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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.
311

Can monkeys and humans co-exist? Land-use and primate conservation : conflicts and solutions in Tana River National Primate Reserve, Kenya

Gachugu, David Mukii, n/a January 1992 (has links)
This study is based in Tana River National Primate Reserve (TRNPR), Kenya. The reserve, established in 1976 to protect remnant patches of riverine forests from increasing human pressure is home to two endemic endangered primate subspecies, Tana River Red colobus (Colobus badius rufomitratus) and Tana River Crested mangabey (Cercocebus galeritus galeritus). Habitat encroachment through indigenous farming and forest uses was thought to be one of the causes of drastic colobus and mangabey population decline after 1975. This study aimed at; generating information on the impact of these human land-uses on the habitat, this would facilitate the preparation of management recommendations which would improve the chances of survival of primate habitats without compromising the welfare of indigenous people. Using 3 sets of aerial photographs and a geographic information system, information on land-use changes over time has been generated. A 3 month field work generated information on agriculture, forest uses and other relevant socio-economic information. Results from the study indicate that: (i) human population has increased by more than two-folds between 1969 and 1991; (ii) this has not corresponded to a net increase in forest area decrease or farm area increase; (iii) there has been a net increase in area under forest and decrease in area under agriculture; (iv) spatial and temporal changes in forest area explain colobus population crash observed between 1975 and 1985, (v) indigenous farmers interviewed prefer a compromise, where they are allowed controlled access to land within the reserve. They showed a keen knowledge of conservation costs and benefits and cause-effect processes between humans and the environment. Management recommendations advocate measures that encourage indigenous people to be partners in conservation.
312

Habitat relationships of seven breeding bird species in the Leon River Watershed investigated at local scales

Juarez Berrios, Edwin Alfredo 17 February 2005 (has links)
Over the past 100–150 years Texas rangelands have dramatically changed from native open savannahs to dense woodlands. On the Edwards plateau, a major management concern is the increasing encroachment of Ashe juniper (Juniperus ashei). Preceding an anticipated brush management program, I investigated the presence, co-occurrence, and habitat relationships of 7 breeding bird species in the Leon River Watershed in central Texas, USA: black-capped vireo (Vireo atricapillus), golden-cheeked warbler (Dendroica chrysoparia), northern bobwhite (Colinus virginianus), white-eyed vireo (Vireo griseus), Bell’s vireo (Vireo bellii), painted bunting (Passerina ciris), and brown-headed cowbird (Molothrus ater). Vegetation characteristics were compared between sites occupied by each species and unoccupied sites using univariate analysis. Models for predicting species site occupancy were developed (using logistic regression) based on habitat characteristics correlated with the presence of each species. Two species of special concern, the endangered black-capped vireo and golden-cheeked warbler occupied 5.6% of sites and 13.8% of sites respectively, while the brood parasite brown-headed cowbird was the most widespread, occupying 86.8% of sites. Species co-occurrence patterns revealed significant associations between the golden-cheeked warbler and each of 5 other species. For most species, variables included in habitat models could be explained by knowledge of species known habitat associations. For example, the black-capped vireo was positively associated with increasing low-growing (<1.5 m) hardwood cover and with Low Stony Hill ecological sites. The golden-cheeked warbler was positively associated with increasing density of larger juniper trees, increasing variability in vertical vegetation structure, and decreasing midstory canopy of deciduous nonoaks (e.g., cedar elm [Ulmus crasifolia]). It also preferred Low Stony Hill and Steep Adobe ecological sites. Site occupancy seemed to be driven by variables that describe overall vegetation structure. In particular, cover of low-growing non-juniper vegetation and juniper tree density appeared to be important in determining site occupancy for several species. Although the models constructed were not very robust, resource managers can still benefit from such models because they provide a preliminary examination of important controlling variables. Managing rangelands to maintain or restore a mosaic of juniper patches and open shrublands are likely to help meet the habitat requirements of these bird communities.
313

The effect of different management strategies on the dynamics of saproxylic insect habitats

ŠEBEK, Pavel January 2016 (has links)
The thesis concerns studies on habitats utilized by insects associated with deadwood. It presents a review of current issues in the conservation of saproxylic biodiversity. The effects of active intervention on temperate lowland woodland habitats, such as pollarding or coppicing, are evaluated in terms of their suitability for saproxylic communities and other groups. Further, the importance of open-grown trees for saproxylic diversity is assessed.
314

The viability of legalising international trade in Rhino horn and the possible effect on Rhino poaching in South Africa

De Beer, Willem 02 1900 (has links)
The existence of the rhino is under serious threat. South Africa has experienced a dramatic increase in rhino poaching since 2008. With the current trend of poaching, rhino in South Africa will soon become extinct. The current strategies to protect rhino have proved to be ineffective. The common view is that rhino poaching is morally wrong, and associated with greed and evil intentions and that rhino poaching must be stopped; however, there are two schools of thought regarding two main approaches (in association with current strategies) to be used in order to stop or limit poaching. The first school of thought supports the CITES ban on international trade in rhino horn, and believes that rhino poaching can only be stopped by eliminating demand (the “conventional approach”). The second school of thought is in favour of the legalisation of international trade, and argues that any solutions to the rhino poaching problem must address the underlying economic forces. This is called the sustainable approach. The research aimed to investigate the effectiveness of the ban on international trade in rhino horn, as well as the viability of legalising international trade. The effectiveness of the current strategies was also investigated. A qualitative research design was used, and eighteen participants were selected in order to obtain information by means of semi-structured interviews and questionnaires.The first school of thought supports the CITES ban on international trade in rhino horn, and believes that rhino poaching can only be stopped by eliminating demand (the “conventional approach”). The second school of thought is in favour of the legalisation of international trade, and argues that any solutions to the rhino poaching problem must address the underlying economic forces. This is called the sustainable approach. The research aimed to investigate the effectiveness of the ban on international trade in rhino horn, as well as the viability of legalising international trade. The effectiveness of the current strategies was also investigated. A qualitative research design was used, and eighteen participants were selected in order to obtain information by means of semi-structured interviews and questionnaires. A literature review was also conducted, for the purpose of evaluating the responses of participants, and also for the purpose of validity and reliability. The findings indicated that the scales tip in favor of a well-managed, legalized trade, inter alia, to make funds available to rhino owners, rhino custodians and the government, on the one hand, and, on the other hand, to reduce the reward and increase the risk to the poacher. Findings also indicated that a legalized trade cannot be implemented in isolation; it goes hand in hand with increased security and improved law enforcement, while strategies such as dehorning and translocation still have a role to play. Finally, findings also indicated that communities need to be involved in the sustainable use approach. These communities are currently excluded from the benefits derived from the neighboring protected areas, thereby making them susceptible to being recruited as poachers. / Environmental Sciences / Ph. D. (Environmental Management)
315

Estrat?gia de vida do peixe anual Hypsolebias antenori (Cyprinodontiformes: Rivulidae) do semi?rido brasileiro

Nascimento, Wallace Silva do 04 June 2014 (has links)
Made available in DSpace on 2014-12-17T15:36:43Z (GMT). No. of bitstreams: 1 WallaceSN_TESE.pdf: 8655030 bytes, checksum: d55633f6c1ca42d23115efea83e7b07c (MD5) Previous issue date: 2014-06-04 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This work deals with the life strategy of an endangered annual fish, Hypsolebias antenori (Cyprinodontiformes: Rivulidae), of the Brazilian semiarid region. The eggs of these fish hatch at the onset of the rainy season, grows rapidly and they reproduce during the rainy season. When the water puddles dry out, the entire population dies. The resistant eggs which are buried in the bottom of the dried pools go through diapause stages, during which time the embryonic development becomes temporarily arrested. With the onset of the next rainy season, the eggs hatch and a new generation is formed. Specimens of H. antenori were captured during 2011 and 2013, in temporary water pools located in the hydrographic basin of river Jaguaribe in Cear?, Brazil. Sex ratio, the length-weight relationship, the growth type, first sexual maturity, anatomy and histology of the digestive tract, development of gonads, reproductive strategy, karyotypic pattern of the species, and the conservation status of H. antenori were investigated. The results of this study are presented in the form of eight articles. The first article is about the fish faunal composition of the hydrographic basins of Rio Grande do Norte, Brazil, wherein the record of H. antenori is included. The second article deals with the sex ratio, secondary sexual characteristics of males, the length-weight relationship and the type of growth. Males show a pattern of intense coloration with well developed fins. The sex ratio showed a significant predominance of females (1M:1.7 F). Males were larger in length and weight. The equation of weight and total length relationship was Wt=0.0271Lt3,8937, showing a positively allometric growth, indicating greater increase in weight than in length. The third article discusses the anatomy and histology of the digestive tract of H. antenori. It is considered as a generalist feeder with characteristics of omnivore, which utilizes different food sources. The fourth article discusses the stages and phases of gonad development and type of spawning of H. antenori. The fifth article is about the r reproductive strategy adopted by H. antenori which helps in successful reproduction over a short period of life. The sixth article deals karyotypic pattern of the species, constituting the first cytogenetic contribution to the genus. The seventh article discusses about the risk of extinction of this species which suffers a series of threats, such as, habitat loss through land use, deforestation, construction of reservoirs, pollution due to domestic and industrial sewage, besides pesticides and agrochemicals. Furthermore, decreasing rainfall and intensification of aridity due to global climate changes, interferes with the reproductive cycle. The eighth article deals with aggressive behavior adopted between males and among females during reproduction. All temporary water pools sampled during this study were in high degree of degradation, mainly due to human action. There is a great need for conservation measures to protect the populations of annual fish, including the creation of protected areas in the semiarid ephemeral aquatic environments of Brazil / Este trabalho trata sobre a estrat?gia da vida de um peixe anual em perigo Hypsolebias antenori (Cyprinodontiformes: Rivulidae), do semi?rido brasileiro. Os ovos dessa esp?cie nascem em po?as tempor?rias, crescem rapidamente, reproduzem e no per?odo de estiagem quando a po?a seca, toda a popula??o morre. Os ovos resistentes depositados no substrato da po?a s?o capazes de passar por um est?gio de diapausa, quando seu est?gio de desenvolvimento embrion?rio ? estacionado. Com a chegada do per?odo de chuvas, os ovos eclodem e uma nova gera??o ? formada. Os exemplares de H. antenori foram capturados durante 2011 e 2013, nas po?as tempor?rias localizadas na bacia do rio Jaguaribe no Cear?, Brasil. Foram investigadas a propor??o sexual, a rela??o peso-comprimento, o tipo de crescimento, a primeira matura??o sexual, anatomia e histologia do trato digest?rio, desenvolvimento das g?nadas, estrat?gia reprodutiva, dados cariot?picos da esp?cie, e o estado de conserva??o de H. antenori. Os resultados desse trabalho est?o apresentados sob a forma de oito artigos. O primeiro artigo ? sobre a composi??o da ictiofauna das bacias hidrogr?ficas do Rio Grande do Norte, Brasil, incluindo o registro de H. antenori. O segundo artigo trata sobre a propor??o sexual, caracter?sticas secund?rios sexuais dos machos, a rela??o pesocomprimento e o tipo de crescimento. Os machos apresentam um padr?o de colora??o intensa com nadadeiras mais desenvolvidas. A propor??o sexual apresentou uma predomin?ncia significativa de f?meas (1M: 1,7F). Os machos foram maiores em comprimento e em peso. A equa??o originada da rela??o peso total e comprimento total foi Wt = 0,0271Lt3,8937, apresentando um crescimento alom?trico positivo, indicando maior incremento no peso do que em rela??o ao comprimento. O terceiro artigo trata sobre a anatomia e histologia do trato digest?rio de H. antenori. ? considerado como um generalista com as caracter?sticas de on?voria, que aproveita fontes alimentares diferentes. O quarto artigo trata sobre os est?dios e fases de desenvolvimento das g?nadas e o tipo de desova de H. antenori. O quinto artigo trata sobre a estrat?gia reprodutiva r adotada pela H. antenori que auxilia na reprodu??o bem sucedida durante um curto per?odo de vida. O sexto artigo trata sobre os dados cariot?picos da esp?cie, constituindo a primeira contribui??o citogen?tica para o g?nero. O s?timo artigo trata sobre o risco de extin??o dessa esp?cie, que v?m sofrendo uma s?rie de amea?as, tais como, a perda de habitats pela ocupa??o do solo, desmatamento, constru??o dos reservat?rios, polui??o devido aos efluentes dom?sticos, industriais, pesticidas e agrot?xicos. Al?m disso, a diminui??o da pluviosidade e intensifica??o da aridez em decorr?ncia das mudan?as clim?ticas globais vem interferindo em seu ciclo reprodutivo. O oitavo trabalho trata sobre o comportamento agressivo adotado entre os machos e entre as f?meas durante a reprodu??o. Todas as po?as tempor?rias amostradas durante este trabalho estavam em um alto grau de degrada??o, principalmente devido ? a??o antr?pica. H? uma grande necessidade de medidas de conserva??o para proteger as popula??es de peixes anuais, entre elas especialmente a cria??o de ?reas de prote??o nos ambientes aqu?ticos ef?meros do semi?rido brasileiro
316

Flora e ecologia dos campos de Itararé, São Paulo, Brasil / Flora and ecology of Itararé grasslands, São Paulo, Brazil

Carlos Alberto de Mattos Scaramuzza 26 February 2007 (has links)
(Cartografia morfopedológica e de ocupação das terras como subsídio à avaliação ecológica: o caso dos campos de planalto em Itararé, SP). Duas abordagens cartográficas pouco utilizadas no Brasil, morfopedológica e de ocupação das terras, foram aplicadas como parte de um projeto de análise florística, fitogeográfica, ecológica e de conservação dos remanescentes de campos de planalto, na porção sul do município de Itararé, São Paulo (escala 1:50.000). As duas abordagens traduzem em termos ecológicos a paisagem. A carta morfopedológica mapeia unidades cuja evolução, estrutura e problemática sejam correlacionadas, correspondendo a interações específicas entre o material, o modelado, a morfogênese e a pedogênese sob condições climáticas precisas; a carta de ocupação das terras mapeia uma combinação entre as formações vegetais e a influência humana em um território. Ambas as abordagens têm um potencial pouco explorado na gestão da paisagem e no ordenamento territorial no Brasil. (Análise florística e fitogeográfica dos campos de Itararé, São Paulo). A região de Itararé, no sudoeste do estado de São Paulo, junto à divisa do estado do Paraná, possui uma considerável diversidade climática, geológica, pedológica, florística e paisagística, onde ainda podem ser encontrados remanescentes significativos e bem preservados de campos de planalto, uma formação singular e pouco conhecida no estado de São Paulo. Como um primeiro passo para estudar a ecologia dos campos de planalto de Itararé e subsidiar um plano para sua conservação, a flora dos campos foi analisada. Um intensivo levantamento possibilitou a preparação de uma lista florística com 1.000 espécies em 120 famílias, dentre as quais 23 espécies são novas ocorrências para o estado de São Paulo, 71 são consideradas espécies vulneráveis e 22 em perigo, segundo a lista de plantas ameaçadas do estado de São Paulo. As oito famílias que mais contribuem para a riqueza de espécies são: Asteraceae (17,8 %); Poaceae (9,7 %); Fabaceae (7,0 %); Myrtaceae (4,1 %); Cyperaceae (3,9 %); Melastomataceae (3,9 %); Rubiaceae (3,2 %) e Apocynaceae (2,9 %). Uma análise de agrupamento foi efetuda para avaliar o posicionamento fitogeográfico dos campos de planalto de Itararé entre 47 listas florísticas disponíveis para localidades das regiões Sul e Sudeste e dos estados da Bahia, Goiás e Distrito Federal. Uma análise de correspondência canônica indicou as variáveis isotermalidade, sazonalidade térmica e precipitação do mês mais úmido como as mais correlacionadas com a distribuição das espécies dos campos. (Estrutura dos campos e suas relações com o ambiente em Itararé, SP). A estrutura ecológica dos campos na região sul de Itararé, sudoeste do estado de São Paulo, Brasil, foi estudada em uma área de 32.697 ha. Esses fragmentos de campo ainda estão relativamente preservados. O objetivo deste trabalho é diferenciar os tipos de campos existentes na região de Itararé e caracterizar suas relações com variáveis ecológicas. Foi empregada a estratégia de amostragem estratificada aleatória. O critério de estratificação da paisagem foi produzido por meio da interseção do mapa morfopedológico com zonas de influência microclimáticas. A composição florística e sua abundância/cobertura, junto com descritores sobre o meio físico e a estrutura da vegetação, foram obtidos em 115 levantamentos distribuídos pelas unidades de amostragem. Através da aplicação de métodos de estatística multivariada (análise de agrupamentos, de espécies indicadoras e ordenações) foram identificados 4 tipos de campos com suas respectivas espécies indicadoras. O gradiente mais importante presente na matriz de dados está relacionado com o fator umidade. / Two cartographic approaches little used in Brazil, morphopedologic and land occupation, have been applied as part of a project to analyze the flora, phytogeography, ecology and conservation of grassland fragments of the southern portion of the Itararé county in São Paulo State. Both approaches translate the landscape in ecological terms. The morphopedologic theme maps units whose evolution, structure and problematic are correlated, corresponding to specific interactions between the material, the relief, morphogenesis and pedogenesis under precise climatic conditions. The land occupation theme maps the combination between the plant formations and the human influence in a territory. Both approaches have a potential little explored in landscape management and in land zoning in Brazil. ¶ (Floristic and phytogeography of the grasslands of Itararé, São Paulo). The region of Itararé, in southwestern of São Paulo state, at the border with the state of the Paraná, has a considerable climatic, geologic, pedologic, floristic and landscape diversity, where it\'s possible to find significative and well preserved grassland fragments, a singular and little known vegetation type in state of São Paulo. As a first step to study the ecology of the Itararé grasslands and to underpin a conservation plan, the flora of the fields was analyzed. An intensive survey made possible to prepare a floristic list with 1.000 species in 120 families, amongst them 23 new records for the State of São Paulo, 71 vulnerable and 22 endangered species according the Red List of São Paulo State. The eight families with major contributions to the species richness are: Asteraceae (17,8 %); Poaceae (9,7 %); Fabaceae (7,0 %); Myrtaceae (4,1 %); Cyperaceae (3,9 %); Melastomataceae (3,9 %); Rubiaceae (3,2 %) and Apocynaceae (2,9 %). A cluster analysis was performed to evaluate the phytogeographic position of the Itararé grasslands among 47 floristic lists available for South and Southeastern Brazil, as well for the states of Bahia, Goiás and Federal District. A canonical correspondence analysis indicated the climatic variables isothermality, temperature seasonality and precipitation of wettest month as the most correlated with species distribution of grasslands.¶ (Grasslands structure and relations with environment in Itararé, SP). The ecological structure of the grassland in the South region of Itararé, located in southwest of São Paulo state, Brazil, was studied over an area of 32.697 ha. These grassland fragments are still relatively well preserved. The goal of this paper is to distinguish the types of grassland present in the Itararé region and to characterize their relationship with ecological variables. A stratified random sampling strategy was used and the landscape stratification criterion was produced by an intersection of the morphopedologic map with a microclimatic zones layer. Species composition and cover/abundance, together with structural and abiotic parameters were recorded in 115 relevés distributed throughout the sampling units. By the application of multivariate statistical analysis methods - such as cluster analysis, indicator species analyses, and ordination techniques - four grasslands vegetation types were identified with its diagnostic species. The most important ecological gradient present in the data matrix is related with humidity.
317

Determinantes ecológicos do risco de extinção: abundância local, amplitude de nicho, capacidade de dispersão e a resposta das espécies de pequenos mamíferos à fragmentação florestal no Planalto Atlântico Paulista / Ecological determinants of extinction risk: local abundance, niche breadth, dispersal ability and response of small mammals to forest fragmentation at the Atlantic Plateau of São Paulo

Thais Kubik Martins 25 November 2011 (has links)
Alterações antrópicas nos ecossistemas, em especial a perda e a fragmentação de habitat, são consideradas as principais causas do grande aumento nas extinções de espécies nas últimas décadas. Uma vez que o risco de extinção varia grandemente entre as espécies, os determinantes ecológicos associados à chance de extinção têm sido um tema central e muito debatido na literatura ecológica. Atributos ecológicos relacionados à raridade, como amplitude de nicho e abundância local, e a capacidade de dispersão são recorrentemente citados na literatura como determinantes do risco de extinção local. A partir de dados de ocorrência em fragmentos, matas contínuas e áreas de agricultura, e de captura-recaptura em três grades de 2 ha em mata continua, no Planalto Atlântico Paulista, investigamos o efeito desses três atributos ecológicos sobre o risco de extinção local em espécies de pequenos mamíferos. Utilizamos a abordagem de seleções de modelos e o critério de Akaike (AICc) para avaliar qual das hipóteses existentes na literatura sobre a relação destes atributos com o risco de extinção é mais plausível. Foram realizadas duas seleções de modelos: uma considerando os três atributos para sete espécies; e outra considerando apenas a amplitude de nicho e abundância local para 18 espécies. Os resultados de ambas as seleções indicam a amplitude de nicho como determinante principal do risco de extinção local, que aumenta à medida que a amplitude de nicho diminui. Abundância local apresentou uma importância secundária, com um efeito positivo sobre o risco de extinção, mas que é mais forte para espécies com menor amplitude de nicho. Este resultado é consistente com a idéia de que a abundância local é influenciada pelo grau de especialização e pela capacidade competitiva das espécies, a qual está negativamente relacionada à capacidade de colonização através de uma demanda conflitante. Como a capacidade de dispersão variou pouco entre as espécies estudadas e a capacidade de colonização é determinada também pela taxa de crescimento populacional, é possível que o risco de extinção das espécies de pequenos mamíferos especialistas de habitat seja secundariamente definido pela taxa de crescimento populacional / Anthropogenic disturbances, particularly habitat loss and fragmentation, are considered the main causes of the increased extinction rates observed in the last decades. Since the risk of extinction is extremely variable among species, the ecological determinants of the chance of extinction have been in the center of the debates in the ecological literature. Ecological traits associated with rarity, as niche breadth and local abundance, and dispersal ability are recurrently mentioned in the literature as the main determinants of the risk of local extinction. Using data on occurrence in fragments, continuous forest and areas of agriculture, and on capture-recapture in three 2-ha grids in continuous forest, in the Atlantic Plateau of São Paulo, we investigate the effects of these three ecological traits on the risk of local extinction in small mammals. We used a model selection approach and the Akaike criterion (AICc) to evaluate which of the existing hypotheses on the relationship of these traits with the extinction risk is most plausible. Two model selections were run: one considering the three traits and seven species, and another considering only niche breadth and local abundance and 18 species. The results from both selections point to niche breadth as the main determinant of the risk of local extinction. Local abundance was secondarily important, with a positive effect on extinction risk, which is stronger among the species with smaller niche breadth. This result is consistent with the idea that local abundance is influenced by species degree of ecological specialization and competitive ability, which is negatively related to colonization ability through a trade-off. As dispersal ability varied little among studied species, and colonization ability is also determined by population growth rate, it is possible that the risk of extinction among habitat specialist small mammals is secondarily defined by population growth rate
318

Quality assessment of cryopreserved spermatozoa of the blesbok (Damaliscus pygargus phillipsi), blue wildebeest (Connochaetes taurinus) and African buffalo (Syncerus caffer)

Mynhardt, Neil Philip 22 August 2012 (has links)
M.Sc. / Climate change, loss of habitat and over-exploitation of natural resources as well as the introduction of invasive alien species through human activities are resulting in an ever increasing risk of extinction of many plant and animal species. There are two major approaches to conserving threatened and endangered species. Firstly the large scale preservation of natural habitat and ecological processes, thereby protecting the species inhabiting the habitat. The second approach involves the ex-situ breeding of rare and endangered species. It is estimated that in the next 200 years approximately 800 mammalian species will require the assistance of breeding programs to ensure long term genetic viability. Biological Resource Banks (BRB) can potentially contribute to this challenge by providing a source of genes that can be used to counter the effects of external selection pressures, genetic drift and inbreeding depression in small or fragmented populations. These banks commonly contain biological materials such as cryopreserved sperm, embryos and cell cultures mainly as genetic and research resources. . Biological resource banks can potentially use these cryopreserved gametes together with assisted reproductive technologies (ART), such as artificial insemination (AI), in vitro fertilisation (IVF), embryo transfer (ET), intracytoplasmic sperm injection (ICSI) and nuclear transfer (NT) to maintain genetic heterogeneity in ex-situ and wild populations. Ascertaining the appropriate protocols for developing the ARTs necessary for non-domestic species is one of the major challenges faced by reproductive physiologists. Typically, there is very little available information about the processing of semen, the effects of diluents, concentration and type of cryoprotectants and freeze-thaw methods for sperm samples of non-domestic species. Procedures proven to be highly effective in humans and laboratory or domestic species, are frequently adopted and modified for use in related wildlife species. It is thus necessary to gain knowledge of the reproductive physiology of wildlife species in order to define effective protocols for the cryopreservation of biomaterials which assists in the conservation of South Africa‘s diverse wildlife species. Sperm quality assessment is a useful tool for assessing the reproductive health of free-ranging populations as well as for selecting individuals for future assisted reproduction programs.
319

Phylogeography and conservation genetics of waders

Rönkä, N. (Nelli) 29 March 2016 (has links)
Abstract Many waders are in decline, and the number of endangered species and populations is increasing. Their protection and management requires knowledge of both ecological and genetic state of the populations. In this thesis, I studied the distribution-wide genetic variation, structure and phylogeography of the Temminck’s Stint (Calidris temminckii) and Terek Sandpiper (Xenus cinereus) using microsatellites and sequence data from the mitochondrial control region and cytochrome oxidase I gene. I compared these regionally endangered species to other waders with varying evolutionary histories, breeding systems and habitat preferences to examine the levels of genetic variation and structure at different spatial scales. In addition, I studied the genetic structure of the endangered Baltic population of the Southern Dunlin (Calidris alpina schinzii) with microsatellites. I used genetic information in all three study species to determine units for conservation. The Temminck’s Stint and Terek Sandpiper, both not restricted to the Arctic, had low distribution-wide structuring. They also had quite low levels of variation when compared to other species breeding at similar latitudes, indicating reductions in population sizes during past climate changes. Especially the peripheral breeding populations were differentiated and showed signs of inbreeding and genetic drift when compared to the main range. The Temminck’s Stint populations at the Bothnian Bay and Yakutia, and Terek Sandpiper populations in Finland and Belarus, should be treated as separate management units. The broader interspecific comparison of waders suggests that habitat availability, mating system and the extent of philopatry may affect the genetic composition of species. The genetic analyses of the Southern Dunlin indicated strong effects of philopatry and inbreeding throughout the range. Local subpopulations at the Bothnian Bay and in Sweden need to be considered as separate management units. Management efforts at the Baltic should be focused on increasing connectivity and providing large enough breeding habitats for potential immigrants and recruits. / Tiivistelmä Useat kahlaajapopulaatiot ovat pienentyneet ja uhanalaistuneet maailmanlaajuisesti. Lajien ja populaatioiden ekologiaa ja genetiikkaa on tunnettava, jotta suojelutoimia voidaan kohdistaa oikein. Tutkin väitöskirjassani lapinsirrin (Calidris temminckii) ja rantakurvin (Xenus cinereus) geneettistä rakennetta, muuntelua ja fylogeografiaa levinneisyysalueen laajuisesti mikrosatelliittien ja mitokondrion kontrollialueen ja sytokromioksidaasi I -geenin sekvenssien avulla. Tutkin, mitkä tekijät vaikuttavat geneettisen rakenteeseen ja muunteluun vertaamalla näitä lajeja muihin kahlaajiin, joilla on erilaisia lisääntymisstrategioita, jotka pesivät vaihtelevissa ympäristöissä ja joista monet eroavat toisistaan myös fylogeografialtaan. Lisäksi tutkin Itämeren rannalla pesivän etelänsuosirrin (Calidris alpina schinzii) geneettistä populaatiorakennetta mikrosatelliittien avulla. Käytin geneettistä tietoa hyväksi luonnonsuojeluyksikköjen määrittämisessä kaikille kolmelle tutkimuslajilleni. Lapinsirrin ja rantakurvin fylogeografinen historia oli samankaltainen. Geneettisen muuntelun määrä oli vähäisempää verrattuna muihin, samankaltaisissa ympäristöissä pesiviin kahlaajiin. Molemmat lajit ovat todennäköisesti kärsineet historiallisten ilmaston-muutosten aiheuttamasta populaatioiden pienenemisestä. Erityisesti levinneisyysalueen reunoilla pesivät populaatiot olivat erilaistuneita, ja niissä näkyi sukusiitoksen ja geneettisen satunnaisajautumisen merkkejä. Perämeren ja Jakutian lapinsirri- sekä Valko-Venäjän ja Suomen rantakurvipopulaatioita tulee kohdella erillisinä suojeluyksiköinään. Vertailu muihin kahlaajiin osoitti, että niin pesimä- ja talvehtimisalueiden laajuus kuin lisääntymisstrategiat ja paikkauskollisuus voivat vaikuttaa lajien geneettiseen koostumukseen. Etelänsuosirrin geneettiset analyysit paljastivat merkkejä sukusiitoksesta, joita paikkauskollisuus ja populaatioiden pienuus ovat voimistaneet. Perämeren ja Ruotsin populaatioita tulee kohdella erillisinä suojeluyksiköinään. Suojelutoimet on kohdistettava tarpeeksi suurien, hyvälaatuisten pesimäpaikkaverkostojen ylläpitämiseen.
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Linking demography with dispersal and habitat selection for species conservation

Pakanen, V.-M. (Veli-Matti) 29 November 2011 (has links)
Abstract In conservation biology, informed and sound management decisions depend on target specific information about the life history and demography of the endangered populations. I used long-term, individual-based life history data (breeding and capture-recapture data) to examine life-history and demography in order to assess population viability and management. My study systems consist of metapopulations of two endangered, long-distance migratory wader species breeding on Baltic coastal meadows, the Temminck’s stint (Calidris temminckii) and the Southern Dunlin (Calidris alpina schinzii), whose breeding habitats are mainly managed by livestock grazing. Demographic models indicated that both study populations were sinks, which persist through immigration due to low local recruitment insufficient to compensate for adult mortality or emigration. Philopatric Temminck’s stints had higher nest and apparent adult survival compared to immigrants. Consideration of dispersal status in population models resulted in the most realistic estimates of population growth and revealed a low demographic impact of immigrants. Immigrants had low return rates after reproductive failure, suggesting that the difference in apparent survival was partly caused by different breeding dispersal strategies. Thus, management actions improving reproduction, and thus site fidelity, should also influence viability. An artificial nest experiment indicated high trampling rates under recommended stocking rates on managed meadows. This was attributed to similar space use of nesting Dunlin and cattle. Cattle presence did not affect nest predation. Young Dunlin preferred intensively grazed low sward habitat over high sward habitat. Reproductive success was also higher in low sward habitat. However, nests in the preferred habitat had the highest risk of being trampled if not artificially protected. Thus, low sward habitat was found to work as an ecological trap if grazing was started too early in the breeding season. Due to the sink nature of the Dunlin population even small reductions in reproductive success caused by trampling were detrimental to long term viability. The results encourage continuation of the use of cattle grazing as a management tool, but also highlight the need for more detailed consideration of local grazing practices, especially when sketching management plans for endangered species. / Tiivistelmä Uhanalaisten lajien suojelussa tehokkaiden suojelutoimien suunnittelu edellyttää tietoa hoitokohteen elinkierron eri vaiheista ja niiden demografisesta merkityksestä. Käytän tutkimuksessani pitkäaikaisaineistoja (pesintä ja merkintä-takaisinpyynti) kuvatakseni tutkimuslajien demografiaa ja arvioidessani populaatioiden elinkykyä sekä hoitotoimia. Tutkimuskohteinani ovat lapinsirrin ja etelänsuosirrin, kahden uhanalaisen kahlaajan, Perämeren rantaniityillä pesivät metapopulaatiot. Näiden lajien elinympäristöjä hoidetaan pääosin laiduntamalla. Demografinen mallinnus osoitti molempien populaatioiden olevan nielupopulaatioita, joiden säilyminen on tulomuuton varassa sillä poikastuotto ei kompensoi aikuisten kuolleisuutta ja poismuuttoa. Tutkimusalueella syntyneiden ja sinne rekrytoituneiden lapinsirrien pesä- ja aikuissäilyvyydet olivat paremmat kuin tulomuuttajilla. Tämän huomioiminen populaatiomalleissa tuotti realistisimman kasvukertoimen arvion ja osoitti paikallisten rekryyttien olevan tulomuuttajia merkittävämpiä populaation kasvun kannalta. Pesinnässään onnistuneet tulomuuttajat palasivat seuraavina pesimäkausina epäonnistuneita todennäköisemmin. Paikallisilla rekryyteillä vastaavaa eroa ei havaittu. Ilmiö heijastellee tulomuuttajien muuttoalttiutta myöhemminkin ja voi kertoa erilaisista pesimädispersaalistrategioista. Lisääntymismenestyksen parantaminen voisi parantaa elinkykyä myös pienentämällä poismuuttoa. Tekopesäkokeen perusteella pesien tallausriski oli laidunnetuissa ympäristöissä korkea vaikka laidunnuspaine noudatteli hoitosuosituksia. Tämä johtunee ainakin osin laskennallista korkeammasta todellisesta laidunpaineesta, mikä puolestaan johtui lintujen ja karjan yhtäläisestä tilankäytöstä. Rekrytoituvat suosirrit suosivat voimakkaasti laidunnettuja matalakasvuisia niittyjä, joissa poikastuotto oli parempi kuin, laiduntamattomilla niityillä. Toisaalta, tallausriski on voimakkaasti laidunnetuilla niityillä suuri ja jo pienetkin pesätappiot uhkaavat suosirripopulaation elinkykyä. Täten laitumet voivat toimia ns. ekologisina loukkuina, jos laidunnus aloitetaan liian aikaisin suhteessa pesintään. Laidunnus on kuitenkin suositeltava hoitomuoto, sillä se näyttää tuottavan parhaita pesimäympäristöjä etelänsuosirrille. Tulosten mukaan laidunnuksen ajoitusta, laajuutta ja laidunnuspainetta on muokattava kohdekohtaisesti, jotta saavutetaan paras tulos uhanalaisten lajien suojelun kannalta.

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