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Unformatted text preview: tems, also operating in a complex and murky
w orld, in which decisions are reached on a preponderance of M A DAG A SC A R CO NSERVAT I O N & D E V ELO PM EN T VOLUME 8 | I SSUE 1 — J ULY 2013 t he evidence. Still, we have to be careful with our metaphors;
a nd the familiar criterion of ‘beyond reasonable doubt’ used in
c riminal cases may be a little too stringent for some real - world
b iological data sets. We might more appropriately look to civil
l aw, in which more general probabilities apply. Much as tidyminded systematists might wish they were not, very closely
related species are often genetically leaky vessels, which means
t hat reasonable doubt as to individuation can in some cases be
v ery difficult to banish. As a systematist, I would instinctively
p refer in those cases to apply the presumption of innocence,
a nd to regard sister populations as conspecific unless there
a re compelling reasons to conclude otherwise. But it is also
a pparent that from a conservation standpoint the evidence
m ight be interpreted differently, particularly where distinctive
a nd highly localized populations are imperfectly known; and
c learly, in an arena as complex and nuanced as this, a ‘one size
f its all’ solution is never going to apply. As in the law, a judicious
c ase - by - case approach is indicated.
Still, the reasons for adopting a restrained general attitude
t oward species recognition are compelling; and they relate not
s imply to the multifaceted nature of species as reflected in
t he plethora of definitions available, but to the nature of the
e volutionary process that produced the diversity we see in
M adagascar today. For there is every reason to believe that, far
f rom being some kind of passive relict that in isolation long ago
e stablished an equilibrium with its environment, the Malagasy
b iota is, instead, in a dynamic state of evolutionary flux (cf.
c ontributions in Goodman and Benstead 2003). This is perhaps
m ore than ever the case since the recent elimination of the
i sland’s megafauna.
Above the level of the genome, the fixation of heritable
n ovelties in local populations belonging to existing species is
t he most fundamental process involved in generating biodiversity. This process is synonymous with the formation of those
d iagnosable variants we call subspecies. And it is an essential
p art of the evolutionary dynamic. To promote all subspecies to
s pecies simply on the grounds that they are diagnosable is to
r ob the Malagasy fauna of the very mechanism that we know
m ust have operated to produce the island’s famous diversity at
l ow taxonomic levels.
C ONSERVATION AND SPECIES. S o, what does all this imply for
c onservation? People concerned with protecting the
w hole environment at particular places on the planet’s surface
– w hich, captive propagation of individual species aside, is all
t hat can be effectively done in this arena – often get rather
i mpatient at what they see as the quibbling of taxon...
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- Fall '08