1. A study of the ecology of the native red squirrel (Sciurus vulgaris leucorus) was carried out in a mature Scots pine (Pinus sylvestris) plantation in East Scotland. 2. The aims of this study were:- 1)To determine the population size, its structure, and the dispersion of squirrels in a selected area of habitat. ii) To determine qualitatively and quantitatively the food eaten by that population. iii) To relate, where possible, the population findings to the food resources. 3. Consideration of the distribution of the red squirrel led to the conclusion that there is a habitat preference for mature conifer woodland, and that the red phase of this squirrel is associated particularly with Scots pine woodland. 4. A brief literature review showed that there had been no integrated study of the population dynamics and dispersion of the red squirrel, and only preliminary attempts to relate food resources to population density. 5. The advantages and disadvantages of the red squirrel for this type of study are considered. 6. The location, history, physical features, vegetation and fauna of the study area are described. 7. Approximately 93% of the I23 hectares of woodland consisted of mature pine, 39 to 49 years old, with about 1,400 trees per hectare. A gale midway through the study caused about 25% loss of trees due to windblow. 8. The past history and present distribution of the red squirrel in Scotland are sunmarised. Its fluctuations and relations with the grey squirrel are discussed. 9. A tentative classification of known behaviour patterns of th red squirrel is given for both individual and social behaviour. Relevant features of the basic biology are also reviewed. IO. Methods for the population study included live-trapping, field observation, drey surveying, and carcase examination. 11. Most of the population parameters estimated were based on data obtained from live-trapping, so a full account of these methods is given, including trap type and dispersion, trapping procedure, sex and age determination, and marking methods. 12. The squirrel's reaction to the trap is discussed and it is concluded that sampling approximated to random. 13. The population size was relatively stable at about 100 squirrels over three years. 14. Initially the sex ratio was equal, but became biased in favour of females, corresponding to excess recruitment of females. 15. The annual increment of young was between 20% and 40% of the total population, and the minimum turnover period was 4.5 to 5 years. After a high juvenile mortality before the weaning stage life expectancy was high, with slightly higher mortality rates amongst the older age classes. 16. Immigration and emigration apparently contributed little to recruitment and losses. 17. Methods for the feeding study included field observation, analysis of stomach contents, measurement of cone production and feeding signs, assessment of bark stripping damage, and the use of captive squirrels. 18. The production cycle of Scots pine is outlined. 19. The main and subsidiary foods of red squirrels are tabulated seasonally; they depend on Scots pine for seeds, buds, shoots, pollen ard vascular tissue, as well as for nesting sites and cover. 20. An increased use of ground food was made from March to July, as tree-borne seed was reduced by seedfall. Selection of cone sizes occurred, but this only affected the availability of the cone crop marginally. 21. Both live and dead trees were barked by squirrels; the vascular tissue below the bark was eaten as a subsidiary food source. 22. About one-third of the available cones, the main food source, was utilised for seed extraction, representing an intake of 5% of the body weight per day. Little over half of the daily activity period was spent feeding. 23. The available food was apparently not limiting population size, though the short potential critical period, when the main food source was depleted, coincided with the production of young. 24. Management recommendations for the control or conservation of squirrel populations are proposed, and suggestions for future work are given.

Molecular genetic studies of European seahorses revealed the presence of two native species (European long snouted seahorse Hippocampus guttulatus and European short snouted seahorse Hippocampus hippocampus) the primary focus of the present study. Ecological studies across the entire geographic range of the species confirmed low density and patchy population distribution. Habitat and holdfast preferences were different for the two seahorse species, with substantial variation between population locations. Morphological characteristics of the seahorses varied considerably across their range, but significant differences were observed within just one population of each species. No environmental parameters were consistent across all populations, and no specific indicators for seahorse presence were discovered. The tissue collection technique, fin clipping, was confirmed to not significantly affect seahorse mortality or growth; this technique was used for all tissue biopsies during this study. Genetic analysis using mitochondrial DNA sequences and data from five microsatellite markers revealed significant population structuring across both species' geographic range. Contemporary environmental factors for this structuring were both physical barriers to gene flow and geographic distance between populations. Most physical barriers identified have also affected other marine species; however a proposed barrier at Cape Finisterre, observed for both seahorse species, has previously only been documented in a few other species. Historic events appear to have influenced the contemporary structure of the two seahorse species differently, with H. hippocampus showing less population structuring. Population expansion and founder effects were seen in most geographic regions. Previously acknowledged refugia sites of the last glacial maximum were also seen in seahorses, but these were different in each species. Microsatellite markers revealed monogamy within broods and breeding cycles for the social polygamous H. guttulatus. Finally the findings of this study were used to suggest specific management and conservation practises for seahorse species across Europe.

The work presented in this thesis investigates the implications of migration strategies and choice of winter location in a population of a migratory shorebird, the Icelandic Blacktailed Godwit Limosa limosa islandica. Measures of the environmental conditions experienced by individuals in different parts of the winter range are used to explore the energetic trade-offs associated with choice of winter location. The costs of migrating different distances to the Icelandic breeding grounds are also explored, as winter locations range from Britain and Ireland to Iberia. These studies suggest that winter locations in the south of the range are energetically more favourable, and that the resources available at these sites are more than sufficient to fuel migration. However, Icelandic godwits wintering in Iberia have to fly more than twice the distance to reach Iceland than their conspecifics in the north of the winter range, and models of potential flight range indicate that most birds from Iberia have to stop and refuel during spring migration. Despite this, population-wide tracking of marked individuals indicates that godwits from southern winter locations are able to reach Iceland earlier than birds from more northerly winter sites. In the Iberian winter sites, Icelandic black-tailed godwits overlap with continental black-tailed godwits (Limosa limosa limosa), but detailed field studies in Portugal indicate clear habitat segregation between these two subspecies, with Icelandic godwits primarily foraging on estuarine mudflats and continental godwits foraging in rice-fields. Estuarine prey resources vary in availability and profitability and, as in most shorebird species, female godwits are larger than males and have higher energy requirements. Thus, the extent and implications of sex differences in distribution and resource use are explored in this thesis. Finally, the impact of ongoing efforts to reduce organic inputs to the Tejo estuary, west Portugal (the main Iberian winter site), on the distribution of black-tailed godwits and their invertebrate prey are explored.

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This study evaluates diet overlap between Himalayan brown bear and livestock, requirement and competition for forage resources and livestock impacts on habitat suitability for brown bear, economics of the grazing systems and opportunity cost of exclusion and conflicts between pastoralists and Himalayan brown bear. Research questions were tested between resident grazed buffer, nomad grazed buffer, nomad grazed core and ungrazed core. The study area comprised the Deosai National Park (hereafter referred to as the DNP, 2,950 krrr'), the contiguous Sadpara Wildlife Sanctuary (SWS, 300 km2) to the northeast, and the unprotected Chota Deosai (400 km2) to the south (Fig. 1; chapter 1). For the conservation of the Himalayan brown bear, the DNP is divided into strictly protected core zone where any pastoral activities are prohibited, surrounded by buffer zone grazed by resident and nomadic communities. However, nomadic pastoralists encroach upon the protected core and managed to maintain camps. The observed stocking density was greater in resident grazed buffer, followed by nomad grazed core. Resident pastoralists maintained higher stocking rates than the optimum stocking density suggesting their will to maximize income. Among all the grazing categories, off-take was significantly greater in resident grazed buffer. Livestock density was higher in resident grazed buffer than nomad grazed buffer and core. All the vegetation parameters studied showed impact of livestock grazing. Mean sward volume, species diversity (richness, equitability and Simpson's index) were significantly lowest in resident grazed territories. Total percent cover of grass and herb species was higher in ungrazed territories and lower in resident grazed buffer. Sward volume of the vegetation suggested impacts were similar between different grazing regimes. Buffer valleys grazed by residents experienced intense grazing pressure amounting to 90 % of potential biomass production, while buffer and illegally grazed core valleys used by nomads experienced lower but nevertheless substantial rates of biomass removal (40 - 50 %). Dietary overlap was very high between brown bear and each livestock class (Pianka's Index ranged 0.932 - 0.995) as well as among the different classes of livestock (0.891 - 0.983). Accumulated biomass and sward height (within exclosures) was greater in core areas than in the grazed buffer, suggesting that pastoralism has reduced sward productivity and .volume in grazed territories. Costs of livestock predation were less than US$ 973 (± 444 SD) yr") borne disproportionately by nomadic pastoralists, with those grazing within the strictly protected core were particularly vulnerable. Livestock predation, restricted access and crop raiding were the issues of conflicts pastoralist and brown bear. Estimated livestock production value was higher in the resident grazed buffer (35.6 US$ ha") than for nomads in the core (34.5 US$ ha") or buffer (17.4 US$ ha"). Total opportunity cost (2006 and 2007) under complete exclusion of livestock from. DNP scenario is expected to be 1,256,114 and 1,209,805 (US$) for nomads and resident communities respectively.