Preserving the Earth's Biodiversity
What must we consider?
  1. We must establish the importance of all life forms (i.e. why do we need them?)
  2. We must consider the extinction problem (are we causing it?)
  3. We must find ways to preserve biodiversity (what's the best way?)

What is biodiversity?
  • Variety of living organisms
  • The simple measure is to count the number of species (Species richness)
    • is this enough? what if each species only had a few individuals?
  • Must also look at representation. How evenly distributed are the organisms across all species?
  • Other forms of diversity matter: genetic diversity within a species, ecosystem diversity (habitats)

How much diversity is out there?
  • Approximately 1.5 million named and categorized species (bacteria, plants, animals, etc.)
  • Estimates range between 14 and 114 million total species!
  • Where and what are all the undiscovered species?

Is biodiversity valuable?
  • Instrumental Value = direct $ value to humans (fish, lumber, etc.)
    • makes conservation important and easier when $ is apparent
  • Intrinsic Value = value for its own sake (pandas)
    • more philosophical question of conservation
    • makes it harder to conserve
  • Ecosystem Services = what the environment does for us for free
    • Estimates of the value of "natural capital" are $38 trillion/year!
    • Total global GNP is only ~$18 trillion
    • Clean air, water, soil, pollination, food, fiber, lumber, nutrient cycling, decomposition, medicine, pest control, recreation, genetic diversity, etc.
    • Protecting biodiversity then protects the investment in the environment
    • Can we afford to replace?

What is extinction?
  • Death of a species - when the last member dies
  • Background Extinction = natural extinction through evolution. Fossil records indicate the rate is about 1 mammal per 400 years and 1 bird per 800 years.
  • Mass Extinction = large-scale die off of species. Fast in terms of geologic time. 5 prior episodes, last was the dinosaurs.
  • Current extinction rates indicate that 20-25 mammals have gone extinct in the last 100 years
  • Are we in a mass extinction? Did we cause it?
    • There have been ~500 extinctions of plants, animals, birds, etc. in North America since colonization
    • 1/3 of North American species are threatened or endangered
    • Globally, there have been over 700 animal extinctions and 90 plant extinctions since 1500
    • 24% of all mammals are threatened - and mammals are a well studied group. What about insects, fungi, bacteria, or fish?
  • Endangered Species = in imminent danger of extinction throughout all or most of its range
    • If we can help declining species in time, perhaps we can prevent extinction
    • US Engangered Species Act
      • Lists species and provides protection
      • Protects critical habitat (controversial because it conflicts with private property rights)
      • Detailed recovery plan
      • Currently 1,272 speices listed (threatened and engangered)
        • 14 have been delisted, 9 have gone extinct
      • Program suffers from complete lack of data, limited funding, and private property rights debate

What characteristics are common among endangered/extinct speies?
  1. Small Range - the entire species is only found in limited areas
  2. Large Territory - individuals cover lots of ground (more conflicts possible)
  3. Endemic to an island - evolved in isolation, very specialized
  4. Low reproductive rates - populations cannot rebound quickly
  5. Specialized feeding habits - eat limited things
  6. High on the food chain - impacted by everything below it (also conflicts with humans)

Where is the most biodiversity? Where are the problem areas?
  • Biodiversity is everywhere and everywhere is important
  • However, some areas contain more species and more unique (endemic) species
  • Tropics, coastal areas, islands
  • nIn tropical rainforests, biodiversity his highest. For example: 43 species of ant on 1 tree, 300 species of tree in 2.5 acres, 10,000 species of insects on 1 tree.
  • Developing countries have lots of diversity and also have big impacts. Why?

Global Biodiversity "Hot-spots"
  • hotspots.gif
external image moz-screenshot.jpgimage from

What are the reasons for biodiversity loss?
  • Habitat Loss - conversion to other things (agriculture), fragmentation, simplification, intrusion
  • Invasive Species - biotic pollution
  • Pollution - acid rain, global warming, eutrophication, toxic spills, etc.
  • Population - human overpopulation (again)
  • Over exploitation - commercial harvest (fish), pet trade, poverty, greed, poor mangement

How can we protect biodiversity?
  1. Conserve habitats (in situ conservation)
    • stop habitat loss
    • protect reserves/preserves
    • connect critical areas
    • Single large reserve or several small?
    • US has a good system
    • 10% of land area is ideal
  2. Restoration ecology (in situ)
    • Return area to natural states, reintroduce native speices
    • Expensive and time consuming
    • US has good track record: deer, otters, elk, falcons, prairie habitats
  3. Zoos, Aquariums, Botanical Gardens, Seed Banks (ex situ)
    • Captive breeding & reintroduction
    • Expensive, doesn't work for all species

Who is protecting biodiverity?
  1. IUCN (World Conservation Union)
    • maintains the Red List (11,000+ globally endangered species)
    • TRAFFIC database (Trade Records Analysis for Flora and Fauna in International Commerce)
  2. World Wildlife Federation
    • fund raising for research and awarness

There are others - look them up

What legal strategies are in place?
Endangered Species Act (ESA)

    • nDetailed study of species to determine if it is endangered or threatened
    • nLegal protection of organisms
    • nRecovery plan
    • nNo compensation for private land occupied by endangered species
    • nTends to conserve “popular” species
    • n>1200 species (1,000 endangered)
      • n9 or so have been delisted

  • n1982 amendment to ESA allows landowner to“take” an endangered species if it does not interfere with the recovery plan of the species
  • nGreat deal of controversy around this provision

CITES – Convention on International Trade in Endangered Species of Wild Flora and Fauna (160 nations)
  • Bans the hunting, capturing and selling of endangered or threatened species (30k)

  • nEnforcement varies from country to country n
  • Banned ivory in 1990

n Convention on Biological Diversity n

  • International committee formulated the Biodiversity Treaty nPart of 1992 Rio Earth Summit
  • nBasic Guidelines:n

    • Intrinsic value of biodiversity n

    • Significance of biodiversity to human welfare n

    • Sovereignty of nations nNation’s obligations to conserve biodiversity n
  • Emphasis on invasive species, genetic resources, deforestation, coordination n
  • 188 participating countries US participation in limbo n

What can you do?

  • Public awareness n(Sierra Club, WWF)
  • nSupport Research n
  • Support Establishment of International Systems of Parks
  • nPollution control n
  • Economic Incentives to Landowners
  • nEconomic help to those abusing ecosystems n

Readings & Homework

Biodiversity Student Pages

Are Humans Responsible for the Possible Biodiversity Crisis?
How does agriculture effect biodiversity? CM KS AS
How does overharvesting effect biodiversity? JA, SR, PC

How does deforestation affect biodiversity? LA, JG
What are the impacts of invasive species on biodiversity? PO, PM, FM
What biodiversity exists in remote areas? AR KK AB

How does water pollution affect biodiversity? SP, CD, JB
How do exotic species effect biodiversity? JB, GS, EZ
How does climate change effect coral reefs? AR, WM, SF
What are the effects of deforestation? PM FC CM
What are the effects of the illegal pet trade? HarLin, JarBow, TayJo

What is the impact of Global Warming on Biodiversity? CE, GA, AS
What methods are used to preserve Biodiversity? SC, RA, WW
What are the extinction rate trends and how are they influenced by different species?
How do endangered species affect biodiversity? JB JW AH
What environmental factors foster biodiversity? SP, PD, CL