Phylogeny and Conservation
Shueyi at AOL.COM
Tue Jan 27 18:46:54 CST 1998
There seems to be at least a couple of threads spinning in reponse to my
original reponse to Russell Seymour - less than I'd hoped but still fun. Here
are my personal thoughts on some of the threads:
1 - Phylogenitic species concept - I happen to beleive stongly in this one,
and I personally think that all biological lineages should be conserved. But
do we want to target every lineage in the world, one by one? Or should we
select targets in a way that maximizes our efficiency? At The Nature
Conservancy, we are really trying to maximize the later. Using ecoregional
units for the ares that we work (North, Central and South America plus
selected parts of the South Pacific), we are trying to identify and protect
viable examples of ALL community types (terrestrial, aquatic and subterranian)
in each ecoregion - note that communties are loosely defined as repeatable
assesemblages of species and are even harder to define than species - but we
try our best). If this is succesfully implemented, we should indeed capture
the bulk of individual species where we work. Then we look for the species
that both need conservation assistance and which got missed by selecting the
best sites for community conservation. A 2-tiered approach that minimizes the
species-by-species. The result of this process alone can be overwhelming, and
we are guessing that around 10-12,000 sites in the US alone need conservation.
Thus you can see why I consider using phylogenetic information as a
2 - the evultionary uniqueness argument. I do not really buy this argument.
Building on my comments above - are some biological lineages more important
than others? Would I modify my assessment of the conservation need of a
living fossil over a more imperiled but less divergent species? No.
Importance is a judgement call, and is usually based on the interest that a
3 - the phylogenetic divergence at the population level approach. Again, I
don't buy into this as an optimal way to protect biodiversity. The rhino
example is pretty illustrative. If an animal with a pretty open population
structure like a rhino has diverged significantly at the population genetic
level, then chances are that many other species that co-occur with the two
populations have experienced similar pressures. Is it really ethical to air-
lift out the rhinos and allow the diversity of one or another of these
communities to become extinct? No. A better approach would be to use a
targeting system that differentiates amoung the environmental gradients that
produced the divergence, and to select targets (entire communities) that
capture the other 100,000 or so lineages in addition to the rhino. There is
nothing in my ethical background that says that a rhino is more important than
an owlfly. Wasting resources to conserve populations of cool giant
vertebrates is certainly not ethical if those resources could have been used
to conserve the entire commuity - saving the rhino and much, much more.
4 - and the utilitarian approach to selecting targets - I simply don't buy.
How can anyone predict the future (and is it ethical to spend that much money
on a 1-900 number for professional help in this matter). I do use this
argument on a regular basis to fund raise . The largest charitable endowment
in the US is less than 5 miles from my office and they are very interested in
secondary plant compounds. - the Lilly Endowment is indeed an easy sell with
this aurgument and they have kicked in over $8,000,000 to our program over the
years. But, that still does not allow me to actually use this criterion to
select conservation targets.
And finaly, I loved 99% of Stuart G. Poss post - with one exception of course.
Measuring relative species richness alone is not really a great way to select
targets. For example, in Indiana caves support very low diversity
communities, but almost 30% of the community of 20-30 species may be endemic
to a "cave-shed". Certain botanical communities are likewise species poor but
highly endemic - Alabama glades come to mind. That's why I love targeting
communities, because the caves of the Lost River system in Indiana support a
different community than do the caves in the Mitchell Karst Plain, just 15
miles away. Between the systems there is about a 40% species turn over, but
within the each geological formation the communities are reasonably
consistent. Thus, we target a few caves in both systems to capture all
species of both community types.
I'll go home now.
long-winded Director of Conservation Science
Indiana Office of The Nature Conservancy
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