Biodiversity – What is it? Definitions Contraction of “biological diversity”

1. Biodiversity – What is it? • Definitions • Contraction of “biological diversity” • Fundamental unit = species • What is a species?? • A group of genetically similar organisms that interbreed naturally and freely to produce viable, fertile offspring, but do not share this behavior and outcome with individuals of other species • Problem: Some people consider this definition to be inadequate. Why?? • Some natural interbreeding between species • Not all species distinct and static; hybrid swarms • Some exchange of DNA without interbreeding • Genetic polymorphism; species flocks

2. Biodiversity – What is it? • Definitions • Components • Term “biodiversity” often used incorrectly or incompletely • Not synonymous with “species diversity” • Encompasses three measures • Species Diversity • Species richness – Total number of species • Often cited incorrectly as “biodiversity” • Evenness – Proportions of species in a community • More difficult to determine (requires more complete survey) • Genetic Diversity – Variety of genotypes • Ecosystem Diversity – Variety of habitat types

4. Biodiversity – What is it? • Definitions • Components • Term “biodiversity” often used incorrectly or incompletely • Not synonymous with “species diversity” • Encompasses three measures • Species Diversity • Species richness – Total number of species • Often cited incorrectly as “biodiversity” • Evenness – Proportions of species in a community • More difficult to determine (requires more complete survey) • Genetic Diversity – Variety of genotypes • Keystone Species • Ex:Sea otters in kelp forests

5. Biodiversity – Estimation • Estimates of Biodiversity • Described species ~ 1.8 million • Insects > 1,000,000 species • Plants > 290,000 species • Probably an underestimate • Only ~11,000 species of bacteria • Less conspicuous species studied less often • Estimates range from 3 – 100 million • Around 6200 new eukaryote species described each year • Recent estimate ~ 8.75 million (Mora et al. 2011) • Still doesn’t capture microbial diversity (could exceed all other diversity combined) • Biases • Splitting of taxa more common than lumping • Tendency to increase number of described species • Cryptic species

6. Biodiversity – Estimation • Biodiversity Hotspots • Myers – Up to 20% of the world’s plant species and more than 20% of the animal species are confined to 0.5% of the land surface • Biodiversity Hotspot – Area with high degree of • Biodiversity • Endemism • Risk of habitat degradation/loss • Concept originally intended for tropical and subtropical areas • Endemism less prevalent in temperate and polar regions

7. Biodiversity – Value • Value to Humans • Economic • Ex – Lomborg: $3-33 trillion annually • Biodiversity loss could lead to removal of species that benefit humans but aren’t currently known to do so • Ex – Chapin et al. (2002) suggested increase in frequency of Lyme disease during 20th century may have been related to increase in abundance of tick-bearing mice (once controlled by food competition with passenger pigeons) • Species extinction reduces potential pool of species containing chemical compounds with pharmaceutical or industrial applications • Problem – Benefits may not be obvious • Difficult to convince people that it’s important to preserve something with no immediately apparent value to them • Ex – Economic value of viral resistance added to commercial strains of perennial corn through hybridization with teosinte (Mexican wild grass) is ~ $230-300 million/year

8. Biodiversity – Value • Ecosystem Value • Biodiversity can have large effects on ecosystem stability and productivity • Benefits of biodiversity • Productivity • Halving species richness reduces productivity by 10-20% (Tilman) • Nutrient retention • Loss of nutrients through leaching is reduced when diversity is high • Ecosystem stability • Ex – Higher diversity (unfertilized) plots of native plant species maintained more biomass during drought than lower diversity (fertilized) plots • Ex – Higher diversity plots of native plant species had greater resistance to fungal diseases, reduced predation by herbivorous insects and reduced invasion by weeds

9. Biodiversity – Value • Ecosystem Value • Considerations • Species richness vs. evenness • Simple species richness may be deceptive as an indicator of biodiversity and ecosystem stability • Evenness usually responds more rapidly to perturbation than richness and may have important ecosystem consequences • Richness is typical focus of studies and policy decisions • Importance of individual species • Charismatic megafauna: What about non-charismatic species? • Different species affect ecosystems in different ways (keystone species vs. non-keystone species) • Ex – Sea otters/Sea urchins/Kelp forests in eastern Pacific Ocean • Question:How many species are required to maintain “normal” ecosystem function and stability? • No magic number • Losing one ant species in a tropical forest may have less immediate impact than losing one species of fungus that is crucial to nutrient cycling in the soil

10. Biodiversity – Factors • Nutrient Availability • Oligotrophic • Dominated by a few species able to survive on limited nutrients • Low diversity, Low biomass • Mesotrophic • Support greater numbers of species • Rapid colonizers held in check by nutrient limitation • Less aggressive species capable of surviving • High diversity, Medium biomass • Eutrophic • Dominated by a few species able to grow and/or colonize rapidly with abundant nutrients • Low diversity, High biomass

11. Biodiversity – Factors • Selective Mortality • Predation • Ex – Birds with colorful plumage • Ex – Sea urchins (sushi) • Species-specific diseases/pests • Ex – Dutch elm disease • Ex – Bark beetles

12. Biodiversity – Factors • Habitat Disturbance • Non-selective habitat disturbance has potential to increase diversity • Prevents competitive exclusion • Intermediate disturbance  Maximum diversity

13. Biodiversity – Factors • Habitat Disturbance • Fire and fire-dependent species • Ex – Peter’s Mountain Mallow (Iliamna corei) • Discovered in 1927 (50 plants) • Endemic to meadow in western Virginia • 1986 - Three plants remaining • Not setting seed • Listed as endangered • Research on seeds indicated importance of fire • Cracks hard seed coat, aiding germination • Removes competing vegetation • Had been suppressed in the area • Controlled burns in 1992 and 1993 led to appearance of 500+ seedlings

14. Biodiversity – Factors • Habitat Fragmentation/Destruction • Most significant factor causing species loss • Smaller habitats support fewer species and smaller populations than large habitats • Population sizes tend to fluctuate more in smaller habitats than large habitats • Reduced population  Lower genetic diversity • Behavior of territorial species changes in fragments • Fragments may not support self-sustaining populations

15. Mount Hood National Forest, Oregon • Patches due to timber removal

16. Biodiversity – Factors • Habitat Fragmentation/Destruction • Most significant factor causing species loss • Smaller habitats support fewer species and smaller populations than large habitats • Population sizes tend to fluctuate more in smaller habitats than large habitats • Reduced population  Lower genetic diversity • Behavior of territorial species changes in fragments • Fragments may not support self-sustaining populations

17. Biodiversity – Factors • Exotic Species • Species invasions may profoundly affect ecosystems • Detrimental exotic species usually are • Superior competitors • Ex – Argentine ants, starlings, zebra mussels • Effective predators • Ex – Nile perch, mongeese

18. Biodiversity – Factors • Exotic Species • Zebra mussel • Competitor in Great Lakes and elsewhere • Transported from Europe in ballast water • Fouling organism • Restricts movement of water through intake pipes • Colonizes boat hulls, pier pilings, buoys, etc. • Fouls other organisms (clams, mussels) • Filter feeder – removes larvae and particulate material • Outcompetes native shellfish species for food and space • Removes larvae from water

20. Biodiversity – Factors • Exotic Species • Mongoose • Predator in Hawaii • Introduced in 1883 to combat rat population • Prey on native birds • Lionfish • Venomous predator • Introduced in Caribbean/W Atlantic ca. early/mid 1990’s • Preys on 65+ spp. of fishes • No natural predators

21. Nile perch – Lake Victoria Brown tree snake - Guam Argentine ants - California Caulerpa taxifolia - California

22. How might we justify a particular environmental ethic? 1. Anthropocentrism 2. Moral extentionism: zoocentrism/sentientism/psychocentrism, and biocentrism 3. Novel features or entirely new approach such as ecocentrism

23. Albert Schweitzer (1875-1965)Reverence for Life A predecessor to later biocentric environmental ethics. Life is good in itself, inspiring, and deserving of respect: “I am life which wills to live, in the midst of life which wills to live.” Schweitzer’s reverence for life can be interpreted as an attitude, moral virtue, or character trait—environmental virtue ethics. But Schweitzer seemed to regard reverence for life as reverence for life in and of itself, akin to an ethical norm or rule. This, however, leads to “Schweitzer’s paradox.”

24. “On Being Morally Considerable” (1978)Kenneth Goodpaster What makes something morally considerable? Animal ethics people correctly argue that it is arbitrary to stop at something like rationality and that sentience is morally considerable because, in part, rationality presumes sentience. But why stop at sentience? Sentience presumes something more basic: that something is alive. Goodpaster: To avoid arbitrary distinctions, we should ground morality in a life criterion: anything alive is morally considerable.

25. Respect for Nature: A Theory of Environmental Ethics (1986) Paul W. Taylor

26. Another Biocentric Environmental Ethic Gary Varner Varner develops a psycho-biological theory of individual welfare.

27. And Another Biocentric Environmental Ethic Nicholas Agar Agar develops a theory based on living things having bio-preferences.

28. And Still Another Biocentric Environmental Ethic James Sterba uses liberal justice to ground a biocentric environmental ethic: An organism has a good of its own if it can be harmed or benefited. If an organism has a good of its own, it is wrong to harm it unless we have a good reason for doing so. There are no non-question-begging reasons to assume that human interests always override the good of a nonhuman organism. An organism that has a good of its own has moral standing and is thus subject to the same fundamental principles of justice that govern human relationships. Liberal justice—a balancing of liberty and equality—is the most defensible principle of social justice to guide human-nonhuman relationships. Sterba argues that species and ecosystems can also be said to have goods of their own. Sterba’s EE thus bridges biocentrism and ecocentrism.

29. Aldo Leopold’s Land Ethic

30. Ecocentrism • Ecocentrists believe that anthropocentrism, zoocentrism, and biocentrism are all inadequate because of their individualist focus. • From ecology: We cannot fully understand an organism without also examining things such as: • its species • its interaction within species populations • its relationship with ecosystem processes • what it eats • what eats it • etc. • Ecocentrism: We cannot fully understand the value of an organism without also locating value in holistic entities, and probably also in processes and relationships.

31. Ecocentrism The central feature of ecocentrism is its holism. Three kinds of holism: Epistemological or methodological holism: We cannot understand something or have knowledge of it without taking into account holistic entities, processes, and relationships. Metaphysical holism: Holistic entities really exist. Ethical holism: holistic entities (and probably processes and relationships as well) have noninstrumental value.

32. Three Problems for Ecocentrism Getting its ecology right Naturalistic fallacy: Trying to derive values straight from facts, or prescriptive norms about what we should do straight from descriptive, factual statements Ecofascism

33. “Animal Liberation: A Triangular Affair” (1980) by J. Baird Callicott Ethical Humanism (Anthropocentrism) Humane Moralism Leopold’s Land Ethic (Animal Liberation) (Holistic Ecocentrism)

34. Callicott’s Conclusions Animal liberationists fail to make a distinction between domestic and wild animals, but this distinction is crucial. From the perspective of Aldo Leopold’s land ethic, many domestic animal species ruin nature. Domestic animals have no natural behavior. We cannot “liberate” animals back to the wild; if left alone, many domesticated species might go extinct. It is wrong to prevent pain (sentientism) because pain provides important information for nervous systems. Animal liberation denies our natural participation in nature through activities such as hunting.

35. “Animal Liberation versus the Land Ethic” (1981) by Edward Johnson Johnson replies to Callicott: Animal liberation is directed toward individual animals that can be liberated; there is no direct concern with species. The sentientist point about pain is that pointless pain is morally wrong. Natural participation with nature? What’s this?

36. Tom Regan pours fuel on the fire between animal ethics and environmental ethics (1983) “The implications of [Leopold’s] view include the clear prospect that the individual may be sacrificed for the greater biotic good, in the name of ‘the integrity, stability, and beauty of the biotic community.’ It is difficult to see how the notion of the rights of the individual could find a home within a view that…might be fairly dubbed ‘environmental fascism.’ To use Leopold’s telling phrase, man is ‘only a member of the biotic team,’ and as such has the same moral standing as any other ‘member’ of ‘the team.’ If, to take an extreme, fanciful but, it is hoped, not unfair example, the situation we faced was either to kill a rare wildflower or a (plentiful) human being, and if the wildflower, as a ‘team member,’ would contribute more to ‘the integrity, stability, and beauty of the biotic community’ than the human, then presumably we would not be doing wrong if we killed the human and saved the wildflower.” (pp. 361-362 from The Case for Animal Rights, 1983, bold and underline added)

37. “Animal Liberation and Environmental Ethics: Bad Marriage, Quick Divorce” (1984) Mark Sagoff: If animal liberationists such as Singer are committed to minimizing the suffering of animals, logically they should be committed to intervening in wild nature to lessen suffering. This could lead to many proposals and policies such as killing predators. But these kinds of proposals and policies will strike an environmentalist as being absurd. Thus, a holistic environmental ethic cannot stem from the interests of individual animals.

38. A Possible Utilitarian Response Utilitarian intervention to minimize suffering in the lives of wild animals might damage ecosystems, resulting in a lower quality of life for animals in the wild (and possibly a lower quality of life for people). Removal of animals from the wild to minimize suffering might likely lead to unhappier lives for the now captive animals. Thus, leaving wild animals alone might be our best policy to minimize animal suffering. This could result in a habitat ethic that might be compatible with holistic environmental ethics.

39. A Possible Animal Rights Response A wild animal’s right to life is a right not to be killed by moral agents (who have a duty to respect rights), but this doesn’t imply a duty on the part of moral agents to protect the animal from being killed by non-moral agents such as other wild animals. We should manage human wrongs and not wild animals. Thus, respecting the rights of wild animals simply means letting them be, with as little human interference as possible.

40. “Animal Liberation is an Environmental Ethic” (1998) by Dale Jamieson Sentient humans and animals have primary value, while non-sentient entities have derivative value. But in some cases derivative value should trump primary value. Animal liberation and environmental ethics can be likened to a Hollywood romance: 1. They can complement each other—there are good animal ethics and good environmental ethics reasons to not eat meat. 2. We can value non-sentient nature intrinsically and intensely. 3. An animal ethic can give us a habitat ethic that is indistinguishable from a biocentric or ecocentric environmental ethic