Population assessment of the mountain hares (Lepus timidus) of England: distribution, abundance and genetics

Bedson, Carlos PE (2022) Population assessment of the mountain hares (Lepus timidus) of England: distribution, abundance and genetics. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

In the 1870s a small founder group of mountain hares (Lepus timidus) was translocated from Scotland to the Peak District moors, England. They succeeded as a pioneer of rewilding for 150 years, playing important ecological roles within the upland ecosystem,. Nonetheless these mountain hares frequently went unmonitored. From 1971 to 2002 only four formal studies attempted distribution or abundance assessments. Subsequently there were doubts regarding the persistence of the population. In 2008 the species was added to UK Biodiversity Action Plan, which recommended ongoing monitoring. The aim of the thesis was to provide a fundamental assessment of this mountain hare population, informing conservation status reviews and enabling subsequent potential population viability analysis. The research draws upon a considerable amount of newly collected field observations, citizen science records, geographic information and laboratory investigations. I employ new survey methods, quantitative ecology, geospatial analysis and genetic techniques to describe the distribution, abundance and genetic structure of this population This work presents evidence that Peak District mountain hares occupy a geographically confined set of hills comprising ~360km2. They favour cold environments at high elevations and appear completely dependent on heather for food and shelter. Mountain hares frequent different habitats than their sister species, the European brown hare (L. europaeus), because of different climatic and dietary preferences. Accordingly, the main threats to mountain hares are climate change which may reduce their range by ~80%; and impending competition with European brown hares. Surveys of mountain hares are notoriously challenging, since this nocturnal cryptic creature may hide by day to avoid predators. To evaluate day and night time survey methods, I compared daylight transect surveys with night-time thermal imaging and camera traps operating 24 hours per day for 5 months. Census surveys using daylight visual sampling are shown to be highly effective and statistically reliable. Consequently, some 800km of surveys were conducted, covering much rugged difficult ground, with sufficient encounter rates to enable robust estimation of density, based on high detection probability, observing ~20% of the sampled hares to a range of 520m. These surveys showed the mountain hares as a stable population of ~3,500 individuals (winter adults), with one population centre concentrated on a few square kilometres. Densities are not randomly distributed and appear influenced by anthropogenic land use. Numbers in restored blanket bog areas are highest; upon managed grouse moors numbers are two thirds less. This finding notably contradicts most preceding mountain hare research from the UK. Research sourced genetic material, mostly roadkill mountain hares, provide matter for DNA extraction and microsatellite sequencing. Owing to technical challenges, results were partial yet appeared to indicate the mountain hare population is mostly randomly mating, having a diverse genetic population structure. There appears to be a low level of hybridisation with European brown hares. Continued monitoring of this Peak District mountain hare population is necessary to support UK biodiversity conservation goals. The mountain hare population experiences the normal ecological factors that govern natural population fluctuations: weather, food availability, predators, parasites, disease and population cyclicity. There is substantial human caused mortality from roads and persecution. These could be greatly reduced, if society were willing. This thesis may serve as primary reference for conservation assessments.