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Climate change is predicted to have huge impacts on the distribution of species, and the current rate of anthropogenically-driven climate change is of great concern to conservation biologists. Future climatic conditions are likely to affect all aspects of biodiversity from individuals to biomes, and although the field of climate change ecology is advancing, our knowledge of the impacts on biodiversity are hindered by methodological limitations. The main aim of this thesis was to assess the processes which contribute to the macroecology of the 'order Lagomorpha, in particular studying their interspecific interactions and the impact of climate change, whilst addressing methodological issues. Lagomorphs are comprised of 87 species of pikas, rabbits, hares and jackrabbits and are of great scientific and economic importance. They are especially important to study in terms of macroecology because they are extremely widespread, occupy a huge range of environmental conditions, a quarter of species are threatened and due to the relatively low number of species, compared to other mammalian orders an entire trophic level can be studied providing significant insights into food webs. However, the factors which lead to the importance of the order also suggest likely vulnerability to future climate change. In this thesis, the responses to future climate change are assessed at a species-level for the entire order using species distribution modelling techniques and projected future climate scenarios. These techniques are then improved to include interspecific interactions in the modelling of distributions, as well as environmental factors. Two-thirds of species are likely to be affected by climate change. with larger leporid species predicted to shift polewards with little overall change in range extent, but. smaller lagomorph species like pikas are predicted to shift upwards in elevation with dramatic declines in range. Interspecific interactions are common in the order and therefore incorporating them into models is vital. Interspecific interactions and environmental factors are shown to be equal determinants of species ranges and appear to be similar in terms of strength and direction at numerous scales, but the effects are spatially heterogeneous. Combining improved species distribution models with network analysis techniques provides more reliable estimates of climate change impacts on a community-level, and suggests high turnover and substantial changes in ecological network properties for lagomorphs.

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The European hare is a native of open grasslands in Europe and the Asian steppe. The species is a successful invader, and has been introduced to a large number of countries and small islands worldwide. It was introduced to Ireland in the mid-to-late 1800s for field sport. A substantial population was identified during 2005 in Mid-Ulster, a site with no records of introduction. Ecological Niche Modelling described the endemic Irish hare as being ecologically distinct from other mountain hare subspecies, and more similar to the European hare. Models of species-specific habitat use confirmed that the invader and the native are ecologically similar, with comparable niche breadths, and almost complete niche overlap. Under projections of predicted climate change, Irish hare niche space is projected to contract, and that of the European hare expand, by 2070. The range of the European hare in Northern Ireland expanded three-fold between 2005 and 2012-13. Spatial patterns in hare density and abundance describe an invasive-native species replacement process. The European hare has a consolidated core range where it outnumbers the native 5:1, often displacing it entirely. Analyses suggest that the European hare population of Mid-Ulster was introduced ca. 1970, and is dispersing at 0.73 km/year. There is some support for Government intervention (i.e. lethal culling), with a view to eradicating the European hare from Mid-Ulster. Support was strongest (66%) among members of Countryside Alliance Ireland. While support was lower among non-members (44%), systematic engagement and outreach may be effective in appreciably raising levels of support. Invasive European hares represent an immediate ecological threat to the endemic Irish hare. Rapid development and implementation of an invasive Species Action Plan (iSAP) is required if the impacts of the invader are to be effectively mitigated so as to prevent the loss of one of Ireland’s only endemic species.

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This thesis describes a twelve year study of the Skomer vole (Clethrionomys glareolus skomerensis) which highlighted remarkable similarities between the voles' biology and that of other island rodents. Capture-recapture trapping provided demographic data. The population fluctuated annually with a trough at the beginning and a peak at the end of the breeding season. There was no regular multi-annual population cycle. Densities between 58/ha and 475/ha were recorded. Most young were produced by over-wintered animals; few animals bred in the year of birth. The numbers of adult males present during the breeding season varied little from year to year; the number of adult females was more variable. A removal experiment showed that interactions with adult females did not prevent the maturation of females in the year of birth. The dispersion of adult males and females was random. Intrinsic population regulation was by reduced litter size, a shortened breeding season and delayed maturation of both sexes. Extrinsic factors appeared to influence the timing of the breeding season and the maturation of animals in the year of birth. Factors affecting the over-winter survival of females and the survival of young of both sexes during the breeding season were thought to be important in regulating the population. The animals required dense cover and were closely associated with bracken (Pteridium aquilinum) and bluebells (Endymion non-scriptus). Dense grass under the bracken led to a reduced vole population. The voles' diet consisted mainly of bracken, bluebells and grass; they ate little animal material. They had an annual fat cycle with a winter peak. Predation may have exerted a local effect but probably did not regulate the population. There was no link between haemoparasitic infections and fluctuations of the vole population. Infections with pneumotropic viruses may have played a part in limiting the population of voles.

For several centuries following their introduction into the British Isles by the Normans, rabbits were farmed on man-made warrens. The right to hunt rabbits during the medieval period was restricted to the highest strata of society and warrens, and rabbit products, carried connotations of wealth and exclusivity. During the post-medieval period, as rabbits became less expensive, their exclusivity declined and access to the species increased across a wider spread of the population. Consequently, later warrens tended to be purely commercial ventures that in places lingered as a form of animal husbandry up until the early twentieth century. Evidence of these warrens is particularly common across England and Wales and typically, although not exclusively, takes the form of pillow mounds, earthworks created to encourage rabbits to burrow. Despite their longevity and high numbers, warrens remain relatively little studied. This thesis investigates surviving warren architecture within south-west England, incorporating archaeological data into a GIS in order to identify the locational, morphological and typological trends of the region’s warrens. It also assesses associations between warrens and other classes of archaeology, notably elite residences and parks, large ecclesiastical institutions and prehistoric earthworks. Doing so allows for a better understanding of warrens’ roles within their immediate environs and of their relationships with other aspects of the human landscape. This study also addresses natural geographical aspects of the landscape in order to determine the principal factors that influenced where warrens were installed. This study investigates documentary reference to warrens as many have not survived within the landscape. Medieval chancery rolls in particular allow for the creation of a national framework of warrening so that the South West can be compared and contrasted to other regions of medieval England. Documentary references, both medieval and post-medieval, to the South West’s warrens allow for the creation of a discrete regional history that defines the context for the establishment of the region’s warren architecture. This study assesses how rabbits were interpreted by medieval society and discusses symbolism, particularly the visual role played by warrens in advertising their owners’ wealth and any possible religious concepts associated with rabbits.