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The Meaning of Biodiversity William Silvert IPIMAR-INIAP, Lisboa, Portugal The Politics of Conservation Conservation originally meant maintenance of important(?) species. Then it came to mean maintenance of every species. This is simply unrealistic.

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the meaning of biodiversity

The Meaning of Biodiversity

William Silvert

IPIMAR-INIAP, Lisboa, Portugal

the politics of conservation
The Politics of Conservation
  • Conservation originally meant maintenance of important(?) species.
  • Then it came to mean maintenance of every species.
    • This is simply unrealistic.
  • So now we are trying to measure and conserve something called biodiversity.
what is biodiversity
What is Biodiversity?
  • We all want to conserve biodiversity.
  • Everyone can define biodiversity.
  • These definitions are often:
    • Different and inconsistent
    • Vague and imprecise
    • Difficult or impossible to implement
    • Distorted by bias or ignorance.
realistic expectations
Realistic Expectations
  • We cannot conserve every species.
  • Population growth and industrialisation and war inevitably lead to loss of habitat and risk of species extinction.
  • So we may not want to play G*d, but we have to fight battles that we can win, and pick our conservation goals carefully.
  • Physicians working in the battlefield divide casualties into three groups:
    • Likely to recover
    • Likely to die
    • Responsive to medical care
  • Species at risk are similar:
    • Likely to persist
    • Likely to go extinct
    • Worth fighting for.
setting value on species
Setting Value on Species
  • Are all species of equal value?
  • Society will never accept the loss of a species of great whale to save several species of amphipod or nematode or copepod.
  • We have to be willing to assign values to different species in order to set realistic conservation priorities.
what makes a species valuable
What makes a species valuable?
  • Charisma!
  • Does it have intrinsic value to man?
  • What does it do (what is its role)?
  • How important is this role, and could some other species replace it?
  • Is it unique?
  • Some species have to be conserved, this is a social imperative:
    • Great whales
    • Fuzzy white harp seals
    • Pandas
  • Conservation of charismatic species has little to do with ecology.
intrinsic value to man
Intrinsic Value to Man
  • Some species need to be conserved because they are a key part of our ecosystem, whether or not they are very important in general ecological terms.
  • Examples include food fish like cod and their major prey species (e.g., capelin and sand eel), and valuable species like lobster and sturgeon.
what does it do
What Does it Do?
  • Some species have obvious and vital ecological roles:
    • Polar Bears
    • Calanus finmarchicus
    • Amphipods
    • Earthworms
    • Alligators
    • Dung beetles
can it be replaced
Can it be Replaced?
  • If certain key species are exterminated the entire ecosystem will change.
  • If we eradicate one species of copepod or dung beetle, will another fill its place?
  • If so, how long will replacement take?
  • Will the replacement be a good fit, both ecologically and in human terms?
uniqueness and speciation
Uniqueness and Speciation
  • Some species are unique – there is nothing like them, and nothing to replace them.
  • Other species are stamped out in “speciation factories”, like archipelagos and other “biodiversity hotspots” where we find lots of similar but separate species.
unforeseen effects
Unforeseen Effects
  • When venturing into the unknown there is always the risk of the unexpected.
  • We could lose a species whose toxin contains the cure for cancer.
  • A replacement species might be the vector for a dangerous parasite.
  • Anything can happen – extinction, like life, is a gamble.
  • We cannot hope to conserve all species.
  • Concepts of biodiversity should serve as guides to social and political action.
  • Anything we do involves risk, and while we try to minimise risk, we cannot avoid it.
  • We have to mix idealism with pragmatism.