Marmots, landscape change and predation : the conservation biology of North America’s rarest mammal. Sourki, izmenenie landchafta i khichtchnitchestvo : sokhranenie redkikh mlekopitaïouchtchikh severnoï Ameriki. [Marmottes, changements de paysage et prédation : biologie de la conservation des plus rares mammifères américains].

Résumé

The Vancouver Island marmot (Marmota vancouverensis) is probably North America’s most endangered mammal. The wild population of this island endemic has declined from over300 individuals during the 1980s to fewer than 35 individuals at present. The species also provides an unusual case study in conservation. Apart from climate-vegetation change over lengthy time scales, there has been no direct « loss » or « destruction » of habitat. However, the small habitat patches in which marmots live are embedded in a landscape matrix that has exceptionally high economic value (commercially valuable forests), and the landscape has been extensively modified by clearcut logging. Populations of predators such as wolves (Canus lupus) and cougars (Puma concolor), together with prey species such as Black-tailed deer (Odocoileus hemionus), have also changed dramatically. The result has been unsustainably-high levels of predation and near-extinction of marmots in the wild. Fortunately a captive-breeding program, established literally at the last minute in 1997, has apparently been successful at preventing extinction. However, restoring wild marmot populations also represents a conservation challenge on several levels. The first challenge is to raise sufficient marmots in captivity to furnish the raw material for reintroduction. Evidence to date suggests that this challenge will be met. The second challenge is to remove the proximate cause of decline by reducing current losses from predation. The third and largest, challenge must be to determine how the already-modified landscape can be managed in such a fashion as to allow marmot population processes (births, deaths and between-patch dispersal) to return to more sustainable levels. Here I report on the encouraging progress so far made in captive-breeding and reintroducing marmots, and discuss the options for short and long-term landscape management.