GRAY WOLF POPULATION PROJECTION WITH INTRASPECIFIC COMPETITION

摘要

Competition effects are incorporated into a model of wolf-population dynamics. A classic single-state model is augmented into a dual-state mapping of the evolution of the size of wolf packs and the number of wolf packs. This dual-state model, unlike the single-state density dependent model, is amenable to analyzing intraspecific competition. The single-state, dual-state and dual-state with competition models are estimated using Yellowstone National Park (YNP) data on wolf populations and pack structures from 1996 to 2011. The dynamic properties of each model are examined under an array of harvesting policies. Results suggest that intraspecific competition matters when projecting wolf populations. Wolf pack removal has competition-reducing effects from added territory availability, making populations more sensitive to pack size reduction than reduction in the number of packs. This research suggests that wildlife managers may consider monitoring the composition of wolf kills throughout a harvesting season, adaptively adjusting harvesting quotas and delineating harvesting zones over a few pack territories rather than spreading these effects evenly across all packs.