The effect of culling on a roe deer (Capreolus capreolus L.) population
The impact of three different culling regimes on a roe deer ( Capreolus capreolus) population in a Scottish commercial forest was investigated. For three years, two sites within the forest were unshot ('Unculled'). At two other sites, culling was maintained at pre-study levels ('Normal cull'), and on two further sites the deer were heavily culled ('Heavy cull'). Deer densities on the 'Unculled' sites increased while they were unshot, but on the others changes in deer densities were variable. The cull on the 'Heavy cull' sites often exceeded the deer density. However, deer numbers on the called sites never declined below approximately half the previous years' density, suggesting that the sites were rapidly recolonised. In the final study year, all sites were shot to obtain comparative data on age structure, reproductive performance and physiological indices (size, weight and condition) of the deer under the ceiling regimes. Weights of kids and male deer declined as the level of culling increased. The deer's diet also broadened with increased culling. The decline in weight was possibly due to the deer changing their foraging behaviour in response to the increased risk of being shot. Deer densities were calculated for the whole forest. These declined from 10.9 to 4.8 deer km-2, indicating the total cull exceeded the population's recruitment rate. There was no yearly variation in the reproductive performance or physiological indices, suggesting the total population was below the threshold when density-dependent effects began. There was significant variation in the density of deer between habitats. Deer numbers declined in all habitats during the study, with the greatest decline on Restock, attributable to its open nature, making deer more vulnerable there. There was significant variation in kid body weights and condition for deer living in different habitats. The different deer density and physiological indices between habitats were probably related to the decline in food availability with canopy-closure.