Revised Recovery Plan for the Vancouver Island Marmot (2000).

Résumé

The purpose of this document is to reassess the goals, objectives and tasks of the initial National Recovery Plan for the Vancouver Island Marmot (Janz et al. 1994), and provide an overview of changes needed to achieve down-listing of Marmota vancouverensis from endangered status. The original recovery goal of 400-600 marmots dispersed in three metapopulations on Vancouver Island has not changed and remains justifiable on geographic, habitat, genetic and demographic grounds. New data have clarified past and present marmot distribution and abundance. Inventory techniques are now properly developed and the population status of this animal is well known compared to most other species at risk in British Columbia. Within the « core » metapopulation south of Alberni Inlet, populations have declined by approximately 60% in the last decade. Marmots disappeared from the western Strathcona metapopulation within the last several decades, and the Forbidden Plateau metapopulation is now represented only by small colonies on Mount Washington. The entire population of the species was estimated at fewer than 100 individuals in 1998, of which >50% live in recently logged habitats. The spatial structure of colonies has changed in response to logging of high elevation (>700 m) forests. Additional colonies will probably continue to be formed and found, but it is unlikely that significant populations remain undiscovered. It is difficult to determine why marmots disappeared from areas north of Alberni Inlet because so few historical (1900 to present) population data exist. Contributing factors may include weather, predators, changing patterns of climate, predation, disease, hunting by humans, and reduced landscape connectivity. Empirical evidence for any of these processes is weak. Apart from concluding that post-glacial forest succession has generally reduced the amount of potential marmot habitat, we know only that disappearances occurred relatively recently. South of Alberni Inlet, forestry has produced dramatic effects on populations. Survival of marmots is lower in clearcuts and logging has apparently inhibited dispersal movements by providing « easy » alternative places in which to settle. The most important result of forestry was to concentrate the population, thereby increasing the risk of mortality from other factors. Wolves, cougars and golden eagles prey upon marmots. Radio-telemetry indicates that predation has played an important role at some colonies. The significance of parasites and infectious disease remains unclear although mortality has been associated with some parasitic and bacterial infections. Survival data are consistent with a hypothesis of localized mortality factors such as disease or hunting patterns by individual predators. Mark-recapture work suggests that most mortality occurs during winter hibernation, particularly in clearcuts. Weather plays a role but explains only a small amount of the variation in survival rates. There is no evidence to suggest that reproductive rates have declined. Survival rates have declined and the frequency of high-mortality episodes has increased. Most research objectives contained in the 1994 Recovery Plan have been met although population objectives have not. Population distribution, trends, and ecology are now reasonably well understood. Health issues constitute the most important unanswered research questions. Progress has been made towards characterizing potential reintroduction habitats although more work is required. With a handful of exceptions, additional habitat protection or habitat manipulation is not required. Experience on Vancouver Island and elsewhere supports the belief that reintroduction presents a realistic management tool. Substantial progress has been made towards increased public awareness, funding and political support. Changes to the 1994 recovery plan : Much of the initial plan was focused on activities designed to de