The Small Mammals of Isle of Wight County, Virginia, as Revealed by Pitfall Trapping

Abstract

In a study conducted in mid-winter, pitfall traps were used to assess the small mammal communities on 14 grids set in open habitats in Isle of Wight County in eastern Virginia. In all, 136 shrews of three species and 103 rodents of five species were trapped. Least shrews (n= 110) comprised 46 percent of small mammals and 80 percent of shrews. Eastern harvest mice (n=62) were the most common rodents. Reproduction was detected only in pine voles and southern bog lemmings. The majority of small mammals of the region were trapped during this month-long study. INTRODUCTION As part of a study to determine the western extent of populations of the then federally threatened Dismal Swamp southeastern shrew, Sorex longirostris fisheri, I conducted a survey of small mammals in Isle of Wight County, located just west of the City of Suffolk and lying approximately 40 km west of the Great Dismal Swamp National Wildlife Refuge in eastern Virginia. Using a standard protocol to study the Dismal Swamp southeastern shrew, an assistant and I established 14 study grids at different locations throughout the county. Trapping between 6 January and 6 February 1992, we collected 239 small mammals of eight species. This report relates the details of the types of small mammals, and their associations, in a coastal plain county in eastern Virginia. MATERIALS AND METHODS The southeastern shrew, the species of particular interest, is known to achieve greatest numbers in early successional habitats, such as oldfields, recently clearcut forests, and sites that are infrequently mowed (Rose et al. 1990). Powerline rights of way provide excellent habitat for such small mammals because they are mowed at 3-5 year intervals to prevent excessive growth of shrubs and trees, thereby continually setting back biological succession and promoting the persistence of perennial grasses and other herbaceous plants. Furthermore, because powerlines cross roadways, these habitats are easily reached, an additional benefit. Several high-voltage powerlines form a network across Isle of Wight County (Figure 1 ), many radiating from the Surry Nuclear power plant located on the south side of the James River. Thus, wherever county roads crossed the 30 m wide powerlines, I examined the vegetative stage of the habitat and usually was able to establish one or two study grids nearby. The trapping grids were placed on sites with vegetation that is typical of early succession in the region. Grasses, mostly in the genera Andropogon, Panicum, and Uniola, dominated the vegetation of most grids, but sedges (Carex spp.) and even softrushes (Juncus spp.) were present on wetter places. Many grids had American cane (Arundinaria gigantea) and other woody elements, such as brambles (Rubus spp.), Jananese honevsuckle {f,onicera ianonicat and tree seedlings_ esneci::illvofsweet P-11m Virginia Journal of Science, Vol. 56, No. 2, 2005 http://digitalcommons.odu.edu/vjs/vol56/iss2 1111 84 VIRGINIA JOURNAL OF SCIENCE