Changes In Small Mammal Communities Research Articles

Effects of forest fragmentation on small mammals in an Atlantic Forest landscape

Recent studies on the effects of tropical forest fragmentation indicate that fragmented landscapes are complex and heterogeneous systems influenced by factors other than the size or degree of isolation of forest remnants: of particular importance are the quality of the matrix and the edge-induced habitat changes. In order to investigate the influence of these factors, small mammals were surveyed in 36 sites in the landscape of Una, a region that encompasses some of the last and largest Atlantic Forest remnants in northeastern Brazil. Six sites were distributed on each of six landscape components – the interiors and edges of small remnants, the interiors and edges of large remnants, and the most common forested habitats found in the matrix. The survey comprised 46,656 trap-nights and yielded 1725 individuals of 20 species of rodents and marsupials. Results revealed: an increase in beta-diversity caused by fragmentation; the contrasting effects of the altered forested habitats of the matrix, which harbor both forest and disturbance-adapted species; a greater importance of edge effect than of patch size to the observed changes in small mammal community in remnants; an association among terrestrial forest species and among arboreal forest species in terms of the distribution and abundance in the Una mosaic; and a distinctive vulnerability of these two groups of species to fragmentation. Results emphasize the biological importance and conservation value of both fragmented landscapes and small remnants in the Atlantic Forest, as well as the importance of management techniques to control and attenuate edge effects.

Small Mammal Communities Associated with Pine Plantation Management of Pocosins

To assess how habitat alterations can affect community structure, we compared small mammal populations in undisturbed pocosins with those in pocosins managed as pine (Pinus spp.) plantations. We used snap traps and pitfalls to sample small mammals in 3 pine plantations and 2 undisturbed pocosin habitat types in eastern North Carolina from May 1991 to May 1992. Small mammal community composition differed (P 0.05) an effect of plantation management on species associated with pocosins (short-tailed shrew [Blarina brevicauda], southeastern shrew [Sorex longirostris], cotton mouse [Peromyscus gossypinus], golden mouse [Ochrotomys nuttalli], white-footed mouse [P. leucopus]), possibly because pocosin-like habitat persisted in managed stands. Alternatively, the study design may have lacked statistical power to detect negative responses to disturbance evident in capture trends for these species. We hypothesize that management-related disturbance causes short-term declines or local extinctions of some small mammals, associated with pocosins, which later recover or recolonize. To minimize small mammal community changes associated with disturbance, we recommend managing habitat structure in pine plantations to emulate habitat of undisturbed pocosins.

Changes in small mammal communities after fire in northcentral Ontario

Changes in small mammal communities after fire in northcentral Ontario

Changes in small mammal communities after logging in north-central Ontario

Changes in small mammal communities following logging were monitored in clear-cut and strip-cut upland black spruce (Picea mariana) stands and in selectively cut mixed wood stands in north-central Ontario. Clear-cutting and subsequent scarification essentially eliminated the vegetative cover. Much of the ground cover recovered within 5 years and shrubs within 12 years, but mosses and lichens took much longer. The small mammal community in both clear-cut and strip-cut stands changed over the first three years after logging from one dominated by southern red-backed voles (Clethrionomys gapperi) to one dominated by deer mice (Peromyscus maniculatus) and then remained relatively stable for up to 13 years after harvest. That shift was not apparent in selectively cut mixed wood stands where the composition of the small mammal community was similar between uncut stands and stands 4–23 years after harvest. There was relatively little change in total numbers of small mammals after logging. In general, the diversity and evenness of small mammals increased or remained stable in the first 1–3 years following harvest, decreased on older (3–16 years) cuts, and then increased to values similar to those in uncut stands on the oldest (19–23 years) cuts.