A study of white-footed mice (Peromyscus leucopus) in a dune habitat: distribution and seed predation.

Abstract

This study examined the distribution of white-footed mice (Peromyscus leucopus) in a heterogeneous environment and what influence that distribution had on seed predation levels in the different habitats created by environmental heterogeneity. The sand dunes along Lake Michigan were the site of the study. The dunes were divided into three basic habitat types based on vegetation types and abundances: a foredune habitat near the lake, an intermediate habitat on stabilized unforested dunes, and a habitat of forested dunes. Based on the data collected on twelve trap nights, I found that the density of P. leucopus on the foredune was significantly higher than would be expected by an even distribution and that it was lower than expected by an even distribution on the stabilized unforested dunes. It was also discovered that the foredune appears to be a suboptimal habitat since mice there had a significantly lower average mass than the mice living on the forested dunes. The similarity in distances between consecutive captures for the mice captured on the foredune and mice captured on the forested dunes suggests that the foredune may consititute a stable population of mice. In a related study, the levels of seed predation were examined across the dunes using seed-predation plots consisting of a petri dish containing ten white pine (Pinus strobus) seeds with two smoked cards adjacent to them. The seeds were eaten at almost all of the sites, and there were no signficant differences in the number of sites where seeds were eaten between the three habitats. This showed that the uneven distribution of P. leucopus on the dunes was not having a strong impact on the relative levels of seed predation in the three habitats. This was mainly due to the high number of other small mammals that were believed to be eating the seeds on the stabilized unforested dunes.