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Despite a reduction in exploitation of Atlantic salmon stocks, there continues to be a decline in many populations. The factors regulating these populations remain poorly understood, although contamination of the freshwater environment has been implicated as a causative factor. The major aim of these studies was to investigate the impact of environmental contaminants on salmon throughout their life cycle. Laboratory studies were carried out to assess the impact of environmental levels of pesticides (atrazine, cypermethrin 1'. and diazinon); brominated flame retardants (hexabromocyclododecane, HBCD and Tetrabromobisphenol A, TBBPA); and the pharmaceutical caffeine, on salmon during smoltification, reproduction and embryo development. Exposure to 5.0jlgrl atrazine for 81 days in freshwater reduced migratory activity over a 28 day period that coincided with the peak smolt run, while exposure to caffeine for 5 days in freshwater had an impact on the osmotic balance ofthe smolts, but this was not sufficient to induce mortalities upon transfer to seawater for 24 hours, either individually or in combination with HBCD. Exposure to 5ngrl HBCD over the peak smoltification period (30 days) did disrupt plasma thyroid hormone levels, although HBCD and TBBPA had no impact on olfactory responses in mature male salmon parr. Atrazine had no effect on plasma sex steroid levels in adult female brown trout, although exposure to environmental levels for 5 days prior to ovulation reduced the survival of the fertilised eggs, particularly when fertilisation occurred in atrazine-spiked (0.5jlgrl ) water. Fertilisation of gametes in water containing cypermethrin and diazinon (2 minute exposure) also affected both the number of fry that emerged and the timing ofthat emergence. The results of these studies show that the presence of common contaminants within the freshwater environment can have impacts on the physiology and behaviour of salmon. These impacts may affect the ability of salmon to survive at sea 'and to return to the natal river to successfully spawn. This may have significant implications for salmon populations in the wild.

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This thesis is concerned with the study of land use pattern, and landscape value in terms of ecological and economic components, using Classification And Regression Tree analysis and a choice experiment to quantify the ecological and economic values of land use pattern respectively. The Chiltern Hills and the Red Kite (Milvus milvus) are chosen for study, as they are an important landscape and species within the UK, as recognised by various legislations, and are readily identifiable. A Classification Tree model of the Red Kite nest occurrence in the Chiltern Hills in the UK is determined and applied to future land use scenarios, derived from Reading University’s Land Use Allocation Model (LUAM). A Model Tree model of the Red Kite nest abundance is determined and applied to the same scenarios. The population is deemed to be stable in the face of divergent land use scenarios, and the reestablishment is thus opined to be successful, having created a sustainable population. A questionnaire survey of Chiltern Hills users is conducted to determine the characteristics of the users, and features of the landscape deemed important in making a day trip. The results are used to inform the creation of the variables and levels of those variables for use within a choice experiment. A choice experiment is conducted to determine the values of site features in terms of landscape, species, and available facilities for the recreational use of the countryside. The Red Kite, hilltops, and woodlands are valued by the public. Willingness to Travel estimates of the attributes are plotted to a map, which may be the first time this has occurred from choice experiment estimates. Willingness to Pay estimates are also derived, and used to suggest that the re-establishment has recouped its costs.

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