Phylogeny and Conservation
James Francis Lyons-Weiler
weiler at ERS.UNR.EDU
Tue Jan 27 13:17:17 CST 1998
On Tue, 27 Jan 1998, Shueyi wrote:
> In a message dated 98-01-27 04:05:07 EST, Russell Seymour writes:
> < I plan to briefly introduce terminology and basic principles of phylogeny
> < reconstruction; a little on species concepts; the 'agony of choice' reserve
> < selection procedure; and molecular markers as conservation tools. A few
> > case studies will also be introduced. Some of this content will get only
> < cursory attention and a full reference list will be supplied.
And then Sheuyi:
> I couldn't resist commenting on the idea that conservation biologists actually
> develop conservation targets based on phylogeny. While this idea generates
> lots paper, especially out of the British Museum of Natural history, its
> impact has been minimal. It's essentially an academic answer to an applied
> problem - how to best choose targets for conservation efforts. Thus I'll
> throw out a discussion that seems likely to generate some lively discussion on
> the list.
> Few conservation groups feel that a species approach to conservation is really
> the most appropriate mechanism for making decisions, given the limited
> resources available and the magnitude of the biodiversity crisis (Zoological
> gardens are notable exceptions to this generality). When species approaches
> are used, the conservation targets are chosen based on imperilment - for
> example we (in Indiana, USA) have a fairly intensive and ongoing effort that
> targets the last known population of _Epioblasma o. obliquata_ the white
> catspaw mussel. But the catspaw is simply part of a larger community of
> imperiled mussels at the site, and to be honest, we would be working on this
> watershed even if the catspaw was not present. The site is a pretty good
> place to conserve a high-quality example of an aquatic invertebrate community
> that contains numerous species at risk. There are other, better rivers in my
> region that support richer communities of mussels, fishes, and insects, and we
> work on the two additional rivers that support amazingly rich communities.
> But neither of these are the best sites to conserve paddle fish (although both
> have respectable populations), an imperiled and phylogenetically unique
> animal. Should we bail out of these solid systems and move to a degraded
> river which happens to have a mega-population of paddle fish? These are the
> forced choices that choosing targets based not on need, but on some relatively
> arbitrary criteria create. Keep in mind that each of these projects literally
> represents millions of dollars committed into the foreseeable future - three
> watershed based projects is all we can afford in Indiana.
> Other conservation efforts, especially in the neotropics, target ecosystem-
> level targets. The assumption is that by conserving intact ecosystems, you
> get the whole biodiversity package - including those species that we know
> nothing about. Thus in Latin America, we and our partners target intact
> systems that represent the complete array of habitats present on a ecoregional
> basis. As soon as you start choosing targets at the species level, you make
> compromised choices about those unseen targets. Moving back to my own back
> yard, should I spend time and money to protect Black Terns at the only site
> they nest in Indiana - which happens to be a powerplant cooling pond? (Maybe).
> Would it make a difference if the Black Tern represented the only taxon of
> some bizarre phylogenetic lineage? (No). What if this were the only place on
> Earth to protect Black Terns? (then YES!!!).
> The concept to remember is this. Conservation resources (=$$$ and time) are
> limited. Conservation targets are almost unlimited. If you really want to
> make a difference in the World, utilize limited resources such that they
> maximize conservation impact. And you best accomplish that by conserving ALL
> ecosystems (or what's left of them) on Earth. Targeting unique phylogenetic
> lineages per say, is at best a distraction from the greater task at
Naturally, there are alternative perspectives on the utility of
phylogenetic information for making conservation priorities.
There's the idea of conserving an "evolutionary front", that
is, lineage that are likely to represent a significant base for
future diversification... this idea (Erwin, references
not at hand) has not been well recieved, for the obvious
want a way to tell which lineages hold the most promise for
future evolution (future conditions being unknown and all). Then
there is the distinctive lineage argument... which although
characterized as a distraction can indeed be considered
relevant for real-time, on-the-ground conservation decisions
(Ihave $500,000 to relocate rhinos; not enough to relocate
all populations; reality = only some can be helped = question:
which ones? and thus genealogical distictiveness may be a
The distinctiveness argument is also cogent for selective
reserves. The argument is that rarity alone is perhaps not
the only criterion for attention. Living fossils should
outweigh any species of hooved mammal, for instance, even
if the particular mammal species is rarer than the living
fossil. It does not follow that living fossils represent
evolutionary "dead ends" - they may proliferate and speciate
thousands of years from now, and we have no way of knowing
(hence the "evolutionary front" argument is relatively
Given that conservation = finite resources, I think it
worthwhile to consider evolutionary distinctive as a
criterion to be considered in conjunction with
rarity and a suite of other factors when the chips
Here are some refs:
Crozier, R.H. 1992. Genetic diversity and the agony of choice. Biol.
Daughtery, C.H., Cree, A., Hay, J.M., M.B. Thompson. 1990. Neglected
taxonomy and continuing extinctions of tuatara, Sphenodon. Nature, Lond.
Erwin, T.L. 1991. An evolutionary basis for conservation strategies.
Faith, D.P. 1992. Conservation evaluation and phlyogenetic diversity.
Krawjewski, C. 1994. Phylogenetic measures of biodiversity: a comparison
and critique. Biol. Conserv. 69:33-39.
May, R.M. 1990. Taxonomy as destiny. Nature: 347:129-130.
Moritz, C. 1995. Use of molecular phylogenies for conservation. Phil.
Trans. R. Soc. Lond. B. 349:113-118.
Nixon, K.C. and Q.D. Wheeler. 19$$. Measures of phylogenetic diversity. In
Extinction and phylogeny, M.J. Novacek and Q.D. Wheeler, eds. Columbia
University Press, NY.
Vane-Wright, R.I., C.J. Humphries and P.H. Williams. 1991. What to
protect?Systematics and the agony of choice. Biol. Conserv. 55:235-254.
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