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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.
191

The Consequences of Buffelgrass Pasture Development for Biodiversity in the Southern Sonoran Desert

Franklin, Kimberly Anne January 2009 (has links)
Decades of overgrazing have left many rangelands in northwestern Mexico in poor condition. This has led to the practice of converting native rangeland plant communities to buffelgrass pastures. Buffelgrass (Pennisetum ciliare) is a perennial bunchgrass native to Africa. Both the extent of buffelgrass pastures within Mexico and the impacts of land conversion on biodiversity and ecosystem functioning. In the present study I address the effects of land conversion on the productivity and diversity of rangelands in the southern Sonoran Desert in the state of Sonora, Mexico. First, using satellite imagery from the Landsat mission, I found that rates of land conversion in the most heavily affected region of Sonora have continued to accelerate over the past three decades and that productivity of buffelgrass pastures is lower than that of native rangeland. Next, I examined the impacts of land conversion on the diversity and structure of plant communities and ant assemblages across a rainfall driven gradient of productivity in central Sonora. The regional extent of this land use change allowed me to explore the interaction between site productivity and land conversion. Within native rangeland I detected strong positive relationships between productivity and the species richness of perennial plant communities, but only weak positive relationships between productivity and species richness of ant assemblages. These results were discussed in the context of species diversity theory. Land conversion reduced the species richness of perennial plant communities by approximately 50% at both local and regional scales, whereas the species richness of ant assemblages was reduced by 17% at the local scale and only 8% at the regional scale. I found no evidence for an interaction between site productivity and land conversion in either plant communities or ant assemblages. The implications of these findings for long-term trajectories of biodiversity in the southern Sonoran Desert are discussed.
192

The effects of the structural adjustment programme on deforestation in Ghana, with a comparison to Cameroon

Benhin, James Kofi Appiah January 2000 (has links)
No description available.
193

Improving the conservation value of invertebrates through ecotourism : component A.

Huntly, Philippa. January 2003 (has links)
Invertebrates are suffering the greatest species loss in the current biodiversity crisis. These animals perform essential ecosystem functions upon which humanity depends yet they are largely ignored m conservation efforts. The main challenges facing invertebrate conservationists, in terms of raising public awareness, are to change common negative perceptions regarding invertebrates and to apply some form of value to them. Conservation efforts can be improved by raising public awareness of, and appreciation for, invertebrates in the context of ecotourism. Current levels of inclusion of invertebrates in ecotourism activities were gauged, using qualitative research methods of participant observation and semi-structured interviews. The response of tourists to the concept of the inclusion of both western/scientific and indigenous knowledge regarding invertebrates into current and planned ecotourism activities was determined using the quantitative research method of a structured questionnaire. Canvassing of tourists was done at a popular ecotourism destination (Hluhluwe-Umfolozi Nature Reserve) and 121 questionnaires were completed. In addition to tourists the opinions and attitudes of a range of people working in ecotourism and conservation were examined via semi-structured interviews. The respondents were specifically selected according to the positions they held in the ecotourism and conservation field and a total of eight people in management, ten ecotourism guides and seven ecotourism trainers were interviewed. The findings revealed that there is currently negligible information regarding invertebrates in ecotourism activities. There was an overwhelmingly positive response from tourists, with 95% indicating that they would like to see information regarding invertebrates included in ecotourism activities. Ecotourism service providers, such as tour guides and those in conservation management also indicated a positive attitude toward the concept. There is thus potential to increase levels of information regarding invertebrates in ecotourism and it is recommended that ecotourism include a focus on invertebrates. Recommendations on how to address the lack of invertebrate information in ecotourism are provided and examples of the types of invertebrates to include in specific ecotourism activities are given. Including a focus on invertebrates in ecotourism will serve the multiple purposes of placing value on invertebrates; raising public awareness and hence the conservation status of invertebrates, and finally will increase the scope of ecotourism. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
194

The taxonomic name resolution service: an online tool for automated standardization of plant names

Boyle, Brad, Hopkins, Nicole, Lu, Zhenyuan, Raygoza Garay, Juan Antonio, Mozzherin, Dmitry, Rees, Tony, Matasci, Naim, Narro, Martha, Piel, William, Mckay, Sheldon, Lowry, Sonya, Freeland, Chris, Peet, Robert, Enquist, Brian January 2013 (has links)
BACKGROUND:The digitization of biodiversity data is leading to the widespread application of taxon names that are superfluous, ambiguous or incorrect, resulting in mismatched records and inflated species numbers. The ultimate consequences of misspelled names and bad taxonomy are erroneous scientific conclusions and faulty policy decisions. The lack of tools for correcting this 'names problem' has become a fundamental obstacle to integrating disparate data sources and advancing the progress of biodiversity science.RESULTS:The TNRS, or Taxonomic Name Resolution Service, is an online application for automated and user-supervised standardization of plant scientific names. The TNRS builds upon and extends existing open-source applications for name parsing and fuzzy matching. Names are standardized against multiple reference taxonomies, including the Missouri Botanical Garden's Tropicos database. Capable of processing thousands of names in a single operation, the TNRS parses and corrects misspelled names and authorities, standardizes variant spellings, and converts nomenclatural synonyms to accepted names. Family names can be included to increase match accuracy and resolve many types of homonyms. Partial matching of higher taxa combined with extraction of annotations, accession numbers and morphospecies allows the TNRS to standardize taxonomy across a broad range of active and legacy datasets.CONCLUSIONS:We show how the TNRS can resolve many forms of taxonomic semantic heterogeneity, correct spelling errors and eliminate spurious names. As a result, the TNRS can aid the integration of disparate biological datasets. Although the TNRS was developed to aid in standardizing plant names, its underlying algorithms and design can be extended to all organisms and nomenclatural codes. The TNRS is accessible via a web interface at http://tnrs.iplantcollaborative.org/ webcite and as a RESTful web service and application programming interface. Source code is available at https://github.com/iPlantCollaborativeOpenSource/TNRS/ webcite.
195

The diversity of flower-visiting insects in the gardens of English country houses

Erenler, Hilary E. January 2013 (has links)
No description available.
196

Právní úprava vytvoření a ochrany soustavy Natura 2000 / Legal regulation of creation and protection of Natura 2000 network

Papíková, Daniela January 2015 (has links)
The aim of this thesis was to analyze the legal regulation of the creation and protection of the Natura 2000 network from the perspective of international environmental law, the EU law and the Czech law. The thesis is divided into five major chapters. The first chapter explains the concept of Natura 2000 and what are the purposes pursued by the system. The second chapter covers the area of legal regulation in the area of nature protection from the perspective of international law and its relationship to Natura 2000. Next chapter deals with the regulation of the Natura 2000 from the perspective of EU law. The fourth chapter focuses on mapping the decision- making of the Court of Justice of the European Union concerning the Natura 2000 network. The fifth part describes legal regulation of Natura 2000 network from the perspective of the Czech legal order.
197

Právní úprava ochrany biodiversity / Legal regulation of the protection of biodiversity

Fidler, Libor January 2014 (has links)
Legal Regulation of Biodiversity Conservation The thesis deals with applicable legal regulation of biodiversity conservation in the Czech Republic. First it defines biodiversity (biological diversity) from the point of view of natural science and as the subject matter of legal protection. Then the thesis presents the most significant international sources of soft law and hard law in the field, the European Union's strategic documents and law and the Czech Republic's national strategic documents and law concerning biodiversity conservation. In its conclusion the thesis summarizes some problems associated with biodiversity conservation and its regulation.
198

Adopting a heterogeneity paradigm for understanding and managing elephants for biodiversity : a case study in riparian woodlands in Kruger National Park

Gaylard, Angela January 2016 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2015. / Decades of study devoted to solving the “elephant problem” have generally concurred that increasing elephant populations inevitably reduce biodiversity. However, recent evidence suggests that such reductions can be accompanied by increases in other components of biodiversity, and that ultimately elephant effects are scale-dependent. Although this new perspective now underpins elephant management strategies in savannas such as the Kruger National Park (KNP), South Africa, few empirical studies in support of this strategy have incorporated the contribution of spatial context, or allowed for the emergence of relevant scales, in their interpretations of heterogeneity. Moreover, use of traditional modes of scientific enquiry and statistical approaches for investigating heterogeneity in complex systems have been challenged. Recent advances in spatial statistics, together with an alternative mode of science that draws upon multiple lines of converging evidence rather than testing narrowlyfocused hypotheses, have the potential to address these challenges. However, their practical application for understanding elephants as agents of change remains lacking. Riparian zones along the ephemeral rivers in northern KNP provided an ideal landscape to explore the spatial and temporal parameters of elephant effects in response to surface water, as a critical resource, and hence to develop a framework for a heterogeneity approach for understanding and managing elephants as agents of change in savannas.
199

Protéger les petites îles de méditerranée occidentale : de l'identification des enjeux de la conservation de la biodiversité insulaire à la mise en place d'actions de protection / Protecting the small islands of the western Mediterranean basin : From identification of environmental issues to the implementation of conservation actions

Crouteix, Orianne 04 February 2019 (has links)
Soumise à une pression anthropique forte et croissante, la nature méditerranéenne connue pour sarichesse interspécifique est menacée sur les espaces continentaux et les plus grandes îles. Lespetites îles et les îlots se présentent alors comme les derniers refuges d’une biodiversité rare etmenacée. Dans ce contexte, la délégation Europe et International du Conservatoire du Littoral a créél’Initiative PIM, un programme d’assistance et d’échanges pour la protection de ces territoires.Par conséquent, même en Méditerranée, les îles, et particulièrement les plus petites d’entre ellesdeviennent un enjeu environnemental discuté dans les sphères politiques nationales etinternationales. En effet, si jusqu’à nos jours les îles ont occupé une place centrale dans laconstruction des savoirs scientifiques en sciences naturelles et en sciences sociales, elles seretrouvent aujourd’hui sur le devant de la scène dans de nombreuses politiques environnementales.Rendue possible par le dispositif CIFRE, ce travail de recherche s’intègre dans l’Initiative PIM par uneimmersion de plus de deux ans. Cette dernière s’incarne dans la réalisation d’un atlas encyclopédiquedes petites îles de Méditerranée occidentale. L’objectif de cet ouvrage est d’être le socle d’unplaidoyer pour la protection de la biodiversité de ces territoires, réalisé en s’appuyant sur les donnéesenvironnementales pour construire des stratégies de conservation. Les acteurs de la sciencedeviendraient alors centraux dans l’élaboration de ces stratégies. Ce travail de recherche interroge lesplaces prises par les scientifiques dans la fabrique des politiques environnementales. Qu’ils s’agissentde la construction de l’enjeu ou de la mise en place d’actions concrètes, les scientifiques peuvent êtreamenés à jouer différents rôles. En s’appuyant sur l’analyse de différentes actions environnementalesmenées pour protéger la biodiversité des petites îles de Méditerranée, une typologie des rôlesoccupés par les scientifiques est alors établie. Si les scientifiques prennent parfois une place enamont de la politique environnementale en orientant la décision, ils leur arrivent aussi d’être intégrés àl’action et les considérations écologiques qu’ils soulèvent sont mises en regards de nombreux autreséléments tels que l’acceptabilité sociale ; enfin dans certains cas, ils deviennent des cautions etjustifient l’action environnementale. / Under strong and increasing human pressure, the Mediterranean environment, famous for its richnessis threatened especially along continental areas and larger islands. Small islands and islets appear asthe last refuges of endemic and endangered biodiversity. In this context, the European andInternational delegation of Conservatoire du Littoral created the PIM Initiative, a program to promotethe exchange of best practices for the protection of these territories.Therefore, even the Mediterranean nature composed of the islands, and particularly the smaller ones,has become an environmental issue discussed on the national and international political stage. Islandshave occupied a specific place in the accrual of scientific knowledge in natural and social sciences oftoday, which are highlighted in many environmental policies.The resultant research work is part of the PIM Initiative and was performed in the frame of a CIFREprogram for three years. The main goal of the operational work was the realization of anencyclopaedic atlas of small islands in the western Mediterranean basin. Its aim was to buildconservation strategies by using environmental data. These strategies must be the basis for theprotection of biodiversity in these territories. So, the sciences stakeholders should become central inthe development of new conservation policies. This research work raises the question of the placesoccupied by scientists in the process of setting up environmental policies. From the construction of theissue to the implementation of concrete conservation actions, scientists play different roles. A typologyof the roles occupied by scientists is established based on the analysis of several environmentalactions developed in order to protect the biodiversity of small Mediterranean islands. Occasionallyscientists are involved upstream of the environmental policy by guiding the decision. Sometimes theyare more integrated in the action and the ecological regards that they raise are viewed as one elementamong other such as social acceptability. Finally, in some cases, scientists become a guarantee andjustify the environmental action.
200

Dinâmica das comunidades de aves no mosaico de hábitats do Pantanal do Rio Negro, MS /

Rosa, Gustavo Adolfo Braga da. January 2009 (has links)
Orientador: Reginaldo José Donatelli / Banca: Luiz Octavio M. Machado / Banca: Fátima do Rosário N. Knall / Banca: Neiva Maria R. Guedes / Banca: Maria Cecilia B. de Toledo / Resumo: O Pantanal abriga formações florestais, savânicas, fluviais e lacustres em um mosaico de hábitats singularmente heterogêneo. Os objetivos deste trabalho foram avaliar a diversidade, a estrutura das comunidades e o uso de hábitats por aves no Pantanal do Rio Negro, MS (cap. I); e avaliar o uso de ambientes aquáticos (cap. II). I. Através de observações diretas amostramos quatro ambientes terrestres e três aquáticos. Registramos 279 espécies, com a maior riqueza no cerradão (189 espécies) e a menor riqueza nos campos (84 espécies). A diversidade beta (entre ambientes) contribuiu com 68% da diversidade regional. 22 % das espécies foram encontradas em seis ou todos os sete ambientes, destacando-se os nãopasseriformes, onívoros e aquáticos/limnícolas. As maiores abundâncias foram encontradas nas salinas e no rio. A correlação positiva entre abundância e distribuição espacial indicou que o hábito generalista em relação ao uso de hábitat deve contribuir para o incremento da abundância. A abundância de frugívoros foi maior no período seco, possivelmente devido a um aumento no deslocamento frente à maior escassez de frutos. II. No meio aquático amostramos 7.817 aves aquáticas, representando 58 espécies, das quais 32 são migratórias. A riqueza nos três ambientes foi muito similar (43 a 45 espécies). As salinas obtiveram a mais baixa equidade e a mais alta densidade. A similaridade na composição entre os ambientes foi maior entre baías e salinas e menor entre salinas e rio. As espécies mais abundantes foram Himantopus melanurus e Tringa flavipes nas salinas, Dendrocygna viduata e Jacana jacana nas baías, Phalacrocorax brasilianus e Megaceryle torquata no rio. Houve flutuação sazonal na avifauna, mais expressiva nas salinas, com abundância 100% maior na seca e riqueza de espécies 40% maior na cheia. Fatores como nível d'água, disponibilidade... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Pantanal comprises several forest, savanic and aquatic formations in a peculiar mosaic of habitats. The aims of this study were to assess diversity, community structure and use of habitats by birds in the Pantanal of Rio Negro Region (chapter I); and assess the use of aquatic habitats by birds (chapter II). We surveyed four terrestrial and three aquatic habitats through direct observations. 279 bird species were found, with the highest species richness in the semidecidual forest (189 species) and the lowest (84 species) in the grasslands. Beta diversity (turnover of species) was responsible for 68% of the regional diversity. 22% of the species were found in six or in all seven habitats, with high proportion of non-passerines, omnivores and aquatic birds in this group. The highest abundances were found in salt lakes and in the river. A positive correlation between abundance and spatial distribution suggests that habitat flexibility in birds increases abundance. The abundance of frugivores was higher in the dry season, possibly as a consequence of fruit scarcity and increased movement of foraging birds. In the aquatic habitats we surveyed 7.817 aquatic birds, from 58 species, with 32 migrant species. Species richness was similar among fresh-water lakes, salt lakes and the river (43 to 45 species). Salt lakes showed highest density and lowest equitability. Similarity in species composition was highest between the lakes and lowest between salt lake and river. The most abundant species were Himantopus melanurus and Tringa flavipes in salt lakes, Dendrocygna viduata and Jacana jacana in fresh water lakes, Phalacrocorax brasilianus and Megaceryle torquata in the river. Seasonal changes in bird communities were prominent in salt lakes, with 100% higher abundance in dry season and 40% higher species richness in wet season. Water level, mudflats, riparian vegetation, and aquatic diversity... (Complete abstract click electronic access below) / Doutor

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