DEMOGRAPHIC AND BEHAVIORAL-RESPONSES OF SOUTHERN FLYING SQUIRRELS TO EXPERIMENTAL LOGGING IN ARKANSAS

This study investigated responses of populations of southern flying sq uirrels to a range of experimental even-aged and uneven-aged timber-ha rvest 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; wheth er a disturbance threshold existed within the range of harvest practic es implemented beyond which squirrels would not nest on a stand; and w hether squirrels would show selection in the use of nest boxes in logg ed and unlogged habitats. Winter nest-box surveys were conducted in th e Ouachita National Forest, Arkansas, USA, in 21 15-ha stands represen ting three replicated groups of six silvicultural treatments (pine-har dwood 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 a fter harvest in 1994-1996. Neither densities of nesting squirrels nor use of boxes for nests or feeding stations differed among treatment gr oups prior to harvests. Densities declined on all harvested stands aft er treatment in 1994; during the same period population growth was obs erved on control stands. A partial rebound in squirrels' use of nest b oxes in some harvested stands occurred in 1995 and 1996. Prior to harv est, squirrels used boxes in all habitats in similar proportions. Afte r logging, frequency of box use in greenbelt habitat (unharvested buff er strips along intermittent streams) was significantly greater than i n 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 densitie s 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 sn ags 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 disturbanc e and resource depletion that is too severe for flying squirrel persis tence.