Jf. Taulman et al., DEMOGRAPHIC AND BEHAVIORAL-RESPONSES OF SOUTHERN FLYING SQUIRRELS TO EXPERIMENTAL LOGGING IN ARKANSAS, Ecological applications, 8(4), 1998, pp. 1144-1155
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.