of forage partially offsets the lower plant biomass at col-
ony sites, and the higher quality might help to explain the
preferential grazing at colony sites by American bison and
pronghorn (O’Meilia et al. 1982; Coppock et al. 1983;
Whicker and Detling 1988; Detling 1998).
Because it is a keystone species, conservation is impor-
tant not only for the prairie dog, but also for its grassland
ecosystem. The two are not necessarily synonymous. A con-
servation plan that specifies thousands of small colonies
scattered throughout the former geographic range, for ex-
ample, might support the longterm survival of prairie dogs.
But such a plan probably would not ensure the longterm
survival of either those species that depend on prairie dogs
or the ecosystem processes typical of the western grasslands.
Black-footed ferrets, for example, need largeprairie dog
colonies (Clark 1989; Miller et al. 1996). Similarly, moun-
tain plovers and burrowing owls are especially attracted to
large prairie dog colonies (Knowles et al. 1982; Knowles
and Knowles 1984; Olson 1985; Griebel 2000).
To promote the longterm survival of prairie dogs and
their grassland ecosystem, conservation biologists should
formulate plans that identify the minimal area that will al-
low not only the coexistence of prairie dogs and other or-
ganisms that associate with them, but also the ecological
processes discussed previously. But what is that minimal
area? Bigger is always better, but 4,000 hectares for a col-
ony site (or complex of nearby colony sites) is probably the
minimal area necessary for a fully functional grassland /
prairie dog ecosystem (Proctor et al. 2006). Density varies
among colonies (Biggins et al. 2006), but a colony that oc-
cupies 4,000 hectares usually contains100,000 adult and
yearling prairie dogs (Hoogland 1995; Proctor et al. 2006).
How Can We Save Prairie Dogs from Extinction?
In theory, the solution for saving prairie dogs is simple, and
it involves the following steps: (1) restore all the suitable
habitat that has been converted for farming and urban /
commercial development, (2) kill fleas at all colonies, and
thereby deter transmission of plague, (3) prohibit all poi-
soning and recreational shooting, (4) abolish the capture
and sale of prairie dogs as pets, and (5) change negative
attitudes toward prairie dogs. In practice, of course, these
steps are impractical and unrealistic. In this section I pro-
pose several steps that are more reasonable.
Identify focal areas
Restoring prairie dogs over their entire former geographic
range is impossible, but finding representative areas where
the grassland ecosystem can be restored is feasible (Proctor
et al. 2006; see also Miller et al. 1994; Wuerthner 1997). A
focal areais a locale where we can allow prairie dogs to oc-
cupy at least 4,000 hectares, with minimal impact on other
areas — so that species that associate with prairie dogs can
thrive, and so that ecological processes such as changes in
species composition and recycling of nutrients can occur.
Four criteria are important for the evaluation of poten-
tial focal areas (Proctor et al. 2006): (1) suitability of habi-
tat, (2) opportunities for management, (3) geography, and
(4) probability of plague. (1) Evaluation of the suitability
of habitat includes an examination of soil type, slope, and
height and type of vegetation. The best proof that habitat
is suitable for prairie dogs is to find colonies already there.
Consequently, the most promising regions for restoration
and conservation are those where prairie dogs currently live.
(2) Opportunities for management improve the suitability
of focal areas. Public lands — e.g., those belonging to the
Bureau of Land Management and the United States Forest
Service — offer tremendous potential for restoration and
management because they often occur in large, contiguous
blocks; they are not cultivated for crops; conservation of
biodiversity is a priority there; and large colonies of prairie
dogs already live there in many cases. Similar potential ex-
ists on certain private lands owned by groups interested in
the conservation of prairie dogs. Some of these groups are
Turner Enterprises (with lands in South Dakota, Kansas,
and New Mexico), The Nature Conservancy (Montana,
Wyoming, and Colorado), the Southern Plains Land Trust
(Colorado), and the Gray Ranch (New Mexico). (3) In or-
der to preserve possible genetic differences associated with
geography, the restoration and conservation of prairie dogs
should include focal areas distributed throughout the for-
mer geographic range, including areas at the periphery
(Lomolino and Smith 2001, 2003). (4) Finally, focal areas
should be sufficiently numerous and widespread to maxi-
mize the probability of long-term survival against plague.
Proctor et al. (2006) have identified eighty-four focal ar-
eas, ranging in size from 4,300 hectares to 2 million hect-
ares. Of highest priority are the five focal areas that are al-
ready inhabited by 4,000 hectares of prairie dogs; three
of these are on the Cheyenne River, Pine Ridge, and Rose-
bud Native American reservations in South Dakota. Second
in priority are the three focal areas where restoration of a
4,000-hectare prairie dog complex is currently underway:
Vermejo Park, New Mexico; Bad River, South Dakota; and
the Northern Cheyenne Reservation, Montana (USFWS
2002; Long et al. 2006). Most of the other focal areas are
on federal lands and already have prairie dogs, but the area
inhabited is usually 4,000 hectares.
For focal areas that currently contain no prairie dogs,
translocations from other areas will be necessary. For years
I have been telling people that 5% of translocated prairieConservation of Prairie Dogs 475