My $0.02 on phylogeny and conservation

[Harvey E. Ballard, Jr.]

Relatively few species complexes (in my opinion) have been adequately
studied at both the population and species levels across the range of the
group, using appropriate tools (including molecular methods) AND with
initial verification of taxonomic units based on solid classical taxonomic
studies.  This is true of all land masses on earth--including the eastern
U.S., where many widespread complexes deserve thorough study and have not
received it.  As a beginning point, let's assume one aims for a
scientifically justifiable study--neither a slip-shod one that never
attempts to reevaluate taxonomic units initially before phylogenetic
analysis (do people ever examine type material prior to phylogenetic
analysis?), nor one using methods at inappropriate levels for the question,
nor one with inadequate sampling of populations.  Even if the study aims at
a single species, the study should include at least sparse sampling of
"outgroups" for comparative purposes to root the tree.  If one is not
making a priori assumptions, one will perhaps wish to examine an entire
complex of species and their populations.  For the sake of argument, then,
one might deal with 5 ostensibly closely related species over a sizeable
range, one or more of which might be rare.  In most cases herbarium DNA
extractions may not be adequate to cover the ranges of each species, but at
least a handful of populations for each of the species should be sampled
wherever possible--giving, say, 15 populations.  In order to sample
population variation, one should have a minimum of, say, 15 individuals (I
can hear population geneticists screaming in the background).  But if the
complex spans a considerable area and the species are not roadside weeds,
collecting merely adequate samples for study (to use at the population
level, remember) may take 2-4 weeks of travel.  With a travel budget (in
North America) of $35/day (OK, I admit I'm a softie and stay in cheap
hotels rather than camping), the average 3 week collecting trip (not
counting collecting supplies) costs $735 and takes the better part of a
month to get 225 samples.  (Before the trip, of course, the investigator
has demonstrated adequately by preliminary studies over a few weeks or more
that they can identify individual taxonomic units (species or distinctive
infraspecific taxa) and have worked out a satisfactory initial taxonomy on
which to base a justifiable phylogenetic study.)  Relatively few molecular
methods exist that are cheap and effective at the population level; if one
uses either protein electrophoresis or an anonymous marker system such as
RAPDs or ISSRs, processing the 225 samples will take a month or two if you
have the luxury of working non-stop or have a lab technician, three or four
months if not (most of us have to teach some, too).  If the lab work takes
3 months, in addition to the 3 weeks of preliminary study and the 3 weeks
of collecting, we now have 4-1/2 months (under maybe ideal circumstances).
I don't know what 225 perfectly run samples would cost for electrophoresis;
using RAPDs or ISSRs with 4 "perfect" primers would cost roughly $750
including DNA extraction.  One would wish to take a month or two of time to
analyze the data and digest it into a meaningful product, hopefully tying
it into existing literature and developing the broader implications of the
study.  It appears that we are pushing the envelope of a year, simply to do
an adequate, minimally justifiable job (again, in my opinion) with a
complex of 5 species, spending approximately $1520--if one did the work
oneself with abundant free time.

Even if such studies focused attention only on the flora in the eastern
U.S. for phylogenetic interpretation of conservation units (ignoring
western populations of more widespread species), they ought to be dealing
with the--what, 2500-3000 native species in the region?  If all of the
systematists on earth focused their attention on the region and bent all of
their resources to the task (and cared enough to learn the methods to do
it), it wouldn't be done--properly--without financial ruin to most and a
century of time elapsed.  By then, as others have observed, much of the
range of the rarer species will have been utterly destroyed, leaving major
phylogenetic gaps for others studying those species!  It sounds good on
paper, and is an ideal a posteriori situation to be able to utilize species
ALREADY PROTECTED in adequately large landscape units that may (MAY) be
viable in the long term.  But it's only a fantasy to argue that the
scientific community can manage to pull off phylogenetic analysis in front
of conservation.  It's hard enough to get most of the scientific community
to utilize available traditional scientific data to reevaluate their
"fundamental" taxonomic units prior to phylogenetic analysis.  And I don't
trust decisions based on studies of 2 or 3 species as representative of an
entire landscape mosaic.  This was done in the past with conservation, and
I'm thrilled that many institutions dedicated to conservation of natural
areas AND the species they harbor have moved definitely away from the
postage stamp-sized sites to grapple with much larger areas.  Happily, most
have been developing methods which deemphasize a handful of rare species as
indicators of a "good" site and have been evaluating natural community
mosaics.  If larger landscape units with a number of regionally represented
natural communities, scattered across the continent, are protected and
managed, hopefully by attempts to mimic the natural processes lost during
human colonization and settlement, then the details of individual species
largely become moot.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Harvey E. Ballard, Jr., Assistant Professor, Plant Evolution and Systematics
Department of Environmental and Plant Biology
Porter Hall, Ohio University
Athens, OH 45701
(740) 593-4659 (office & lab phone)
(740) 593-1130 (fax)
email: ballardh at oak.cats.ohiou.edu