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The great crested newt Triturus cristatus is one of Europe's fastest declining amphibian species. This thesis aimed to increase our knowledge of the microhabitat use and ecology of great crested newts within a woodland area in the British Isles and suggest ways of improving measures for conservation. The study was conducted at Epping Forest Field Centre and surrounding deciduous woodland at High Beach, Epping Forest, which is situated to the north-east of London. Capture-mark-recapture of adults in four ponds over 5 years within a 1 km area revealed that great crested newts exhibited large fluctuations in detection probabilities, highlighting the importance of calculating detection before making inferences of population size or survival. Apparent annual survival was constant between ponds and years; male survival was 0.40 compared to 0.58 in females. Only 11 inter-pond movements were recorded. Many terrestrial juveniles occupied cover objects close to breeding ponds for many months of each year. Growth rates were fastest in smallest individuals (35.to 39 mm SVL) and juvenile body condition varied through each year. Juveniles had high monthly survival (0.56 to 0.77) and a low constant apparent annual survival of 0.19. Adult males exhibited lowest body condition index (BCI) in March and June while females had high BCI in March and lowest in April. Larger males with a higher body condition were more likely to possess taller crests. Experiments showed increased mortality in great crested newt embryos when raised in the presence of caged predatory sticklebacks compared to controls. Great crested newt larvae utilised vegetated microhabitats for a significantly greater proportion of the time when in the presence of caged predatory sticklebacks but not when faced with non-predatory crucian carp. Finally, great crested newt females exhibited a non-random distribution in egg laying. Individuals preferred to lay eggs on clean compared to occupied strips. These findings are discussed in relation to improving our understanding of great crested newt ecology and conservation.

Conservation genetics theory predicts that isolated populations on the periphery of a species range will display reduced levels of genetic diversity compared to those more centrally located. Low levels of diversity can potentially compromise individual fitness and population viability among peripheral populations and so from a conservation perspective, understanding genetic structure among populations with low levels of diversity is a priority. Here I examine the levels and spatial distribution of both neutral and adaptive DNA polymorphisms across populations of the palmate newt (Lissotriton helveticus); including both island and mainland populations at the northern extent of their distribution and putative source populations from which postglacial expansion occurred. Five different classes of molecular marker were assayed: (1) mitochondrial DNA sequence variation, (2) micro satellite length variation, (3) MHC allelic diversity, (4) AFLP profiling and (5) candidate nuclear locus (sodium-calcium exchanger) allelic diversity, with an overall prediction that neutral markers will exhibit reducing diversity with increasing latitude and then from mainland to island; and that neutral diversity will be a poor predictor for adaptive diversity given the additional effects of selection on these genes. These predictions were not wholly confirmed. Mitochondrial data demonstrated that refugial populations harboured more genetic diversity than postglacial populations. Conversely, micro satellite diversity did not decline gradually with increasing latitude and insular populations were not necessarily depauperate compared to those on the mainland. Adaptive diversity was not reduced among peripheral or island populations but a signature of directional selection was detected. Lastly, genome-wide AFLP diversity was not reduced among island populations whilst no clear inference was possible from the sodium-calcium exchanger gene. There was a lack of concurrence between neutral and adaptive markers and the results are discussed in relation to the effects of micro-evolutionary processes acting in populations of varying size and isolation. The significance of these findings is discussed in relation to the long term conservation of palmate newt populations.