Effect of Harvest on Previously Unexploited Populations of Fox and Gray Squirrels

Effect of exploitation on sympatric southern squirrel populations has not been documented. Additionally, opportunities to study effects of harvest on unexploited populations are rare. Consequently, we investigated the effect of exploitation on a previously unharvested population of fox (Sciurus niger) and gray squirrels (S. carolinensis) on Twin Oaks Wildlife Management Area, Mississippi, from 1993-1998. We annually collected age, body morphometrics, color, sex, and species composition of harvested squirrels at voluntary check stations. A population decrease was documented for both species with stabilization occurring at different times (P≤0.001). Fox squirrel age ratio changed following exploitation (P=0.031), but color and sex ratios did not (P>0.05). Gray squirrels exhibited no change in age, color, or sex ratios following exploitation (P>0.05). Body morpho-metrics of both species were affected by exploitation (P≤0.003) and demonstrated a density dependent response. We hypothesized that exploitation reduced competition and allowed for increased body size. Fox squirrels exhibited reproductive compensation for exploitation, whereas gray squirrels did not. We hypothesized that gray squirrel compensation occurred through survival. Additionally, our data demonstrated that fox and gray squirrel populations in this study followed Caughley's (1985) partial compensation model.

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