Abstract

Large mammalian herbivores have reached such high densities in many temperate regions that culling is frequently used to reduce their impacts on vegetation. However, little is known about the long-term responses of ecosystems to landscape-level reductions in herbivore densities. The responses of ecosystems to herbivore removal may have important implications for global carbon sequestration in plant biomass. I use long-term permanent monitoring plots to compare the effects of deer (Cervidae) culling on vegetation change in New Zealand, Canada, and England, in order to predict whether ecosystems can recover from deer-disturbance. Forest simulation models provide an important tool for predicting the outcomes of deer management and I develop a spatially explicit forest simulation model to predict the spread of upland birchwoods in the central Scottish Highlands in response to deer browsing pressures.

My results suggest that even low deer densities may restrict vegetation recovery, and therefore, restoring herbivore-disturbed ecosystems may not only require patience but a range of active management strategies.