The effects of varying deer density on natural regeneration in woodlands in lowland Britain

Relatively little information is available to indicate how the impacts of deer vary in relation to densities of deer encountered in lowland environments in Britain. Population densities and impacts of deer on advance regeneration were therefore assessed at 15 sites, embracing a range of densities from 0 to 54.9 deer km(-2) in woodland and 0-74.5 km(-2) in adjacent fields. Deer densities tended to be higher on sites with drier and more fertile soils, a relationship which may have arisen for either nutritional or management reasons. The log seedling density was negatively correlated with deer density, relative use of woodland vs adjacent fields and deer species (expressed as a proportion of 'larger' species, mainly Fallow deer Dama dama). The abundance of smallest seedlings (< 30 cm tall) was also correlated with soil moisture content and tree canopy cover; however, these effects were not significant for larger seedlings (30-150 cm tall), which were instead associated primarily with deer variables. Seedling density declined most sharply at relatively low deer densities, indicating that advanced regeneration is particularly sensitive to deer presence. The results indicate that regeneration is most likely to be inadequate at densities above 14 deer km(-2).