Global ETD Search

11	Private ownership of wild animals including endangered species: Conflict on the urban fringe Kochera, Stephanie S. 19 August 2002 (has links) No description available. Agriculture, Forestry and Wildlife Animal Cruelty Wild Animals Endangered Species Captive Breeding Animal Hoarding
12	Reintroducing captive bred species : a community ecological perspective Svensson, Joakim January 2011 (has links) Throughout history species has gone extinct due to anthropogenic activities. During the last century efforts have been done to reintroduce species back into the wild. Zoos that originally were created as amusement parks for people have today a new purpose; to keep and breed species in captivity for later reintroductions in the wild. However a relaxed environment such as a zoo leads to a general fitness decline of up to 40% per generation in captivity. The probability of a successful reintroduction of a species that has been bred in a zoo will be lower the longer time it has been kept in captivity. The reintroduction of a captive bred species can also cause secondary extinctions and other negative effects on the food-web. Both changes in the community caused by the loss of a species and changes in the species itself caused by captivity can be expected to affect the outcome of a reintroduction attempt. Using a modeling approach I here investigate how the reintroduction of a captive bred species (at three different trophic levels; basal, intermediate and top predator species) affects a food-web and what risks there are in reintroducing it. A Lokta-Volterra model with type II functional response is used. I investigate three scenarios: the reintroduction of a species with 0% change in its attributes, 40% change in its attributes and 75% change in its attributes. It was found that the most important factor for reintroduction success when reintroducing a species is whether it is a producer species (basal species) or a consumer species (intermediate and top predator species). The producer species were most sensitive to the changes in their attributes, whilst consumer species were more sensitive to change in the food-web (Euclidian distance). The producer species were found to cause most secondary extinctions in all scenarios, hence indicating that it is a bottom-up controlled food-web. The present study suggests that the success of a reintroduction attempt is affected both by the degree of changes in the food web caused by the initial loss of the species and the degree of change in the species itself caused by captivity. Captive breeding species reintroductions species interactions food-web secondary extinctions Lokta-Volterra models. Biology Biologi Other biology Övrig biologi
13	Science, Practice, and Policy: The Committee on Rare and Endangered Wildlife Species and the Development of U.S. Federal Endangered Species Policy, 1956-1973 January 2011 (has links) abstract: The Committee on Rare and Endangered Wildlife Species (CREWS) of the U.S. Fish and Wildlife Service (FWS) made important and lasting contributions to one of the most significant pieces of environmental legislation in U.S. history: the Endangered Species Act of 1973 (ESA). CREWS was a prominent science-advisory body within the U.S. Department of the Interior (DOI) in the 1960s and 1970s, responsible for advising on the development of federal endangered-wildlife policy. The Committee took full advantage of its scientific and political authority by identifying a particular object of conservation--used in the development of the first U.S. list of endangered species--and establishing captive breeding as a primary conservation practice, both of which were written into the ESA and are employed in endangered-species listing and recovery to this day. Despite these important contributions to federal endangered-species practice and policy, CREWS has received little attention from historians of science or policy scholars. This dissertation is an empirical history of CREWS that draws on primary sources from the Smithsonian Institution (SI) Archives and a detailed analysis of the U.S. congressional record. The SI sources (including the records of the Bird and Mammal Laboratory, an FWS staffed research group stationed at the Smithsonian Institution) reveal the technical and political details of CREWS's advisory work. The congressional record provides evidence showing significant contributions of CREWS and its advisors and supervisors to the legislative process that resulted in the inclusion of key CREWS-inspired concepts and practices in the ESA. The foundational concepts and practices of the CREWS's research program drew from a number of areas currently of interest to several sub-disciplines that investigate the complex relationship between science and society. Among them are migratory bird conservation, systematics inspired by the Evolutionary Synthesis, species-focused ecology, captive breeding, reintroduction, and species transplantation. The following pages describe the role played by CREWS in drawing these various threads together and codifying them as endangered-species policy in the ESA. / Dissertation/Thesis / Ph.D. Biology 2011 History of Science Environmental Studies Captive breeding Endangered Species Act Policy Whooping Cranes
14	Habitat composition and restocking for conservation of the white-backed woodpecker in Sweden Stighäll, Kristoffer January 2015 (has links) In Sweden, intense human land use, especially forestry, has led to profound changes in the landscape over time, especially within the forest ecosystems. A consequence of this is that several specialist species have become endangered. One group of specialists is the woodpeckers. The middle spotted woodpecker became extinct in Sweden in 1982 and the white-backed woodpecker is today Sweden’s most critically endangered forest-living bird. The white-backed woodpecker is dependent on old deciduous forests, rich in dead wood. The woodpecker is areademanding and hence one of the best indicators or umbrella species for biodiversity in this region. A long-term goal within the conservation of the species is to be able to make more accurate predictions of what is needed in the species habitat to establish a viable population, both in terms of composition of landscape and breeding territories. In addition to earlier studies better tools are needed for measuring the distribution of suitable and potential habitats and finding faster ways of creating optimal habitats. In an attempt to secure the future existence of the white-backed woodpecker in Sweden, restocking of birds are carried out. This presupposes availability of suitable habitats as well as strong enough landscape. Due to intense forestry the presumption for the species is, as stated above, alarming. Comparing the different populations around the Baltic Sea and Norway, great differences but also similarities can be seen, in landscape as well as in territory composition. It seems that fragmentation of foraging patches as well as amount of dead deciduous wood within the breeding territory is critical matters. Grey alder stands in Sweden should have high priority in conservation of habitat for the species. / <p>Funding agency: Swedish Society for Nature Conservation (SSNC)</p> White-backed woodpecker Dendrocopos leucotos Sweden deciduous forest suitable habitat fragmentation saproxylic insects captive breeding restocking Biological Sciences Biologiska vetenskaper
15	The Influence of Population Structure on Genetic Variation in Captive Bred Species Jones, Andrew Treymane January 2014 (has links) No description available. Biology Evolution and Development Wildlife Conservation Wildlife Management Captive breeding population genetics evolution computational modeling wildlife conservation wildlife management
16	Improving Assisted Reproductive Technologies in the Endangered Black-Footed Ferret: Artificial Insemination and Sperm Cryopreservation Strickler, Tara Leigh 20 August 2010 (has links) No description available. Biology Zoology black-footed ferret cryopreserved sperm captive breeding artificial insemination gene diversity density gradient centrifugation cholesterol-loaded cyclodextrin
17	Analyzing Factors Influencing Reproductive Success of the Mountain Chicken : Nordens Ark Captive Breeding Program Donaldson, Chad January 2019 (has links) Amphibians globally are declining with roughly a third facing extinction due primarily to threats linked to human impacts. One way in which this is being combated is by captive breeding programs. Nordens Ark in Sweden, in collaboration with other organizations, is attempting to breed one of the most threatened frogs for future reintroduction to the wild. The mountain chicken (Leptodactylus fallax) has unique characteristics related to its reproduction which make it challenging to breed successful offspring. Using Nordens Ark’s data on environmental conditions within breeding enclosures, this study attempts to determine which extrinsic factors are having the most influence on reproduction, in order to increase the success of the captive breeding program. Multiple linear regression analysis and model simplification using Stepwise regression and Akaike information criterion (AIC) were performed in order to determine which explanatory variables had the most influence in relation to foam nests. A reduced model with significant values for explanatory variables was deemed the best model based on the dataset. Of the 14 environmental variables tested, minimum temperature after nest construction had the most influence on foam nest length. When compared to wild habitats, temperatures within enclosures may be too high or lack seasonal cyclical patterns. Barometric pressure and humidity also had influence on foam nests, but the relationships between these environmental conditions is difficult to parse. Food supplements were also a significant factor and suggest that lack of vitamins or nutrients can have a negative effect on reproductive success. Ensuring the optimal conditions can be difficult for captive breeding programs, especially as amphibians are under-represented and face biases in conservation and research. frog frogs mountain chicken mountain chicken frog leptodactylus fallax herpetology amphibian amphibians multiple linear regression statistical analysis Nordens Ark captive breeding zoo zoology conservation endangered species grodor groda kycklinggroda Nordens Ark amfibier zoologi herpetologi analys hotade arter bevarande avel Biological Sciences Biologiska vetenskaper

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