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The Meaning of Biodiversity William Silvert IPIMAR-INIAP, Lisboa, Portugal silvert@ipimar.pt 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

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The Meaning of Biodiversity

William Silvert

IPIMAR-INIAP, Lisboa, Portugal

silvert@ipimar.pt


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?

  • 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

  • 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.


Triage

  • 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

  • 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?

  • 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?


Charisma

  • 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

  • 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?

  • Some species have obvious and vital ecological roles:

    • Polar Bears

    • Calanus finmarchicus

    • Amphipods

    • Earthworms

    • Alligators

    • Dung beetles


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

  • 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

  • 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.


Summary

  • 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.


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