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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.
1

Wintering activity range and population ecology of Black-faced spoonbills (Platalea minor) in Taiwan

Liu, Liang-Li 17 September 2007 (has links)
Black-faced Spoonbill (BFS), Platalea minor, numbers during the non-breeding season increased steadily from 1990 to 2004 in Taiwan. Numbers of the BFS in Taiwan accounted for more than 50% of the total population, with 96% of the BFS in southwestern Taiwan at the town of Chi-Ku and Tainan City. The percentage of adult BFS remained constant from 2000-2003. Relatively constant high survey counts, with similar ratios of adult to non-adult birds, suggested that the BFS has a healthy population. With the exception of avian botulism resulting in 73 BFS deaths in the 2002 winter, several other mortality factors were documented with no more than four birds lost in a year from 1849-2004. I counted numbers of BFS at the town of Chi-Ku and Tainan City almost daily during the winter months from September 1998 to May 2001. Although variable, overall population numbers increased sharply from September to October. From November to February, the BFS maintained a high, stable population-level. Migration began during March, and population numbers decreased from March to May. I used visual observations and radio-telemetry data to locate, count and monitor BFS during the day and night, respectively, and also to assess nocturnal habitat use. Information obtained through these methods showed that habitat use was not in direct proportion to its availability. Activity ranges obtained from radio tracking and visual observations showed an increase in activity range size by BFS just prior to migration with more of the study area used north of the core-roosting area. Sizes and weights of potential prey items were measured at fish ponds used by BFS. Available prey in fish ponds was dominated by fish prey less than 5 cm in length and at least 30 gm in size. Similar size classes of prey items were selected by a captive BFS. Biomass of prey in fish ponds around the primary roosting site declined sharply in the pre-migration stage (March-April), compared to the middle winter stage (November-February). I suggest that this low biomass of prey items may have stimulated the northward movement of BFS in the late stage of winter. In addition, the activity range expansion may have related to preparation for migration.
2

Wintering activity range and population ecology of Black-faced spoonbills (Platalea minor) in Taiwan

Liu, Liang-Li 17 September 2007 (has links)
Black-faced Spoonbill (BFS), Platalea minor, numbers during the non-breeding season increased steadily from 1990 to 2004 in Taiwan. Numbers of the BFS in Taiwan accounted for more than 50% of the total population, with 96% of the BFS in southwestern Taiwan at the town of Chi-Ku and Tainan City. The percentage of adult BFS remained constant from 2000-2003. Relatively constant high survey counts, with similar ratios of adult to non-adult birds, suggested that the BFS has a healthy population. With the exception of avian botulism resulting in 73 BFS deaths in the 2002 winter, several other mortality factors were documented with no more than four birds lost in a year from 1849-2004. I counted numbers of BFS at the town of Chi-Ku and Tainan City almost daily during the winter months from September 1998 to May 2001. Although variable, overall population numbers increased sharply from September to October. From November to February, the BFS maintained a high, stable population-level. Migration began during March, and population numbers decreased from March to May. I used visual observations and radio-telemetry data to locate, count and monitor BFS during the day and night, respectively, and also to assess nocturnal habitat use. Information obtained through these methods showed that habitat use was not in direct proportion to its availability. Activity ranges obtained from radio tracking and visual observations showed an increase in activity range size by BFS just prior to migration with more of the study area used north of the core-roosting area. Sizes and weights of potential prey items were measured at fish ponds used by BFS. Available prey in fish ponds was dominated by fish prey less than 5 cm in length and at least 30 gm in size. Similar size classes of prey items were selected by a captive BFS. Biomass of prey in fish ponds around the primary roosting site declined sharply in the pre-migration stage (March-April), compared to the middle winter stage (November-February). I suggest that this low biomass of prey items may have stimulated the northward movement of BFS in the late stage of winter. In addition, the activity range expansion may have related to preparation for migration.
3

Dna Profiling of Captive Roseate Spoonbill (Ajaia Ajaja) Populations As a Mechanism of Determining Lineage in Colonial Nesting Birds.

Sawyer, Gregory M. 05 1900 (has links)
Roseate spoonbills are colonial nesting birds with breeding grounds extending from the United States Gulf coast to the pampas of Argentina. The U.S. population suffered a severe bottleneck from 1890 to 1920. The population's recovery was slow and partially credited to migrations from Mexican rookeries, but a gene pool reduction would be expected. Five polymorphic Spoonbill autosomal short tandem repeat (STR) loci [three (GAT)n, one (AAAG)n and one (GT)n] and one Z/W-linked microsatellite exhibiting sex-specific dimorphism were isolated and characterized. The Z/W-linked STR locus accurately confirmed the sex of each bird. Allelic profiles for 51 spoonbills obtained from Dallas (Texas), Fort Worth (Texas) and Sedgwick County (Kansas) zoos revealed a non-continuous distribution of allele frequencies, consistent with the effects of a population bottleneck. Allelic frequencies also differed significantly between the isolated zoo populations. Although extra-pair copulations were suspected and difficult to document, zoos commonly used observational studies of mating pairs to determine familial relationships among adults and offspring. STR parentage analysis of recorded family relationships excluded one or both parents in 10/25 cases studied and it was further possible to identify alternative likely parents in each case. Mistaken familial relationships quickly lead to the loss of genetic variability in captive populations. Here, a decreased heterozygosity (HO) in 2nd generation captive-bred birds was observed at 3 out of 4 loci evaluated. Although these results could not be statistically validated because of the small number of individuals available for study (15 wild birds with no offspring vs. eight 2nd generation captive birds), they are considered biologically important, as decreased HO is an indicator of inbreeding and this apparent decrease occurred within two generations of removal from the wild. Collectively, the evidence obtained from this study suggests that captive spoonbill populations are experiencing rapid loss of diversity from an already depleted wild gene pool.
4

DNA profiling of captive roseate spoonbill (Ajaia ajaja) populations as a mechanism of determining lineage in colonial nesting birds

Sawyer, Gregory M. January 2002 (has links)
Thesis (Ph. D.)--University of North Texas, 2002. / Title from PDF title page (viewed on Dec. 9, 2004). Includes bibliographical references (p. 350-356).
5

Aves aquáticas como indicadores de contaminação por metais em áreas úmidas no sul do Brasil

Barreto, Cindy Tavares January 2013 (has links)
Submitted by dayse paz (daysepaz@hotmail.com) on 2016-04-06T18:14:47Z No. of bitstreams: 1 Disserta_o_de_Mestrado_de_Cindy_Tavares_Barreto.pdf: 1526539 bytes, checksum: 1df2010b2061af8f93607669b374dccd (MD5) / Approved for entry into archive by cleuza maria medina dos santos (cleuzamai@yahoo.com.br) on 2016-04-18T20:17:10Z (GMT) No. of bitstreams: 1 Disserta_o_de_Mestrado_de_Cindy_Tavares_Barreto.pdf: 1526539 bytes, checksum: 1df2010b2061af8f93607669b374dccd (MD5) / Made available in DSpace on 2016-04-18T20:17:10Z (GMT). No. of bitstreams: 1 Disserta_o_de_Mestrado_de_Cindy_Tavares_Barreto.pdf: 1526539 bytes, checksum: 1df2010b2061af8f93607669b374dccd (MD5) Previous issue date: 2013 / Os Pelecaniformes são aves associadas aos ambientes aquáticos, estando em contato constante com contaminantes de origem antrópica. Neste contexto, o presente estudo quantificou concentrações de chumbo (Pb) e cádmio (Cd), metais não essenciais e tóxicos, relacionando-as com as características de dois habitats, técnicas de forrageamento e níveis tróficos da garçabranca-grande (Ardea alba) e do colhereiro (Platalea ajaja), no sul do Brasil. Amostras de sangue, penas e ovos (separados em casca e conteúdo) foram coletadas para as duas espécies em dois ninhais, um de ambiente exclusivamente límnico e outro predominantemente estuarino. A concentração de Pb no sangue foi diferente entre os locais de amostragem, sendo maior nas amostras coletadas no ambiente estuarino. Já a concentração na casca do ovo foi maior nas amostras do ambiente límnico. Quanto ao Cd, a concentração sanguínea foi maior na garça do que no colhereiro. Na pena e na casca do ovo, as concentrações foram maiores nas amostras coletadas no ambiente límnico. Os resultados mostraram uma correlação positiva entre as concentrações de Pb e Cd na casca e no conteúdo dos ovos, além de um alto índice de correlação entre as concentrações dos metais na casca do ovo. Embora as concentrações destes metais no sangue e penas das espécies estudadas sejam inferiores àquelas relatadas na literatura, as concentrações dos metais nos ovos foram até 605 vezes maiores que aquelas relatadas para espécies semelhantes amostras em outros ambientes aquáticos. Os ovos mostraram-se como bioindicadores mais sensíveis que os demais tecidos analisados, permitindo a constatação de contaminação por Pb e Cd nos ambientes úmidos na região sul do Brasil. Desta forma, foi verificado que as aves aquáticas analisadas no presente estudo podem ser consideradas como indicadoras/sentinelas quanto à contaminação ambiental por Pb e Cd. / Pelecaniformes are birds associated with wetlands, in close contact with contaminants of anthropogenic origin. The current study quantified lead (Pb) and cadmium (Cd) concentrations, both non-essential and toxic metals, in tissues of great egrets (Ardea alba) and roseate spoonbills (Platalea ajaja), comparing with foraging techniques, trophic levels and estuarine vs. limnetic habitats. Blood, feathers, egg content and eggshells were sampled in two colonies, the first one limnetic and the second one estuarine. Pb concentration in blood differed between places, higher in the estuarine colony, while concentrations in eggshell were higher in the limnetic colony. Cd concentrations in blood were higher in egrets than spoonbills. In feathers and eggshells, Cd concentrations were higher in samples from the limnetic site. Positive correlations between concentration of each metal in eggshell and egg content were found, as well as a high correlation among both metals in eggshell. Despite concentrations of both metals found in blood and feathers were below those reported in other studies, concentrations in eggs were up to 605 times higher than in other similar species studied elsewhere. In general, eggs seem to be more sensitive bioindicators of contamination by metals in comparison with other tissues analyzed, indicating Pb and Cd contamination in wetlands in southern Brazil. Therefore, waterbirds investigated in the current study could be regarded as suitable indicators/sentinels of environmental contamination by Pb and Cd.
6

Genética de populações e relações de parentesco em Ciconiiformes (Aves)

Miño, Carolina Isabel 06 August 2010 (has links)
Made available in DSpace on 2016-06-02T20:20:30Z (GMT). No. of bitstreams: 1 3280.pdf: 5102569 bytes, checksum: f511b08e43998ea79e0f9b0ac5ed969b (MD5) Previous issue date: 2010-08-06 / Universidade Federal de Sao Carlos / Population genetic parameters and genetic relatedness estimates were carried out for Roseate Spoonbill (Platalea ajaja), Wood Stork (Mycteria americana) and Great Egret (Ardea alba egretta) reproductive colonies in Amapa, Pantanal and Rio Grande do Sul (RS), Brazil. Microsatellite genotypes were used to investigate kinship patterns between nestlings sampled inside the same nests, using a variety of analytical approaches. Unrelated nestling-pairs were observed in Roseate Spoonbill nests (6.12% of analyzed nests) and in Wood Stork nests (11.34%); half-siblings were present in Roseate Spoonbill nests as well (1.36%). Only full-siblings were detected inside Great Egret nests. Conspecific brood parasitism (CBP) and extra-pair paternity were proposed to account for the presence of unrelated nestmates and half-siblings, respectively, in Roseate Spoonbill and Wood Stork nests. Those results suggest the occurrence of a mating system different than genetic monogamy in natural populations of those waterbirds. Genetic relatedness was also investigated for adults and offspring, as well as for supposed siblings in Roseate Spoonbill families kept in three zoological facilities in the U.S. Paternity and maternity allocation analyses through maximum-likelihood revealed that errors were present in zoo‟s studbooks in relation to the familial records. We also identified mating between related individuals that were not detected previously by zookeepers. Population genetic parameters were also estimated and demographic processes were assessed for Great Egret reproductive colonies in the Pantanal and Rio Grande do Su, Brazil. Bayesian clustering analyses, assignment tests, analysis of molecular variance, F-statistics estimates, allelic frequency distribution and the G-W index revealed that: i) Pantanal reproductive colonies are genetically differentiated from Rio Grande do Sul colonies; ii) an IBD-like pattern alone cannot explain that differentiation; and iii) genetic signal of a reduction of population size was present for two colonies in the Pantanal and one in Rio Grande do Sul. Results were discussed considering a metapopulation dynamic and also considering that populations from both Brazilian regions represent distinct units and deserve to be treated separately when planning and carrying out conservation and management programs that aim to preserve the species‟ genetic diversity. / Estudos de genética de populações e de parentesco genético foram desenvolvidos em colhereiro (Platalea ajaja), cabeça-seca (Mycteria americana) e garça-branca-grande (Ardea alba egretta), de colônias reprodutivas do Amapá, Pantanal e Rio Grande do Sul (RS), Brasil. Genótipos em locos de microssatélites foram utilizados para se investigar os padrões de relacionamento entre ninhegos amostrados dentro dos mesmos ninhos com diferentes metodologias de análise. Pares de ninhegos não-relacionados foram encontrados nos ninhos de colhereiro (6,12% dos pares analisados) e de cabeça-seca (11,34%); meio-irmãos foram observados nos ninhos de colhereiro (1,36%). Em garça branca grande foi detectada apenas a presença de irmãos-completos dentro dos ninhos. Parasitismo de ninho intraespecífico e paternidade extra-par podem explicar a presença de ninhegos não-relacionados e meio-irmãos nos ninhos de colhereiro e cabeça-seca, o que indica a presença de um sistema de acasalamento diferente da monogamia genética nas populações naturais dessas espécies. Relações de parentesco entre adultos e filhotes e entre supostos irmãos foram determinadas em famílias de colhereiro de três zoológicos dos EUA. Análises de atribuição de maternidade e paternidade por máxima verossimilhança revelaram erros nos registros dos zoológicos quanto às relações progenitor-progênie e identificaram acasalamentos entre indivíduos aparentados que não tinham sido registrados. Parâmetros genético-populacionais e processos demográficos foram investigados em populações de garça-branca-grande do Pantanal e do Rio Grande do Sul. Análises Bayesianas, testes de alocação de indivíduos, análises de variância molecular, estimativa de estatísticas F, exame da distribuição das freqüências alélicas e cálculo do índice de G-W permitiram identificar que: i) há diferenciação genética significativa entre colônias reprodutivas do Pantanal e do Rio Grande do Sul; ii) o padrão de isolamento pela distância não explica essa diferenciação; e iii) duas populações no Pantanal e uma população no RS apresentaram sinais genéticos de redução demográfica. Os resultados foram discutidos considerando que as populações de garça-branca-grande localizadas no Pantanal e no Rio Grande do Sul são unidades populacionais independentes e devem se tratar separadamente no planejamento e desenvolvimento de programas de manejo para a conservação da diversidade genética total da espécie.

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