Dl. Allen et Dl. Otis, RELATIONSHIP BETWEEN DEER MOUSE-POPULATION PARAMETERS AND DIELDRIN CONTAMINATION IN THE ROCKY-MOUNTAIN ARSENAL NATIONAL WILDLIFE REFUGE, Canadian journal of zoology, 76(2), 1998, pp. 243-250
A small-mammal capture-recapture study was conducted in the Rocky Moun
tain Arsenal National Wildlife Refuge to quantify the effects of soil
contamination with dieldrin on demographic parameters of deer mouse (P
eromyscus maniculatus) populations. Increased dieldrin concentrations
were significantly associated with larger deer mouse populations, alth
ough the size of populations on contaminated sites decreased during th
e study. The most parsimonious model for estimating survival rates was
one in which survival was a decreasing function of dieldrin concentra
tion. A significantly higher proportion of female deer mice in the pop
ulations residing on the more highly contaminated sites exhibited sign
s of reproductive activity. Development of genetic resistance in P. ma
niculatus to chronic chemical exposure is suggested as a possible mech
anism responsible for the species' observed dominance and relatively h
igh densities on contaminated sites. Under the additional stress of un
favorable environmental conditions, however, these populations may suf
fer disproportionately greater mortality. The design and analytical me
thods presented offer a rigorous statistical approach to assessing the
effects of environmental contamination on small mammals at the popula
tion level.