Long-term Population Trends in White-Footed Mice and the Impact of Supplemental Food and Shelter

摘要: Central to most models of population regulation is the idea that degree intraspecific competition in some way proportional availability limiting resources. Although laboratory research has demonstrated a number proximate mechanisms by which behavior might affect growth, little known about resources are actually density field or how animals compete for them. Long-term studies reveal white-footed mouse, Peromyscus leucopus , exhibits two types pronounced changes density: intra-annual (seasonal) and inter-annual. The former seem be due ultimately climate lack winter breeding, but populations often decline sharply late summer midst plentiful food; fall recruitment new density-dependent usually poor. Differences peak densities from one year next as high 13-fold have been recorded. Weather, shelter, food possible ultimate Food received themost attention, supplemental feeding experiments yielded mixed results. A review social this polygnous species suggests each sex limited different combinations factors. Females may defend source nest sites; males search actively females at low adult densities, covering large areas, access densities. Additional long-term needed, both provide direction on data base understanding role weather, food, shelter Enough short-term published permit comparisons across habitats through time will give better perspective habitat variables. Field necessary demonstrate operation behavioral, physiological, genetic natural populations.