Diversidad & hotspot conservation

Lynn Raw RAW at GATE2.CC.UNP.AC.ZA
Mon Jul 24 13:06:27 CDT 1995


I would be really interested in testing the Diversidad software
but, unfortunately, I do not have
access to Mac hardware. Is there any chance of an IBM/MSDOS
compatible version one day?.

The ability to detect areas of high landscape diversity and thus
be able to predict areas of high
biodiversity is very useful but I am concerned that some users
may stop at that point and believe
that they have thus identified areas of prime conservation
importance.

This is merely a first step in analysing conservation priorities.
Of course, if the high biodiversity
indices obtained are the result of large numbers of endemic
species only found in the identified
area then its conservation importance is confirmed.

If, however, the high biodiversity results from the interface of
many wide-spread habitat types and
their related biotas, then such an area may be of very low
conservation priority. For example, an
area of high biodiversity may result from the juxtaposition of 5
habitat types. If this area is set
aside for conservation, one would expect that all 5 biotas will
be protected for posterity. But is
this necessarily true? What happens if climatic change results in
a habitat shift geographically in
which  one habitat type is able to expand and thus replace the
other four types. In this case it is
likely that the biodiversity now conserved will only represent
that single habitat type. In a
hypothetical case where each of these habitats originally had an
equal amount of diversity, it may
be seen that 80% of the biodiversity intended to be conserved in
such an area will be lost.

In such cases it would seem that careful analysis of the habitat
requirements of target species
should enable potential refugia in times of environmental
extremes to be identified and included
in areas set aside for conservation. These target species are
likely to be those with restricted
ranges and specific habitat requirements, i.e. local endemics.
Other, wide-ranging and habitat-
diversity tolerant species should be accommodated and considered
in deciding buffer and corridor
zones in conservation area planning.

It seems to me that too much emphasis has been placed on JUST
identifying biodiversity hotspots
and not looking at the long term implications of conserving such
hotspots.

I look forward to comments from Taxacom and Amphibian Decline
subscribers.

Lynn Raw (Mr)
Raw at zoology.unp.ac.za
University of Natal, Pietermaritzburg, South Africa.




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