Ecology of a landscape-scale deer assemblage

This thesis investigates the ecology of a multi-species ungulate assemblage and their impacts to inform management in commercial forestry (Thetford Forest, eastern England, 195km2). The aims were to analyse environmental factors influencing deer densities, to identify the species causing the greatest damage to young crop plantings, and to analyse how habitat, landscape context and intra- and inter-specific competition affect roe deer performance. Local roe and muntjac densities (collected in 2018) were related to habitat, landscape context and recreation. Roe deer densities were higher in young (0-5 since planting) stands and lower closer to grasslands and in areas of high recreational activity. Muntjac densities were higher in mature (≥46 years) stands, on calcareous soils, and with high recreation, while being lower closer to grasslands. Effects of local species-specific densities (from 2018 to 2020) of muntjac, roe, fallow deer and large deer (comprising fallow and red deer) on scots pine (Pinus sylvestris) leader browsing were assessed while controlling for hares presence and ground vegetation. More pine leaders were browsed in localities with higher densities of fallow or ‘large’ deer. Using a long-term dataset (2002-2015) we analysed effects of habitat and landscape context on roe deer fertility and body mass. Yearling and adult roe deer were more fertile when heavier; adult body mass was higher closer to arable lands, however, adult fertility was lower closer to arable. Relative importance of intra- and interspecific competition of fallow deer and muntjac on the condition and fertility of adult roe deer was tested using data from 2011-2016. Densities of muntjac were negatively related to fallow deer densities. Roe deer fertility was lower at higher muntjac densities, while being higher at higher roe deer densities. Roe deer are, therefore, subject to inter-specific competition from muntjac while intra-specific competition wasn’t detected. This is among the first studies showing effects of inter-specific competition of introduced species on reproductive output of a native vertebrate. Deer management should focus on reducing large deer and introduced species numbers to reduce impacts on regeneration and alleviate interspecific competition on native roe.