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Sciurus niger niger (Southern Fox Squirrel) Density and the Diurnal Patterns, Occupancy, and Detection of Sympatric Southern Fox Squirrels and S. carolinensis (Eastern Gray Squirrel) on Spring Island, South Carolina

Amspacher, Katelyn, Bauer, Beau, Waldron, Jayme, Wiggers, Ernie, Welch, Shane
Southeastern naturalist 2019 v.18 no.2 pp. 321-333
Pinus palustris, Sciurus carolinensis, Sciurus niger, diurnal activity, diurnal variation, ecosystems, fire frequency, habitat conservation, habitat destruction, habitats, prescribed burning, probability, sympatry, temperature, South Carolina
Sciurus niger niger (Southern Fox Squirrel, hereafter, SFS) are habitat specialists within the Pinus palustris (Longleaf Pine) ecosystem of the southeastern US whose populations are declining due to habitat loss and fragmentation. Sciurus carolinensis (Eastern Gray Squirrel, hereafter, EGS) are generalists found throughout the eastern US that have historically avoided competition with SFSs through habitat-partitioning. Spring Island, SC, once reported the densest population of SFSs in the southeast, but residents of the island community recently reported decreasing SFS populations and increasing EGS populations. We used baited game-cameras at stratified random points to estimate SFS density, observe patterns of SFS and EGS diurnal activity, and examine the influence of habitat structure and management techniques (e.g., prescribed fire) on SFS and EGS occurrence on Spring Island. Our estimate of SFS density on Spring Island (0.28–0.97 SFSs/ha) was similar to the high density previously reported (0.758 SFSs/ha). SFSs and EGSs had similar diurnal patterns, but SFSs were most active around midday while EGSs were most active in early morning and evening hours. EGS occupancy was negatively associated with fire frequency. EGS detection probability was negatively associated with maximum daily temperature. These data suggest that habitat management via prescribed fire has allowed stable populations of both SFSs and EGSs to persist despite anthropogenic land changes.