Demographic and behavioral responses of southern flying squirrels to experimental logging in Arkansas

Abstract

This study investigated responses of populations of southern flying squirrels to a range of experimental even-aged and uneven-aged timber-harvest practices along a gradient of increasing disturbance intensity. The goals were to determine whether measurable demographic parameters of squirrels in experimental forests would change after logging; whether a disturbance threshold existed within the range of harvest practices implemented beyond which squirrels would not nest on a stand; and whether squirrels would show selection in the use of nest boxes in logged and unlogged habitats.

Winter nest-box surveys were conducted in the Ouachita National Forest, AR, USA, in 21 15 ha stands representing three replicated groups of six silvicultural treatments (pine-hardwood single-tree selection; pine single-tree selection; pine-hardwood shelterwood; pine shelterwood; pine-hardwood seed tree; and pine seed tree), plus an unaltered control during 1993, prior to harvest, and after harvest in 1994-1996. Neither densities of nesting squirrels nor use of boxes for nests or feeding stations differed among treatment groups prior to harvests. Densities declined on all harvested stands after treatment in 1994; during the same period, population growth was observed on control stands. A partial rebound in squirrels' use of nest boxes in some harvested stands occurred in 1995 and 1996. Prior to harvest, squirrels used boxes in all habitats in similar proportions. After logging, frequency of box use in greenbelt habitat (unharvested buffer strips along intermittent streams) was significantly greater than in harvested areas. On control stands the ratio of boxes used to those available did not change throughout the study. The ratio of boxes used per squirrel increased on harvested stands, even as squirrel densities declined, indicating a reduction in natural nesting resources after logging. The presence of mature forests adjacent to harvested stands, as well as retention of greenbelt habitat, overstory hardwoods, and snags within harvested areas, reduced the severity of logging impacts on flying squirrels. The seed-tree harvest regime, particularly without retained overstory hardwoods, appears to produce a level of disturbance and resource depletion that is too severe for flying squirrel persistence.

Citation

Taulman, James F.; Smith, Kimberly G.; Thill, Ronald E. 1998. Demographic and behavioral responses of southern flying squirrels to experimental logging in Arkansas. Ecological Applications. 8(4): 1144-1155.