Effects of culling fox populations at the landscape scale: A spatially explicit population modeling approach.
Abstract
Understanding how culling practices impact target populations is essential in identifying optimum strategies for controlling population size. Red fox (Vulpes vulpes) populations are subject to attempted control throughout much of their range due to their impacts on livestock and game, and disease transmission (e.g. rabies); however, the efficacy of different methods in controlling fox populations is low. For mesomammal species, experimental approaches are often limited by issues of scale. We used an individual-based, spatially explicit population model to investigate the efficacy of different culling practices in artificial landscapes. Model outputs were the number of social groups, the fox population before and after breeding, the extent of successful dispersal within the landscape, and the number of migrants out of the landscape. We investigated 4 different population management strategies using our model: 1) hunting with hounds, 2) winter shooting, 3) culling at the den in spring, and 4) fertility control. Population density in the absence of control was most strongly related to carrying capacity and the extent of immigration from surrounding fox populations. Culling at the den was most successful at suppressing fox populations, while fertility control was least effective, but the effect depended on the carrying capacity of the landscape. We conclude that effective control of populations at landscape scales (e.g., 1,600 km2) is not feasible or practical unless immigration from outside populations is low or can be controlled. These results can be used to inform policy on the management of United Kingdom (UK) fox populations and contribute to the ongoing debate on hunting with hounds as practiced in the UK.