

Good morning class, 

The book “The Sixth Extinction” by Kolbert speaks to the first five extinction events and concludes with our own anthropogenic induced defaunation- the sixth extinction. In the book, Kolbert discusses some of the methods humans are using to halt or slow species loss- ultrasounds on rhinoceros, stimulating crows, and employing people to pollinate plants in many areas of China. As in-  humans are going out with pollen and dusting flowers, plants, trees, and more. I’ve always found this last one fascinating so I was happy to see an article on agricultural production in China. Fun fact before I get into the objectives and the article; did you know that there are companies testing using drones to pollinate?

The objectives for the week were: 

Module 9

• Review how elemental cycles move among ecologic, atmospheric, oceanic and biological pools at global scales.

• Identify that food webs are conceptual models of the trophic interactions in an ecosystem and that there is a limit to the number of trophic levels controlled by available energy.

• Describe criteria for stability and trophic cascades in both aquatic and terrestrial systems.

• Explain how energy originates from primary production by autotrophs and that secondary production is generated through consumption by heterotrophs.

• Explain how net primary productivity is constrained by abiotic and biotic factors.

As mentioned, I read the article on grain production with less environmental cost- actually a really interesting topic as much of our modern environmental rights movements were initially based on similar research, notably Paul Ehrlich’s “Population Bomb” which addressed human population growth against agricultural carrying capacity. As populations continue to rise, agricultural capacity will be stretched further. The research team in this article addressed methods to maximize the efficiency of output in the cultivation of Rice, Wheat, and Corn in 153 sites in mainland China. Controlling for regular farming practices, they tested the uptake, release, and efficiency of limiting nutrients such as Nitrogen and GHGs against crop productivity. Through four separate studies- 1) Farming as usual, 2) Improved Practice Farming, 3) High Yield Farming, and 4) ISSM: Integrated Soil-crop system management, the researchers found that ISSM farming was most efficient at yielding greater crop output while maximizing efficiency of Nitrogen use and GHG release- a promising finding that, if implemented, would enable China to stay ahead of population growth while reducing GHG emissions, land-use changes, and even reducing agricultural imports. Unfortunately, a major item lacking from the article was the time and financial requirements for the various farming methods; I.e. what are the opportunity costs and time requirements and financial inputs necessary for ISSM vs the rest? A second issue not addressed was the problem with maximizing efficiency of a species- there must be tradeoffs with maximization? Of note- the improved practice farming which was simple education was also similarly net positive. 

This article nicely touches on the last objective for the week: constraints of primary productivity by abiotic and biotic factors. The growth of these crops are limited by water, nitrogen, phosphorous, CO2, light, and more. And a reduction or increase in any of these factors will impact plant output. I know this firsthand as my tomato plant was destroyed by caterpillars and my beet plant is not receiving enough sun and the seeds were placed WAY too closely together- the biotic and abiotic factors matter. 

The issues in agriculture seem profound- diversion and overuse of water, hybrid crop breeding- GMOs, land use conversion, factory farming, toxic pest control solutions, GHG emissions, overuse of synthetic fertilizers, and the list goes on. How do you take studies like this- showing the net benefits of solutions like ISSM and provide them down to the individual farm and farmer level? Should farms have overwater use regulations or over-fertilization limits similar to car’s mpg consumption minimums? Do they already? 

-Eric 

References

• Chen et al. Producing more grain with lower environmental costs (23 Oct, 2014). Nature, Vol. 514. 

  
  
  
  
  
  
  
  
  
  

I read the article “Defaunation in the Anthropocene” which discussed Anthropogenic induced species loss and its hidden, or indirect, impact on biodiversity. Of note: Defaunation is the global, local, or functional extinction of animal populations or species from ecological communities (thank you, wikipedia). The article looked at the impact of species loss on biodiversity demonstrating what the authors called “cascades of extinction,” such that the loss of one species, particularly those with larger biomass, directly and indirectly impacted species below them in the food web via cascading effects- similar or even synonymous with trophic cascades, but on a much larger time scale. These “extinction cascades” impact not only the species and their networks in the food chain themselves, but also lead to reduced pollination rates, increased pest control requirements, decreased nutrient cycling and decomposition, reduced water quality, reduced human health, and even have the potential for reduction in evolutionary patterns; all of which are wicked (from the book Nudge) problems that we must face today. 

The article addresses many of the weeks objectives highlighting how species extinction and even loss in species richness has lasting repercussions ecologically as trophic cascades, oceanographically as reductions in water quality, and terrestrially as rates of phosphorous influx into the Amazon have reduced by 98% from species loss during the Pleistocene! Nicely in line with objective three, the criteria for stability in these larger biodiversity networks as addressed in the article seems to be proportional to species abundance with much less extinction cascades in relatively undisturbed ecosystems- as shown by the article. 

The authors note a couple ways forward; mitigating animal overexploitation and addressing land use changes. However, how we address either of these in the near term, I really do not know. One of the articles for discussion post 9.2 addresses maximizing the efficiency of agricultural lands using specialized methods when growing and harvesting rice, corn, and wheat, which may be one option, but like all matters, most likely comes with it’s own set of tradeoffs. Does anyone have any ideas for how we address animal overexploitation in a policy sense on a world scale?

-Eric

References

• Dirzo et al. Defaunation in the Anthropocene (25 Jul, 2014). Science, Vol. 345, Issue 6195. 

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 Q6: Reversing Defaunation

Good evening class, 

After reading articles last week on defaunation events, I had no choice but to choose the article on “Reversing Defaunation” for this weeks discussion thread. Summed up briefly because it is only tangentially applicable to the questions this week: 

“Reversing Defaunation: Restoring Species in a changing world” discusses the various conservation methods including Translocation and Conservation Introduction. The former, translocation, is the release (or re-release), of species into their known indigenous ranges for the purpose of reinforcement- releasing a species into a population of the same species to increase viability and/or reintroduction- the release of a species into an area after a local extinction. The latter, conservation introduction, is the release of species into non-native ranges for the purpose of ecological replacement- releasing an appropriate species in order to reestablish a lost ecological function and assisted colonization- the intentional movement of an organism outside its native range to increase resilience due to abiotic and biotic changes. All methods of conservation seemed targeted against invasive species- humans being at the forefront and the article continually mentioned the importance of “analyzing the risk of unintended effects to be evaluated and weighed against the expected benefits” but never mentioned the negative benefits of conservation efforts- only pointed out, rather, that only ~23% had been successful thus far. If you’re more of a picture speaks a thousand words (as opposed to the 167 I have above) type person, then Figure 1 on page 408 of the article spells all of this out quite nicely. 

All this being said- the questions for this thread are fairly profound and could, probably, fill volumes. 

Lawton makes an interesting inference in his article on the “General Laws of Ecology?” stating “the patterns (in ecology) only emerge by ignoring the details.” Although I did not pick up the importance of this during the first reading, it now seems extremely applicable given this weeks question. Chapter 22 of the textbook hits on this concept as well highlighting the work of Garcia and Chacoff who studied Tree Fitness on different scales and found different results at different scales. This is similarly seen in power formulas and biogeography and many, if not most other tenets of science. That is, general trends appear across a spectrum (species, in this case) when zooming out from fine grain. Almost every article we’ve read so far has included r^2 values to assess the “fit” of the data to highlight how applicable the individual elements of the fine scale data fit the general pattern- hence how hypotheses may become theories. 

Biodiversity and ecosystem-level functions are related in myriad ways- excess energy in an ecosystem allows for niche partitioning which increases species diversity which allows further niche partitioning and so on, until some equilibrium level or carrying capacity is met. An issue I took in this regard in respect the article was the seemingly impossibility of getting right the complexity in which conservation method with which species works best- particularly when introducing vice translocating. The fine scaled understanding has to be nearly impeccable, otherwise the effect on the ecosystem-level functioning could be profoundly negative. 

The reversing defaunation article spoke to the destruction of a Mauritian Giant Tortoise population and the ensuing conservation methods that, after much trial and error, ended with the replacement of a “less degraded ecosystem with introduced tortoises.” In this case the habitat destruction, fragmentation, and degradation was nearly total- the Mauritian Giant Tortoise was replaced by an “introduced tortoise” (a different species of tortoise) and the “conservation” came full circle. Despite acknowledging the need for keystone species in this article, I couldn’t help but consider my favorite quote from the beginning of this class stating, paraphrasing “if you never take the time to understand the species diversity around you, then going for a walk outside is like taking a stroll through the worlds most amazing art museum with 90% of the pictures turned over and facing the wall.” The parallel here is going to the Louvre in Paris to see the Mona Lisa, but seeing the replica hanging on the wall and somehow knowing it’s fake. Does replacing the Mauritian Giant Tortoise with an Aldabra Tortoise (what took place in the study) do the ecosystem, and maybe by parallel, humanity its justice? Does moving the Kakapo to islands without predators (a form of assisted colonization) do anything other than preserve the species for prosperities sake? 

Global climate change and, as important to biodiversity, humans and land use change (our prevailing abiotic and biotic factors) will create more island biogeography with edge effects, more competition, greater extinction as these factors change, and my best estimate, invasive species and pioneer species may, inevitably, prevail across the world with decreasing areas of specialized habitats. I’m not sure if that’s realism or pessimism and I’m interested to read everyone’s thoughts on this last question. 

Of note: The April, 2020 Nat Geo addresses this last question for the discussion thread nicely. 

-Eric 

References

• Seddon et al. Reversing Defaunation: Restoring species in a changing world (25 Jul, 2014). Science, Vol 345, Issue 6195. 

• John Lawton. Are There General Laws in Ecology? (Feb, 1999). Nordic Society Oikos, Vol 84, No. 2. 

• Singer, Fred D.. Ecology in Action (Ch. 22). Cambridge University Press. Kindle Edition. 

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 Q7: Objections to CC

What is global climate change? Name five objections to its reality and five rebuttals. Briefly discuss five major consequences of global climate change to life.

Hey everyone, what a fun question for this week. I sporadically save climate denier arguments and posts so I can find ways to strengthen my own. I’m going to start out of order and answer what I see as the process, then discuss the five major consequences of global climate change, and finish with the objections. Of note, there is very little disagreement that humans are the cause of today’s warming rates of change, so this question, for me and I assume all of us, is inherently linked to global human population and consumption, i.e. it’s difficult to speak to one without addressing the other: 

How the process works: 

• Human Burning of Fossil Fuels via Transportation, Farming, Agriculture, etc. 

• More reflected long wave radiation is absorbed causing radiative forcing. 

• The Ocean steadily absorbs much of the C (although with a corresponding decrease in pH and CaCO3 concentration. 

• The ocean can not absorb all released Carbon, possibly only 50% given the period and amount of release. 

• Atmospheric CO2 increases with the potential for a positive feedback loop to slowly develop. 

• The Greenhouse Effect magnifies due to increase in CO2 in atmosphere. 

• This can be further compounded by Astronomical Theory (Milankovitch et al). 

• Surface Temperatures Increase and Deep Ocean Temperatures Increase- impacting biodiversity (us included). 

• Shift in the distribution and intensity of precipitation polewards (hotter air holds holds more water). 

• Higher Latitude Ice Melts increasing sea levels and decreasing salinity of seawater in higher latitude.

• Continued Increased Solar Absorption leads to increase Radiative Forcing. 

• Deep Ocean Thermohaline Circulation slows.

• The Cycle compounds over the resident time of Carbon in the atmosphere and Carbon in the Hydrosphere. 

Five Major Consequences:

• Biodiversity Loss: Increasing temperatures will negatively impact countless species leading to trophic cascades. 

• Land Use Change: Increasingly fragmented landscapes are adding GHGs to the atmosphere, acting as C sources, fragmenting habitats creating edge effects, and more. 

• Freshwater use: This one is huge. Population growth and resource extraction have led to aquifer drying, river/lake/aquifer pollution, and even water wars and water refugees. This is not going to happen, it already is, and it’s incredibly disconcerting (see Yemen, for example). Fun fact: CA looked at a proposal to truck freshwater from Lake Superior about a decade ago and Saudi Arabia was looking into the feasibility of shipping icebergs to ports for freshwater extraction. Similarly, a stair step exchange was created to tap the ogallala aquifer in the case that the Colorado River went completely dry at Lake Mead from extraction (this almost happen in 2018). 

• Ocean warming/acidification: The oceans act as a sink for excess atmospheric Carbon (taking in as much as 50% of anthropogenic C leading to small decreases in Oceanic pH levels with profound impacts on marine biodiversity. Similarly, increases in Sea Temperatures will slow down global thermohaline circulation disrupting heat exchange at the poles/equator.

• Runaway Global Warming (positive feedback loop): The PETM scenario is probably the worst case disaster here (runaway release of trapped Methane in Polar Permafrost). See question at the end. 

Five fun objections: 

• “It’s really cold outside; it even snowed!”- “Climate and Weather are not synonymous. Climate predicts changes based on multi-decadal observations (generally, 30 years) whereas weather is an hourly/daily prediction/observation.

• “Dude, we just came out of an ice age, this is normal!”- Although natural fluctuations are generally observed in GHGs and Temperatures, the present rate of change is unlike anything that has been seen in scientific history. 

• “Most GHGs come from volcanoes and the earth- not humans.”- This is true, generally nature through volcanoes and natural processes emit upwards of 30x the amount of GHGs as humans do annually. I like to think of this one using the backup drain that most bathtubs have. CO2 in the atmosphere is both natural and positive for biodiversity. The earth is at equilibrium when the Carbon sinks are proportional to Carbon Sources (the water is at the level of the metaphorical bathtub drain and all new water is draining out). We are adding extra water to the tub and the drain is no longer able to keep up, the water overflows; i.e. carbon sources are ahead of carbon sinks. 

• “It’s such a slow process- when the water level rises in Florida, I’ll just move elsewhere.”- This is generally true. Despite the relatively high rate of change to previous global warming periods, people in developed nations may have the time and the resources to respond effectively (in a relative sense). In fact, some areas of the world will benefit from increased temperatures. The issue becomes the nations and the peoples who can not- those in the developing world who may not be able to move (small island archipelagos) or those who rely on resources that will be negatively impacted by rising temperatures (Some 90% of the Philippines are reliant on Coral Reefs as their primary protein source). 

• Some smart person somewhere will design something to fix this at the last minute (some panacea, of sorts)- this one upsets me the most. The solutions are all there and they are myriad. The April 2020 Nat Geo focused their article on where we will be in 50 years on Climate Change. The solutions for energy, transportation, pollution, agriculture, etc, are mostly out there, and now it’s up to us as individuals to respond appropriately. The big issue, for me, is simply the lack of global leadership and global direction on a political level; i.e. I really wish the USA (my country) would work closely with the UN to empower them as global leaders with REAL authority to focus planning, direction, and policy. 

The interesting (and scary) question that I think about is at what point do we get to the release of methane trapped in high latitude permafrost which could quickly raise CO2 levels to some 2000ppm, as it did during the PETM, 55 ma. Or should I not be worried about this one?

-Eric 

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 Q8: Biogeochemical C & N Processes

Good afternoon class, 

The objectives for the week were: 

• Explain the biogeochemical processes by which carbon and nitrogen are moved through the global system.

• Describe what is meant by global climate change, some objections and rebuttals to this idea, and the consequences of climate change to life on Earth.

• Discuss some of the factors that affect the structure and functioning of temperate and tropical ecosystems.

• Explore options to alleviate the survival status of populations of endangered species.

Summarizing the articles I read:

• Climate- induced range contraction drives genetic erosion in an alpine mammal: Have you ever been hiking or climbing in the Sierras? Rockies? Cascades? Etc? Sporadically in these areas you’ll run into alpine chipmunks, which although I know we shouldn’t, are nearly impossible not to feed trail snacks to. The habitat, distribution, and genetic diversity of these chipmunks, T. Alpinus, were studied in Yosemite National Park. Researchers found that the species moved their habitat 500m vertically in response to a 3 degree celsius rise in average temperature (in Yosemite National Park) over the last 100 years. This vertical move in species habitat led to an overall decrease in distribution with a corresponding decline in allelic richness, indicating “clear evidence of a relationship between climate-driven habitat loss and fragmentation and loss of genetic diversity and gene flow in a terrestrial mammal.” 

• Anthropogenic Carbon and Ocean pH: Researchers used the Lawrence Livermore Ocean Circulation models to predict how Ocean pH levels will respond to Anthropogenic GHG releases and found that, with current trends, the ocean pH level will decrease by approximately .7, which is the lowest pH in the last 300 million years of Earth’s history. They also found that the oceans are resilient at rates of change on the order of 10^5 years or more but much less resilient at present rates of change (in this case on the order of 10^4 years or less). The model predicts that atmospheric CO2 by 2300 may rise to as much as 1900ppm with a .7 decrease in ocean pH. 

Both articles address several objectives for the week. The Ocean acidification article speaks to the complexity of predicting changing ocean acidification levels of absorbed Carbon from the atmosphere highlighting the importance of rate of change in carbon sinks. In regards the first objective for the week, it’s important to note that even massive carbon sinks like the ocean can be resilient at high levels of absorption, but lose that resilience in respect to temporal rates of change. The first article on the Alpine Chipmunk speaks to the last two objectives for the week highlighting the relationship between a mammalian species and its abiotic environment. Temperature rise led to migration of the species vertically which led to habitat shrinkage resulting in a declining genetic diversity. Unfortunately no solutions were offered for T. Alpinus in regards climate change in this article although assisted colonization for conservation may be feasible If numbers and genetic diversity continue to decline. 

-Eric 

References

• Rubidge et al. Climate- induced range contraction drives genetic erosion in an alpine mammal (Apr, 2012). Nature Climate Change, Vol. 2. 

• Caldeira and Wickett. Anthropogenic Carbon and Ocean pH (25 Sep, 2003). Nature, Vol. 425.

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 Q9: Anthropocene?

Discussion 12.1: Why do you think there are so many people in the USA who believe that modern changes in the global climate are not primarily caused by humans? 

Good evening class, 

Another interesting question to the start out the week! I've always found it fascinating how skilled some people are at convincing themselves that, more or less, accepted scientific theories are invalid based on the most absurdly flawed 'reasoning' or 'data.' A fun side story: I had an employee that was absolutely convinced that the NASA Moon landings were faked- he'd seen the youtube videos and had spoken to a couple friends who might have agreed on some aspect. In the face of overwhelming evidence to the contrary he was absolutely certain that it was staged. I was concerned. I printed out, reviewed, highlighted, and returned to him a 75 page book that scientifically debunked every single known myth on the moon landings and how you can, by yourself, see evidence of the moon landings with a telescope. His response was to not read it. :-/ (insert "shrug" emoji)

A quick advertisement for one of the best books I've ever read on this very subject: "Mistakes were Made (but not by me): Why we justify foolish beliefs, bad decisions, and hurtful acts by Caroll Tavris and Elliott Aronson- highly highly recommended. The book explains how easily people can be misled by group think, implict bias, and self-justification, which together lead to cognitive dissonance. I'll let George Orwell and Richard Feynman help get me into this thread: 

"We are all capable of believing things which we know to be untrue, and then, when we are finally proved wrong, impudently twisting the facts so as to show that we were right. Intellectually, it is possible to carry on this process for an indefinite time: the only check on it is that sooner or later a false belief bumps up against solid reality, usually on a battlefield."-George Orwell, 1946.

"It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what their name is—if it disagrees with [the] experiment it is wrong. That is all there is to it."-Richard Feynman.

Before I briefly speak to the role of politics, misinformation (worse- disinformation), influencers, and more, here are the pew polls on climate denial in the USA as of June-July, 2020 (https://www.pewresearch.org/science/2020/06/23/two-thirds-of-americans-think-government-should-do-more-on-climate/): 

• 63% of polled US citizens believe believe climate change is affecting their local community. 

• 65% of polled US citizens believe the government is not doing enough to reduce the effects of global warming. 

• 90% of polled US citizens favor planting one trillion trees to capture excess CO2 in the atmosphere. 

• 84% of polled US citizens favor tax credits for businesses that develop C capture/storage. 

• 80% of polled US citizens favor tougher restrictions on power plant C emissions. 

• 73% of polled US citizens favor taxes on corporations for C emissions. 

• 79% of polled US citizens favor prioritizing the development of alternative energy sources. 

Although not as high I'd like to see, this is, at the very least, somewhat promising in that a) the trend in proponents for policy changes targeting climate change is going up, and b) many US citizens, nearly 2/3's, believe climate change is an issue that must be addressed, regardless of the potential for negative cost.

So what's going on with the other 1/3? Historically, this is not new. Galileo was ostracized for proposing the heliocentric model, Darwin was ostracized for the theory of evolution, Wegner was ostracized for hypothesizing Continental Drift, and the list goes on most likely back to time immemorial. Humans seem to be very bad at changing their minds on what they perceive as established truth and worse yet, we tend to be horrible at long term planning- particularly in regards issues that we can not see, that are difficult to comprehend, and, from a scientific standpoint, are multi-disciplinary and involve a lifetime of study in a variety of fields. 

There's a greek proverb that goes "A society grows great when old people plant trees whose shade they know they will never sit in." For me, this nicely wraps up a lot of the contentions the 1/3 of US citizens have with climate change- it's difficult to comprehend the immediacy of confronting a problem that may not effect you personally in your lifetime on a meaningful level. This is even scaled up from the personal to the political level as a constitutional republic with terms of office and elections, our politicians tend to make decisions on 2yr, 4yr, and at best, 6r cycles; so much for long term planning. This is further compounded by media, confirmation bias (only listening to, seeking out, or debating people that already agree with you), and discounting evidence to the contrary with meaningless conversation stoppers such as "fake news." 

The issue with US citizens who deny climate change tends to be based on the development of an implict theory established by your parents, friends, and role models political beliefs and their own implicit theories and confirmation biases throughout childhood and into young-adulthood; which many people then carry for the rest of their lives (I'm sure we all have some). This implicit theory is further ingrained through confirmation bias, explained above, which is so readily found today in regards which media source you tune into, what ig or fb influencer you follow, or which youtube channels you watch. The social media/confirmation bias aspect is even further compounded as the majority of these applications use machine learning to assess your likes and views and then present you with options that further confirms your biases! For example, if all you do is watch climate denial videos on youtube, the program will actually begin to only present you with climate denial videos! And of course this issue has been stained by the politicization of science. All you need to do is watch how people attack Dr. Fauchi, a doctor, not a politician, to get a sense of this one. 

There does seem to be some hope out there. The percentages in favor of change in the pew polls above were higher than I expected and younger generations far more readily see climate change as a realistic issue worthy of addressing- and, most importantly, this goes across party lines (for the younger generations).

-Eric 

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 Q10: Ocean Threat

Discussion 12.2: The ocean, which produces half of the oxygen we breathe and absorbs 30% of human-generated CO2, is equivalent to the planets heart and lungs. This huge integrated system is under constant threat. Today, we are actually witnessing these changes before scientists can predict or event model many of them. For example, mass coral bleaching and mortality, the result of increasing temperatures, is already reducing the richness and density of coral reef fishes and other organisms.

Good evening class, 

I watched the TED talks titled "Ecology from the air" for this discussion thread and it was good! Global Ecologist, Greg Asner, speaks to his Global Airborne Observatory (GAO) which mixes sensor systems with GIS to map numerous metrics from the sky including biodiversity, carbon storage, soil changes, photosynthesis levels, and more. If you're on the GIS track or interested in GIS in any capacity, this is a fascinating TED talks and worth 15minutes of your time. Unfortunately Dr. Asner did not speak to Maritime observations in any capacity but his GAO project would be incredible in the marine domain. 

A healthy ocean is difficult to characterize but, generally, has a well formed oceanic gyre system that transports cold polar water to the equator and warm equatorial water to the poles while transporting excess CO2 from cold polar air which sinks and eventually rises back to the surface de-gassing when warm air sits above warm water, as a thermohaline circulation. This process keeps the Earth's heat balance in check while providing O2 to biodiversity in the deep ocean. Additional nutrients are provided via the decay of phytoplankton and denitrifying bacteria. Any change in this system has consequences on the entirety of Earth's biome. A slow down in thermohaline circulation and oceanic gyres due to a rise in SST's could impact the ocean in several ways: changes in nutrient flow throughout the system would adversely impact marine biodiversity while disrupting the heat balance of the planet. In the short term, and mixed with increased input from excess CO2 emissions, this leads to terrestrial ice melt (compounded by a decrease in albedo as ice melts), a drop in pH (hypothesized to drop by .7 by 2300, the lowest pH in the last 300 million years), and a cumulative rise in sea level due to both input from freshwater and, more importantly, thermal expansion. These processes will work in tandem as the oceans absorb some excess CO2, delivering them into thermohaline circulation, and eventually de-gassing them as ocean temperatures continue to rise, setting up a positive feedback loop. A causal atmospheric impact develops thanks to the ability of warmer air to hold excess water will be an increase in storm intensity- as we are all so well aware. 

Biodiversity around the planet IS facing catastrophe as storms become more intense, as sea levels rise, and SSTs increase. Coastal communities (particularly island archipelagos) face pending disaster as even modicum rises in sea level have the capacity to bury entire cities such as in the Maldives, China, Indonesia, India, Brazil, Venice, the Netherlands, and the list goes on. Unfortunately there seems to be an inversely proportional relationship between extent of possible damage and HDI level with many of the worlds most developing populations suffering the greatest. Worse still, marine biodiversity will either adapt or go extinct, as is the case with many localized populations to rises in SST. 

Do any of you have any personal observations or firsthand accounts you can speak to?

-Eric 

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 Q11: Project Holothurian

Good afternoon class, 

I live in Tropical Japan and am surrounded by pristine coral reefs with some amazing diving and snorkeling so I chose to study the distribution of Holothurians (sea cucumbers) in areas of differing water quality. Holothurians are essentially roomba vacuums of the ocean- they ingest sand, silt, and water through their anus (which some species such as the pearlfish use as homes to which some holothurians have adapted to form anal teeth to keep them out). Their bodies encase a large digestive track which filters out any nutrients from the detritus. They are very important in maintaining a nutrient balance in the oceanic benthic zone which many other species use- particularly corals and seaweeds, use. I hypothesized that holothurians would be more prevalent (measured as density) in area of lower water quality due to an increase in benthic nutrients. 

I focused on three separate study areas in the East China Sea with varying levels of water quality: one at a pristine coral reef known as Mermaids Grotto, the second in a port off Kouri Island, and a third at the output of a rainwater/effluent drainage pipe that empties directly into the ocean. I cordoned each study area using agricultural poles and conducted a systematic count of species abundance. I then used Google Earth to calculate Area to find a Holothurian density for each site that I compared against each other in the discussion section. The following were my results:

Due to varying levels of underwater visibility and adaptations in some species to bury themselves or camouflage, I calculated a "miss" error which I then factored into the total species density that was relative to each site. I found my hypothesis to be correct in that holothurian density is relatively greater in areas of lower water quality and reduced visibility. Although I accept the foundation of my hypothesis, far more works needs to be done to further control for the abiotic factors in the separate study areas and to better calculate a miss error in order to approximate a better overall density. 

I learned a lot from this study- namely, the inordinate difficulties in proper sampling techniques, particularly underwater which I assume were prevalent in many people's studies. Were I to do this again, I'd use a more similar abiotic environment between both studies and I'd return to the study areas numerous times to count, recount, and re-average, at different times of day/night; I'd also use a friend or two and reduce the size of the study area. A couple fun facts from the study: Holothurians emit cuverian tubes when they think they are being attacked, Box Jellyfish stings are in fact very painful, and I found eight separate species of holothurians and several species of cowfish, zebrafish, lionfish, sea snakes, innumerable small territorial fish, and even two octopus. 

-Eric 

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 Q12: Article Summaries

Discussion 13.1: Now that we have a background in calculating and evaluating biodiversity, we can consider alternatives to repopulating some species. Seddon et al. (2014) comment that the traditional goals of "having self-sustaining wildlife populations within pristine landscapes untouched by human influence" are "increasingly unobtainable." Instead, they suggest that creating 'wildness' rather than restoring 'wilderness' is the most practical way forward. This 'rewilding' approach may involve translocations to restore ecological processes, such as predator-prey interactions, within landscapes shared by humans and wildlife.

Consider that this approach to preserving biodiversity or reversing defaunation includes the contentious practice of ecological replacement, where an appropriate substitute species is released to restore an ecological function lost with the extinction of the original species.

Take a pro or con stance on the approach these authors take on species management and then respond to a post by your peers providing additional support or playing devil’s advocate to that post.

Good morning class, 

Summarizing the articles for this discussion thread: 

• Alien Species: to remove or not to remove? This was an interesting meta-analysis of literature in regards IAS impacts on health, biodiversity, economies, and more. The author’s goal “was to provide valuable insights for a paradigm shift from focusing on the negative effects of IAS to recognizing the potential positive contribution of non-native organisms.” A shift in thinking of IAS in terms of “invasive” and “biological warfare” to “non-native” and “ecosystem services” make the case that IAS ecology has done a poor job highlighting the benefits that a carefully studied and carefully managed IAS could have on an ecosystem. The study concludes stating that the assessment of IAS should not necessarily be measured immediately as harmful but is better assessed as to the value IAS provides in regards ecosystem services.

• “Reversing Defaunation: Restoring Species in a changing world” discusses the various conservation methods including Translocation and Conservation Introduction. The former, translocation, is the release (or re-release), of species into their known indigenous ranges for the purpose of reinforcement- releasing a species into a population of the same species to increase viability and/or reintroduction- the release of a species into an area after a local extinction. The latter, conservation introduction, is the release of species into non-native ranges for the purpose of ecological replacement- releasing an appropriate species in order to reestablish a lost ecological function and assisted colonization- the intentional movement of an organism outside its native range to increase resilience due to abiotic and biotic changes. All methods of conservation seemed targeted against invasive species- humans being at the forefront and the article continually mentioned the importance of “analyzing the risk of unintended effects to be evaluated and weighed against the expected benefits” but never mentioned the negative benefits of conservation efforts- only pointed out, rather, that only ~23% had been successful thus far. Figure one on page 408 does an incredible job simplifying this article in a single photo. 

One of the most fascinating stories of IAS in modern world history begins with the European discovery of the tuber (potato) in Incan South American in the 16th century by Spanish Conquistadors while in search of gold and silver (and very violent missionary work). The tuber was brought back to Europe and planted far and wide as the tuber would yield far greater crop mass in comparison to wheat, soy, maize, and other solid foods. The tuber was studied and found to contain most of the vitamins that the human body needed and French King Louis XIV (the sun King) was even persuaded to dress up as a potato to advertise and promote the benefits of the tuber. The tuber presented a potential solution to malnutrition and vitamin deficiency while promoting good health and much larger populations as it dominated farms and agriculture across Europe. By the early to mid 1800’s, most European’s relied on tubers as one of their main solid food sources; in Ireland prior to 1840, the tuber comprised >90% of the average non-liquid diet. The potato blight, also native to South America, eventually made it’s way over to Europe (supposedly on a passenger ship landing in newly formed Belgium). It spread throughout Europe collapsing farming and agriculture and killing millions. In Ireland alone, with a population so reliant on the tuber, over 1million people died with a population reduction estimated to be nearly 25%; this led to one of the first massive migrations of the Irish to the Americas. That is, the introduced tuber, with all its initial success as a translocated species, so to speak, inevitably killed millions due to entirely unforeseen, unstudied, and unknown consequences.

I’d have to follow this story up with the words of caution of one of my favorite Ecologists- Peter Whollebein: “When we save individual animals or plants, we really believe we’re doing something good for the environment. Yet this is rarely what happens, mostly because when we have to change conditions in the environment to ensure the survival of one species, the survival of many others ends up in jeopardy." As much as I'd like to take a stance on this one, I'm not really sure I can. There seem to be some species such as the European honeybee that can help pollinate plants in the America's...or in Asia conducting billions in ecosystem services, annually. However, the 23% success rate discussed in the "Reversing Defaunation" article paints the opposite image of the ecological valuable translocated honeybee. I suppose, in a VERY carefully controlled and continually assessed study- possibly like the Yellowstone Wolves or the British Columbia Sea Otters or the Mauritian Tortoises, there is a case to be made for translocation. 

-Eric 

References

• Charles Mann. 1493: Uncovering the world Colombus created (9 Aug, 2011): I paraprhased this source to summarize the tuber story. 

• Giuseppe Bonanno. Alien species: to remove or not to remove? That is the question (2016). Journal of Environmental Science and Policy, Vol 59. 

• Seddon et al. Reversing Defaunation: Restoring species in a changing world (25 Jul, 2014). Science, Vol 345, Issue 6195. 

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 Q13: Key Ecological Issues

Discussion 13.2: After reading (or watching) at least two of the assigned articles (or videos), please offer reasons for hope or doomsday scenarios on the key ecological issues discussed in the papers.

Good evening class, 

Summarizing the articles I read for this week's discussion thread: 

• Fact of Fiction? The Sixth Mass Extinction Can Be Stopped?: This article nicely summarized several different modules of the textbook with a number of discussion thread articles from throughout this course. The article describes how changes in Carbon have been the predominant cause of mass extinction events and how anthropogenic defaunation is leading to a sixth Carbon-based mass extinction; which I, weirdly, hadn't really put together before (Carbon being the base of previous mass extinction events). The article presents numerous upsetting statistics, namely: "The population of any given animal among the five million or so species on the planet is, on average, 28% smaller, thanks to humans." On a positive note, we still have a couple centuries (on currently estimated trends) before we actually fulfill Elizabeth Kolbert's renowned prediction of an anthropogenic sixth mass extinction. 

• Climate change to disrupt nutrient cycles in global dryland soils: This was an interesting and very short read from a study in the Middle East (actually, why I chose the article) describing the impacts to dryland nutrient cycles in increasingly arid environments. The study tested several hundred drylands and determined that aridity decreases the level of Carbon and Nitrogen while increasing Phosphorous in the soils. This is an interesting result as it's surmised that global warming may promote physical processes relative to biological processes in an ecosystem that covers 41% of the planet, supports 38% of the global human population, and is increasing. 

I am ever the optimist and there is some room for hope. In fact, Nat Geo in the Apr, 2020 edition (50th anniversary of earth day) created two magazines in one predicting what 2070 would look like- an optimistic first half covering how humanity came back from the brink of climate change and a pessimistic second half showing how we failed. Although there are numerous understandable reasons for pessimism on this subject, I, and the pew polls, optimistically see a population better educated as to the problem and more inclined to personal sacrifice in the battle to confront anthropogenic climate change. Today's populations, predominantly younger, are driving less, trending towards more sustainable eating, and are seemingly relatively more knowledgeable than ever as to the fundamentals of the problem at hand. I tend not to think that we are waiting for a panacea of some kind that will save humanity. The solutions are here and they are myriad and diverse and what we lack, and what humanity will inevitably find, is the global leadership required- be it the USA, the UN, or otherwise to politically respond in an adaptive and resilient manner that, for once, puts biodiversity and the environment before humanity. 

What do you all see as the major hurdles to any hopes of alleviating anthropogenic climate change?

-Eric 

References

• Mohammed Yahia. Climate change to disrupt nutrients cycles in global drylands soils (30 Oct, 2013). doi:10.1038/nmiddleeast.2013.198 

• David Biello. Fact or Fiction?: The Sixth Mass Extinction Can Be Stopped (25 Jul, 2014). Scientific American. 

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 Q14: Defaunation

Discussion 13.3: While no one can agree on what exactly will happen when an ecosystem loses a species, all of us can agree that if ecosystems lose most of their species, it will likely be a disaster. In general, the preponderance of the evidence shows several trends, such that genetic diversity increases the yield of commercial crops, enhances the production of wood in tree plantations, improves the production of fodder in grasslands, and increases the stability of yields in fisheries. Without an understanding of the fundamental ecological processes that link biodiversity, ecosystem functions and services, attempts to forecast the societal consequences of diversity loss, and to meet policy objectives, are likely to fail.

Among the many arguments I have heard to support biodiversity are the following:

• Right to life. Just as each human as an inalienable right to life, liberty, and the pursuit of happiness, so does each species. By the very fact that millions of extant species, described and undescribed, have made it this far in evolutionary history, they should be protected.  Yet, over an estimated 95-99% of all species that have ever existed on Earth are now extinct.

• Responsibility. Another reason that is put forward to protect biodiversity is that we, humans, have an obligation to act as stewards of the Earth.

• Intrinsic value. Others state that biodiversity has an intrinsic value that is worth protecting regardless of its value to humans. This argument focuses on the conservation of all species, even if they are ecologically equivalent. Many argue that this state of variety ought to be important to us as a species, either, or in relation to our survival, and as such should take precedence in conservation matters.

Review Pecl et al. (2017) and the online extinction documentary for this week. Consider that I have provided three non-scientific arguments offered to protect biodiversity (above). Yet, this is a science course and as such you are charged with making a scientific argument, with examples, that protecting biodiversity is important.

Good afternoon class, 

Summarizing the articles for this discussion thread: 

Biodiversity redistribution under climate change: Impacts on ecosystems and human well being. This one page article speaks to the importance of accounting for species migration due to global warming and its impact on overall ecosystem health in regards their impact on human system planning. The article briefly speaks to the connection between human societies and ecosystem services and expounds on this concept concluding that human societies do not fully “appreciate the implications of unprecedented redistribution for life on Earth, including for human lives.” 

12 Extraordinary pictures show animals headed for extinction: This is a very short article with literally 12 pictures showing various species facing risk of extinction. It’s a bit sad to scroll through and the Nat Geo article highlights Sumatran Rhinos, Mong Seals, lemurs, and more. The author, who I assume must have the most amazing job in the world writing small summaries and collating amazing nat geo pictures, highlights the major threats to these animals as habitat loss and poaching. 

A really fun psychological show to watch is “Naked and Afraid.” It’s two random people who have to survive in an unknown environment for a couple weeks with, literally, nothing. Almost the entirety of the resources required from the “team” are biologoical- trees for shelter, bushes for insulation, fish or fruit or meat for sustenance. It’s obvious in every respect that humans require resources from nature in order to survive, just like every other species. As such, I’ve always wondered if it would be possible to extract laws for humanity from nature and the first one that comes to mind is so blatantly obvious yet endlessly ignored: Extraction can not exceed recharge- and this seems to be where we continually fail as a species. Overfishing, overexploitation, mass consumption all push the extraction- recharge balance out of equilibrium in favor of extraction. Kate Rawsworth provides an interesting ted talk in re-imagining economic systems in the guise of Donut Economics- such that extraction is capped at levels of recharge (it’s absolutely worth watching if you have a free 15minutes- there’s also a book if you have a free few hours). 

As humans prevail and succeed at the expense of the majority of biodiversity while extracting much greater than nature is recharging, we seem to be inevitably approaching some natural barrier beyond which point we may encounter some failure of a number of planetary boundaries (the IPCC names nine of them). Beyond these boundaries we risk a positive feedback loop of trophic cascades with consequential outcomes on humanity. Championing biodiversity as both social and policy goals is akin to championing human rights, a connection many people seemingly fail to make. A final note on this subject; I lived in Belgium for 2.5 years and there was a traveling museum that was put up in the city of Brugge as a collection of pictures which stayed up for about a week. It was pictures and stats of cows, chicken, pigs, goats, and other species of animal that sustain billions across the planet daily. The monument left the overall message of “don’t forget the sacrifice we make.” It was moving- and I hope something many of us consider daily. 

-Eric 

References

• Pecl et al. Biodiversity redistribution under climate change: Impacts on ecosystems and human well-being (31 Mar, 2017). Science, Vol 355, Issue 6332. 

• Anna Lukacs. 12 Extraordinary pictures show animals headed for extinction (22 Oct, 2018). Retrieved from: https://www.nationalgeographic.com/news/2015/05/150517-endangered-species-pictures-wildlife-animals-science/#/01endangeredspecies.ngsversion.1431779406943.jpg Accessed on: 12 Aug, 2020.

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