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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.
151

Transição agroecológica no assentamento rural Fazenda Pirituba : percepções, práticas e perspectivas / Agroecologic transition in the agricultural nesting Pirituba farm : perceptions, practice and perspective

Narezi, Gabriela 26 June 2008 (has links)
Made available in DSpace on 2016-06-02T18:57:18Z (GMT). No. of bitstreams: 1 1892.pdf: 22355304 bytes, checksum: 085115e10ed2bcac989d623a3ecd668a (MD5) Previous issue date: 2008-06-26 / Universidade Federal de Minas Gerais / The importance of agroecologic transition for the agricultural nesting in the agrarian reform it s as an alternative front to the economic situation, in the recovery of degraded areas, the balance of agroecosystems and the viability of alimentary agricultural production to attend the needs of the families. The objective of this research was to analyze the agroecologic transition in the agricultural nesting Pirituba farm, in the cities of Itapeva and Itaberá, SP. The used methodology was the research-action and bibliographies. In the field work participative methodologies and half-structuralized interviews had been used. Five groups of agroecologic experimentation, the pointers of sustainability and the phases of each experimental agroecologic transition was identified and analyzed. It was shown that some families had interest in proceed in the agroecologic transition and that some areas demonstrated potential for agroecologic production. However, the continuity of these practices is compromised by some factors representing challenges for the families and also for the public policy of sustainable agricultural development. This work presents the perceptions, practice and perspective for the agroecologic transition in the agricultural nesting Pirituba Farm. / A importância da proposta da transição agroecológica no contexto dos assentamentos rurais se encontra na possibilidade da alternativa frente à atual situação econômica, na recuperação de áreas degradadas, na busca pelo equilíbrio dos agroecossistemas e na viabilidade de produção agrícola para atender as demandas alimentares das próprias famílias assentadas. Dessa forma, o objetivo desta pesquisa foi analisar a questão da transição agroecológica no assentamento rural Fazenda Pirituba, nos municípios de Itapeva e Itaberá (SP). O arcabouço metodológico foi baseado na pesquisa ação e em levantamentos bibliográficos. Foram utilizadas metodologias participativas e entrevistas semi-estruturadas para coleta de dados na área do assentamento. Foram identificados e analisados cinco grupos envolvidos nos projetos de experimentação agroecológica, seus respectivos indicadores de sustentabilidade e as fases de transição agroecológica que cada área experimental representou. Foi possível constatar que determinadas famílias assentadas possuem interesse no avanço das práticas produtivas nas escalas do processo de transição agroecológica e respectivas áreas do assentamento se constituem em espaço potencial para a produção agroecológica. Entretanto, a continuidade das práticas agroecológicas já desenvolvidas por algumas famílias assentadas então sendo comprometidas por uma série de fatores identificados e que configuram-se como desafios para a comunidade local, bem como, para as políticas públicas que visam o desenvolvimento rural sustentável. Os dados apresentados neste trabalho compõem a análise acerca da transição agroecológica no assentamento rural Faz. Pirituba e apresenta as percepções, as práticas e as perspectivas dos diversos atores sociais envolvidos nesse processo.
152

Leptina e grelina na regulação do comportamento alimentar da tartaruga Eretmochelys imbricata (Linnaeus 1766) / Leptin and ghrelin regulates the feeding behavior of the sea turtle Eretmochelys imbricata (Linnaeus, 1766)

Daphne Wrobel Goldberg 28 January 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Durante a temporada de nidação, fêmeas de tartarugas marinhas costumam reduzir ou cessar por completo a ingestão de alimentos. Este fato sugere que o armazenamento de energia e nutrientes para a reprodução ocorra durante o período que antecede a migração para os sítios reprodutivos, enquanto estes animais ainda se encontram nas áreas de alimentação. Do ponto de vista fisiológico, tartarugas em atividade reprodutiva são capazes de permanecer longos períodos em jejum. Fatores neuroendócrinos vêm sendo recentemente apontados como os mais relevantes para a manutenção da homeostase energética de todos os vertebrados; entre eles, a leptina (hormônio anorexígeno) e a grelina (peptídeo orexígeno). Com o objetivo de compreender o mecanismo de fome e saciedade nas tartarugas marinhas, investigamos os níveis séricos destes hormônios e de outros indicadores nutricionais em fêmeas de Eretmochelys imbricata desovando no litoral do Rio Grande do Norte, Brasil. Foram coletadas amostras de sangue de 41 tartarugas durante as temporadas reprodutivas de 2010/2011 e 2011/2012. Os níveis séricos de leptina diminuíram significativamente ao longo do período de nidação, de modo a explicar a busca por alimentos ao término da temporada. Ao mesmo tempo, registramos uma tendência crescente nos níveis séricos de grelina, fator este que também justifica a remigração para as áreas de alimentação no fim do período. Não foram observadas tendências lineares para alguns dos parâmetros avaliados, entre eles: hematócrito, alanina aminotransferase (ALT), aspartato aminotransferase (AST), fosfatase alcalina (FA), gama glutamil transferase (GGT), lipoproteínas de baixa densidade (LDL) e lipoproteínas de alta densidade (HDL). É possível que a maior parte dos indicadores nutricionais tenha apresentado redução gradativa devido ao estresse fisiológico decorrente da vitelogênese e de repetidas oviposições. No entanto, é valido ressaltar que o quadro de restrição calórica por tempo prolongado é o principal responsável pelas alterações em índice de massa corpórea e padrões bioquímicos nestes animais. / Reproductive female sea turtles rarely have been observed foraging during the nesting season. This suggests that prior to their reproductive migration to nesting beaches, the adult females must store sufficient energy and nutrients at their foraging grounds, and must be physiologically capable of undergoing months without feeding. Leptin (an appetite-suppressing protein) and ghrelin (a hunger-stimulating peptide) affect body weight by influencing energy intake in all vertebrates. We investigated the levels of these hormones and other physiological and nutritional parameters in nesting female hawksbill sea turtles in Rio Grande do Norte State, Brazil, by collecting consecutive blood samples from 41 turtles during the 2010/2011 and 2011/2012 reproductive seasons. We found that levels of serum leptin decreased over the nesting season, which potentially relaxed appetite suppression and led females to begin foraging either during or after the post-nesting migration. Concurrently, we recorded an increasing trend in ghrelin, which stimulated appetite towards the end of the nesting season. Both findings are consistent with the prediction that post-nesting females will begin to forage, either during or just after their post-nesting migration. We observed no seasonal trend for other physiological parameters: PCV values, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT) low-density lipoprotein (LDL) and high-density lipoprotein (HDL) serum levels. The observed downward trends in general serum biochemistry levels were likely due to the physiological stress of vitellogenesis and nesting in addition to limited energy resources and probable fasting.
153

DE ARRENDATÁRIOS A PROPRIETÁRIOS: A sociabilidade no assentamento Brejo de São Félix / THE PROPRIETORS TO THE OWNERS: The sociability in settlement Brejo of St. Felix

Miranda, Aurora Amélia Brito de 30 November 2007 (has links)
Made available in DSpace on 2016-08-18T18:53:56Z (GMT). No. of bitstreams: 1 Aurora Amelia Brito de Miranda.pdf: 999970 bytes, checksum: 8ef4028b556cf7905fbcda651e9f23ca (MD5) Previous issue date: 2007-11-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / It analyses the sociability´s´ on Brejo nesting from São Félix, situated in Parnarama city, Maranhão State. It searchs understand how the groups has been becoming the bows that articulate them, how the seated ones interact building the bows that articulate them, in a historical perspective, detaching new relations in a seated condition, as well the new mediators which they pass to relationate. It argues the following questions: what does it means nesting? In which measure the seated ones conquests the property and the land´s control? It takes as reference the sociability notion developed by Velho(2001) to understand how diferents sociabilities build symbolic the different spaces from this nesting, detaching news and old management´s forms of the territory and clientelism that has been accomplished from the relations with the institutions that acts in it. / Análise da sociabilidade no assentamento Brejo de São Félix, situado no município de Parnarama, estado do Maranhão. Busca compreender como os grupos foram se constituindo, como os assentados interagem construindo os laços que os articulam, numa perspectiva histórica, destacando as novas relações que se constituem na condição de assentados, assim como os novos mediadores com os quais passam a se relacionar. Discute as seguintes questões: o que significa assentamento? Em que medida os assentados conquistam a propriedade e o controle sobre a terra? Toma como referência a noção de sociabilidade desenvolvida por Velho (2001) para compreender como distintas sociabilidades vão construindo simbolicamente os diferentes espaços deste assentamento, destacando novas e velhas formas de gestão do território e de clientelismo que se efetivam a partir das relações com as instituições que nele atuam.
154

História natural, comportamento e ecologia de Camponotus rufipes e Camponotus renggeri (Formicidae: Formicinae) : um estudo comparativo em vegetação do Cerrado / Natural history, behavior and ecology of Camponotus rufipes and Camponotus renggeri (Formicidae: Formicinae) : a comparative study in Cerrado vegetation

Ronque, Mariane Ueda Vaz, 1986- 23 August 2018 (has links)
Orientador: Paulo Sérgio Moreira Carvalho de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T08:30:11Z (GMT). No. of bitstreams: 1 Ronque_MarianeUedaVaz_M.pdf: 2627170 bytes, checksum: 2339d86b839d160545b331e1cbdb3009 (MD5) Previous issue date: 2013 / Resumo: O gênero Camponotus é considerado o segundo gênero mais diverso em espécies da região Neotropical, sendo a maioria das espécies oportunistas com relação ao local de nidificação e onívoras em sua dieta. As duas espécies de estudo -- Camponotus rufipes e Camponotus renggeri -- são morfologicamente semelhantes e conhecidas por apresentarem relações mutualísticas com trofobiontes e nectários extraflorais no Cerrado. Este estudo apresenta a história natural de C. rufipes e C. renggeri em área de Cerrado, na Reserva Biológica de Mogi Guaçu, estado de São Paulo. Foram investigados aspectos ecológicos e comportamentais dessas duas espécies, com relação à nidificação, ao padrão diário de atividade, às áreas de vida utilizadas e aos substratos visitados para forrageamento. O estudo foi desenvolvido em área de cerradão e cerrado sensu stricto, tanto na estação chuvosa quanto na estação seca. No capítulo 1 (referente à ecologia de nidificação), observamos que C. rufipes nidificou em ninhos de palha seca, palha seca e tronco, no solo, em troncos mortos eretos e caídos. Já C. renggeri nidificou em três categorias diferentes de ninhos: no solo e em troncos mortos eretos ou caídos. O padrão de distribuição dos ninhos de C. rufipes foi agregado, enquanto de C. renggeri foi aleatório. Comparativamente, ninhos de C. rufipes persistiram mais ao longo do tempo. Esse fato pode estar correlacionado com a disponibilidade de locais de nidificação nos dois ambientes. Colônias de C. rufipes são em geral mais populosas do que as de C. renggeri e em ambas as espécies encontramos mais de uma rainha, podendo se tratar de espécies poligínicas. No capítulo 2 foram evidenciadas diferenças entre as áreas de vida utilizadas pelas duas espécies, sendo que C. rufipes apresentou áreas de vida maiores do que as de C. renggeri. As áreas de vida de C. rufipes variam sazonalmente, enquanto as de C. renggeri não diferem entre estações e entre fisionomias do Cerrado. Adicionalmente, C. renggeri foi mais frequente no substrato arbóreo do que C. rufipes, embora as duas espécies sejam conhecidas por forragear na vegetação devido às relações mutualísticas com trofobiontes e nectários extraflorais. Ambas as espécies tiveram períodos de atividade predominantemente noturnos, com temperatura e horas do dia influenciando no nível de atividade. A resposta às mudanças de temperatura entre as duas espécies foi diferente, sendo que a termopreferência de C. rufipes foi mais alta do que a de C. renggeri. Neste estudo foi possível observar diferenças notáveis entre C. rufipes e C. renggeri com relação a sua ecologia e comportamento, nos indicando que são de fato espécies distintas. Com esses resultados esperamos contribuir para um melhor entendimento do status taxonômico de C. rufipes e C. renggeri, além de ressaltar a importância de estudos de história natural para servir de base para pesquisas de ecologia, comportamento e sistemática / Abstract: The genus Camponotus is the second most diverse genus in species in the Neotropics, and most of the species are opportunistic with respect to nesting locations and omnivorous in their diets. The species in this study -- Camponotus rufipes and Camponotus renggeri -- are similar morphologically and are known to exhibit mutualistic interactions with insect trophobionts and with plants bearing extrafloral nectaries in the Brazilian savannah (Cerrado). This study provides an account of the natural history of C. rufipes and C. renggeri in area of Cerrado near Mogi Guaçu, state of São Paulo. We investigated ecological and behavioral aspects of both species with respect to their nesting habits, daily activity schedules, home range, and foraging substrates. The study was carried out in area of cerradão and cerrado sensu stricto, in the hot/rainy season and in the cold/dry season. Camponotus rufipes presented five categories of nests: nests of dry straw, dry straw and trunk, beneath the ground, erect dead trunk and fallen dead trunk. C. renggeri had three categories of nests: beneath the ground, erect dead trunk and fallen dead trunk. All C. rufipes nests were found in cerrado sensu stricto, whereas C. renggeri was observed in cerradão (78.3% of the nests) and cerrado sensu stricto (21.7%). The distribution pattern of C. rufipes nests was aggregated whereas of C. renggeri nests was random. Nest persistence over time was higher in C. rufipes compared to C. renggeri. This fact may be correlated with the availability of the nesting sites in the two types of Cerrado. Colonies of C. rufipes were generally more populous than those of C. renggeri and in both species we found more than one dealated queen, suggesting a polygynous habit. The home range of C. rufipes colonies varied seasonally and were larger compared to C. renggeri. The home range in C. renggeri colonies did not vary seasonally or between Cerrado physiognomies. Foragers of C. renggeri were more frequent in the arboreal substrate than those of C. rufipes. Both species, however, were seen interacting with insect trophobionts and extrafloral nectaries on plants. Camponotus rufipes and C. renggeri were predominantly nocturnal, and their level of activity was affected both by the temperature and time of day. The two species differed in their response to temperature, with C. rufipes presenting a higher thermal preference than C. renggeri. In this study was possible to observe differences between C. rufipes and C. renggeri, which indicate that they are different species. We hope that this study can contribute for a better understanding of the taxonomic status of C. rufipes and C. renggeri and highlight the importance of natural history data as a basis for research in ecology, behavior and systematics / Mestrado / Ecologia / Mestra em Ecologia
155

Beach Compaction Impact on Nesting Success of Loggerhead (Caretta caretta) Sea Turtles: A Comparison Between a Natural and Renourished Beach in Northern Broward County, Florida

Kleppan, Danielle R. 01 August 2013 (has links)
The beaches of Broward County, Florida are a prevalent nesting site for loggerhead (Caretta caretta) sea turtles, however extensive beach erosion is threatening critical nesting habitat. Beach renourishment, the process of transporting offshore or upland sediment onshore, is a widely used method of replenishing lost sand. However, renourishment can negatively affect sea turtle nesting habitat by increasing beach compaction; the resistance to applied pressure in pounds per square inch (psi). Increased sand compaction impedes the digging of the female which affects nesting success. The influence of beach compaction on sea turtle nesting patterns has never been previously examined over the course of a nesting season on Hillsboro and Deerfield Beach. Therefore, this study was designed to examine beach compaction data for Hillsboro, a mostly natural beach, and Deerfield, a completely renourished beach, during the 2010 nesting season and analyze the compaction data against 2010 nest and false crawl (FC, non-nesting emergence) data. Compaction readings were collected during every other week March-October using a soil compaction meter at every other street address along three beach positions, the dune base, mid-beach, and average high tide line (HTL); and at three depths, 15 cm, 30 cm, and 45 cm. Values were not statistically different throughout the season for each beach, so seasonal mean compaction values were used for each beach position and depth. Hillsboro compaction values were rarely over 500 psi (35 kg/cm2), even at 45 cm depth. Deerfield compaction values exceeded the 600 psi (42kg/cm2) measurement limit of the meter in approximately 60% of the compaction values at 30 cm or 45 cm depth. Sand compaction data was analyzed for any trends between beaches as well as within each beach. Historical data shows higher loggerhead nesting success, the number of nests/total number of crawls (including FC) x 100, on Hillsboro Beach than on Deerfield Beach. The average beach compaction values were compared to nesting success and to nest and FC density within each station area. There was a significant inverse relationship (p<0.05) between beach compaction and nesting success at each of the beach positions and depths, when both Hillsboro and Deerfield Beaches were analyzed together, except at the Mid 30 cm and Dune 45 cm depth. The strongest relationship for the combined beaches was at the HTL 15 cm depth (R2=0.3821, p<0.001). When Hillsboro was analyzed alone, beach compaction and nesting success was only significantly inversely related (R2=0.0875, p<0.02) at the HTL 15 cm depth. This demonstrates that while increased beach compaction may partially influence nesting success, there are likely other beach characteristics that contribute to nest site selection of loggerheads in Northern Broward County. The inverse relationship between Hillsboro mean beach compaction and nest density (nests per meter) was significant only at the HTL 15cm depth (p<0.002) and the inverse relationship between mean beach compaction and false crawl density (FC per meter) in Hillsboro was only significant at the Dune 15 cm (p<0.019) and the Dune 30 cm (p<0.038) depths. Although, increased beach compaction was expected to relate to higher FC density, FC density showed a significant inverse relationship to mean beach compaction at all Deerfield Beach positions and depths in and this suggests off-shore factors may be affecting nest site selection.
156

Padrões de abundâncias entre estrelas muito pobres em metais no halo da galáxia / Abundance patterns among very metal-poor stars in the halo of the Galaxy: a statistical approach

Vinicius Moris Placco 31 August 2007 (has links)
Um dos maiores desafios da Astrofísica é tentar compreender a complexidade da composição química das estrelas. Elementos com massas atômicas acima de A>60 são formados pelos chamados processos de captura de nêutrons (processo-s e processo-r). A presença destes em espectros de estrelas de baixa massa (longo período de vida) e com pouco conteúdo metálico sugere episódios de enriquecimento por estrelas massivas nos primórdios da Galáxia. Portanto, o estudo das estrelas chamadas \"pobres em metais\" enriquecidas por elementos formados por captura de nêutrons pode reproduzir as condições físicas dominantes à época de sua formação. O objetivo deste trabalho é explorar os padrões de abundâncias das estrelas muito pobres em metais observadas no survey HERES. Através deste estudo, é possível inferir correlações entre elementos químicos e restringir a operação dos processos de captura de nêutrons na Galáxia. Para tanto, utiliza-se técnicas estatísticas como a análise de conglomerados, que permite o estudo da formação de grupos naturais baseado na relação entre as abundâncias elementais. Este estudo fornece uma análise compreensiva de uma amostra de 382 estrelas pobres em metais, além de introduzir duas novas subclasses para estrelas pobres em metais enriquecidas em elementos formados por captura de nêutrons. / One of the most challenging subjects of Astrophysics is trying to understand the complexity of the chemical composition of stellar objects. Spectroscopic observations are widely used nowadays in order to achieve these goals, as they provide the chemical composition of the atmosphere of the stars. Elements with atomic masses above A>60 are formed by the so called neutron capture processes (r-process and s-process). Its presence on low-mass star spectra (which have long life-time) and low metal content suggests episodes of enrichment by high-mass stars that took place in the early times in the Galaxy formation. Then, the study of those \"metal-poor\" stars enriched by neutron-capture elements may help reproduce the physical conditions of the environment from where they were formed. The main goal of this project is to explore the abundance patterns of the very metal-poor stars observed by the HERES survey. This study allows the analysis of the correlations between chemical elements and place some constraints on the operation of the neutron capture processes in the early Galaxy. This approach made use of statistical tools, such as agglomerative nesting, which can identify the formation of natural groups based on relations among elemental abundances. In this context, this study provides a comprehensive analysis of a 382 metal-poor stars sample, and introduces two new subclasses for metal-poor stars with determined abundances of neutron-capture elements.
157

Legacy Effects of Habitat Degradation by Lesser Snow Geese on Ground-Nesting Savannah Sparrows along the Hudson Bay Lowlands

Peterson, Stephen L. 01 May 2013 (has links)
Increased growth of the mid-continent population of Lesser Snow Geese (LSGO) has led to the degradation of coastal salt marsh and sedge meadow habitats across Canadian Arctic and sub-Arctic ecosystems. It is believed that a human-induced trophic cascade caused by agricultural habitat modification along migratory routes and wintering grounds has contributed to the increase in LSGO numbers, which has resulted in the alteration of habitat quality and connectivity along northern breeding and stopover sites used by various avian species. This habitat degradation has been shown to decrease the presence and temporal persistence of ground-nesting passerine and shorebird species at a local level and may lead to decreases of Arctic / sub-Arctic breeding avian species across landscapes that LSGO utilize and degrade. In 1999, four paired study plots were established, and used in conjunction with a single study plot from 1976, in order to measure the composition of habitat parameters (barren ground extent; graminoid and shrub cover) and to estimate the number of avian nests found in these plots. Using this historical data along with our findings from 2010 and 2011, our main objectives were to: 1) document the change in the aforementioned habitat parameters over time; 2) estimate the local nesting occupancy rates of the common Savannah Sparrow (SAVS), a robust and adaptable ground nester; and 3) determine which habitat variables are indicative of the rates of change and occurrence of nesting by SAVS within the study plots. By using ANOVA, linear mixed effects, and multi-state occupancy models, results suggest that an increase in barren ground, decreases in shrub and graminoid cover, and a loss of connectivity between suitable nesting patches has led to a 10% (λ = 0.90) annual decline in the probability that SAVS nesting occurred across the study plots from 1999 to 2010. These model results may be used to estimate long-term trends in persistence of breeding SAVS and other similar ground-nesting avian species that share habitats with LSGO along Arctic and sub-Arctic ecosystems. (93 pages)
158

Ecology of Isolated Greater Sage-Grouse Populations Inhabiting the Wildcat Knolls and Horn Mountain, Southcentral Utah

Perkins, Christopher J. 01 May 2010 (has links)
Greater sage-grouse (Centrocercus urophasianus) currently inhabit about 56% of pre-settlement distribution of potential habitat. In 2005, the Castle Country Adaptive Resources Management Local Working Group (CaCoARM) was formed to address concerns regarding local sage-grouse populations in Carbon and Emery counties. In 2006-2007, CaCoARM identified the Wildcat Knolls and Horn Mountain as areas of special concern for greater sage-grouse conservation. Both sites selected by the group were inhabited by what appeared to be small isolated sage-grouse populations. Factors limiting small isolated greater sage-grouse populations throughout its range are diverse and largely site-specific. During 2008-2009, I captured, radio-collared, and monitored 43 sage-grouse between the two populations to document their ecology and seasonal habitat use patterns. The sites are only 24 km apart, but the populations appear to be isolated from each other. Sage-grouse on Horn Mountain and Wildcat Knolls are one-stage migratory and non-migratory, respectively. Although nesting and brooding success varied between sites, my results were comparable to those published in studies throughout the species' range. Overall male survival was lower on the Wildcat Knolls than Horn Mountain (P = 0.003). Hens that selected brood sites exhibiting increased shrub cover and grass height were more successful than hens that selected sites with lower shrub cover and lower grass height. Potential nesting habitat on the Wildcat Knolls and Horn Mountain were estimated at 2,329 and 5,493 ha, respectively. Hens that selected nest sites farther from non-habitat edge were more successful than hens that selected nest sites that were closer to non-habitat edge on the Wildcat Knolls. Higher nest success observed on the Wildcat Knolls was attributed to less habitat fragmentation. Isolated populations of greater sage-grouse are more susceptible to lower amounts of genetic diversity that may lead to inbreeding depression and increased rates of disease and parasites. I collected mitochondrial DNA samples from both the Wildcat Knolls and Horn Mountain populations. Although the haplotype frequencies recorded in the Wildcat Knolls and Horn Mountain populations were low, one was shared with several Utah populations. The documented low genetic diversity (especially on Horn Mountain) confirmed the isolation suspected by the local working group. Microsatellite tests may provide insights to enhance understanding of genetic differences among sites, and assist managers in determining whether or not translocations are necessary to maintain population genetic diversity. Biologists should not only continue to take samples for genetic comparison, but also record morphometric and behavior data.
159

Habitat use and distribution of the loggerhead sea turtle (Caretta caretta) in the Mediterranean Sea: Implications for marine planning strategies

Abalo Morla, Sara 06 November 2023 (has links)
Tesis por compendio / [ES] Las tortugas bobas son organismos de gran movilidad que ocupan hábitats extensos y diversos, lo que las expone a varias amenazas que pueden afectar negativamente a la persistencia de sus poblaciones. Delinear medidas prioritarias de conservación para esta especie es todo un reto debido a la escasez del conocimiento integrado sobre su supervivencia, uso de hábitat y exposición relativa a amenazas, especialmente durante las primeras etapas de su ciclo vital. En la cuenca occidental del mar Mediterráneo esto adquiere mayor relevancia si se contextualiza en el proceso de colonización que está teniendo lugar en la zona durante la última década. Se ha registrado un aumento en el número de nidos y hembras nidificantes, para cuya protección se han tomado medidas de gestión como la reubicación de nidos y la inclusión de neonatos en programas de "head-starting". Esta coyuntura ha ofrecido una oportunidad única para incrementar el conocimiento sobre la supervivencia, dispersión y uso de hábitat de hembras nidificantes y post-neonatos de tortuga boba. Ninguna investigación previa ha realizado un seguimiento por satélite de hembras nidificantes en el Mediterráneo occidental, ni de post-neonatos mediterráneos con tamaño inferior a 35 cm. La finalidad de esta tesis es abordar las lagunas de conocimiento mencionadas y aportar herramientas para mejorar las estrategias de planificación marina dirigidas a la conservación de la tortuga boba en el Mediterráneo. Los principales objetivos fueron: i) proporcionar las primeras estimaciones empíricas de supervivencia de post-neonatos, ii) dilucidar las rutas de dispersión y el uso de hábitat en las diferentes etapas del ciclo vital, iii) identificar áreas relevantes para su protección, iv) evaluar la eficacia de las actuales áreas marinas protegidas (AMPs) para la conservación de la tortuga boba, y v) proponer medidas de conservación basadas en el análisis espacial. Para ello, se analizaron las trayectorias de 117 tortugas seguidas vía satélite entre 2003 y 2022. Estos datos incluyen las primeras trayectorias de hembras nidificantes en España y de post-neonatos mediterráneos, que se han publicado en un repositorio. Además, se realizó la primera evaluación del uso de hábitat y de AMPs por tortugas bobas marcadas en el Mediterráneo occidental, a lo largo de su ciclo vital. Los resultados de esta tesis muestran, por primera vez, la capacidad de supervivencia y dispersión, así como uso de hábitat de post-neonatos de tortuga boba en el Mediterráneo. Los mares Jónico y de Levante se identificaron como zonas potenciales de desarrollo de post-neonatos. Por otro lado, las hembras mostraron dos comportamientos diferentes durante el periodo de inter-anidación: i) fidelidad a la zona de nidificación, o ii) comportamiento exploratorio de nidificación. Durante la etapa no reproductora, la mayoría de las hembras permanecieron alimentándose en aguas oceánicas de la cuenca argelina. Además, se registró por primera vez la reemigración de esta especie para nidificar de nuevo en España, lo que confirma que las hembras pueden mostrar un cierto grado de fidelidad al lugar de nidificación entre ciclos reproductores. La presente tesis confirma la importancia de la cuenca argelina para las tortugas bobas del Mediterráneo occidental, en particular para los juveniles y adultos. Otras zonas identificadas como importantes son el sur del mar Balear, el mar de Alborán, el canal de Sicilia, el noreste de Túnez, las aguas de Malta, el mar Tirreno y el mar Jónico, según la etapa vital. El análisis de la distribución espacial de la tortuga boba también ha revelado que la distribución y cobertura actuales de las AMPs mediterráneas no contribuyen a alcanzar los objetivos de conservación para esta especie. Los resultados obtenidos en esta tesis contribuyen al conocimiento de la supervivencia y uso espacial de la tortuga boba a lo largo de su ciclo vital en el mar Mediterráneo. / [CA] Les tortugues babaues són organismes de gran mobilitat que ocupen hàbitats extensos i diversos, la qual cosa les exposa a diverses amenaces que poden afectar negativament la persistència de les seues poblacions. Delinear mesures prioritàries de conservació per a aquesta espècie és tot un repte degut a l'escassetat del coneixement integrat sobre la seua supervivència, ús d'hàbitat i exposició relativa a amenaces, especialment durant les primeres etapes del seu cicle vital. En la conca occidental de la mar Mediterrània això adquireix major rellevància si es contextualitza en el procés de colonització que està tenint lloc en la zona durant l'última dècada. S'ha registrat un augment en el nombre de nius i femelles nidificants, per a la protecció de les quals s'han pres mesures de gestió com la reubicació de nius i la inclusió de nounats en programes de "*head-*starting". Aquesta conjuntura ha oferit una oportunitat única per a incrementar el coneixement sobre la supervivència, dispersió i ús d'hàbitat de femelles nidificants i post-nounats de tortuga babaua. Cap investigació prèvia ha realitzat un seguiment per satèl·lit de femelles nidificants en el Mediterrani occidental, ni de post-nounats mediterranis amb grandària inferior a 35 cm. La finalitat d'aquesta tesi és abordar les llacunes de coneixement esmentades i aportar eines per a millorar les estratègies de planificació marina dirigides a la conservació de la tortuga babaua al Mediterrani. Els principals objectius van ser: i) proporcionar les primeres estimacions empíriques de supervivència de post-nounats, *ii) dilucidar les rutes de dispersió i l'ús d'hàbitat en les diferents etapes del cicle vital, *iii) identificar àrees rellevants per a la seua protecció, *iv) avaluar l'eficàcia de les actuals àrees marines protegides (*AMPs) per a la conservació de la tortuga babaua, i *v) proposar mesures de conservació basades en l'anàlisi espacial. Per a això, es van analitzar les trajectòries de 117 tortugues seguides via satèl·lit entre 2003 i 2022. Aquestes dades inclouen les primeres trajectòries de femelles nidificants a Espanya i de post-nounats mediterranis, que s'han publicat en un repositori. A més, es va realitzar la primera avaluació de l'ús d'hàbitat i de *AMPs per tortugues babaues marcades en el Mediterrani occidental, al llarg del seu cicle vital. Els resultats d'aquesta tesi mostren, per primera vegada, la capacitat de supervivència i dispersió, així com ús d'hàbitat de post-nounats de tortuga babaua al Mediterrani. Les mars Jònic i de Llevant es van identificar com a zones potencials de desenvolupament de post-nounats. D'altra banda, les femelles van mostrar dos comportaments diferents durant el període de *inter-implantació: i) fidelitat a la zona de nidificació, o *ii) comportament exploratori de nidificació. Durant l'etapa no reproductora, la majoria de les femelles van romandre alimentant-se en aigües oceàniques de la conca algeriana. A més, es va registrar per primera vegada la reemigració d'aquesta espècie per a nidificar de nou a Espanya, la qual cosa confirma que les femelles poden mostrar un cert grau de fidelitat al lloc de nidificació entre cicles reproductors. La present tesi confirma la importància de la conca algeriana per a les tortugues babaues del Mediterrani occidental, en particular per als juvenils i adults. Altres zones identificades com a importants són el sud de la mar Balear, la mar d'Alborán, el canal de Sicília, el nord-est de Tunísia, les aigües de Malta, la mar Tirrena i la mar Jònica, segons l'etapa vital. L'anàlisi de la distribució espacial de la tortuga babaua també ha revelat que la distribució i cobertura actuals de les *AMPs mediterrànies no contribueixen a aconseguir els objectius de conservació per a aquesta espècie. Els resultats obtinguts en aquesta tesi contribueixen al coneixement de la supervivència i ús espacial de la tortuga babaua al llarg del seu cicle vital en la mar Mediterrània. / [EN] Loggerhead sea turtles (Caretta caretta) are highly mobile organisms, which occupy diverse habitats that often span large distances, exposing them to threats that can negatively impact the ability of their populations to persist. Delineating conservation priority measures for this species is challenging since integrated knowledge on survival, habitat use and the relative exposure to threats remains scarce, especially during the early life stages. In the western Mediterranean basin this is particularly relevant when considering the current colonization process taking place in the area within the last decade. During recent years, records on nesting females and clutches have increased and, when possible, management measures such as nest relocation and head-starting programs have been undertaken. This offers a unique opportunity to fill in the knowledge gaps on survival, dispersal routes and habitat use of loggerhead nesting females and post-hatchlings. No research prior to this thesis has satellite-tracked nesting and post-nesting females in the western Mediterranean, nor Mediterranean post-hatchlings smaller than 35 cm. The present thesis aims to address the aforementioned knowledge gaps and enhance marine planning strategies for loggerhead conservation in the Mediterranean Sea. The main objectives were: i) to provide the first empirical survival estimates for head-started post-hatchlings, ii) to elucidate the dispersal routes and habitat use at different life stages, iii) to identify areas that should be considered for protection, iv) to assess the effectiveness of current marine protected areas (MPAs) and other protection measures for loggerhead conservation, and v) to propose spatial conservation measures based on research findings. To achieve these objectives, trajectories of 117 turtles satellite-tracked between 2003 and 2022 were analyzed. This dataset includes the first tracking data of nesting and post-nesting females in Spain and Mediterranean post-hatchlings, which have been made publicly available in a data repository. Moreover, the first assessment of habitat use and the use of MPAs for loggerhead sea turtles tracked from western Mediterranean thorough their life cycle was conducted. The outcomes of this thesis revealed, for the first time, the capability of survival and dispersal, as well as the habitat use of post-hatchlings in the Mediterranean Sea. The Ionian and Levant Seas were identified as potential developmental areas for post-hatchlings. Nesting females exhibited three different behaviours during the inter-nesting period: i) some degree of fidelity to a nesting area, ii) an exploratory nesting behavior, or iii) movement towards oceanic waters after tagging. In addition, the first-time remigration of this species to nest in Spain was recorded, confirming that females show some degree of nest site fidelity between breeding cycles. During the non-breeding stage, females remained in most cases foraging in oceanic waters of the Algerian basin. The present thesis has validated the significance of the Algerian basin for loggerhead sea turtles satellite-tracked from the western Mediterranean, particularly for juveniles and adults. In addition, other important areas inhabited by the loggerhead turtles were identified in the southern Balearic Sea, the Alboran Sea, the Sicilian Channel, the Northeast Tunisia, Maltese waters, the Tyrrhenian Sea and the Ionian Sea, depending on the life stage. The analysis of the spatial distribution of the loggerhead sea turtle has also revealed that the current distribution and coverage of Mediterranean MPAs are not effective in achieving this species' conservation goals. Outcomes from the present thesis significantly enhance our understanding of the survival and spatial use of the loggerhead sea turtle throughout its life cycle in the Mediterranean Sea. / I would like to express my gratitude to the Ministry of Education, Culture and Sports of Spain for the opportunity to develop this thesis under the predoctoral training grant [FPU15/01823], MEC, Spain. Satellite tagging conducted in the Valencia region was supported by the “Servicio de Vida Silvestre de la Generalitat Valenciana”. Additionally, I am thankful for the support received from the contracts: “Seguimiento mediante marcaje satelital de 10 crías de tortuga boba (Caretta caretta) nacidas en 2016 en el litoral valenciano" and "Marcaje satelital y seguimiento de hembras reproductoras de tortuga boba (Caretta caretta) ante episodios de anidación en las playas del Mediterráneo peninsular y Baleares en 2019", both contracts in the framework of the project "LIFE IP-PAF INTEMARES [LIFE15 IPE ES 012] "Gestión integrada, innovadora y participativa de la Red Natura 2000 en el medio marino español”, coordinated by the Biodiversity Foundation. Similarly, I would like to mention and thank the support received from the contract "Marcaje satelital y seguimiento de hembras reproductoras de tortuga boba (Caretta caretta) ante eventos de anidación en el litoral español" funded by the "Ministerio de Transición Ecológica y Reto Demográfico", Spain. The results of Chapter 6 "Marine protected areas and loggerhead turtles in the Mediterranean Sea" are also part of action C2.2 of the project LIFE IP INTEMARES. / Abalo Morla, S. (2023). Habitat use and distribution of the loggerhead sea turtle (Caretta caretta) in the Mediterranean Sea: Implications for marine planning strategies [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/199233 / Compendio
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Population Dynamics of Piping Plovers (Charadrius melodus) on the Missouri River

Catlin, Daniel H. 09 June 2009 (has links)
Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 – 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate. Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 – 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required. / Ph. D.

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