Habitat fragmentation is widely recognised as a major threat to global biodiversity and by decreasing the size of habitat patches and disrupting important ecological processes through exposure to edge effects, is detrimental to many taxonomic groups, including insects. This research aimed to determine the influence of edge effects on the ecology of the wood ant, Formica rufa L. through an intensive study of a single site in Northamptonshire. The study focused upon the impact of both aspect and distance-related edge effects, measured along three edge to interior transects, a total of 82 sample nests and five control points within four study aspects located around the wood. Nest location and characteristics, density, colony structure, and the phenology of activities were also recorded. Overall, southern transects received more light but lower wind speeds than the other aspects and also supported a greater diversity of tree species. Southern nests also received significantly more light in the early and late parts of the year than nests in other aspects. At the random sampling points, nests received significantly more light and lower wind speeds than the controls. Compared with the controls, nests supported a higher plant species richness, but in terms of abundance, only sycamore (Acer pseudoplatanus) and elder (Sambucus nigra) were found in greater numbers at nest sites than controls. The south also supported significantly higher nest densities and had a higher percentage of polydomous colonies than the other aspects. The results showed that aspect mediated edge effects caused differences in wood ant phenology. Colonies in the south left hibernation earlier, began reproduction earlier, and had completed the reproductive cycle before colonies in the other aspects had begun theirs. Overall, these results are the first to show the impacts of aspect and distance related forest edge effects on F. rufa

Despite its large volume, Lake Baikal has been experiencing recent changes within its limnological and biological structure, as well as changes within lake water nutrient and dissolved organic carbon concentrations. The biological changes within Lake Baikal include alterations within the distribution and abundance of major phytoplankton and zooplankton groups. These limnological changes are likely to be from both climate warming and anthropogenic impact, particularly over the last few decades. Recent shoreline observations in the South and North regions of Lake Baikal have found large blooms of filamentous green algae, which has been associated with nutrient enrichment from surrounding settlements and growing tourism. This highlights the question as to whether the pelagic regions are similarly showing any signs of anthropogenic driven nutrient enrichment. The aim of this thesis was to examine if pelagic Lake Baikal is showing any evidence of eutrophication and/or response to climate warming. The main themes of the research were to assess the modern-day limnological condition of Lake Baikal in the summer (August 2013) and winter (March 2013) months,and to examine Baikal’s phytoplankton response to nutrient enrichment via the construction of mesocosm experiments. High-resolution limnological change was then reconstructed from sediment cores across the lake. Sites were chosen within pelagic regions, bays and shallow waters nearby river inflows, and palaeolimnological records were used to assess primary production changes and floristic changes over the last few centuries. This timespan enables both natural variability within the system to be explored, and more recent changes pre and post known human influence within the catchment area (c. 1950 AD). The main palaeolimnological techniques applied for primary production proxies were sedimentary algal pigments, stable isotope analysis of bulk organic carbon and diatom valve concentrations. Mercury analyses was also applied to water samples and sediment cores as a pilot study to explore toxic metal pollution at Lake Baikal, due to mining activity along the Selenga River, and examine historic levels of mercury contamination, and examine historic levels of mercury contamination. Both modern-day limnological surveys and palaeolimnological records seem to be showing increasing algal biomass (chlorophyll-aconcentrations) over the last 60 years, with decreasing trends in diatom production (from diatoxanthin pigment concentrations and diatom valve concentrations) in the South basin. Spatial survey data represents a snap shot in Baikal’s limnology in late summer (August 2013), and shows higher than expected concentrations of total phosphorus within the mixing layer, which fall within the meso-eutrophic range. Dissolved organic carbon concentrations seem to now be higher within Lake Baikal’s waters, and both nitrate and silicate concentrations appear to be similar to known previous concentrations at Lake Baikal. A pilot study of mercury concentrations within Lake Baikal waters and sediments, show no signs of mercury contamination from mining activity along the major river inflows, and atmospheric deposition. Experimental results show that within the pelagic regions of Lake Baikal, nitrogen, phosphorus and silicon are influencing algal communities, with Si addition stimulating diatom growth, nitrogen and phosphorus addition stimulating chlorophyte growth, although overall nutrient treatments did not increase chlorophyll-a yield. Interestingly, experimental findings also highlight the potential influence of picocyanobacteria populations on silicon cycling. Concentrations of sedimentary chlorophyll-a concentrations (plus its derivatives) rise prior to major industrial influence within the Baikal catchment region, and stable carbon isotope records show a positive correlation with chlorophyll-a concentrations in the South basin, Selenga and Maloe More sites. Total phosphorus concentrations could be a result of both anthropogenic nutrient pollution, entering into the lake via the Selenga River, and climate driven changes in lake stratification and nutrient utilisation by algae. Results from limnological surveys and palaeolimnological records are thus likely to be reflecting both recent anthropogenic impact and climate change (rising lake water temperatures, declining ice cover thickness and duration and increasing river inflow from permafrost thaw), within the pelagic regions, especially given that recent work provides evidence of toxic cyanobacterial and chlorophyte blooms within the shallow waters of Lake Baikal. For the Maloe Moresite, which is a bay of the Central basin, results show a rise in sedimentary chlorophyte pigments post 1950 AD, suggesting that this bay region of Lake Baikal is currently being affected more than deeper water sites, by human influence, showing signs of eutrophication due to a switch in algal community composition.

This thesis describes PatchMapper, a model combining a population simulator based on individual behaviour, with a spatially explicit representation of a landscape. To investigate the robustness of the technique, representatives of three major taxa were modelled: the nuthatch (Sitta europaea L.), the white-footed mouse (Peromyscus leucopus Rafinesque) and the black hairstreak (Satyrium pruni L.). For the nuthatch and white-footed mouse, the performance of PatchMapper was compared with published models of the same species, but using different approaches, including, for the nuthatch, a comparison against observed numbers in a real landscape. To investigate the behaviour of the model, a sensitivity analysis was also undertaken. Written in Java, for portability, the model enables the user to select demographic and behavioural parameters via an interactive interface and includes a real-time (computer) display of the position of individuals during the simulation. Novel aspects of the model include perceptual range and field-of-view. Internally generated neutral landscapes can be used for modelling general cases, with imported digitised landscapes enabling specific study areas to be modelled. Habitat area and habitat quality dynamics can also be modelled. Dispersal flow diagrams can be generated, providing a visual explanation of the effects of landscape changes on inter-patch dispersal paths and populations in target patches. Performance compared well with published models, predicting a feasible match with observed numbers of nuthatches in the real landscape. Revealing predictable and realistic responses, the sensitivity analysis revealed that the model coding was valid. The value of specific case studies was illustrated, along with the dangers of relying on intuition when evaluating the response of species to habitat fragmentation. The individual-based SEPM approach was found to be best suited to the modelling of univoltine territorial species (such as nuthatch), with a single dispersal phase between fledging and territorial establishment. When demonstrating the model, the visual outputs proved particularly effective. Providing a set of features not seen in published models and enabling modelling at both local and landscape scales, PatchMapper is offered as a prediction tool for those engaged in activities such as biodiversity conservation and habitat management