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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.
71

Does Additional Habitat Protection Facilitate the Recovery of Species Protected by the Endangered Species Act?

So, Rachel I. 16 April 2014 (has links)
Earlier studies have found that endangered species recovery is only weakly associated with the tools enabled by the U.S. Endangered Species Act (ESA). With habitat loss often cited as a leading cause of species declines, we tested whether the recovery of ESA-listed species is instead associated with the protection of critical habitat (CH) by protected areas. We tested the relationship for 299 species using recovery indices derived from the biennial status reports to Congress (1990-2010), as well as NatureServe and IUCN population status data. We found no overall relationship between recovery and the extent to which CH is protected. However, restricting the analysis to recovering species, listed species with larger areas of protected (R2 = 0.158) or strictly protected (R2 = 0.194) CH fared better than species with less protected or strictly protected CH areas. Declining species (199 of 273 species studied) fared no better with more protected habitat. We conclude that the abatement of habitat loss alone does not necessarily facilitate recoveries for the majority of ESA-listed species. We also note that the weak relationships we observed in this study may be reflective of poor recovery status estimates.
72

Optimal decision-making in conservation: management,uncertainty and monitoring.

Miss Eve Mcdonald-Madden Unknown Date (has links)
Abstract The world is losing its biodiversity at an alarming rate and many agencies are committing to considerable investment in global conservation. Given the enormity of environmental issues, the funding available to managers is insufficient. Managers must make decisions about how to act within the bounds of this limited funding. Conservation decision-making is also limited by a lack of knowledge about the systems we are trying to conserve. Much of the information required for effective conservation is uncertain. In this thesis I focus on practical ways of approaching the immense predicament of how to make good conservation decisions in the face of these two limitations. In chapter two I provide both an optimal framework and analytic rule of thumb for allocating limited funding among subpopulations of a threatened species. My results show that the number of subpopulations we can effectively manage is driven by the economic constraints placed on management and the risk of extinction of the species we are trying to protect. We discover that it is rarely optimal to manage all the remaining isolated subpopulations of a threatened species. This highlights the importance of a triage approach to the management of subpopulations of a threatened species under the current climate of limited funding, leading us to coin the term ‘subpopulation triage’. One key area of uncertainty that links directly with how we allocate resources for conservation is uncertainty in the impact of our management actions on the systems we are trying to protect (the impact-investment curve). This relationship often drives the outcomes of our decision-making frameworks. In chapter three I investigate how uncertainty in the impact-investment curve, assumed in chapter two, alters our optimal management decision. Again, I find that limited conservation finances are a major limiting factor in the robustness of a strategy to our incomplete understanding. I discover that ‘subpopulation triage’ can be a natural consequence of robust decision-making. Uncertainty is not, however, always beyond our control. We can reduce it by diverting funding from management to collect data on our systems. This entails monitoring costs that must also be considered when making optimal conservation decisions. There are a number of reasons why we could monitor; to reduce our uncertainty in the status of threatened species where management is driven by species status; to aid learning about a component of the system we are managing; for both initial surveillance and adaptive approaches; and to report on the performances of conservation action to stakeholders. In chapter four I assess the benefit of initial surveillance to gain information on biodiversity value before we acquire a land parcel for the reserve network. The risk here is that the land parcel may be removed from the market during surveying. I describe both an optimal method, using stochastic dynamic programming (SDP), and a simple rule of thumb, for how to make such decisions. The solutions to this problem illustrate how optimal conservation is necessarily dynamic and that immediate implementation of a conservation plan may not always yield the best conservation outcome. Learning does not always need to take place in the absence of management. In chapter five I investigate adaptive learning for a threatened species where we must discriminate between multiple hypotheses of how the system works by implementing different management actions. We find that the optimal action depends on our belief in each model being the true model of our system, the benefit from each action under each model, and the number of sites available to implement an active adaptive strategy. In chapter six I investigate when one should learn about the state of the system through monitoring when management is state-dependent. Here our management of subpopulations of a threatened species is based on whether these subpopulations persist. I ask when should we survey or manage a subpopulation, and when, if ever, should we do nothing in a subpopulation of a threatened species. I find that management actions should not only be driven by the return on investment gained by managing a subpopulation but also by our certainty of the persistence of a subpopulation. This is the first work to show a direct trade-off between return on investment from conservation action and reduced uncertainty. One key evaluation method currently adopted worldwide is the use of ‘State of the Environment’ reporting. In chapter seven I assess the flaws of ‘State of the Environment’ reporting, the current method adopted worldwide for evaluating conservation policy. I show the positive biases inherent in such reporting and provide a new metric for reporting on conservation performance that is simple, transparent and provides an unbiased report on performance in reaching conservation objectives. I show that without honest reporting of conservation gains – and losses – we limit our ability to assess where we are in terms of conservation progress. Overall my thesis shows the need for managers to consider a triage approach to threatened species management, not as a process of giving up, but as a tool for ensuring species persistence in light of the urgency of most conservation requirements and the realities of financial and knowledge limitations. Indeed if conservation is a field dedicated to the protection of biodiversity then those responsible for decision-making––politicians, scientists and environmental managers––must use whatever approach gives the best outcome for the environment. Under current limitations, triage is often a necessity not an option.
73

Distribuição e conservação de orquídeas terrestres em florestas subtropicais brasileiras / Distribution and conservation of terrestrial orchids in Brazilian subtropical forests

Colla, Frediny Bettin January 2014 (has links)
As orquídeas terrestres estão distribuídas amplamente em ambientes tropicais e temperados do mundo. O habitat terrestre, para orquídeas, engloba distintas formações vegetais, como florestas, savanas, campos e banhados. Neste estudo consideramos, para a estimativa da amplitude e da ocorrência destas plantas, nove tipos de florestas no estado do Rio Grande do Sul no sul do Brasil, localizadas totalmente em latitudes subtropicais. Revisamos amostras de espécimes depositadas em sete herbários regionais e atualizamos a identificação das espécies para as circunscrições genéricas atuais. Com base nas localizações das amostras estimamos dois parâmetros de amplitude, nomeados extensão de ocorrência e área de ocupação, objetivando determinar o estado de conservação das espécies de acordo com as categorias da IUCN. Como resultado, encontramos 22 gêneros e 50 espécies, a maioria dos gêneros (15) possui apenas uma espécie no estado. Os gêneros mais diversificados foram Cyclopogon, Aspidogyne e Malaxis, com 14, oito e quatro espécies, respectivamente. Outros quatro gêneros apresentaram três (Pelexia) ou duas (Habenaria, Prescottia, e Sarcoglottis) espécies nos ambientes florestais. As estimativas de amplitude, especialmente a área de ocupação, resultaram em um elevado número de espécies ameaçadas. Espécies criticamente ameaçadas, considerando a extensão de ocorrência, estão distribuídas em sete gêneros e 18 espécies. O tipo de floresta mais diversificado foi a floresta estacional da Serra Geral, seguido pela floresta Atlântica e pela floresta estacional do Escudo Cristalino. Um total de 19 espécies ocorreu somente em uma formação e apenas quatro espécies ocorreram em seis ou sete tipos de florestas. O número de registros neste estudo mostrou que as orquídeas terrestres em ambientes florestais são um grupo subamostrado, que possuem poucas coletas e são pouco avaliadas em estudos ecológicos com populações e comunidades de sub-bosque. Mais estudos são necessários para determinar com maior precisão a extensão de ocorrência, o tamanho das populações, e o estado real de conservação das espécies nativas. / Terrestrial orchids occur widespread in tropical and temperate environments around the world. The terrestrial habitat for orchid species comprises several distinct plant formations, like forests, woodlands, grasslands and wetlands. In this study we focused the estimation of range sizes and the occurrence of these plants in nine forest types in the South Brazilian state of Rio Grande do Sul, located entirely in subtropical latitudes. We revised sampled specimens deposited in seven regional herbaria and updated species identifications to current generic circumscriptions. Based on sampling locations we estimated two range size parameters, namely extent of occurrence and area of occupancy, aiming to determine the conservation status according to IUCN categories. As a result we found 22 genera and 50 species, most genera (15) having of them a single species in the state. The most diversified genera were Cyclopogon, Aspidogyne and Malaxis, with 14, eight and four species, respectively. Four additional genera presented three (Pelexia) or two (Habenaria, Prescottia, and Sarcoglottis) species in forest environments. Range size estimations, especially through area of occupancy, resulted in an outstanding number of threatened species. Critically endangered species according to extent of occurrence were distributed in seven genera and 18 species. The most diversified forest types were the central Serra Geral seasonal forests, followed by the Atlantic rainforest and the southeast Crystalline Shield seasonal forests. A total of 19 species occurred in a single forest formation and only four species occurred widespread in six or seven forest types. The number of recordings in this study showed to be exponentially related to species range according to forest types. Our study showed that terrestrial orchids in forest environments are an overlooked plant group, which has been poorly sampled and poorly evaluated in ecological studies concerning understory populations and communities. Further studies are necessary to determine more precisely the extent of occurrence, the size of populations, and the real conservation status of native species.
74

Distribuição e conservação de orquídeas terrestres em florestas subtropicais brasileiras / Distribution and conservation of terrestrial orchids in Brazilian subtropical forests

Colla, Frediny Bettin January 2014 (has links)
As orquídeas terrestres estão distribuídas amplamente em ambientes tropicais e temperados do mundo. O habitat terrestre, para orquídeas, engloba distintas formações vegetais, como florestas, savanas, campos e banhados. Neste estudo consideramos, para a estimativa da amplitude e da ocorrência destas plantas, nove tipos de florestas no estado do Rio Grande do Sul no sul do Brasil, localizadas totalmente em latitudes subtropicais. Revisamos amostras de espécimes depositadas em sete herbários regionais e atualizamos a identificação das espécies para as circunscrições genéricas atuais. Com base nas localizações das amostras estimamos dois parâmetros de amplitude, nomeados extensão de ocorrência e área de ocupação, objetivando determinar o estado de conservação das espécies de acordo com as categorias da IUCN. Como resultado, encontramos 22 gêneros e 50 espécies, a maioria dos gêneros (15) possui apenas uma espécie no estado. Os gêneros mais diversificados foram Cyclopogon, Aspidogyne e Malaxis, com 14, oito e quatro espécies, respectivamente. Outros quatro gêneros apresentaram três (Pelexia) ou duas (Habenaria, Prescottia, e Sarcoglottis) espécies nos ambientes florestais. As estimativas de amplitude, especialmente a área de ocupação, resultaram em um elevado número de espécies ameaçadas. Espécies criticamente ameaçadas, considerando a extensão de ocorrência, estão distribuídas em sete gêneros e 18 espécies. O tipo de floresta mais diversificado foi a floresta estacional da Serra Geral, seguido pela floresta Atlântica e pela floresta estacional do Escudo Cristalino. Um total de 19 espécies ocorreu somente em uma formação e apenas quatro espécies ocorreram em seis ou sete tipos de florestas. O número de registros neste estudo mostrou que as orquídeas terrestres em ambientes florestais são um grupo subamostrado, que possuem poucas coletas e são pouco avaliadas em estudos ecológicos com populações e comunidades de sub-bosque. Mais estudos são necessários para determinar com maior precisão a extensão de ocorrência, o tamanho das populações, e o estado real de conservação das espécies nativas. / Terrestrial orchids occur widespread in tropical and temperate environments around the world. The terrestrial habitat for orchid species comprises several distinct plant formations, like forests, woodlands, grasslands and wetlands. In this study we focused the estimation of range sizes and the occurrence of these plants in nine forest types in the South Brazilian state of Rio Grande do Sul, located entirely in subtropical latitudes. We revised sampled specimens deposited in seven regional herbaria and updated species identifications to current generic circumscriptions. Based on sampling locations we estimated two range size parameters, namely extent of occurrence and area of occupancy, aiming to determine the conservation status according to IUCN categories. As a result we found 22 genera and 50 species, most genera (15) having of them a single species in the state. The most diversified genera were Cyclopogon, Aspidogyne and Malaxis, with 14, eight and four species, respectively. Four additional genera presented three (Pelexia) or two (Habenaria, Prescottia, and Sarcoglottis) species in forest environments. Range size estimations, especially through area of occupancy, resulted in an outstanding number of threatened species. Critically endangered species according to extent of occurrence were distributed in seven genera and 18 species. The most diversified forest types were the central Serra Geral seasonal forests, followed by the Atlantic rainforest and the southeast Crystalline Shield seasonal forests. A total of 19 species occurred in a single forest formation and only four species occurred widespread in six or seven forest types. The number of recordings in this study showed to be exponentially related to species range according to forest types. Our study showed that terrestrial orchids in forest environments are an overlooked plant group, which has been poorly sampled and poorly evaluated in ecological studies concerning understory populations and communities. Further studies are necessary to determine more precisely the extent of occurrence, the size of populations, and the real conservation status of native species.
75

Biologia reprodutiva, seleção de sítios de nidificação e sucesso reprodutivo em aves campestres de cerrado na Estação Ecológica de Itirapina, SP / Breeding biology, nest-side selection and reproductive sucess in cerrado grassland birds in the Ecological Station of Itirapina, SP

Maikon de Souza Freitas 07 August 2014 (has links)
As regiões tropicais têm sofrido drásticas modificações na paisagem ao longo do tempo. No Brasil, o bioma Cerrado é considerado um dos mais vulneráveis devido à crescente destruição ocasionada pela ação antrópica, sendo o bioma mais ameaçado do mundo. Restam apenas 20% da cobertura original do Cerrado em todo o país e somente 2,2% estão inseridos em áreas protegidas. Com essa crítica situação de conservação, além da rápida destruição de seus hábitats naturais e também por possuir uma elevada riqueza biológica, o Cerrado foi incluso entre os 25 hotspots mundiais. A redução excessiva das áreas nativas pode provocar a extinção de muitas espécies de aves, principalmente espécies especialistas de áreas campestres. Em aves, a seleção de hábitat é entendida como um processo hierárquico de respostas comportamentais que influenciam a sobrevivência e a aptidão dos indivíduos. A diminuição de sítios adequados para a nidificação no ambiente pode ser um fator crítico que determina a extinção local de muitas espécies de aves. Outro aspecto de extrema importância, é a compreensão de fatores relacionados à história de vida das espécies. Descrições detalhadas sobre a biologia reprodutiva da avifauna são de fundamental importância, ainda mais que muitas das espécies de aves neotropicais ainda não possuem descrições sobre informações básicas de suas histórias de vidas. Diante disso, visamos no capítulo I descrever a biologia reprodutiva de Alecturus tricolor e Sporophila pileata, dois Passeriformes dos quais muito pouco se sabe sobre aspectos fundamentais das suas histórias de vida. No capítulo II visamos entender como algumas aves de fitofisionomias campestres de cerrado selecionam o microhábitat para a nidificação e como essas escolhas podem influenciar no sucesso reprodutivo dessas espécies / Tropical regions have undergone drastic changes in the landscape over time. In Brazil, the Cerrado is considered one of the most vulnerable biomes due to increased destruction caused by human action; it is the most threatened biome in the world. Only 20% of the original cover of the Cerrado remains across the country and only 2.2% is included in protected areas. With this critical conservation situation, the rapid destruction of their natural habitats along with its high biological richness, the Cerrado has been included among the 25 global \"hotspots\". Excessive reduction of native areas can cause the extinction of many bird species, principally species specific to grassland areas. Among birds, the habitat selection is understood as a hierarchical process of behavioral responses that influence the survival and fitness of individuals. The reduction of suitable nesting sites in the environment may be a critical factor that determines the local extinction of many species of birds. Another very important aspect is the understanding of factors related to the life history of the species. Detailed descriptions of the reproductive biology of birds are of fundamental importance, even more so since many of neotropical birds still do not have descriptions of basic information of their life histories. Therefore, we aim in chapter I to describe the reproductive biology of tricolor Alecturus tricolor and Sporophila pileata, two Passeriformes of which very little is known about key aspects of their life histories. In Chapter II we aim to understand how some birds of grassland physiognomies of the cerrado select the microhabitats for nesting and how these choices can influence the reproductive success of these species
76

Distribuição e conservação de orquídeas terrestres em florestas subtropicais brasileiras / Distribution and conservation of terrestrial orchids in Brazilian subtropical forests

Colla, Frediny Bettin January 2014 (has links)
As orquídeas terrestres estão distribuídas amplamente em ambientes tropicais e temperados do mundo. O habitat terrestre, para orquídeas, engloba distintas formações vegetais, como florestas, savanas, campos e banhados. Neste estudo consideramos, para a estimativa da amplitude e da ocorrência destas plantas, nove tipos de florestas no estado do Rio Grande do Sul no sul do Brasil, localizadas totalmente em latitudes subtropicais. Revisamos amostras de espécimes depositadas em sete herbários regionais e atualizamos a identificação das espécies para as circunscrições genéricas atuais. Com base nas localizações das amostras estimamos dois parâmetros de amplitude, nomeados extensão de ocorrência e área de ocupação, objetivando determinar o estado de conservação das espécies de acordo com as categorias da IUCN. Como resultado, encontramos 22 gêneros e 50 espécies, a maioria dos gêneros (15) possui apenas uma espécie no estado. Os gêneros mais diversificados foram Cyclopogon, Aspidogyne e Malaxis, com 14, oito e quatro espécies, respectivamente. Outros quatro gêneros apresentaram três (Pelexia) ou duas (Habenaria, Prescottia, e Sarcoglottis) espécies nos ambientes florestais. As estimativas de amplitude, especialmente a área de ocupação, resultaram em um elevado número de espécies ameaçadas. Espécies criticamente ameaçadas, considerando a extensão de ocorrência, estão distribuídas em sete gêneros e 18 espécies. O tipo de floresta mais diversificado foi a floresta estacional da Serra Geral, seguido pela floresta Atlântica e pela floresta estacional do Escudo Cristalino. Um total de 19 espécies ocorreu somente em uma formação e apenas quatro espécies ocorreram em seis ou sete tipos de florestas. O número de registros neste estudo mostrou que as orquídeas terrestres em ambientes florestais são um grupo subamostrado, que possuem poucas coletas e são pouco avaliadas em estudos ecológicos com populações e comunidades de sub-bosque. Mais estudos são necessários para determinar com maior precisão a extensão de ocorrência, o tamanho das populações, e o estado real de conservação das espécies nativas. / Terrestrial orchids occur widespread in tropical and temperate environments around the world. The terrestrial habitat for orchid species comprises several distinct plant formations, like forests, woodlands, grasslands and wetlands. In this study we focused the estimation of range sizes and the occurrence of these plants in nine forest types in the South Brazilian state of Rio Grande do Sul, located entirely in subtropical latitudes. We revised sampled specimens deposited in seven regional herbaria and updated species identifications to current generic circumscriptions. Based on sampling locations we estimated two range size parameters, namely extent of occurrence and area of occupancy, aiming to determine the conservation status according to IUCN categories. As a result we found 22 genera and 50 species, most genera (15) having of them a single species in the state. The most diversified genera were Cyclopogon, Aspidogyne and Malaxis, with 14, eight and four species, respectively. Four additional genera presented three (Pelexia) or two (Habenaria, Prescottia, and Sarcoglottis) species in forest environments. Range size estimations, especially through area of occupancy, resulted in an outstanding number of threatened species. Critically endangered species according to extent of occurrence were distributed in seven genera and 18 species. The most diversified forest types were the central Serra Geral seasonal forests, followed by the Atlantic rainforest and the southeast Crystalline Shield seasonal forests. A total of 19 species occurred in a single forest formation and only four species occurred widespread in six or seven forest types. The number of recordings in this study showed to be exponentially related to species range according to forest types. Our study showed that terrestrial orchids in forest environments are an overlooked plant group, which has been poorly sampled and poorly evaluated in ecological studies concerning understory populations and communities. Further studies are necessary to determine more precisely the extent of occurrence, the size of populations, and the real conservation status of native species.
77

Biotic interactions and vegetation management on coastal meadows

Niemelä, M. (Marika) 12 May 2009 (has links)
Abstract Conservation of rare habitats and species are central elements in the management of semi-natural grasslands of high biodiversity. Understanding the impacts of various abiotic and biotic interactions and management methods on threatened species is fundamental to their conservation. In the present study, effects of competition, plant parasitism, grazing and mowing were studied at the community level in Bothnian Bay coastal meadows and in greenhouse. This was the first time when the impacts of various biotic interactions on the critically endangered creeping alkali grass (Puccinellia phryganodes) have been explored in detail in one of its rare occurrences in the boreal vegetation zone in Europe. In addition, questions related to ecological and economical sustainability of cattle grazing on coastal meadows were examined. Puccinellia phryganodes was found to suffer severely from competition with taller graminoids. Simulated and actual grazing by greylag goose, Anser anser, as well as infection by a hemiparasitic plant, Odontites litoralis, were found to indirectly benefit P. phryganodes by decreasing the competitive advantage of its competitors. In spite of the relatively intensive grazing by greylag goose in the field, P. phryganodes experienced a drastic decrease during four years in the grazed experimental quadrats and simultaneously the proportion of the taller graminoids increased substantially. Primary succession of coastal meadow vegetation was found to progress rapidly and continuous formation of suitable open habitats is therefore crucial for the subordinate species. Mowing was found to be an effective management method for some threatened plant species in coastal meadows, but not for P. phryganodes, which would probably benefit more, for example, from livestock grazing. Both lightly and rather intensively managed large open meadows could provide optimal habitats for the critically endangered lesser white fronted goose (Anser erythropus) as well as for the greylag goose. The relatively low and variable yield of the coastal meadow vegetation compared to that of cultivated grasslands sets limits how management by cattle grazing can be implemented. Key factors for both the biodiversity management and livestock production in coastal meadows are timing of the grazing season, intensity of grazing and selection of suitable types of animals.
78

Does Additional Habitat Protection Facilitate the Recovery of Species Protected by the Endangered Species Act?

So, Rachel I. January 2014 (has links)
Earlier studies have found that endangered species recovery is only weakly associated with the tools enabled by the U.S. Endangered Species Act (ESA). With habitat loss often cited as a leading cause of species declines, we tested whether the recovery of ESA-listed species is instead associated with the protection of critical habitat (CH) by protected areas. We tested the relationship for 299 species using recovery indices derived from the biennial status reports to Congress (1990-2010), as well as NatureServe and IUCN population status data. We found no overall relationship between recovery and the extent to which CH is protected. However, restricting the analysis to recovering species, listed species with larger areas of protected (R2 = 0.158) or strictly protected (R2 = 0.194) CH fared better than species with less protected or strictly protected CH areas. Declining species (199 of 273 species studied) fared no better with more protected habitat. We conclude that the abatement of habitat loss alone does not necessarily facilitate recoveries for the majority of ESA-listed species. We also note that the weak relationships we observed in this study may be reflective of poor recovery status estimates.
79

Potřeby pracovníků intervenčních center při práci s ohroženými osobami / Needs of intervention center workers at work with persons threatened by domestic violence

Kadlecová, Barbora January 2011 (has links)
Diploma thesis "Needs of intervention center workers at work with persons threatened by domestic violence" defines basic concepts in the theoretical section that relate to topic - violence, abuse, domestic violence, violent person, threatened person, expulsed person, expulsion. The thesis also defines characteristics of working with threatened persons and the status of intervention centers in the system of services. Besides that, it deals with the authorization of the institutions that provide support and help to threatened persons. In detail talks about social service - intervention center - focusing on its mission, target group, the statutory duties and interdisciplinary cooperation. Experience from abroad, that was originally the source of inspiration for building the intervention centers in the Czech Republic, is surveyed. The practical section presents the results of the research that was focused on the intervention centers workers in Czech Republic. The aim of the research was to find out to what extent their needs at work with threatened persons are satisfied. The system of basic developmental needs (Pesso Boyden System Psychomotor) by Albert Pesso and Diane Boyden-Pesso was used to define the needs. The results of the research lead to the conclusion that intervention center workers needs...
80

Threatened Turtle Species in Ohio and Michigan: The Ecology of Hatchlings and Analysis of GPS Devices

Hulbert, Austin C. January 2020 (has links)
No description available.

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