The Diamondback: Threatened Species?



The Eastern Diamondback Rattlesnake (Crotalus adamanteus) is a large and iconic predator of the
southeastern United States. Historically ranging throughout much of the Coastal
Plain, from eastern Louisiana to southeastern North Carolina, and south through
Florida and the Keys, the Eastern Diamondback Rattlesnake is experiencing rapid
population declines.

Primarily an inhabitant
of the longleaf pine ecosystem, eastern diamondback rattlesnakes have suffered
greatly from the loss, fragmentation, and degradation of this habitat, as less
than 5% of the longleaf pine ecosystem remains today. Several other species
that rely on this habitat have already been listed as threatened or endangered
under the endangered species act (ESA), including the Flatwoods Salamander (Ambystoma
, Gopher Tortoise (Gopherus polyphemus), Indigo
Snake (Drymarchon couperi), and Red-cockaded Woodpecker (Picoides
. The Eastern Diamondback Rattlesnake may be next.

to the decline in Eastern Diamondback Rattlesnakes, a petition was filed to the
United States Fish and Wildlife Service (USFWS) for them to be listed as a
threatened species under the Endangered Species Act (ESA). The petition
prompted the USFWS to conduct a 90-day review, the first step in determining if
the listing of a species as threatened or endangered is warranted (the full
90-day review can be accessed at href=””>
The USFWS examined the available information to determine if there is
substantial evidence in one or more of five different categories of threats to
warrant listing.

  Enlarge PhotoEastern Diamondback Rattlesnake
basking in the dunes

The five categories examined are (A) The present or threatened
destruction, modification, or curtailment of its habitat or range; (B)
Overutilization for commercial, recreational, scientific, or educational purposes;
(C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms;
or (E) Other natural or manmade factors affecting its continued existence. The
USFWS 90-day review found that there was substantial information in four of the
five categories (A, B, D, and E) they reviewed. This substantial finding does
not, however, mean that the Eastern Diamondback Rattlesnake is now a threatened
species. The USFWS must now conduct a 12-month status review to determine if
the Eastern Diamondback Rattlesnake will indeed become a threatened species.

As a potentially
dangerous species, the idea of listing a rattlesnake under the ESA would no
doubt be controversial. Only one other rattlesnake has been listed previously,
the New Mexico Ridge-nosed Rattlesnake (Crotalus willardi obscurus),
which only occurs in a remote region in southeast Arizona and southwest New
Mexico where it is unlikely to cross paths with humans. The eastern diamondback
rattlesnake is much more likely to have run-ins with humans and if protected by
the ESA, it would become illegal to harass or kill them, even if they are found
around your home.

the Eastern Diamondback Rattlesnake were to be listed as a threatened species,
they would not only be protected from direct persecution from humans, but habitats
critical to their survival would also be designated. One potentially critical
habitat is coastal dune systems on barrier islands. Eastern Diamondback Rattlesnakes are known to reside on many of the barrier islands throughout
their range, and often have healthy populations. But these islands are also
popular development areas for tourism and second homes.

The Orianne Society we are currently studying how development of these barrier
islands impacts Eastern Diamondback Rattlesnake populations by conducting
surveys across a number of islands that encompass a range of development
intensity. The results of this research will enable us to
better management decisions for this potentially threatened species.