Researchers in India and from The Earth Institute at Columbia
University have discovered that one of the few remaining populations
of Asian elephants in India is actually two genetically distinct
groups. The results of the study, which appear in the current issue
of the journal Animal Conservation, could have far-reaching
implications in conservation plans for the endangered elephants
as well as other species on the Subcontinent.
Prithiviraj Fernando, a post-doctoral researcher at the Center
for Environmental Research and Conservation (CERC), and Don Melnick,
executive director of CERC, together with colleagues from the Centre
for Ecological Science at the Indian Institute of Science collected
dung samples from nearly 300 wild Asian elephants and 30 captive
elephants for which reliable capture information existed. They
then examined DNA from the samples and found that, of the distinct
populations found in India, the groups that inhabit the forests
in the northeast of the country is actually composed of two genetically
distinct populations separated by the Brahmaputra River.
Despite the low and declining numbers of Asian
elephants, relatively little is known about their genetic diversity—information
that is crucial to plans for preserving the species. An earlier
study of elephants in southern India by the same group identified
two distinct populations where there was previously thought to
be only one. A region known as the Palghat Gap, a wide pass through
the Western Ghat mountain range, was found to act a biogeographical
barrier between the two in that case.
“It is interesting that the Brahmaputra seems to have been
a biogeographical barrier for several species,” the authors
write in their most recent study. “Population genetic studies
of other species would be helpful in corroborating whether the
Palghat Gap and the Brahmaputra River have served as important
biogeographical barriers to a broad range of taxa and thus should
be considered in future conservation planning.”
The Asian elephant (Elephas maximus)
is recognized by the World Conservation Union (IUCN) as an endangered
species, with an estimated 22,700 to 32,400 individuals remaining,
more than half of which are in India. Elephant numbers throughout
Asia have declined drastically over the last several hundred years,
mainly due to habitat loss and fragmentation, capture and domestication,
and, more recently, poaching of males for ivory.
To combat these declines, India established
11 so-called “elephant
ranges” that incorporate more than half of the known elephant
habitat. Fewer than half of these ranges, however, offer the much
stricter protections provided by wildlife sanctuaries or national
parks. Moreover, India is projected to overtake China as the world’s
most populous country by 2030, a fact that almost certain to bring
about increased competition for space between humans and elephants.
Still, Melnick and his colleagues are confident that their work
represents a crucial step in efforts to protect an animal that
is deeply rooted in Indian culture. “If we are going to find
a way to protect elephants for future generations, we need to preserve
the greatest genetic diversity possible.” says Melnick. “We’re
just acting blind if we don’t know where that diversity is. This
study shows us where we need to focus our efforts.”