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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.
611

Analyse des conflits et synergies entre services écosystémiques multiples en vergers de pommiers / Analyzing multiple ecosystem services in apple orchards

Demestihas, Constance 23 February 2017 (has links)
Le concept de « service écosystémique », en plein essor depuis la publication du Millenium Ecosystem Assessment en 2005, a permis de souligner l'importance des performances non-marchandes des écosystèmes. En arboriculture, assurer une bonne productivité tout en préservant les ressources naturelles et la santé humaine est aujourd’hui un défi majeur, qui peut être analysé sous l’angle des services écosystémiques. Quels sont ces services au sein d’un verger de pommiers ? Comment les analyser ? Quels sont les liens - conflits et synergies - entre services écosystémiques multiples et comment les systèmes de culture modifient-ils les profils de services multiples? Ce travail de thèse vise à répondre à ces questions avec une démarche novatrice combinant mesures expérimentales, modélisation et analyse statistique. Suite à une analyse bibliographique des services écosystémiques pouvant être délivrés dans des vergers, cinq services ont été sélectionnés. Il s’agit de la production de fruits, de la disponibilité de l’azote dans le sol, de la régulation du climat reposant sur la prévention de la dénitrification de l’azote et sur la séquestration du carbone, de la maintenance et de la régulation du cycle de l’eau y compris de sa qualité, et de la régulation des bioagresseurs. Conjointement à ces services nous avons considéré les nuisances environnementales dues aux pesticides. Pour chaque service nous avons identifié les fonctions écosystémiques sous-jacentes ainsi que les pratiques agricoles et les conditions pédoclimatiques ayant un impact sur ces fonctions. Les services et fonctions ont été décrits par un ou plusieurs indicateurs et quantifiés à l’aide de modèles dans les cas suivants : (i) neuf systèmes de culture réels sur deux dispositifs expérimentaux dans le sud-est de la France et (ii) 150 systèmes de culture fictifs conçus à partir de la combinaison de cinq leviers de pratiques et de leurs modalités, dans des conditions pédoclimatiques identiques. Les deux modèles utilisés ont été STICS, un modèle générique de simulation du fonctionnement du sol et des cultures sous l’influence des pratiques, qui a nécessité une paramétrisation et une évaluation sur pommier à partir de mesures expérimentales, et IPSIM, une plateforme de modélisation simulant les effets des pratiques et des conditions du milieu sur les dégâts aux cultures causés par les bioagresseurs. IPSIM a été paramétré sur pommier, sur la base d’une importante étude bibliographique et à dires d’experts. Les simulations des modèles ont fait l’objet d’analyses statistiques simples dans le cas des systèmes de culture réels, et d’analyses multivariées à deux tableaux (analyse en composantes principales avec variables instrumentales) pour les systèmes de culture fictifs. Pour les neufs systèmes de culture réels, 14 liens importants entre services écosystémiques ont été identifiés, notamment des conflits comme celui entre la prévention de la dénitrification ou de la lixiviation de l’azote et la disponibilité de l’azote dans le sol à court terme, et des synergies, comme celle entre l’humidité du sol ou la séquestration du carbone et la disponibilité de l’azote dans le sol à court terme. Ces liens entre services sont expliqués par les fonctions écosystémiques sous-jacentes. La comparaison de profils de services entre systèmes a mis en évidence l’impact de pratiques agricoles sur certains services. Ainsi, sur un même site, une forte densité de plantation augmente la production de fruits et la séquestration du carbone. La fertilisation exclusivement sous une forme organique diminue la production de fruits via un stress azoté mais diminue également la lixiviation. Par ailleurs, les profils de services sont fortement influencés par les caractéristiques pédoclimatiques de chaque site. Ces résultats confortent la nécessité d’une prise en compte explicite de l’interdépendance ‘pratiques x conditions du milieu’ pour analyser les services. / The concept of « ecosystem service », which has been used increasingly since the publication of the Millennium Ecosystem Assessment in 2005, has highlighted the importance of ecosystem’s non-marketed performances. In orchards, ensuring high productivity while preserving natural resources and human health has become a real challenge that could be analyzed with the concept of ecosystem service. Which ecosystem services are delivered in an apple orchard? How to analyze them? What are the relationships - conflicts or synergies – among multiple ecosystem services and how do cropping systems change multiple ecosystem service profiles? This PhD work aims at answering those questions with an innovative approach combining experimental measures, modeling and statistical analysis.Based on a literature review of ecosystem services in orchards, five services were selected: fruit production, nitrogen availability in soil, climate regulation based on the prevention of nitrogen denitrification and on carbon sequestration, maintenance and regulation of water cycle, including water quality, and pest control. We also considered the environmental disturbances caused by the use of pesticides. For each service, we identified the underlying ecosystem functions as well as the agricultural practices and soil and climate conditions affecting these functions. Services and functions were described by one or multiple indicators and quantified using models in the case of (i) nine existing cropping systems on two experimental sites in southeastern France differing in terms of soil and climate conditions, and (ii) 150 virtual cropping systems designed out of the combination of five major agricultural practice levers and their modalities, in identical soil and climate conditions. The two models used were STICS, a generic soil-crop simulation model under the influence of practices which required a parameterization and an evaluation on apple orchards based on experimental measures, and IPSIM, a generic modeling framework simulating the impacts of agricultural practices and local conditions on crop injuries caused by pests. IPSIM was parameterized on apple orchards, based on an important literature review and expert opinions. Model simulations were analyzed with simple statistics in the case of the nine existing cropping systems and with two-table multivariate analyses (principal component analysis with instrumental variables) for virtual cropping systems.Concerning the existing cropping systems, 14 important relationships were identified among ecosystem services, especially conflicts, like the one between nitrogen denitrification or leaching prevention and soil nitrogen availability on the short term, and synergies such as the one between soil humidity or carbon sequestration and nitrogen availability on the short term. These relationships are explained by the underlying ecosystem functions. Comparing service profiles among cropping systems highlighted the impacts of agricultural practices on some services. That way, on a same site, a high planting density increases fruit production and carbon sequestration. An exclusively organic fertilization decreases fruit production through nitrogen stress but also nitrogen leaching in drained water. Furthermore, service profiles are strongly influenced by the soil and climate conditions of each site. These results strengthen the need to explicitly consider the ‘agricultural practices x soil and climate conditions’ interdependence in order to analyze ecosystem services. The results obtained with the virtual cropping systems simulations confirmed those of the existing ones and gave precision on the impacts of fertilization, irrigation and pest control for codling moth, rosy apple aphid and apple scab on ecosystem functions and services.
612

A comparison of ecosystem health and services provided by subtropical thicket in and around the Bathurst commonage

Stickler, Meredith Mercedes January 2010 (has links)
Municipal commonage in South Africa offers previously disadvantaged, landless residents access to both direct ecosystem goods and services (EGS) that provide additional income options and indirect social and cultural services. Given that EGS production is a function of ecosystem health, it is imperative that commonage land be managed to maximize current local benefit streams while ensuring future options through the maintenance of natural ecosystem functions. The payments for ecosystem services (PES) model potentially offers an opportunity for contributing to local economic development while providing fiscal incentives for environmentally sustainable natural resource management. PES depends on the demonstration of quantifiable changes in EGS delivery due to improvement in or maintenance of high ecosystem health that are a verifiable result of modifications in management behavior. This thesis therefore compared spatial variations in (i) ecosystem health and (ii) nine direct and indirect EGS values derived from natural resources on the Bathurst municipal commonage and neighboring Waters Meeting Nature Reserve (NR) to explore how different land use intensities affect ecosystem health and the resulting provision of EGS. The results indicate that the total economic value of annually produced EGS on the study site is nearly R 9.8 million (US$ 1.2 million), with a standing stock of natural capital worth some R 28 million (US$ 3.4 million). Nearly 45% of the total annual production is attributed to Waters Meeting NR, with roughly 34% from the low use zone of the commonage and the remaining 22% from the high use zone. Of the total annual production value on the study site, roughly 59% is derived from indirect (non-consumptive) uses of wildlife for the study site as a whole, though this proportion varies from 25% in the high use zone of the commonage to 94% on Waters Meeting NR. The two largest annual production values on the study site derive from ecotourism (R 3.5 million, US$ 0.4 million) and livestock production (R 2.6 million, US$ 0.3 million), suggesting that while increased production of indirect EGS could generate significant additional revenues, especially on Waters Meeting NR and in the low use zone of the commonage, direct (consumptive) EGS will likely remain an important component of land use on the commonage. A PES project to support the adoption of silvo-pastoral practices could provide positive incentives for improved land use practices on the commonage and potentially be financed by conservation-friendly residents of the Kowie River catchment and/or increased ecotourism revenues from Waters Meeting NR. Allowing carefully designed and monitored local access to natural resources within Waters Meeting NR could also reduce pressure on commonage resources. Together, these approaches could lead to a more sustainable subtropical thicket landscape and ensure that critical natural resources remain available to support local livelihoods in the long-term.
613

Developing and testing the congruency of selected biological indicators and an existing tool designed to assess wetland health in agricultural settings in the KZN Midlands

Kubheka, Patrick Skhumbuzo January 2018 (has links)
Despite the fact that wetlands have been understood to be important for a wide range of ecosystem services, wetlands continue to be degraded globally. There has been a growing need to develop biomonitoring tools that reflect the present ecological state of wetlands, but very few attempts have been made in South Africa to achieve this, and those that have attempted this have generally achieved limited success. This study was conducted to develop and test the congruency of four selected biological indicators (dragonflies, frogs, macroinveterbrates and plants) in relation to the assessment of present ecological state using an existing method in South Africa, "WET-Health". WET-Health assessments rely primarily on transformations to a wetland that result from human impacts in both the catchment and the wetland itself. Using the tool, a health score is obtained that is consistent with the Department of Water Affairs (DWA) current "present ecological state” as applied to river health assessment. The study was conducted in agricultural settings of the Midlands of KwaZulu-Natal based on 13 wetlands. The selected wetlands were scored using WET - Health and grouped in four different ecological condition classes (A, B, C and D). Physical characteristics (wetland area, mean depth), biological characteristics (species cover/abundance, presence and species richness), and chemical characteristics (ammonia, pH, sulphate, nitrogen and phosphate) were also recorded in the selected wetlands. Nineteen different species of dragonfly were recorded in this study. The study demonstrated that dragonflies are a promising bioindicator of wetland present ecological state as the dragonfly index was found to be closely correlated with WET- Health scores. Open water bodies within the selected wetlands were the focus of dragonfly sampling, as male dragonflies are territorial and they will patrol or be found around this habitat. Emergent vegetation dominated by sedges formed the focus of macroinvertebrate sampling in this study because greater numbers of macroinvertebrate families were found in this biotope in comparison to open water areas with no emergent vegetation. A total of 47 macroinvertebrate families were recorded in this study, but SASS5 scores based on macroinvetebrates showed no correlation with WET-Health scores. A total of 10 different frog species were recorded in this study. All the species were common frog species found in most parts of the country. Frog species richness and occurrence showed no correlation with WET- Health scores. A total of twenty samples of two meter radius were measured per wetland and sampled for plant species and estimation of cover-abundance of each species per sample. Over 50 different plant species were recorded in this study, and both species accumulation and species richness showed a degree of correlation with WET-Health scores. All the wetlands in class A had generally higher species accumulation rate and species richness compared to the other wetland classes. In addition to testing the congruency of four selected biological indicators with WET- Health, water quality was measured in all the wetlands. Wetlands in class A were associated with improved water quality as the water passes through the wetland. However, wetlands in class C and D did not show consistently improved water quality between the apex and the toe of these wetlands. In some cases the water quality deteriorated as it passed through wetlands in these two classes.
614

Conception et évaluation de systèmes de production intégrant culture et élevage à l'échelle du territoire / Co-design and assessment of integrated crop-livestock systems at territory level

Moraine, Marc 28 April 2015 (has links)
L’intégration culture – élevage à l’échelle territoire représente une voie pour améliorer le fonctionnement métabolique et les services écosystémiques fournis par les systèmes agricoles, malgré les contraintes de spécialisation des exploitations. Cette thèse propose une méthodologie de conception de systèmes culture – élevage au niveau du territoire, dans une démarche participative structurée en trois grandes étapes : diagnostic des enjeux, conception d’options techniques et organisationnelles, évaluation multicritère. Chaque étape est outillée par un cadre conceptuel et une grille d’évaluation multicritère adaptée aux dispositifs de terrain menés sur le bassin versant de l’Aveyron. Les scénarios construits présentent deux modèles de l’intégration culture – élevage : une « filière territorialisée » pour la production de luzerne dans les systèmes de culture de l’aval du bassin à destination des élevages de l’amont, un « collectif d’agriculteurs bio » échangeant directement de la luzerne, des méteils et du fumier dans des groupes locaux. Chaque scénario présente des performances de durabilité améliorées et pourraient être complémentaires pour le changement de pratiques sur le territoire. La méthodologie développée permet la conception multi-niveaux et multi-domaines de scénarios d’intégration, et pourrait être renforcée par une évaluation quantitative des bénéfices attendus et des coûts de coordination entre acteurs. / Crop-livestock integration at territory level may be a pathway to impove metabolic functions and delivery of ecosystem services in agricultural systems, overcoming the constraints of farm specialization. This thesis builds on a methodology of participatory design of integrated crop-livestock systems at territory level in three steps: diagnosis of issues, design of technical and organizational options for change, multicriteria assessment. Each step is supported with a conceptual framework and a multicriteria grid adapted to the case study in Aveyron river basin. The designed scenarios show two approaches of crop –livestock integration: the introduction of alfalfa in downstream cropping systems sold to upstream livestock systems through a local supply chain and the direct exchanges of alfalfa, cereal-legume mixtures and animal manure in local groups of organic farmers. Both scenario present improved sustainability performances and could be complementary to initiate more sustainable practices in local farming systems. The methodology allows designing multi-level and multi-domain scenarios of crop-livestock integration. It could be improved with models for quantitative assessment of benefits and coordination costs among stakeholders.
615

Adaptação às mudanças climáticas baseada em ecossistemas (AbE): análise da revitalização do córrego do sapé (São Paulo). / Ecosystem-based adaptation (EbA) for climate change: analysis from the revitalization of stream Sapé (São Paulo)

Rolo, Daniella Aparecida de Mattos de Oliveira 27 June 2017 (has links)
Submitted by Nadir Basilio (nadirsb@uninove.br) on 2018-04-13T18:05:31Z No. of bitstreams: 1 Daniella Aparecida de Mattos de Oliveira Rolo.pdf: 2430125 bytes, checksum: 5a71113f27fa651e2907fdb24ad51629 (MD5) / Made available in DSpace on 2018-04-13T18:05:31Z (GMT). No. of bitstreams: 1 Daniella Aparecida de Mattos de Oliveira Rolo.pdf: 2430125 bytes, checksum: 5a71113f27fa651e2907fdb24ad51629 (MD5) Previous issue date: 2017-06-27 / The revitalization of urban rivers and streams plays an important role in the quest for environmental sustainability in cities. Notwithstanding the environmental degradation that affects their watercourses, cities are also suffering the impacts of another relevant process that deteriorates the environmental quality, climate change. To face climate change, in addition to mitigation measures, it is imperative to adopt adaptation measures. Green and blue infrastructure are solutions that reconcile engineering, plant restoration and water quality maintenance, which add ecosystem services to the revitalization of urban drainage, and may include ecosystem-based adaptation measures. In this context, the general objective of the research is the revitalization of urban streams in the promotion of measures to adapt to climate change based on ecosystems (EbA), from the case of the Sape stream. With this, we add the specific objectives in order to characterize the activities of the revitalization process of Sapé stream as a green and blue infrastructure; To identify the ecosystem services associated with the revitalization process of Sapé stream; To analyze the ecosystem services associated with the urban and environmental improvements promoted in the revitalization process in relation to measures of EbA and to evaluate if the EBAs meet the recommended in the Adaptation Plan to climate change in the Ministry of the Environment (MMA). This research has a qualitative and exploratory purpose. The sources of evidence for the accomplishment of the case study refer to: bibliographic research, documentary research, field data collection and semi-structured interviews. The results were obtained through documental, bibliographic analysis and interviews analyzed by the software IRAMUTEQ, after a comparison of the literature with the EbA found in the place. Finally, it is concluded that the recognition that urban drainage revitalization programs lead to EbA measures can contribute to a more in-depth discussion of the scope of public programs that aim to reverse the current degradation of urban rivers. / A revitalização dos rios e córregos urbanos assume um papel relevante na busca pela sustentabilidade ambiental nas cidades. Não obstante o quadro de degradação ambiental que afeta seus cursos d´água, as cidades também vêm sofrendo os impactos de outro relevante processo que deteriora a qualidade ambiental, as mudanças climáticas. Para enfrentar as mudanças climáticas, além das medidas de mitigação, se faz premente a adoção de medidas de adaptação. Infraestrutura azul revelam-se soluções que conciliam medidas de engenharia, de recomposição vegetal e de manutenção da qualidade de água, que agregam serviços ecossistêmicos na revitalização de drenagens urbanas e podem abranger medidas de adaptação baseada em ecossistemas. Nesse contexto, insere-se o objetivo geral da pesquisa que consiste na revitalização de córregos urbanos quanto à promoção de medidas de adaptação a mudanças climáticas baseada em ecossistemas (AbE), a partir do caso do córrego do Sapé. Com isso soma-se os objetivos específicos a fim de caracterizar as atividades do processo de revitalização do córrego do Sapé enquanto infraestrutura verde e azul; identificar os serviços ecossistêmicos associados ao processo de revitalização do córrego do Sapé; analisar os serviços ecossistêmicos associados as melhorias urbanas e ambientais promovidas no processo de revitalização quanto a medidas de AbE e avaliar se as eventuais AbE atendem o preconizado no Plano de Adaptação à mudança do clima no Ministério do Meio Ambiente (MMA). Esta pesquisa tem caráter qualitativa e de objetivo exploratório. As fontes de evidências para consecução do estudo de caso referem-se a: pesquisa bibliográfica, pesquisa documental, levantamento de dados de campo e entrevistas semiestruturadas. Os resultados foram obtidos por meio da análise documental, bibliográfica e entrevistas analisadas pelo software IRAMUTEQ, após foi feito uma comparação da literatura com as AbE encontrada no local. Por fim conclui-se que o reconhecimento de que programas de revitalização de drenagens urbanas ensejam medidas de AbE permite contribuir para uma discussão mais aprofundada do alcance dos programas públicos que visam reverter o quadro de degradação atual dos rios urbanos.
616

Forest Management Approaches for Coping with the Uncertainty of Climate Change: Trade-Offs in Service Provisioning and Adaptability

Wagner, Sven, Nocentini, Susanna, Huth, Franka, Hoogstra-Klein, Marjanke 01 August 2014 (has links)
The issue of rapid change in environmental conditions under which ecosystem processes and human interventions will take place in the future is relatively new to forestry, whereas the provision of ecosystem services, e.g., timber or fresh water, is at the very heart of the original concept of forest management. Forest managers have developed ambitious deterministic approaches to provide the services demanded, and thus the use of deterministic approaches for adapting to climate change seem to be a logical continuation. However, as uncertainty about the intensity of climate change is high, forest managers need to answer this uncertainty conceptually. One may envision an indeterministic approach to cope with this uncertainty; but how the services will be provided in such a concept remains unclear. This article aims to explore the fundamental aspects of both deterministic and indeterministic approaches used in forestry to cope with climate change, and thereby point out trade-offs in service provisioning and adaptability. A forest owner needs to be able to anticipate these trade-offs in order to make decisions towards sustainable forest management under climate change.
617

The Social Impacts of Tourism in the UNESCO Champlain Adirondack Biosphere Reserve (USA)

Cerialo, Kelly L. 30 June 2021 (has links)
No description available.
618

Response of rodents to land use gradients in small-holder farms in Northern Limpopo: implications for ecologically-based rodent management (EBRM)

Nembudani, Nkhumeleni Lesly 18 September 2017 (has links)
MENVSC / Department of Ecology and Resource Management / Rodents can quickly respond to land use changes whether the change positively or negatively influences their life. In the case of positive influence, rodents exploit the additional food resources and increase their numbers to potential pest level, especially in the absence of predators. Such a population increase can potentially be harmful to humans due to the diseases that rodents carry and the costs due to damage to crops, stored foods and personal possessions that they may cause to small holder farmers. Small holder farmers live in a mixed landscape that is constantly changing. Such changes are changes in land use and they do not only affect rodent population dynamics and species composition, but also their ecosystem services and integrity. Understanding how rodents respond to these land use changes (crop, grazing and settlement) will not only improve the implementation of Ecologically Based Rodent Management (EBRM), but might also enable the monitoring of ecosystem integrity. Rodent trapping was conducted in two different study sites which experience different rainfalls during wet and dry season. A 70 m x 70 m grid was set in three different land uses (crops, grazing and settlement) per study site. A mark-recapture technique was applied and all captures were processed on a temporal station on site. In all grids at a distance of 30 m a line of 20 snap traps were set. With the tapping effort of 1470 trap nights per season for both seasons in this study we captured 839 rodents and 2 shrews, which represented 469 individual rodents and 1 individual shrew. At Vyeboom, cropping land use had the highest number capture (210) and the highest in species richness (9) rodent species and 1 shrew. The settlement land use was second at 144 captures for 8 rodent species and lastly the grazing land use at 80 captures with 7 rodent species. On the other hand, at Ka-Ndengeza also cropping land use had the highest capture (186) with highest richness at 7 rodent species. When it comes to settlement and grazing, settlement was second (129) to cropping in terms of the number of capture but last in terms of richness (5) whilst grazing was last in terms of number of captures 92 and second in terms of richness (6). Despite the high diversity of rodents, only Mastomys natalensis, Gerbilliscus leucogaster, Steatomys pratensis and Rattus rattus were captured in meaningful sample sizes to allow for robust density estimation. Similarly there were strong seasonal effects on rodent captures, with almost no captures during the wet season.
619

Ecosystem services and disservices of ants in subsistence farming (Limpopo Province) : an experimental approach in mango orchards.

Maphote, Vongani Terrence 18 August 2017 (has links)
MSc (Zoology) / Department of Zoology / See the attached abstract below
620

Policies and Management Practices for Sustainable Oil Palm - Evidence from Indonesia

Rudolf, Katrin 12 May 2020 (has links)
No description available.

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