Synchrony in a Wild Turkey Population and its Relationship to Spring Weather

Abstract

Abstract: Synchrony is an important component of wildlife population dynamics because it describes spatial pattern in temporal population fluctuations. The strength and spatial extent of synchrony can provide information about the extrinsic and intrinsic forces that shape population structure. Wild turkey (Meleagris gallopavo silvestris) populations undergo annual fluctuations, possibly due to variation in weather during the reproductive season. To determine if spring weather plays a role in synchronizing wild turkey populations, we used a modified Mantel‐type spatial autocorrelation procedure to measure the synchrony in fall wild turkey harvest data collected in 443 townships from 1990 to 1995 and compared this to the pattern of synchrony in spring weather variables (May rainfall and temp) over the same period. We measured correlation using Spearman correlation coefficients between the total fall harvests from 1990 to 1995 for each pair of townships, and sorted pairs into 6 50‐km distance intervals. We calculated a mean correlation coefficient for each interval and estimated its P‐value using resampling. We found moderately significant synchrony in the fall harvest (rs = 0.12‐0.34, P < 0.008) among township pairs <150 km apart, but no significant synchrony beyond this distance. In contrast, both May temperature (r = 0.82‐0.90, P < 0.001) and rainfall (r = 0.49‐0.76, P < 0.001) were strongly synchronized across all 6 distance intervals. Visual inspection of time series in the wild turkey fall harvest suggests that populations may be synchronized in some years when weather promotes high reproductive success (i.e., a synchronized growth peak) and asynchronous in other years. Knowledge of the spatial dynamics of wild turkey populations will aid wildlife managers in estimating population change, setting harvest quotas, and managing habitat.