• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 322
  • 105
  • 70
  • 51
  • 15
  • 15
  • 7
  • 4
  • 3
  • 3
  • 3
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 685
  • 685
  • 179
  • 127
  • 113
  • 107
  • 103
  • 91
  • 88
  • 87
  • 85
  • 81
  • 81
  • 79
  • 74
  • 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.
591

Les transformations microbiennes de l’azote dans les grandes rivières

Tall, Laure 02 1900 (has links)
Les rivières reçoivent de l'azote de leurs bassins versants et elles constituent les derniers sites de transformations des nutriments avant leur livraison aux zones côtières. Les transformations de l’azote inorganique dissous en azote gazeux sont très variables et peuvent avoir un impact à la fois sur l’eutrophisation des côtes et les émissions de gaz à effet de serre à l’échelle globale. Avec l’augmentation de la charge en azote d’origine anthropique vers les écosystèmes aquatiques, les modèles d’émissions de gaz à effet de serre prédisent une augmentation des émissions d’oxyde nitreux (N2O) dans les rivières. Les mesures directes de N2O dans le Lac Saint-Pierre (LSP), un élargissement du Fleuve Saint-Laurent (SLR) indiquent que bien qu’étant une source nette de N2O vers l'atmosphère, les flux de N2O dans LSP sont faibles comparés à ceux des autres grandes rivières et fleuves du monde. Les émissions varient saisonnièrement et inter-annuellement à cause des changements hydrologiques. Les ratios d’émissions N2O: N2 sont également influencés par l’hydrologie et de faibles ratios sont observés dans des conditions de débit d'eau plus élevée et de charge en N élevé. Dans une analyse effectuée sur plusieurs grandes rivières, la charge hydraulique des systèmes semble moduler la relation entre les flux de N2O annuels et les concentrations de nitrate dans les rivières. Dans SLR, des tapis de cyanobactéries colonisant les zones à faible concentration de nitrate sont une source nette d’azote grâce à leur capacité de fixer l’azote atmosphérique (N2). Étant donné que la fixation a lieu pendant le jour alors que les concentrations d'oxygène dans la colonne d'eau sont sursaturées, nous supposons que la fixation de l’azote est effectuée dans des micro-zones d’anoxie et/ou possiblement par des diazotrophes hétérotrophes. La fixation de N dans les tapis explique le remplacement de près de 33 % de la perte de N par dénitrification dans tout l'écosystème au cours de la période d'étude. Dans la portion du fleuve Hudson soumis à la marée, la dénitrification et la production de N2 est très variable selon le type de végétation. La dénitrification est associée à la dynamique en oxygène dissous particulière à chaque espèce durant la marée descendante. La production de N2 est extrêmement élevée dans les zones occupées par les plantes envahissantes à feuilles flottantes (Trapa natans) mais elle est négligeable dans la végétation indigène submergée. Une estimation de la production de N2 dans les lits de Trapa durant l’été, suggère que ces lits représentent une zone très active d’élimination de l’azote. En effet, les grands lits de Trapa ne représentent que 2,7% de la superficie totale de la portion de fleuve étudiée, mais ils éliminent entre 70 et 100% de l'azote total retenu dans cette section pendant les mois d'été et contribuent à près de 25% de l’élimination annuelle d’azote. / Rivers receive nitrogen (N) from their watershed and are the final sites of nutrient processing before delivery to coastal waters. Transformations of dissolved inorganic N (DIN) to gaseous N are highly variable and can impact both coastal eutrophication and greenhouse gas emissions. With anthropogenic N loading to aquatic ecosystems on the rise, nitrous oxide (N2O) emission from rivers should increase. Direct measurements of N2O from lake St. Pierre (LSP), an enlargement of the St. Lawrence River (SLR) indicate that although LSP is a net atmospheric source of N2O to the atmosphere fluxes are low compared to others rivers. Emissions are seasonally and inter-annually highly variable due to changes in hydrological conditions. N2O: N2 is also influenced by hydrology and lower ratios are observed in conditions of higher water discharge and elevated N charge into the ecosystem. In a cross system analysis, hydraulic load mitigates the relation between annual N2O flux and nitrate concentrations in rivers. In SLR, cyanobacterial mats colonizing low nitrate areas are a net source of N with high negative di-nitrogen (N2) fluxes. Given that fixation occurred during daylight and that oxygen concentrations in the water column were supersaturated, we hypothesize that N2 fixation is performed by the dominant cyanobacteria in anoxic micro-zone of the mat and/ or possibly by heterotrophic diazotrophs. Our estimates indicate that N fixation in the mats account for the replacement of up to 33% of the N loss via denitrification in the entire ecosystem during the study period. In the tidal Hudson River N2 production is highly variable between vegetated shallows and was associated with species-driven differences in dissolved oxygen (DO) dynamics during the ebb tide. N2 production was extremely high in invasive floating-leaved plants (Trapa natans) but was insignificant in submersed native vegetation. An estimate of summertime N2 production in Trapa beds suggests that these beds are a major seasonal hotspot for N removal. Large Trapa beds represent only 2.7% of the total area of the tidal Hudson but they remove between 70 and 100% of the total N retained in this section of the river during summer months and contribute to as much as 25% of the annual N removal.
592

Etude des compromis et synergies entre services écosystémiques et biodiversité : Une approche multidimensionnelle de leurs interactions dans le socioécosystème des Alpes Française / Addressing trade-offs and synergies among ecosystem services and biodiversity : A multi-dimensional approach of their interactions in the French Alps social-ecological system

Crouzat, Emilie 13 May 2015 (has links)
Dans un contexte de changement climatique global et d'évolution locale de l'usage des terres, le devenir des paysages culturels des Alpes françaises, façonnés au cours des siècles par les interactions mutuelles entre sociétés et environnement, apparaît incertain. Dans le même temps, les écosystèmes qui les constituent abritent une biodiversité riche et sont à l'origine de nombreuses ressources naturelles et fonctions écologiques dont bénéficient les populations humaines. Ces ressources et fonctions sont conceptualisées sous le terme de « services écosystémiques » et font aujourd'hui l'objet d'une attention accrue dans la gestion et la protection des ressources environnementales, au même titre que la biodiversité. L'identification des facteurs liés à leur maintien, en termes écologiques, socio-culturels et politiques, est une étape nécessaire à leur gestion durable, bien qu'encore insuffisamment explorée. Mon projet de thèse visait à accroître la compréhension des interactions positives (synergies) et négatives (antagonismes) entre services écosystémiques et biodiversité via une approche multidimensionnelle du socio-écosystème des Alpes françaises. - Le Chapitre I propose une approche biophysique quantitative et spatialisée de la multifonctionnalité des écosystèmes. Suite à une étape de modélisation, les patrons spatiaux de synergie et d'antagonisme entre services et biodiversité ont été explorés statistiquement et reliés à des enjeux de gouvernance actuels à différentes échelles. Ce travail a permis d'identifier les bouquets de services écosystémiques représentatifs des différentes conditions biogéographiques, de gestion et de d'hétérogénéité du paysage représentées dans le massif. - Cette approche est complétée dans le Chapitre II par une représentation qualitative des relations d'influence entre services écosystémiques et biodiversité, ainsi que de leurs liens avec d'autres variables écologiques et sociales. Nous avons considéré explicitement les dimensions multiples englobées par le concept de service écosystémique (leurs ‘facettes') et proposons un cadre conceptuel pour en cartographier les réseaux d'influence. Ce cadre a servi de base à l'analyse d'un processus consultatif que nous avons mené auprès d'acteurs du territoire. Les analyses ont mis en lumière leur perception globale des relations d'influence importantes au sein du socio-écosystème. - Afin de mieux comprendre les régulations sociales appliquées à la gestion environnementale, nous testons dans le Chapitre III une méthodologie d'analyse de l'efficacité environnementale d'instruments de gouvernance. Notre analyse a privilégié un nombre restreint d'instruments qui encadrent actuellement les interactions entre agriculture, tourisme et biodiversité. L'utilisation d'un ensemble d'indicateurs de performance et d'adéquation avec le cadre socio-culturel et de gouvernance a souligné l'articulation complexe des instruments entre eux et a abouti à la production d'une synthèse pour les décideurs (‘policy brief'). - Le Chapitre IV explore enfin certains enjeux conceptuels et éthiques de la recherche dans le domaine des services écosystémiques. Après une réflexion générale sur les relations entre science et société, je propose une évaluation réflexive et personnelle des projets de recherche auxquels j'ai contribué. Pour conclure, je propose une vision transversale du socio-écosystème alpin mettant en lumière les enjeux majeurs identifiés par les différentes analyses. / In the context of global climate change and local land use changes, the future of the French Alps cultural landscapes, shaped through long-lasting and mutual interactions between human and their environment, appears uncertain. Simultaneously, the ecosystems constituting alpine landscapes host a rich biodiversity and provide the many natural resources and ecological functions that benefit to human societies. These resources and functions are conceptualised as “ecosystem services” and currently attract an increasing attention for the management and the conservation of environmental resources, along with biodiversity. Identifying the variables linked to their maintenance, in ecological, socio-cultural and political terms, is a necessary step of their sustainable management, and yet is still under-explored. My PhD project aimed at increasing the understanding of positive (synergies) and negative (trade-offs) interactions among ecosystem services and biodiversity through a multi-dimensional approach of the French Alps social-ecological system. - In Chapter I, I present a quantitative and spatially explicit biophysical assessment of ecosystem multifunctionality. After a modelling step, we explored spatial patterns of trade-offs and synergies among ecosystem services and biodiversity using a series of statistical analyses of increasing complexity. Results were structured to provide insights for sound environmental governance at multiple scales. We identified various bundles of ecosystem services representative of the different conditions across the French Alps massif in terms of biogeography, management and landscape heterogeneity. - This approach is complemented in Chapter II by a qualitative representation of influence relationships among ecosystem services and biodiversity that also accounts for additional ecological and social variables. We explicitly considered the multiple dimensions encompassed by the ecosystem service concept (their ‘facets') and proposed an innovative conceptual framework to represent their influence networks. This framework was applied to analyse a consultative process that we carried out with stakeholders of regional expertise. This analysis highlighted their general perception of important influence relationships in the alpine social ecological system. - In order to better understand social regulations linked to environmental governance, we test in Chapter III a methodology for assessing the environmental effectiveness of policy instruments. We concentrated on a restricted set of instruments regulating the interactions between biodiversity, agriculture and outdoor tourism. The consideration of multiple indicators assessing the performance and the fit with the socio-cultural and governance setting highlighted the complex articulation of instruments within the broader policy mix. Results were synthesised in a policy brief targeting regional decision-makers. - Chapter IV is conceived as my personal exploration of the conceptual and ethical issues linked to research on ecosystem services. Following some general thinking on the relations between environmental sciences and society, I conducted a personal reflexive assessment of the research projects I contributed to. To conclude, I propose a synthetic vision of the alpine social-ecological system and discuss the major issues revealed throughout the analyses.
593

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) (PDF)
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.
594

Valuing ecological services and community design : implications for the private market and local government

Hegg, Daniel Alexander 25 August 2009 (has links)
Presently, conventional development does not adequately incorporate functional ecosystems into development design. Largely due to the intangible nature of most ecosystem services, functional ecosystems have not been directly identified as valuable and are, therefore, often ignored in economic decision frameworks. This has resulted in the degradation and loss of functional ecosystems and ecosystem services as the value and the associated costs of lost ecosystem services are not accounted for. The valuation of ecosystem services is a means by which ecological costs and values can be adequately represented in urban planning and decision-making processes. However, using current valuation methods, ecosystems are continuously being valued for their aggregated ecosystem service values and not for the value of their ability to resist/recover from disturbances and continue proving goods and services over time. The Swan Lake watershed case study was utilized to show that the estimated ecosystem service values are not risk adjusted to reflect the functional condition of an ecosystem. Specifically, based upon the current valuation estimates alone and without reference to the functional condition, the estimated ecosystem service values for the Swan Lake study suggest that the watershed is in a good (proper) functional condition, when in-fact, the overall health of the watershed is in a poor condition of health and its resilience to disturbance is low. Furthermore, the estimated values do not reflect the loss of ecosystem services due to past urbanization and agricultural activities. Because the estimated values do not provide the critical information decision makers require, the valuation of the functional condition of ecosystems is recommended. Due to the complexity involved in valuing the functional condition of an ecosystem, the integration of ecosystem valuation methods and ecosystem evaluation assessments is proposed and explored. In the context of post-urban planning and development, the proposed approach has immediate application as it would provide effective financial arguments for the preservation and restoration of ecosystems as well as facilitate more informed decisions in managing existing urban ecosystems for their function rather than ecosystem services. In a pre-development application, there exists a opportunity wherein an ecosystem’s functional condition could be valued as part of an integrated development design and planning process (IDP). The British Pacific Properties (BPP) Rodgers Creek development is used as a case study to describe how the proposed approach could be incorporated into the integrated design and planning (IDP) process. By clarifying the ecological tradeoffs between various land-use/development scenarios using a sieve analysis, the proposed approach could help a design team render more informed judgments regarding the functional condition of ecosystems and the value of the ecosystem services. The proposed approach also contributes to a much needed business case, which demonstrates that when urban developments are planned using an IDP process, where the landscape informs the design, there can be greater financial reward to the developer, community and municipality
595

An evaluation of the conservation of New Zealand's threatened biodiversity : management, species recovery and legislation : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Auckland, New Zealand

Seabrook-Davison, Mark Nicholas Hawdon January 2010 (has links)
Content removed from thesis due to copyright restrictions: Seabrook-Davison, M. N. H., Weihong, J. J. & Brunton, D. H. (2010). "Survey of New Zealand Department of Conservation staff involved in the management and recovery of threatened species." Biological Conservation, 143: 212-219. doi: 10.1016/j.biocon.2009.10.005. Seabrook-Davison, M. N. H., Ji, W. & Brunton, D. H. (in press). "New Zealand lacks comprehensive threatened species legislation -- comparison with legislation in Australia and the USA." Pacific Conservation Biology, 16. / It is only recently that New Zealand wildlife managers have become aware of both the taxonomic range of New Zealand’ indigenous biodiversity and the number of species threatened with extinction. The entire New Zealand archipelago has been described as a biodiversity hotspot; a term with both negative and positive connotations as although its biodiversity is unique and diverse, it has lost three quarters of its primary vegetation and much of its remaining endemic biota is in decline. This thesis evaluated aspects of New Zealand’s approach to the management of biodiversity with an emphasis on methods used in the recovery of threatened species. Possible solutions are presented that New Zealand could investigate to improve the delivery of species recovery. A survey was conducted amongst Department of Conservation (DOC) staff to investigate management tools available to them. Results suggest that inadequate resources, staff shortages and an overwhelming workload have resulted in a failure to achieve comprehensive recovery of threatened species. A review of New Zealand wildlife conservation legislation and a comparison with the USA Endangered Species Act 1973 and Australian Environment Protection and Biodiversity Conservation Act 1999, suggests that a lack of dedicated threatened species legislation is hindering the effective recovery of New Zealand’s threatened species. The thesis concludes that New Zealand has the advantage of a large conservation estate but lacks an integrated national management approach to the conservation of its biodiversity. Considerable improvement of the management and recovery of threatened species can be achieved with the enacting of dedicated threatened species legislation. Keywords: Threatened species, biodiversity, biodiversity hotspot, conservation, management, recovery plans, recovery groups, Department of Conservation, legislation, threat classification system, listing, ecological function, ecosystem services, staff survey, New Zealand
596

An evaluation of the conservation of New Zealand's threatened biodiversity : management, species recovery and legislation : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Auckland, New Zealand

Seabrook-Davison, Mark Nicholas Hawdon January 2010 (has links)
Content removed from thesis due to copyright restrictions: Seabrook-Davison, M. N. H., Weihong, J. J. & Brunton, D. H. (2010). "Survey of New Zealand Department of Conservation staff involved in the management and recovery of threatened species." Biological Conservation, 143: 212-219. doi: 10.1016/j.biocon.2009.10.005. Seabrook-Davison, M. N. H., Ji, W. & Brunton, D. H. (in press). "New Zealand lacks comprehensive threatened species legislation -- comparison with legislation in Australia and the USA." Pacific Conservation Biology, 16. / It is only recently that New Zealand wildlife managers have become aware of both the taxonomic range of New Zealand’ indigenous biodiversity and the number of species threatened with extinction. The entire New Zealand archipelago has been described as a biodiversity hotspot; a term with both negative and positive connotations as although its biodiversity is unique and diverse, it has lost three quarters of its primary vegetation and much of its remaining endemic biota is in decline. This thesis evaluated aspects of New Zealand’s approach to the management of biodiversity with an emphasis on methods used in the recovery of threatened species. Possible solutions are presented that New Zealand could investigate to improve the delivery of species recovery. A survey was conducted amongst Department of Conservation (DOC) staff to investigate management tools available to them. Results suggest that inadequate resources, staff shortages and an overwhelming workload have resulted in a failure to achieve comprehensive recovery of threatened species. A review of New Zealand wildlife conservation legislation and a comparison with the USA Endangered Species Act 1973 and Australian Environment Protection and Biodiversity Conservation Act 1999, suggests that a lack of dedicated threatened species legislation is hindering the effective recovery of New Zealand’s threatened species. The thesis concludes that New Zealand has the advantage of a large conservation estate but lacks an integrated national management approach to the conservation of its biodiversity. Considerable improvement of the management and recovery of threatened species can be achieved with the enacting of dedicated threatened species legislation. Keywords: Threatened species, biodiversity, biodiversity hotspot, conservation, management, recovery plans, recovery groups, Department of Conservation, legislation, threat classification system, listing, ecological function, ecosystem services, staff survey, New Zealand
597

An evaluation of the conservation of New Zealand's threatened biodiversity : management, species recovery and legislation : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Auckland, New Zealand

Seabrook-Davison, Mark Nicholas Hawdon January 2010 (has links)
Content removed from thesis due to copyright restrictions: Seabrook-Davison, M. N. H., Weihong, J. J. & Brunton, D. H. (2010). "Survey of New Zealand Department of Conservation staff involved in the management and recovery of threatened species." Biological Conservation, 143: 212-219. doi: 10.1016/j.biocon.2009.10.005. Seabrook-Davison, M. N. H., Ji, W. & Brunton, D. H. (in press). "New Zealand lacks comprehensive threatened species legislation -- comparison with legislation in Australia and the USA." Pacific Conservation Biology, 16. / It is only recently that New Zealand wildlife managers have become aware of both the taxonomic range of New Zealand’ indigenous biodiversity and the number of species threatened with extinction. The entire New Zealand archipelago has been described as a biodiversity hotspot; a term with both negative and positive connotations as although its biodiversity is unique and diverse, it has lost three quarters of its primary vegetation and much of its remaining endemic biota is in decline. This thesis evaluated aspects of New Zealand’s approach to the management of biodiversity with an emphasis on methods used in the recovery of threatened species. Possible solutions are presented that New Zealand could investigate to improve the delivery of species recovery. A survey was conducted amongst Department of Conservation (DOC) staff to investigate management tools available to them. Results suggest that inadequate resources, staff shortages and an overwhelming workload have resulted in a failure to achieve comprehensive recovery of threatened species. A review of New Zealand wildlife conservation legislation and a comparison with the USA Endangered Species Act 1973 and Australian Environment Protection and Biodiversity Conservation Act 1999, suggests that a lack of dedicated threatened species legislation is hindering the effective recovery of New Zealand’s threatened species. The thesis concludes that New Zealand has the advantage of a large conservation estate but lacks an integrated national management approach to the conservation of its biodiversity. Considerable improvement of the management and recovery of threatened species can be achieved with the enacting of dedicated threatened species legislation. Keywords: Threatened species, biodiversity, biodiversity hotspot, conservation, management, recovery plans, recovery groups, Department of Conservation, legislation, threat classification system, listing, ecological function, ecosystem services, staff survey, New Zealand
598

Viabilidade da implantação de um programa de pagamentos por serviços ambientais: uma análise na sub-bacia do Pirajibu, Sorocaba-SP / Implementation viability of payments for environmental services program: an anlysis in the Pirajibu watershed, Sorocaba - SP

Corrêa, Carina Júlia Pensa 20 April 2016 (has links)
Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T19:13:45Z No. of bitstreams: 1 CORREA_Carina_2016.pdf: 35718212 bytes, checksum: 67e15c2afd55ade670a7eb98e27ea9a6 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T19:13:55Z (GMT) No. of bitstreams: 1 CORREA_Carina_2016.pdf: 35718212 bytes, checksum: 67e15c2afd55ade670a7eb98e27ea9a6 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T19:14:02Z (GMT) No. of bitstreams: 1 CORREA_Carina_2016.pdf: 35718212 bytes, checksum: 67e15c2afd55ade670a7eb98e27ea9a6 (MD5) / Made available in DSpace on 2017-08-08T19:14:09Z (GMT). No. of bitstreams: 1 CORREA_Carina_2016.pdf: 35718212 bytes, checksum: 67e15c2afd55ade670a7eb98e27ea9a6 (MD5) Previous issue date: 2016-04-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Public policy incentives are essential to the effectiveness of environmental law and the preservation of services provided by ecosystems. In this context, Payments for Ecosystem Services –PSE programs remunerate environmental services providers through funds built from the user/polluter pays logic. This study aimed to evaluate the possibility of implementing a PSA program in Pirajibu watershed, Sorocaba -SP, and suggest suitable alternatives for the conservation of water resources in the region. To this end, secondary data were collected on public agencies. In addition, were analyzed pictures from the RapidEye satellite (Ministry of Environment-ME), and with the help of satellite images from Google Earth, processed in Quantum GIS 1.6 software- Open Source Information Systems Finally, field trips were made to verify the information found. The results indicate that there is difficulty identifying possible providers and calculate the opportunity cost of the land, since agriculture is a rare activity in the region. Regarding environmental services, there was a great potential of the Pirajibu –Mirim River for water supply. This watershed has been studied in more detail, its water sources were mapped and some of them diagnosed in macroscopic analysis in the field. The water sources are, for the most part, in particular areas, with water having satisfactory aspects. However, there is the presence of garbage, lack of identification, proximity roads and the lack of environmental compliance expected by the Brazilian Forest Code (Lei nº. 12.651/ 2012). This scenario shows the importance that public policy in Sorocaba-SP considers the recovery and protection of water sources, however, not directly compensating the owner. It is suggested that the model has the forecast works for soil conversation on dirt roads, in addition to a donation of inputs and technical assistance to owners interested in recovery. Also considering the characteristics of relief and zoning of the master plan, it is proposed to establish a Private Reserve of National Heritage - PRNP at the head region of Pirajibu -Mirim River. Finally, it is suggested the implementation of other tax incentive policies in the region, such as property tax reduction in suitable properties with economic and social use. / As políticas públicas de incentivo são imprescindíveis para a efetividade das legislações ambientais e para a conservação dos serviços providos pelos ecossistemas. Nesse contexto, programas de Pagamentos por Serviços Ambientais-PSA remuneram provedores de serviços ambientais por meio de fundos construídos a partir da lógica do usuário/poluidor-pagador. O presente trabalho objetivou avaliar a possibilidade da implantação de um programa de PSA na sub-bacia do Pirajibu, no município de Sorocaba-SP, bem como sugerir alternativas adequadas para a conservação dos recursos hídricos na região. Para tanto, foram realizadas coletas de dados secundários em órgãos públicos. Além disso, foram analisadas imagens do satélite Rapideye (Ministério do Meio Ambiente-MMA), e, com o auxílio de imagens de satélite do programa Google Earth, processadas no programa Quantum GIS 1.6. Por fim, saídas de campo foram realizadas para verificação das informações encontradas. A análise dos resultados encontrados indica a dificuldade na identificação de possíveis provedores e nos cálculos do custo de oportunidade da terra, já que a agricultura é uma atividade rara na região. Em relação aos serviços ambientais, a microbacia do rio Pirajibu-Mirim apresentou grande potencial para abastecimento hídrico. Adotada como área prioritária, suas nascentes foram mapeadas e algumas delas diagnosticadas em análise macroscópica em campo. As nascentes estão, em sua grande maioria, localizadas em áreas particulares, com água apresentando aspectos satisfatórios. No entanto, observa-se a presença de lixo, ausência de identificação, proximidade de estradas de terra e a ausência de adequação ambiental prevista pelo Código Florestal brasileiro (Lei nº 12.651/2012). Esse cenário mostra a importância de que uma política pública de conservação em Sorocaba considere a recuperação e proteção de nascentes, entretanto, não remunerando diretamente o proprietário. Sugere-se que o modelo tenha como previsão obras para conservação do solo em estradas de terra, além da doação de insumos e assistência técnica aos proprietários interessados na recuperação. Considerando também as características do relevo e o zoneamento do plano diretor, propõe-se a instituição de uma Unidade de Conservação que incorpore a região de cabeceira do rio Pirajibu-Mirim. Por fim, sugere-se a implantação de outras políticas de incentivos fiscais na região, como redução de IPTU em propriedades adequadas ambientalmente e que apresentem uso econômico e social.
599

Etude des compromis et synergies entre services écosystémiques et biodiversité : Une approche multidimensionnelle de leurs interactions dans le socioécosystème des Alpes Française / Addressing trade-offs and synergies among ecosystem services and biodiversity : A multi-dimensional approach of their interactions in the French Alps social-ecological system

Crouzat, Emilie 13 May 2015 (has links)
Dans un contexte de changement climatique global et d'évolution locale de l'usage des terres, le devenir des paysages culturels des Alpes françaises, façonnés au cours des siècles par les interactions mutuelles entre sociétés et environnement, apparaît incertain. Dans le même temps, les écosystèmes qui les constituent abritent une biodiversité riche et sont à l'origine de nombreuses ressources naturelles et fonctions écologiques dont bénéficient les populations humaines. Ces ressources et fonctions sont conceptualisées sous le terme de « services écosystémiques » et font aujourd'hui l'objet d'une attention accrue dans la gestion et la protection des ressources environnementales, au même titre que la biodiversité. L'identification des facteurs liés à leur maintien, en termes écologiques, socio-culturels et politiques, est une étape nécessaire à leur gestion durable, bien qu'encore insuffisamment explorée. Mon projet de thèse visait à accroître la compréhension des interactions positives (synergies) et négatives (antagonismes) entre services écosystémiques et biodiversité via une approche multidimensionnelle du socio-écosystème des Alpes françaises. - Le Chapitre I propose une approche biophysique quantitative et spatialisée de la multifonctionnalité des écosystèmes. Suite à une étape de modélisation, les patrons spatiaux de synergie et d'antagonisme entre services et biodiversité ont été explorés statistiquement et reliés à des enjeux de gouvernance actuels à différentes échelles. Ce travail a permis d'identifier les bouquets de services écosystémiques représentatifs des différentes conditions biogéographiques, de gestion et de d'hétérogénéité du paysage représentées dans le massif. - Cette approche est complétée dans le Chapitre II par une représentation qualitative des relations d'influence entre services écosystémiques et biodiversité, ainsi que de leurs liens avec d'autres variables écologiques et sociales. Nous avons considéré explicitement les dimensions multiples englobées par le concept de service écosystémique (leurs ‘facettes') et proposons un cadre conceptuel pour en cartographier les réseaux d'influence. Ce cadre a servi de base à l'analyse d'un processus consultatif que nous avons mené auprès d'acteurs du territoire. Les analyses ont mis en lumière leur perception globale des relations d'influence importantes au sein du socio-écosystème. - Afin de mieux comprendre les régulations sociales appliquées à la gestion environnementale, nous testons dans le Chapitre III une méthodologie d'analyse de l'efficacité environnementale d'instruments de gouvernance. Notre analyse a privilégié un nombre restreint d'instruments qui encadrent actuellement les interactions entre agriculture, tourisme et biodiversité. L'utilisation d'un ensemble d'indicateurs de performance et d'adéquation avec le cadre socio-culturel et de gouvernance a souligné l'articulation complexe des instruments entre eux et a abouti à la production d'une synthèse pour les décideurs (‘policy brief'). - Le Chapitre IV explore enfin certains enjeux conceptuels et éthiques de la recherche dans le domaine des services écosystémiques. Après une réflexion générale sur les relations entre science et société, je propose une évaluation réflexive et personnelle des projets de recherche auxquels j'ai contribué. Pour conclure, je propose une vision transversale du socio-écosystème alpin mettant en lumière les enjeux majeurs identifiés par les différentes analyses. / In the context of global climate change and local land use changes, the future of the French Alps cultural landscapes, shaped through long-lasting and mutual interactions between human and their environment, appears uncertain. Simultaneously, the ecosystems constituting alpine landscapes host a rich biodiversity and provide the many natural resources and ecological functions that benefit to human societies. These resources and functions are conceptualised as “ecosystem services” and currently attract an increasing attention for the management and the conservation of environmental resources, along with biodiversity. Identifying the variables linked to their maintenance, in ecological, socio-cultural and political terms, is a necessary step of their sustainable management, and yet is still under-explored. My PhD project aimed at increasing the understanding of positive (synergies) and negative (trade-offs) interactions among ecosystem services and biodiversity through a multi-dimensional approach of the French Alps social-ecological system. - In Chapter I, I present a quantitative and spatially explicit biophysical assessment of ecosystem multifunctionality. After a modelling step, we explored spatial patterns of trade-offs and synergies among ecosystem services and biodiversity using a series of statistical analyses of increasing complexity. Results were structured to provide insights for sound environmental governance at multiple scales. We identified various bundles of ecosystem services representative of the different conditions across the French Alps massif in terms of biogeography, management and landscape heterogeneity. - This approach is complemented in Chapter II by a qualitative representation of influence relationships among ecosystem services and biodiversity that also accounts for additional ecological and social variables. We explicitly considered the multiple dimensions encompassed by the ecosystem service concept (their ‘facets') and proposed an innovative conceptual framework to represent their influence networks. This framework was applied to analyse a consultative process that we carried out with stakeholders of regional expertise. This analysis highlighted their general perception of important influence relationships in the alpine social ecological system. - In order to better understand social regulations linked to environmental governance, we test in Chapter III a methodology for assessing the environmental effectiveness of policy instruments. We concentrated on a restricted set of instruments regulating the interactions between biodiversity, agriculture and outdoor tourism. The consideration of multiple indicators assessing the performance and the fit with the socio-cultural and governance setting highlighted the complex articulation of instruments within the broader policy mix. Results were synthesised in a policy brief targeting regional decision-makers. - Chapter IV is conceived as my personal exploration of the conceptual and ethical issues linked to research on ecosystem services. Following some general thinking on the relations between environmental sciences and society, I conducted a personal reflexive assessment of the research projects I contributed to. To conclude, I propose a synthetic vision of the alpine social-ecological system and discuss the major issues revealed throughout the analyses.
600

Análise e valoração da disponibilidade de bens e serviços ecossistêmicos em uma microbacia hidrográfica predominantemente urbanizada, Paraíba, Brasil. / Analysis and valuation of the ecosystem goods and services availability in a predominantly urbanised microwatershed, Paraíba, Brazil.

FERREIRA, Lucianna Marques Rocha. 24 September 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-09-24T19:53:05Z No. of bitstreams: 1 LUCIANNA MARQUES ROCHA FERREIRA –TESE (PPGRN) 2018.pdf: 4043233 bytes, checksum: 486e1ad8ad7101f70e07637566fa13f8 (MD5) / Made available in DSpace on 2018-09-24T19:53:05Z (GMT). No. of bitstreams: 1 LUCIANNA MARQUES ROCHA FERREIRA –TESE (PPGRN) 2018.pdf: 4043233 bytes, checksum: 486e1ad8ad7101f70e07637566fa13f8 (MD5) Previous issue date: 2018-07-27 / A urbanização tem sido uma das principais causas de mudança do uso e ocupação da terra em todo o mundo, muitas vezes com consequências irreparáveis para a prestação de bens e serviços ecossistêmicos fundamentais para o bem-estar físico, metal e espiritual humano, bem como para a manutenção da vida no planeta. Esta pesquisa analisa a mudança da disponibilidade de bens e serviços ecossistêmicos em função do uso e ocupação da terra, no período de 1989, 2007 e 2014; e a valoração social de benefícios prestados por uma microbacia hidrográfica predominantemente urbanizada, inserida no ecótono Agreste (área de transição entre os biomas Mata Atlântica e Caatinga), no Nordeste do Brasil. Técnicas de sensoriamento remoto e sistema de informação geográfica foram utilizadas para quantificar as mudanças no uso e ocupação da terra na Microbacia Hidrográfica Riacho das Piabas, Paraíba. Método de transferência de benefícios foi aplicado para quantificar as mudanças na oferta de bens e serviços ecossistêmicos, entre os anos analisados. A percepção das partes interessadas (comunidade, técnico e especialista) acerca dos ambientes que ofertam bens e serviços ecossistêmicos na área de estudo e seus respectivos níveis de importância foram obtidos por meio de mapeamento participativo. A substituição de área de vegetação arbórea (46% da área de estudo em 1989 e 5% em 2014) por ambiente construído foi o fator-chave que impulsionou o declínio de 73% da disponibilidade de bens e serviços ecossistêmicos entre os anos de 1989 e 2014. A expansão urbana promoveu a perda de 89% da oferta de oito serviços ecossistêmicos, incluindo regulação do clima, regulação do fluxo de água, moderação de perturbações, ciclagem de nutrientes e controle biológico, que quando se considera a tendência regional de aridificação e as pressões existentes sobre os recursos hídricos, são relevantes localmente. Houve diferença significativa entre a percepção das partes interessadas quanto ao número de áreas mapeadas por seção de bens e serviços ecossistêmicos disponibilizados pela área de estudo para a população (Anova fatorial, F= 21,62; p< 0,001). A visão da comunidade sobre os benefícios oferecidos pela microbacia hidrográfica estudada distinguiu de técnicos e de especialistas. Os ambientes que mais ofertaram bens e serviços ecossistêmicos foram as áreas de transição entre ambiente dulcícola e terrestre; e espaços verdes. O serviço de manutenção do ciclo hidrológico e fluxos de águas apresentou média de nível de importância social muito alto. A gestão que deseja reduzir os impactos do processo de urbanização na provisão de bens e serviços ecossistêmicos deve considerar implementação do planejamento espacial baseado em ecossistemas, com foco na infraestrutura urbana verde e na restauração de habitats naturais e sua conectividade. Ademais, é fundamental abordar a percepção de partes interessadas no processo de planejamento e tomada de decisão para minimizar e gerenciar potenciais conflitos sociais. / Urbanisation has been a main cause of land use land cover (LULC) change worldwide, often with irreparable consequences to the provision of goods and ecosystem services that are fundamental to human physical, mental and spiritual well-being, as well as to the maintenance of life on the planet. This research analyzes the goods and ecosystem services availability change as a function of LULC, in the period of 1989, 2007 and 2014; and the social valuation of ecosystem benefits provided by a predominantly urbanised microwatershed, located in the Agreste ecotone (transition area between Atlantic Forest and Caatinga biomes), in Northeast Brazil. Remote sensing techniques and geographic information system were used to quantify LULC changes in Riacho das Piabas microwatershed, Paraíba. The benefit transfer method was applied to quantify changes in the ecosystem goods and services supply between the years analyzed. The stakeholders perception (community, technical and expert) about the environments that offer ecosystem goods and services in the study area and their respective importance levels were obtained through participatory mapping. Replacement of tree vegetation area (46% of the study area in 1989 and 5% in 2014) by the built environment was the key factor driving the 73% decline in the ecosystem goods and services availability between 1989 and 2014. Urban sprawl resulted losses of 89% in the eight ecosystem services supply, including climate regulation, water flow regulation, moderation of disturbance, nutrient cycling and biological control, which are critical locally when considering the regional trend towards aridification and the existing pressures on water resources. There was a significant difference between the stakeholders perception about the mapped areas number per ecosystem goods and services section available by the study area to the population (Factorial Anova, F = 21.62, p <0.001). The community perception about the benefits offered by the studied microwatershed distinguished from technicians and experts. The environments that most offered ecosystem goods and services were transitional areas between the between freshwater and terrestrial environments; and green spaces. The service maintenance of hydrological cycle and water flux presented very high average importance level. Management that wishes to reduce the urbanisation impacts on the provision of ecosystem goods and services should consider implementation of ecosystem-based spatial planning, focusing on urban green infrastructure and natural habitats restoration and their connectivity. In addition, it is fundamental to approach the stakeholders perception in the planning process and decision making to minimize and manage potential social conflicts.

Page generated in 0.0919 seconds