Both the spatial and temporal patterns of disturbances can affect local populations in dynamic landscapes. Anthropogenic land-use activities often result in landscape pattern and dynamics that differ markedly from those of natural systems. Understanding the effects of the spatial and temporal patterns of anthropogenic disturbance can be critical for management of threatened populations. We used a spatially explicit individual-based population model (HexSim) to explore the potential effects of anthropogenic disturbance due to military training on the population of black-capped vireos (Vireo atricapilla, BCVI) at Fort Hood, Texas. The BCVI is an endangered species which inhabits patches of oak shrublands throughout the installation. Much of its habitat is also useful for military training. We generated a BCVI habitat map based on installation-wide BCVI surveys conducted in 2002-03 and applied disturbance scenarios varying in duration and spatial footprint. We then parameterized the HexSim model using eight years of detailed nesting and mark-recapture data. Finally, we simulated populations on the modified habitat maps and summarized population numbers and vital rates across simulations.
Results/Conclusions
Preliminary results indicate that BCVI populations are sensitive to the temporal and spatial components of training activities as represented by our scenarios. Intermediate levels of training frequency with smaller spatial footprints favored BCVI populations while larger, longer training operations negatively impacted BCVIs. Simulation-based analyses using spatially explicit population models such as HexSim provide a valuable tool for managers interested in ranking site-specific land-use alternatives.
