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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Agricultural economics within the NERC/ESRC Land Use Programme

Moxey, Andrew Paul January 1999 (has links)
No description available.
2

Agrarinės aplinkosaugos rezultatyvumas Lietuvoje / Effectiveness of Agri-Environmental Policy in Lithuania

Skirevičiūtė, Laura 13 June 2014 (has links)
Tyrimo objektas – agrarinė aplinkosauga rezultatyvumo požiūriu. Tyrimo tikslas – įvertinti priemonės „Agrarinės aplinkosaugos išmokos“ programų įgyvendinimo rezultatyvumą. Tyrimo uždaviniai: 1) identifikuoti agrarinės aplinkosaugos būtinumo priežastis ir vietą ES Bendrojoje žemės ūkio politikoje; 2) išnagrinėti ir susisteminti mokslinius tyrimus apie agrarinės aplinkosaugos priemonių rezultatyvumo vertinimą; 3) išnagrinėti priemonės „Agrarinės aplinkosaugos išmokos“ įgyvendinimo mastą ir dinamiką Lietuvoje; 4) įvertinti agrarinės aplinkosaugos rezultatyvumą Lietuvoje. Tyrimo metodai: Teorinėje darbo dalyje naudojama Lietuvos bei užsienio autorių mokslinės literatūros lyginamoji, sisteminė ir loginė analizė bei sintezė, apibendrinimas, grafinis vaizdavimas. Analitinėje dalyje, vertinant agrarinės aplinkosaugos įgyvendinimo mastą, dinamiką bei rezultatyvumą Lietuvoje, naudoti statistinės informacijos rinkimo, sisteminimo ir apdorojimo (duomenų analizė, grupavimas, grafinis vaizdavimas bei apibendrinimas) metodai. Tyrimo rezultatai: • Pirmojoje darbo dalyje išnagrinėta agrarinės aplinkosaugos samprata, būtinumas, agrarinės aplinkosaugos politikos raida ir jos rezultatyvumo vertinimo tyrimai. • Antrojoje darbo dalyje išnagrinėti priemonės „Agrarinės aplinkosaugos išmokos“ programų įgyvendinimo mastas ir dinamika Lietuvoje. • Trečiojoje darbo dalyje, remiantis ES paramos programų rezultatyvumo ir poveikio vertinimo modeliu, įvertintas priemonės „Agrarinės aplinkosaugos... [toliau žr. visą tekstą] / Research Object – Agri-environment in point of effectiveness. Research Aim – Assessment of the effectiveness of “Agri-environment Payments” programmes. Objectives of the Research: 1. to identify key reasons of necessity of agri-environment and its position within the General Agricultural Policy of the EU; 2. to define theoretical aspects of the implementation of agri-environment measures; 3. to analyze scope of implementation of “Agri-environment Payments” and its trends in Lithuania; 4. to define the effectiveness of “Agri-environment Payments”. Research Methods: analysis of scientific literature and documents, qualitative assessment, method of logical analysis and modelling, synthesis, comparison, induction, deduction, graphic representation. Results of the Research: • The first part of the Thesis provides analysis of agri-environment concept, application of policies and appraisal of effectiveness. • The second part of the Thesis provides analysis of the scope of implementation of “Agri-environment Payments”, programmes in Lithuania. • The third part of the Thesis provides assessment of the effectiveness of programmes (“Organic Farming Scheme”, “Environmentally friendly fruits and vegetables' cultivation system”, “Programme for improving the status of water bodies at risk”, “Landscape Stewardship Scheme”, „Preservation of Lithuanian endangered species of animals and poultry“) in terms of the model established for the assessment of the EU support programme effectiveness... [to full text]
3

Effectiveness of UK agri-environment schemes in supporting cavity-nesting solitary bees

Gresty, Catherine January 2017 (has links)
Bees provide a vital pollination service to many important crops and wildflowers yet are experiencing population declines across European and North American agricultural landscapes. The conservation of bee communities on farmland is a priority of the UK agri-environment schemes, which support pollinators through the provision of natural and semi-natural habitat, foraging resources and nesting sites. Data are needed to evaluate the effectiveness of these interventions in supporting bee communities and to allow the refinement of effective, evidence-based policy. This thesis examines the effectiveness of agri-environment management, though the provision of natural habitat, foraging resources and nesting sites, in supporting solitary bees, an important group of pollinators of which there are 250 species in the UK. Cavity nesting solitary bees and wasps were surveyed on 19 farms situated across central southern England, ranging from farms under no agri-environment scheme, to farms showcasing higher-level agri-environment management. Data on bee and wasp communities was collected by deploying solitary bee nest boxes. These nest boxes are marketed widely as nesting resources for solitary bees and are provided to farmers as part of Higher Level agri-environment schemes. Over the course of the study, 4002 solitary bees and wasps, comprising 10 species, were recorded. Natural Habitat: A positive relationship was identified between the abundance and species richness of bees and wasps and the proportion of natural habitat across farms. The availability of natural habitat also had a positive influence on the structural stability of bee and wasp parasitism networks; a positive association was identified with network link density. Link density measures the mean number of links per species within a network. Higher measures of link density are believed to confer greater resilience to species loss as individuals have more flexibility to switch interaction partner, limiting the risk of a cascade of secondary species extinctions. This set of results is encouraging, suggesting that the natural habitat types being promoted are effective in supporting solitary bee and wasp communities. Foraging resources: Examination of bee foraging preferences, through next generation sequencing of brood cell pollen DNA, demonstrated that the agri-environment scheme sown wildflower mixes do not support the foraging requirements of solitary bees effectively. Of the 15 plants included currently in the wildflower mixes that were recorded as present on the study farms, pollen from only one species, Ranunculus acris, was used by the bees. Rosa canina was identified as the most popular forage plant. The leaves of this species are also a preferred nesting material for Megachile leafcutter bees, providing strong justification for the inclusion of R. canina within the selection of hedgerow plants encouraged by agri-environment schemes. Tripleurospermum inodorum and Trifolium repens were also identified as good candidates for inclusion in wildflower seed mixtures. Nesting sites: A strong positive relationship between the density of solitary bee nest boxes and the rate of brood cell parasitism was identified, indicating that a high local density of nest boxes may expose bee larvae to a higher risk of parasitism. An enhanced risk of larval mortality could counteract the benefit of additional nest site provision. No significant effect of nest box provision on nest box colonization was identified across these study sites, suggesting that their placement across landscapes to encourage more pollinators may be counter-productive. It would be prudent to advise, given the results of this study, for the provision of a small number of dispersed nest boxes, this might more accurately mimic the availability of nesting resources in nature and reduce the risk of enhanced parasitism rates.
4

The distribution and dispersion of herpetofauna in lowland farmland : with a focus on the common toad (Bufo bufo)

Salazar, Rosie Diane January 2014 (has links)
Concern over unexplained population declines in the common toad (Bufo bufo) has led to it being recognised as a priority species for conservation research. The general consensus among herpetologists is that the most important cause of the declines seen as part of a global amphibian extinction crisis is habitat loss and degradation. The aim of thesis is to investigate the effect of habitat availability and quality on common toad populations in the United Kingdom, with a particular emphasis on the effect of land under agricultural use. I use occupancy modelling, resource selection function modelling and genetic techniques to determine the effects of both terrestrial and aquatic habitat on common toads. Based on my findings, I consider the impacts of habitat at local, landscape and national scales. My research revealed the importance of pond density and presence of woodland in increasing relative probability of toad occurrence in the terrestrial habitat (Chapters 2 and 3) and the importance of water quality, woodland coverage and available terrestrial habitat coverage in determining common toad presence in ponds. The isolating effect of urban areas is demonstrated in Chapter 4 where Isolation By Barriers (IBB) explains genetic distance between common toad breeding populations better than Isolation By Distance (IBD). In Chapter 5 I again use the resource selection function for terrestrial habitat use developed in Chapter 3, to investigate the importance of terrestrial habitat availability in determining pond use by common toads at a national scale. In my concluding chapter, I make recommendations for management and further research including consideration of potential interactions between the effect of habitat loss, fragmentation and degradation with other potential causes of common toad decline.
5

Reconfiguration de l’État et renouvellement de l’action publique agricole : L’évolution des politiques agroenvironnementales au Québec et en France / State Reconfiguration and the Renewal of Agricultural Public Action : The Evolution of Agri-Environmental Policies in Québec and France

Benoit, Maude 07 December 2015 (has links)
L’avènement des enjeux environnementaux en agriculture est une tendance observable depuis les années 1990 dans l’ensemble des pays industrialisés, qui les intègrent pourtant de manière très différente à leurs politiques agricoles respectives. Cette thèse s’applique à expliquer l’institutionnalisation et l’évolution nationales différenciées de ces enjeux par le biais d’une analyse comparée entre le Québec et la France. Le cadre d’analyse proposé prend en compte à la fois les structures et les acteurs de la construction et du développement de la politique dite agroenvironnementale en étudiant spécifiquement deux variables explicatives : la configuration des politiques agricoles et le rôle des administrations publiques. L’enquête qualitative se déroule sur un temps long (1990-2013) et combine trois techniques de collecte de données : l’analyse documentaire, l’analyse de discours et l’entretien semi-dirigé. Au terme de cette thèse, force est de constater que les organisations fondatrices des politiques agricoles nationales (administration et profession agricoles) jouent un rôle de filtre des dynamiques réformatrices présentes à l’échelle globale et qu’elles « acclimatent » les référentiels de développement durable et du management public aux spécificités de leur pays et de leur secteur d’action publique. / Since the 1990s, environmental issues in agriculture have increasingly become a public policy problem in industrialized countries, notwithstanding the fact that they are integrated very differently in their respective agricultural policies. Based on this observation, this research seeks to explain the various national institutionalization and evolution paths of the so-called agri-environmental policy through a comparative analysis between Quebec and France. The analytical framework considers both the structures and the policy actors in the agri-environmental policy construction by studying specifically two variables: the configuration of agricultural policies and the role of public administrations. This qualitative research investigates a long time frame (1990-2013) and combines three data collection methods: content analysis, discourse analysis and semi-structured interviews. This thesis shows that traditional agricultural policy key players (agricultural administrations and agricultural professional organizations) act as filters of reformist ideas present globally and that they “acclimate” both the sustainable development paradigm and the new public management paradigm to the specificities of their countries and of their public policy sector.
6

Effects of the availability of floral resources on plant-pollinator interactions and the implications for the long-term survival of plant populations

Evans, Tracie Marie January 2018 (has links)
1. Insect pollinators have been shown to alter their foraging patterns in response to habitat and landscape composition, particularly in relation to changes in the availability of floral resources which provide essential pollen and nectar provisions. Changes to pollinator behaviour and community composition, may alter the distance, directness and frequency of pollen movement and thus, the compatibility and genetic relatedness of pollen transferred between plants. We still lack good understanding of how variation in the spatial and temporal availability of floral resources drives pollinator responses and in turn, affects the fitness of outcrossing plants. Knowledge in this area could contribute to improved management interventions to enhance pollination services for plant conservation. 2. Through a combination of habitat and landscape scale field experiments, I explored how the availability of floral resources at different spatial scales affected plant-pollinator interactions, pollen transfer and mating success in plant populations, particularly those isolated from conspecifics. This involved introducing different species of plants in experimental arrays across a range of study systems that varied in structure and floral availability. Over the course of the thesis, I measured the community composition and behaviour of pollinators visiting experimental arrays; focusing on traits considered important for pollen transfer (e.g. Inter-tegular ('IT') span). Pollen movement was quantified within and between populations (5-150m) and the resulting plant outcrossing rates were measured using different methods including paternity analysis and the use of a dominance inheritance system. In addition, the implications of variations in pollinator foraging and pollination services can be attributed to pollen and gene flow and subsequently the reproduction and fitness of plants were assessed as a means of predicting the impacts on longer-term plant survival. 3. Findings from this thesis demonstrate reductions in the activity density (the abundance of actively foraging pollinators) and richness of pollinators and thus, the potential for plant visitation in response to a high abundance of floral resources within a habitat. This led to disruptions in pollen transfer, illustrated through a lower incidence of intra and inter-population pollen movement, and ultimately, reduced plant outcrossing rates. In parallel, plant seed set and germination rates were also reduced in habitats with high resource availability. Changes to pollinator communities and pollination services varied with the spatial scale at which floral resources were measured. Pollinator communities (activity density, richness and IT span) were most affected by floral resource abundance at a local scale (1-50m), particularly within a 20m radius of a plant population. Intra-population pollen movement was similarly affected by floral resources at a local spatial scale (within a 1m radius of a plant population). In contrast, no effect was observed on pollinator communities, intra-population pollen movement or plant reproduction when floral resources were measured at a landscape scale (within a 100-1500m radius of a plant population). However, findings were variable across different experiments at the same scale of measurement. For instance, the availability of floral resources at a local scale did not always elicit an effect on plant reproduction. This reflects differences in plant species identity and the effects of breeding system and floral traits, illustrated through variations in visitation rates between plant species. Inconsistencies were further observed with pollinator activity density and richness, which were not related to floral resources at a habitat scale in one chapter. 4. This thesis highlights the importance of the availability of floral resources at a local scale on plant-pollinator interactions and pollination services to plants. Co-flowering plants within florally rich habitats compete for pollinators and subsequently, visitation and pollen transfer between individuals of low density plant populations is diluted rather than facilitated. This suggests that although pollinator abundance and diversity may be enhanced through florally rich habitats (e.g. habitats implemented under the agri-environment scheme), pollination services are not automatically improved for plants which are present at low frequency in the landscape. This needs to be considered when designing and implementing management for threatened or isolated plants where plants may instead benefit from focused interventions. For instance, pollination services may be increased by efforts to maximise the facilitative effect of surrounding habitats, while increasing the ability of threatened or isolated plants to withstand competition from co-flowering plants.
7

Causes of decline and conservation solutions for Corn Buntings Emberiza calandra in eastern Scotland

Perkins, Allan John January 2012 (has links)
The Corn Bunting Emberiza calandra is one of the most severely declining farmland birds across Europe. In the UK, numbers fell by 86% between 1967 and 2008. Corn Buntings favour open landscapes, nest on or close to the ground, are often polygynous, double-brooded, and have a seed-based diet supplemented in summer by invertebrates. This study investigated the recent causes of decline in arable and mixed farmland in eastern Scotland, and sought to identify potential conservation solutions that could be delivered through agri-environment schemes (AES). Combining new data with analyses of existing long-term datasets, I investigated habitat associations during summer and winter, the timing and success of nesting attempts, and measured reproductive and population responses to AES. Corn Buntings declined almost to extinction in one study area where, over 20 years, the main recorded intensifications of farming were reduced weed abundance within crops and removal of boundaries to make bigger fields. Territory locations, late-summer occupancy and polygyny were all strongly associated with weedy fields. There were also positive associations with overhead wires and in early summer with winter barley and forage grasses. Late-summer occupancy was associated with spring-sown cereals, crops that are amongst the last to be harvested. Changes in habitat associations and to aspects of the mating system as the population declined and agriculture intensified are discussed. Intensive monitoring showed that Corn Buntings laid clutches from mid-May to mid-August, mostly in fields of forage grasses and autumn-sown cereals in early summer, and spring sown cereals in late summer. A preference for nesting in dense swards explained this seasonal variation. Breeding success in forage grasses was poor, due to high rates of nest loss during mowing. However, in experimental trials, nest success in fields with delayed mowing was fivefold that of control fields. With sufficient uptake through AES, delayed mowing could raise productivity to levels required to reverse population declines. In winter, cereal stubbles and AES unharvested crop patches were the main foraging habitats used. Unharvested crops with abundant cereal grain in their first winter of establishment were favoured. Population monitoring over seven years and 71 farms revealed increases on farms with AES targeted at Corn Buntings, no significant change on farms with general AES, and declines on control farms. In arable-dominated farmland, management that increased food availability reversed declines, but on mixed farmland where Corn Buntings nested in forage grasses, delayed mowing was essential for population increase. This study has already influenced the design of AES targeted at Corn Buntings in Scotland, and I make further recommendations for the species’ conservation and design of AES that are applicable to farmland throughout Britain and Europe.
8

CRITICAL REFLECTIONS ON THE ADAPTATION OF SUSTAINABLE FARM PRACTICES PROMOTED BY THE EUROPEAN UNION

SINGH, MANPRIETKAUR 24 March 2017 (has links)
. / This study is about the on-ground implementation of sustainable farm practices supported by policies and directives that form the core of the European Union’s sustainability policy. Its goal is to identify the blockers to effective policy implementation in order to improve the approach to sustainability in the agricultural sector. Exploring ways to engage local stakeholders in farm sustainability has been central to create a holistic understanding about the processes that drive practices in agriculture systems, and the extent to which these processes can be transformed. Sustainability in agriculture is a broad topic, hence this study focuses on one segment of sustainability namely the use and management of water resources in irrigated agriculture. The study’s final recommendations to improve policy design and interventions, however, are general and apply to the implementation of all sustainable farm practices. Practical effectiveness of EU policies and directives for sustainable agriculture is constrained by: a lack of evaluating criteria to measure policy impact and communicate progress; incentives for growers to commit to more than the minimum required, and continuous local renegotiation of proposed measures and programmes which have contributed to a weakening of initial policy proposals. This study demonstrates that policies serve different purposes for different people at different social and political levels. However, sustainability comes into practice on the farm, which is why farmers’ perspective about a sustainable agricultural sector and the proposed voluntary and mandatory policy measures is so important. Farmers’ perspectives are still missing elements in policy design for sustainable agriculture. Co-developing and testing technologies that are meant to deliver sustainability in practice, as well as farm decision support tools, are critical in engaging farmers and other local stakeholders in sustainability and to transform embedded practices and institutions. Collaboration across disciplines is also important to address environmental goals and farmers’ needs in order to extract substantial environmental benefits as well as a long term commitment from land managers in sustainability. This study shows that there are many insights to be gained and learnings to be extracted from scrutinizing policy interventions. It raises awareness about improving policy implementation by providing practical examples from case studies conducted in Spain and in Italy. These insights encourage the use of interdisciplinary approaches, including socio-technical approaches, for an integrated people and technology based perspective on natural resource management to better policy design and interventions and make sustainable agriculture real.
9

The value of agri-environment schemes and farm woodland for bats and nocturnal insects

Fuentes-Montemayor, Elisa January 2011 (has links)
Many bat species in Europe have undergone severe population declines during the last century and one of the driving causes is believed to be the loss of roosting and foraging habitat through agricultural expansion and intensification. Modern agricultural practices have also had strong negative effects on many insect groups, such as moths, which are important components of the diets of many bat species. Agri-environment schemes (AES) have been introduced in many countries as an attempt to counteract the negative effects of intensive agriculture on biodiversity by providing financial incentives for farmers to adopt environmentally-sensitive agricultural practices. AES are potentially beneficial to bats and nocturnal insects, but the response of these taxa to their implementation had not been assessed prior to this study. Here, the potential benefits (or otherwise) that bats and their insect prey species gain from the implementation of certain AES management prescriptions was assessed using ultrasonic detectors (to assess bat activity levels) and heath light traps (to quantify nocturnal insect abundance) at 18 pairs of AES and conventionally-managed farms. In addition, the influence of the surrounding landscape on bats and insects was quantified to evaluate the relevance of a landscape-scale management approach for the conservation of these taxa. Some of the AES prescriptions assessed in this study benefited moths (and are potentially beneficial for moth-eating bats), but not Pipistrelle bats nor their insect prey. The most important factors associated with bat activity on farmland were metrics related to woodland configuration in the surrounding landscape, which suggests that conservation efforts for bats should focus on the creation and management of this habitat. Currently, some AES prescriptions aim to increase the amount and quality of woodland on agricultural land, but little is known about how woodland character relates to bat abundance and insect prey availability; therefore, recommendations for woodland creation and management rarely consider the requirements of foraging bats. Here, the influence of woodland character (e.g. vegetation structure and patch configuration) on bats and nocturnal insects was assessed. Vegetation surveys were conducted and Geographic Information Systems (GIS) were used to quantify the vegetation character and spatial configuration of 34 woodland patches within farmland. Two complementary methods (acoustic monitoring and bat trapping assisted by an acoustic lure) were used to assess the influence of woodland vegetation character, patch configuration and the surrounding landscape on bat populations. Nocturnal insect abundance at each site was assessed using heath light traps. Data presented here demonstrate that bats show species-specific associations with woodland vegetation structure and patch configuration; patterns of higher bat abundance and activity at small and isolated woodland patches suggest that bats utilize this habitat more intensively in landscapes where woodland is scarce. This thesis also shows that moths are strongly influenced by woodland character; in general, large woodland patches of compact shapes, composed of a large number of native tree species and a dense understory cover, and located close to other woodlands were associated with high moth abundance and species richness (and are potentially valuable for moth-eating bats). Other nocturnal insects (mainly Diptera) were not influenced by woodland character. This study also shows that bats and nocturnal insects are influenced by the landscape context; moths are mainly influenced by the extent of semi-natural environment (such as rough grassland and scrub) within small spatial scales (within 250 m; although effects of woodland extent were detected at larger spatial scales for woodland specialists moths). Bats are mainly influenced by woodland-related landscape metrics. Some bat species are influenced by the surrounding landscape at large spatial scales (within 3 km) and would benefit from woodland creation and management at a wide-landscape-scale. The findings presented in this thesis have important management implications for the design of agri-environment schemes. A list of management recommendations to optimize the benefits that bats and nocturnal insects gain from these schemes is presented in the final section.
10

Nesting ecology, management and population genetics of bumblebees : an integrated approach to the conservation of an endangered pollinator taxon

Lye, Gillian C. January 2009 (has links)
Bumblebees have shown both long and short-term declines throughout their range. These declines may be attributed to a range of factors including changes in land use, alterations in climatic conditions and species introductions. However, management strategies for bumblebee conservation often focus on provision of summer forage resources and other factors are frequently overlooked. Provision of spring forage and nesting sites for bumblebee queens are rarely considered, though colony foundation and early colony growth are two of the most sensitive stages in bumblebee life history. Here, the efficacy of certain agri-environment prescriptions for providing spring forage and nest sites for bumblebees is assessed, highlighting a need for specific schemes targeted towards the provision of these vital resources in the rural environment. The nesting ecology of bumblebees is poorly understood because wild colonies are difficult to locate. However, a greater knowledge of the colony-level effects of environmental change is crucial to understanding bumblebee declines. Attracting bumblebee queens to nest in artificial domiciles could provide a valuable tool for studying colony-level responses. However, domicile trials and the findings of a literature review presented here demonstrate that this approach may be largely impractical for use in the UK. Conversely, a nationwide public bumblebee nest survey produced numerous data regarding nest site preferences among bumblebee species and also demonstrated that citizen science may also provide a sensitive method for detecting declines in currently common bumblebee species. An understanding of the ecology of species interactions and coexistence can provide valuable insights into factors that may influence declines. Data presented here suggest that coexistence between some bumblebee species may be maintained by resource partitioning based on diel activity patterns that are linked to species-specific environmental tolerances. If this is the case, the potential role of climate change in bumblebee declines may be severely underestimated. There is also increasing evidence that genetic factors may play a role in bumblebee losses, accelerating declines of small, fragmented populations as a result of reduction in genetic diversity and inbreeding depression. Here, the feasibility of reintroducing British B. subterraneus (now extinct in the UK) from New Zealand into England is assessed using population genetic techniques. The findings suggest that the population history of B. subterraneus in New Zealand has resulted in a dramatic loss of genetic diversity and high genetic divergence from the original UK population, suggesting that it may not be a suitable for use in the reintroduction attempt. This work draws together some understudied aspects of bumblebee ecology with a particular focus on nest site requirements, availability of spring forage, mechanisms of avoidance of inter-specific competition and population genetic processes. The potential role of these in bumblebee declines is considered and new data relevant to the conservation of these important species is presented. It is hoped that this work will inform future management strategies for bumblebee conservation, highlight areas in need of further study and provide a sound starting point for future research in these areas.

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