Sh. Fritts et Ln. Carbyn, POPULATION VIABILITY, NATURE-RESERVES, AND THE OUTLOOK FOR GRAY WOLF CONSERVATION IN NORTH-AMERICA, Restoration ecology, 3(1), 1995, pp. 26-38
Theoretical work on population viability and extinction probabilities,
empirical data from Canis lupus (gray wolf) populations, and expert o
pinion provide only general and conflicting conclusions about the numb
er of wolves and the size of areas needed for conservation of wolf pop
ulations. There is no threshold population size or proven reserve desi
gn that guarantees long-term (century or more) survival for a gray wol
f population. Most theoretical analyses of population viability have a
ssumed a single, isolated population and lack of management interventi
on, neither of which is likely for wolves. Data on survival of actual
wolf populations suggest greater resiliency than is indicated by theor
y. In our view, the previous theoretical treatments of population viab
ility have not been appropriate to wolves, have contributed little to
their conservation, and have created unnecessary dilemmas for wolf rec
overy programs by overstating the required population size. Nonetheles
s, viability as commonly understood may be problematic for small popul
ations at the fringe of or outside the contiguous species range, unles
s they are part of a metapopulation. The capability of existing nature
reserves to support viable wolf populations appears related to a vari
ety of in situ circumstances, including size, shape and topography of
the reserve; productivity, numbers, dispersion, and seasonal movement
of prey; extent of poaching inside; degree of persecution outside; exp
osure to enzootica; attitudes of local people; and proximity to other
wolf populations. We estimate that a population of 100 or more wolves
and a reserve of several thousand square kilometers may be necessary t
o maintain a viable population in complete isolation, although 3000 km
(2) or even 500-1000 km(2) may be adequate under favorable circumstanc
es. In most cases, management intervention is probably necessary to as
sure the viability of relatively small, isolated populations. Because
most reserves may be inadequate by themselves to ensure the long-term
survival of wolf populations, favorable human attitudes toward the spe
cies and its management must be recognized as paramount, and cooperati
on of neighboring management jurisdictions will be increasingly import
ant.