The ecology of the European hedgehog (Erinaceus europaeus) in rural Ireland

This study on the ecology of Irish hedgehogs (Erinaceus europaeus) has provided information on detection techniques, home range, habitat selection, hedgehog prey, nesting, courtship, genetics, road mortality, parasites, ageing and morphology of this species. Data were obtained from a focal study area in rural Cork, in which 24 radio tagged hedgehogs were monitored from June 2008 to June 2010. Further data were obtained through road kill surveys and the collection of hedgehog carcasses from around Ireland. Hedgehogs of both sexes were found to display philopatry. Habitat was not used in proportion to its availability, but certain habitats were selected and a similar pattern of habitat selection was evident in successive years. Hedgehogs preferred arable land in September and October and, unlike studies elsewhere, were observed to forage in the centre of fields. Badgers were regularly seen at the study site and did not appear to negatively affect hedgehogs’ use of the area. Instead the intra- and inter-habitat distribution of hedgehogs was closely correlated with that of their potential prey. Male hedgehogs had a mean annual home range of 56 ha and females 16.5 ha, although monthly home ranges were much more conservative. Male home range peaked during the breeding season (April-July) and a peak in road deaths was observed during these months. The majority of road kill (54%) were individuals of one year old or less, however, individuals were found up to eight and nine years of age. Genetic analysis showed a distinct lack of genetic variation amongst Irish hedgehogs and suggests colonisation by a small number of individuals. The ectoparasites, Archaeopsylla erinacei, Ixodes hexagonus and Ixodes canisuga were recorded in addition to the endoparasites Crenosoma striatum and Capillaria erinacei. In light of the reported decline in many areas of the hedgehogs’ range, it is a species of conservation concern, and this is the first study examining the ecology of the hedgehog in Ireland.

Studies relating to the population dynamics of the European badger (Meles meles) in Ireland

European badgers (Meles meles) are an important part of the Irish ecosystem; they are a component of Ireland’s native fauna and are afforded protection by national and international laws. The species is also a reservoir host for bovine tuberculosis (bTB) and implicated in the epidemiology of bTB in cattle. Due to this latter point, badgers have been culled in the Republic of Ireland (ROI) in areas where persistent cattle bTB outbreaks exist. The population dynamics of badgers are therefore of great pure and applied interest. The studies within this thesis used large datasets and a number of analytical approaches to uncover essential elements of badger populations in the ROI. Furthermore, a review and meta-analysis of all available data on Irish badgers was completed to give a framework from which key knowledge gaps and future directions could be identified (Chapter 1). One main finding suggested that badger densities are significantly reduced in areas of repeated culling, as revealed through declining trends in signs of activity (Chapter 2) and capture numbers (Chapter 2 and Chapter 3). Despite this, the trappability of badgers was shown to be lower than previously thought. This indicates that management programmes would require repeated long-term efforts to be effective (Chapter 4). Mark-recapture modelling of a population (sample area: 755km2) suggested that mean badger density was typical of continental European populations, but substantially lower than British populations (Chapter 4). Badger movement patterns indicated that most of the population exhibited site fidelity. Long-distance movements were also recorded, the longest of which (20.1km) was the greatest displacement of an Irish badger currently known (Chapter 5). The studies presented in this thesis allows for the development of more robust models of the badger population at national scales (see Future Directions). Through the use of large-scale datasets future models will facilitate informed sustainable planning for disease control.