What factors affect national-scale deer population dynamics in the Republic of Ireland?

Abstract

ABSTRACTResearch into deer population dynamics has mostly focused on community or landscape scales in the Republic of Ireland. However, in order to propose national deer management strategies to confront the increasing deer populations in recent years, a larger scale analysis of deer populations is necessary. In this inter-county, national study, generalised linear mixed models were utilised to examine the relationship between the harvest rate (defined as the numbers harvested per 100 ha in this study) data and factors identified in past research as contributing to deer population dynamics on a county basis, where annual county-level deer harvest records were used to reflect deer populations by species. The procedures were repeated for each species and significant factors and their impacts were identified for each county. The results suggested that multiple factors affect deer population dynamics; for instance, increases in forest cover tended to result in increases in deer populations of all species, and the presence of red and sika deer populations in a county had a positive influence on hybrid deer populations. National migration maps for each deer species were produced, as well as predictions of future population trends. The outcome of this study can be used to guide the development of a national deer management strategy and the prioritisation, on a regional basis, of deer control measures.