Methods for measuring populations of arboreal rodents.

Abstract

Three arboreal rodents are sensitive indicators of forest ecosystem function in the Pacific Northwest. The northern flying squirrel (Glaucomys sabrinus) is mycophagous, cavity-nesting, and a major prey of the spotted owl (Strix occidentalis). The red tree vole (Phenacomys longicaudus) is restricted to trees and may prove sensitive to forest fragmentation. The Douglas' squirrel (Tamiasciurus douglasi) responds sharply to fluctuations in conifer seed abundance. Live-trapping and mark and recapture methods can be used to estimate densities of northern flying squirrels and some other rodents in contiguous areas of homogeneous vegetation (stands). We recommend 10- by 1 0-meter grids with 40-meter spacing and two traps per station-one in a tree and one on the ground. Trapping should be done in spring or fall. Techniques are lacking for red tree voles; searching felled trees for nests holds promise. Direct observation can be used to obtain indexes of abundance for Douglas' squirrels.

Citation

Carey, Andrew B.; Biswell, Brian L.; Witt, Joseph W. 1991. Methods for measuring populations of arboreal rodents. Gen. Tech. Rep. PNW-GTR-273. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 24 p