paleo & biodiversity (from H. Hilbrecht)

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Date: Mon, 7 Aug 1995 10:59:24 +0200
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From: Hilbrecht@erdw.ethz.ch (Heinz Hilbrecht)
Subject: paleo & biodiversity


Roger L. Kaesler writes:
>An even tougher connection, however, is the one a lot of our colleagues
>have tried to make:  that you have to understand, e.g., the
>Frasnian-Famennian extinctions in order really to understand what is
>happening in the rain forests today or that we should not worry too much
>because tropical ecosystems seem to bounce back in only ten million years
>or so.  I have never met a biologist worth his salt who does not think the
>study of the history of life is of great (dare I say "vital") importance.
>On the other hand, I know quite a few who are mystified by the connection
>some paleontologists try to make regarding the importance of studying
>ancient extinctions to grasp the modern depletion of biodiversity.

I agree that studies of the rain forests wont't help much to protect their
biodiversity. Economic development may do a better job on this. For
paleontologists, however, the reduction in biodiversity presents a very
important justification of work. In a few analyses we did during the past
few years we found that through speciation and even through migration it
can take hundreds of thousands of years until a new species is established.
Some Pleistocene mammals may do faster but the time scales are still
thousands of years at least. Compare that to 50 Ka half life time of
Plutonium. In anthropogenically induced reduction of biodiversity: aren't
we dealing with a problem of similar magnitude in time than the disposal of
radioactive waste? Moreover, the impact of a leaking disposal site is
probably local to regional. Biodiversity has continental to global scales
and human impact on biodiversity can not be repaired by investment of money
in technical solutions. Why don't we communicate to the public that we are
dealing with a problem comparable to the safe handling of Plutonium?

Our past and recent gambling with biodiversity has created a few deserts
already (strange to say but Europe has been devastated since Roman times -
the original European ecosystem was a huge forest basically). Which impact
had the destruction of the European "rain forest" in historical times? What
can people in the tropics learn from our exercises in deforestation? I was
pretty shocked when I learned that the German forests are artificial. They
had been destroyed until the early last century (about 10% of the forests
of today were left). The consequence was starvation and drought and local
civil war for the spare resources that were left. Trees became vitally
important and were planted and protected at any price in this time. People
lost their head when they caused damage to forests. However, it took us
only 150 years to forget that biodiversity is essentially vital to survive.
Any study of biodiversity involves resources that are far more important
than mining & drilling businesses can offer us. Biologists will always be
like pathologists in medicine in these fields. They will see the reduction
in biodiversity in great detail (and possibly some effects) when it
happened but then the patient may be dead. Paleontologists can exploit
results from experiments mother nature did long ago. These must not be
spectacular extinction events alone. What do we know about causes and
effects of the very "normal" changes in biodiversity that occur in Earth's
history? I would enjoy any discussion about this.

Heinz Hilbrecht




Address:
Heinz Hilbrecht
Geological Institute
ETH Zentrum
Sonneggstrasse 5
CH-8092 Zuerich
Switzerland

Tel.: ++41-1-63 23676
Fax: ++41-1-63 21080
Internet: Hilbrecht@erdw.ethz.ch