Blue / green spaces within urban areas offer a variety of services to human populations as well as habitats for other species. Ponds, despite their designation as nationally important habitats in the UK, are among the least well studied urban habitats. Urban planning policy in the UK is moving towards increasing urban density rather than urban expansion. While compact cities offer benefits in terms of resource utilisation and transportation, they also place increased pressure on blue/green spaces. Ponds offer an ideal microcosm for exploring issues of urban ecology within differing urban settings. Data were collected from thirty seven ponds (a 10% random sample) in the urban area of Halton, northwest England over a three year period (2005 - 2007). A range of complimentary methods were employed to analyses the impact of ecological, chemical and physical parameters, landscape structure and socio-economic factors on pond ecology within both traditional urban centres and a designated New Town development. These data were compared to data, collected in 2006, from fifty one ponds in the adjacent rural landscape of Cheshire. This allowed analysis of variations in pond ecology along an urbanisation gradient. While the species richness of ponds within Halton was comparable with national indicators, they were significantly lower than their rural neighbours in Cheshire. Data also showed that increasing urban density, in already urbanised areas, has less impact on species richness than urban expansion into more rural locations. The most significant impact on pond species numbers was the density of ponds within the surrounding landscape. This research offers insights into the impact of urban development on pond ecology, and suggests the potential impact of future developments and how this may be ameliorated.

No description available.

Nepal has established an extensive network of protected areas to conserve biodiversity. Several problems relating to management of these protected areas have emerged, such as wildlife poaching and park-people conflicts. To address these problems, local communities have been given more responsibilities in protected area management by creating new categories of protected areas. This research investigates the success of such an approach from the perspectives both of biodiversity conservation and the livelihoods of local communities. The perceived success of a community-based protected area management was examined in the Annapurna region, Nepal. An integrated biophysical and social survey was designed and carried out for a stratified sample village communities. A field site sampling strategy was designed to examine the effect of two factors: conservation legislation, referring explicitly to establishment of the protected area, and tourism. To evaluate the impact of legislation, areas both inside and outside the protected area were compared. In addition, areas with and without tourism within the protected area were analysed. A biophysical survey was conducted to assess the present status of wildlife and forest resources, and current pressures on forest resources. This was achieved by assessing the intensity of anthropogenic disturbance in forest stands. A complementary social survey using various tools such as PRA, structured interviews, semi-structured interviews and questionnaire surveys was conducted in 14 village settlements. The social survey measured the economic losses due to crop damage and livestock depredation by wildlife, and gathered information on conservation awareness, local attitudes toward conservation, resource use patterns, effectiveness of the conservation area regulation, relationships between people and the protected area.

The manufacture, use and storage of explosives over decades have seriously contaminated the environment. Hexa-hydro-1,3,5-trinitro-1,3,5-triazine (Royal Demolition Explosive - RDX) is one of the most widely used explosives. RDX is a man-made compound, recalcitrant to degradation and proven to be toxic to organisms. Bacteria capable of utilising RDX as a sole nitrogen source for growth have been isolated from RDX polluted sites including Rhodococcus rhodochrous 11Y. The RDX degrading genes, xplA and xplB encoding a novel flavodoxin fused cytochrome P450 and its reductase partner respectively, were first identified in R. rhodochrous 11Y. This unusual P450 system has now been found in almost all of the RDX degrading bacteria isolated so far. To date, XplA/B remains the only characterised RDX degrading P450 system and is encoded on an operon in strain 11Y, which also contains a putative permease (transporter) and transcriptional regulator. This gene cluster is highly conserved amongst other RDX degrading bacteria from geographically distinct regions including the United Kingdom, Belgium, Australia and North America, suggesting the xplA/B gene cluster may have been rapidly distributed across the globe by horizontal gene transfer. The first aim of this study was to characterise Rhodococcus erythropolis HS4, a bacterium that degrades RDX slowly but did not contain xplA and xplB. A number of approaches have been employed to characterise this strain, which includes whole cell assays, western analysis, cell free extract activity assays, PCR amplification and affinity purification of protein in R. erythropolis HS4. While whole cells of HS4 showed low RDX degrading activity, no RDX activity was observed in HS4 cell free extracts. Attempts to purify an RDX degrading enzyme from R. erythropolis HS4 were unsuccessful. The second aim of this project was to characterise the RDX degrading gene cluster in R. rhodochrous 11Y. Four genes encoding xplB, xplA, a putative permease and a MarR type regulator, were individually deleted using an unmarked gene deletion system (pK18mobsacB). The xplB knockout strain metabolised RDX more slowly than the wild-type suggesting XplA was able to obtain reducing equivalents from another source in the xplB knockout strain. The xplA knockout strain did not show RDX activity in whole cell and growth experiments. Neither xplA nor its gene product XplA was detected in the xplA knockout strain. The findings suggested no alternative RDX degrading system is present in strain 11Y. The permease knockout did not show significant difference in the RDX removal rate compared to wild-type. Another attempt to characterise the permease in 11Y was to express it in E. coli. No significant difference of RDX uptake between the permease-expressing clone and the control (non-expressing clone) in the uptake assays. The regulator knockout strain had a lower RDX degradation rate than wild-type in the presence of nitrate/nitrite. Also, when the regulator knockout and wild-type strains were previously exposed to nitrate/nitrite, the knockout showed lower RDX degrading activity. Further investigation of xplA regulation in strain 11Y showed that XplA activity was induced by nitrogen-limiting conditions and further induced by RDX. This was the first observation on the XplA activity could be induced by low nitrogen availability in medium. These results suggested that the regulator is indirectly involved in controlling the expression of XplA in 11Y, which is linked to central nitrogen metabolism.

Manufacture, use, storage and improper disposal of the explosive 2,4,6-trinitrotoluene (TNT) have led to widespread, global contamination of soil and groundwater. TNT is highly toxic and recalcitrant to degradation resulting in environmental build-up with far reaching ecological and health implications. It is therefore a priority to remove contaminating TNT from the environment. Phytoremediation is a promising solution; suitable plants possess some natural ability to transform TNT, high biomass, deep root systems, requirement for minimal nutrient input and ability to reduce contamination spread by wind or water erosion; making them an attractive remediation system. Key genes involved in the detoxification of TNT by plants have been recently identified by expression studies and the encoded enzymes characterised. This has lead to the thorough investigation of the enzymes in the pathway of TNT detoxification; Phase I transformation includes oxophytodienoate reductases, with uridine diphosphate (UDP) glycosyltransferases (UGTs) playing a role in the Phase II conjugation step. The expression studies identified additional enzymes also likely to be involved in these phases including glutathione transferases (GSTs). GSTs are known to detoxify compounds by conjugation to glutathione (GSH), and like UGTs are Phase II detoxification enzymes. This thesis presents an investigation into whether plant GSTs play a role in the detoxification of TNT. In vitro analysis of recombinant GSTs was performed to elucidate the activity of GSTs towards TNT. Seven GSTs were cloned, expressed and purified from Escherichia coli. TNT assays performed with pure enzyme indicated that at least two of the GSTs were able to transform TNT. Analysis of the reaction product by mass spectrometry showed that TNT was conjugated to glutathione through substitution of a nitro-group, a highly desirable reaction as the removal of a nitro group from TNT is likely to increase the likelihood of subsequent mineralisation of the pollutant. This is the first identification of enzymes capable of this transformation. The two GSTs which exhibited activity towards TNT were overexpressed in Arabidopsis to clarify if the conjugating activity observed in vitro was able to confer increased tolerance to TNT to the transformed plants. Transgenic lines showed no enhanced growth compared to wild type plants on TNT amended media, root lengths appeared slightly shorter while TNT uptake and biomass were reduced. The role of GSTs in the detoxification of TNT remains unresolved however it is likely that GSTs do not play an integral role in TNT detoxification in plants. Nonetheless, the two GSTs characterised in the project are the first examples of plant enzymes which are able to catalyse the removal of nitro groups from TNT. Engineering these GSTs to improve their ability to transform TNT could offer an opportunity for effective environmental remediation.

The importance of extremely slow retention and release has superseded the notion that sorption of pesticides to soil is an instantaneous and reversible process. A fraction of sorbed pesticide is also often reported to bind irreversibly to the soil matrix. This has important implications for pesticide mobility and bioavailability. It is essential to understand sorption phenomena to allow accurate prediction of pesticide fate within the soil environment. This thesis describes the result of applying a sequential extraction procedure, based on the principles of isotope or “self-exchange”, to nine pesticide/soil systems. The significance of irreversible sorption in controlling pesticide mobility was assessed using isotope exchange (12C and 14C) to characterise pesticide exchange kinetics in-situ over protracted time-scales. Sequential extraction increased in harshness in the order: isotope exchange < forced isotope exchange < solvent extraction. Three pesticides (one neutral, one basic, one acidic) and three temperate, arable soils (ranging in texture and pH) were studied. A three-site sorption model was developed to further interpret the data obtained. Although results showed the experimental design of the isotope exchange technique was not powerful enough to identify whether remaining sorbed pesticide was participating in slowly reversible or irreversible sorption, the forced isotope exchange procedure was able to provide an indication of amounts of pesticide not participating in exchange between the soil and solution. Under abiotic conditions, only minimal amounts of initial-applied pesticide were found to take part in irreversible binding. Soil combustion quantified irreversible sorption in the order: chlorotoluron (≤ 2.27 ± 0.36%) > prometryn (≤ 1.35 ± 0.60%) > hexaconazole (≤ 0.50 ± 0.06%). Varying the soil composition had little effect on amounts of irreversibly sorbed pesticide, probably due to the small amounts of irreversible sorption observed overall. These results suggest that the vast majority of sorbed chlorotoluron, prometryn and hexaconazole (in the parent form) participated in very slow but reversible binding, a result also confirmed by the three-site sorption model. Pesticide sorption behaviour is a complex process. Although sorption phenomena are still not fully understood, these results provide a greater insight into the significance of irreversible binding for predicting pesticide fate.

Climate change may produce a variety of responses in populations' ecological and evolutionary dynamics. At opposing limits of populations' ranges, the responses are expected to differ. Some lag in response may be expected due to the rapidity of climate change, with the strength and type of lags varying across space. Importantly responses may contain both ecological and evolutionary components. This thesis provides significant contribution to understanding how structure in populations and the landscape may determine the nature of populations' responses to climate and environmental changes. A number of models and a microcosm experiment are presented. The results show how alternate temporal and spatial population structures are developed when individuals move in space. From defining percolation routes, patterns of gene flow or spatial selection, landscapes provide a large role in determining populations' responses. Even without landscape structure, populations exhibit large levels of regional structure, and indeed substructure, due to localised interactions. This spatial structure may deform during climate change, producing new characteristics of equilibrium spatial distributions. During range deformation the feedback between spatial structure and dynamics can alter populations' evolvability by changing the patterns and strength of intraspecific competition, or the maintenance of genetic variation. These changes produce dynamics that will be sensitive to individual differences in a population. Changes in populations' age and sex structure may modulate ecological and evolutionary interactions. The research presented here highlights an increased importance of understanding populations' spatio-temporal structure and dynamics within heterogeneous landscapes. This is especially so as ecological and evolutionary processes can converge to different degrees during climate change, depending on the landscape a population inhabits. Prediction of populations' responses may require a greater understanding of spatial processes and how range deformation affects the evolution of different kinds of traits. All the above areas feed into a greater understanding of the genesis and maintenance of diversity in any situation.

In this study, a new methodology for a spatial NH<SUB>3</SUB> emissions inventory for the UK has been developed. In contrast to previous methodologies, the new approach employs a spatial model specifically tailored to NH<SUB>3</SUB>, rather than a more general allocation of agricultural sources (livestock and crop categories). Key model input data are agricultural census data (updated to 1996), average nitrogen fertiliser application rates to crops and grassland, landcover data and NH<SUB>3 </SUB>source strength estimates. A major aim of this thesis was to identify sources of uncertainty in NH<SUB>3</SUB> emission inventories, both at the national and at the local scale. While previous studies only considered uncertainties in the applied NH<SUB>3</SUB> source strength estimates, all main sources of uncertainty in the model input data as well as the model assumptions were evaluated here, and quantified where possible. The main causes of uncertainty in the national inventory were found to be due to spatial aggregation effects (MAUP), and due to the spatial and temporal variability in source strength, depending on environmental conditions and agricultural practice. A quantitative assessment of the modelled spatial variability within the 5 km NH<SUB>3</SUB> emission estimates was carried out by calculating the % coefficient of variation of from the underlying 1 km results. High values of >150% were found in areas with intensive pig and poultry farming, as well as at the boundary between intensively farmed lowland areas and extensive upland and hill areas. Low values of ~20% are typical for some grassland areas with predominantly cattle farming.

Urban areas are highly dynamic and diverse systems and the interactions and networks within an urban area are, at present, only partly understood, although some of the most important impacts on human health occur in these areas. It is essential, therefore, to develop a deeper understanding of these urban dynamics and processes especially with regard to exposure and health risk assessment. This thesis describes the development and application of an urban SImulation for ENvironmental health Analysis (SIENA). SIENA provides a controlled, simplified urban environment to develop and test spatial epidemiological concepts and models, to simulate processes and interactions relating to environmental exposure and to explore theoretical and methodological problems in the spatial analysis of environmental health. The development of the simulated urban system focuses on identifying and quantifying fundamental processes and inter-dependencies in the structure of urban areas in Great Britain. Twelve cities are chosen as sample cities and their spatial data structure (topography, transport network, land cover) and relationships between these structures and the urban population are statistically analysed. Based on the results of the statistical analysis SIENA is developed within a Geographic Information System (GIS) using probabilistic models and spatial analysis tools. Beside the identified core structure, topography, transport network, land cover and population, additional data such as traffic flow, air pollution monitoring networks or emissions from industrial sources amongst others are modelled and incorporated into SIENA. To demonstrate the potential of the simulation, SIENA is applied in two case studies both focusing on the misclassification of human exposure to urban air pollution. The first case study explores the representativeness of various air pollution monitoring networks and the resulting implications for exposure assessments. For the second case study, personal exposure is simulated within SIENA and then compared to the use of a location-based exposure proxy and the potential exposure misclassification spatially analysed.

Endocrine Disrupting Chemicals (EDCs) are a diverse array of natural and manmade substances capable of interfering with hormonally mediated processes. They are particularly harmful to cells that are differentiating and dividing rapidly, can stimulate unwanted cell growth, and can interfere with normal epigenetic imprinting causing changes that in some instances are heritable. Due to their epigenetic effects and effects on tissue growth and development, organisms at certain life stages are more vulnerable than others and effects may manifest a long time after exposure. The risks posed to human and environmental health by these compounds are currently unknown, but there is a growing scientific consensus that precautionary measures and further research to understand and quantify these risks are needed. Endocrine Disrupting pesticides represent a subset of EDC capable of reaching humans from a diverse range of sources via many different exposure routes. No definitive lists or screening methodologies exist to identify them. In the UK, exposure routes involving occupational pesticide use for agricultural purposes or the residues of these pesticides in food and water are well quantified but other sources of exposure are not. If risk management measures are to be enacted to protect the population, these exposures will have to be quantified and the risks they pose assessed. This project aims to identify the hazards posed by ED pesticides to humans living in the UK, prepare a framework for the assessment and management of risks they pose, identify the tasks that remain to be completed before such a framework could be implemented, and to investigate poorly documented ED pesticide exposure sources. Current toxicological testing of pesticides was found to be inadequate. Properties frequently exhibited by EDCs, such as non-monotonic (j-type) dose responses and the additive and synergistic actions of compounds were not taken into account. Only active ingredients are legally required to be tested even although adjuvants used to improve formulation effectiveness are not always inert and formulations can be more toxic or have greater ED potential than their active ingredients alone. Adjuvants are assessed on a reactive basis, which is not adequate to protect public health. A tiered risk assessment and management framework capable of screening potential ED pesticides and making recommendations for risk management can be created using existing deterministic and probabilistic models of human pesticide exposure. The identification of critical groups that are more vulnerable than the general population to the effects of EDCs allows risk assessment and management to be tailored to protect these groups, allowing the risk to both these groups and the general population to be minimised, in keeping with the precautionary principle. Further work is required, however, to collect appropriate datasets to model non agricultural exposure routes and model the exposure of rural residents and bystanders. Assumptions made in the creation of foreign models would need to be checked to ensure they were compatible with UK conditions. Appropriate ADIs for EDCs showing non-monotonic dose responses would also need to be determined, and exposure profile differences between people living in urban, periurban and rural environments would also have to be taken into account. A number of ED pesticides used for medicinal, veterinary and domestic purposes and the municipal and commercial maintenance of infrastructure and recreational areas were identified. Unfortunately little could be determined about the factors influencing their use by the public. The number of years spent in secondary education correlated positively with non ED medicinal pesticide use and both ED and non ED veterinary and domestic use. It was unclear why this should be. Golf courses were the most heavily treated publicly accessible areas studied and used the most ED pesticides. Large parks received least, with pesticide use concentrated on hard surfaces and high maintenance ornamental areas. Pesticide use in parks is dominated by herbicides. Applications to pavements and other publicly accessible hard surfaces consisted almost entirely of glyphosate based herbicides. Herbicide applications on pavements and in parks mostly take place in the spring and early summer. The bulk of pesticide applications on golf courses were applied in the autumn. Contractors carrying out maintenance work for local authorities were found to use more pesticides than local authority employees. Non chemical methods of ectoparasite, pest and weed prevention and control have the potential to reduce pesticide use. Some of the methods currently in use, however, were found to be more costly and challenging to implement than chemical methods. The integration of these into parasite, pest and weed prevention and control strategies where possible and their further should be encouraged.