Understanding the life history response of animal populations to environmental selection pressure is a central research theme in evolutionary ecology and conservation biology. Our current knowledge of life history traits in animal populations is, however, mostly based on studies conducted on temperate systems, contrasting with the fact that a large number of species live in the tropics. The roseate tern (Sterna dougallii) is a oceanic seabird showing mainly a tropical distribution with a relatively fragile conservation status, making it an interesting case study. In this thesis, ten years of data (1998-2007) were used to determine the main demographic traits of the tropical roseate tern population breeding on Aride Island, Seychelles (western Indian Ocean), and to explore their relation with environmental factors. We focused on the estimation of reproductive success, age at first reproduction (sexual maturation) and age-specific survival probabilities in relation to both oceanography of the study area (food availability) and quality of the breeding habitat. By using chlorophyll concentrations as a proxy measure of marine fish stocks, we showed that the overall low reproductive success in this population (range 0.0 0.57 chick/pair) is mainly dictated by the strong inter-annual fluctuations in local food supply conditions around Aride Island. Reproductive success was also found to be related to the spatial variation in vegetation characteristics of the nesting (woodland) habitat used by the terns. Birds nesting in densely-vegetated areas with a closed canopy cover had higher chick mortalities, presumably through a high level of parasitism by ticks, when compared to those breeding in more open areas such as forest clearings. By relying on capture-mark-recapture methods, age of first reproduction was estimated at 3-4 years and age-specific survival probabilities at 0.62, 0.77 and 0.81 in juveniles (1-year), immature individuals (2-years), and breeding adults (3-years and older), respectively. Most of these demographic parameters were also found to be influenced by oceanographic conditions (e.g. Indian ocean Dipole) and the levels of tick infestation during the chick-growing period. We further show how these vital rates can be incorporated into a simple population viability analysis in order to model population dynamics (i.e. population growth rate) and, ultimately, to provide local managers with conservation measures. Finally, the contribution of this work to the global knowledge of tropical seabird life histories is discussed through a comparison with demographic parameters of temperate roseate tern populations.

As Daphnia have an important role in freshwater food webs, it is important to understand how environmental stressors affect their survival and life history traits. Daphnia pulex were first acutely exposed to a combination of NaCl salinities (0.00-10.0 g/L) and fish-exuded kairomone. The 24 and 48 hour LC50 values were 0.401 and 0.159 g/L in kairomone-absence and 1.962 and 1.007 g/L in kairomone-presence. Hence, survival decreased with increasing salinity, while the kairomone enhanced daphnid resistance to salinity below 2 g/L. During the chronic exposure to salinity (0.00-1.5 g/L) combined with the fish-exuded kairomone, impacts of temperature and food were also investigated. Survival decreased significantly with increased salinity, while the kairomone had a positive impact on survival at intermediate salinity levels, suggesting an antagonistic relationship. Temperature alone had a significant negative impact on survival and its combined effect with salinity and fish kairomone was synergistic. However, the impact of food limitation was insignificant. Life history parameters were affected by both salinity and the fish-exuded kairomone, the combination of which significantly decreased the body length: width ratio. Egg number/individual decreased with salinity and increased in the presence of the fish kairomone. In conclusion, the combined impact of salinity and fish-exuded kairomone significantly affected daphnid survival and life history traits in a non-linear manner, such that fish kairomone enhanced daphnid resistance to intermediate salinity levels. Moreover, the combined effect of salinity, temperature and fish kairomone on daphnid survival was also significant.

Many aspects of habitat selection have been largely ignored in conservation planning of large mammals, including variation between day and night movement patterns, inter-individual niche variation of conspecifics and translocated individual‟s responses to new environments in relation to the influence of ecogeographical variables. Being a solitary moving animal with a known tendency to move through the night, the black rhino Diceros bicornis is a perfect species to test theories about individual spatial and temporal variation in habitat utilisation. I tested the appropriateness of using carrying capacity (CC) estimates as a tool for population conservation planning, and as an indicator of habitat utilisation for black rhino. I found individual selection was not related to the value of the habitat according to modelled CC. I therefore do not recommend the use of a priori calculations of resource quality and abundance of habitats (CC estimates), which do not take into account the factors that influence an animal‟s selection of a habitat, as indicators of species habitat use. Secondly I tested whether current methods of analyzing mainly diurnal location data of animals result in accurate ecological or conservation conclusions. I found a circadian variation in habitat use for different behaviours, and that excluding nocturnal data from home and browsing range analyses would provide inaccurate results for black rhino habitat use. I then tested for inter-individual niche variation amongst two populations of black rhino at various scales of selection, ranging from habitat through to browse selection. I showed that black rhino, a selective browser, had a significant degree of inter-individual habitat and dietary niche variation. Consequently, pooling habitat location data and diet selection data for black rhino individuals in a population does not reflect the actual selection of any, or many, individuals. To clarify which ecogeographical variables might influence this selection I ran maximum entropy models on individual‟s diurnal locations across the landscape. I was then able to develop a habitat suitability model which was based on the individual rather than population, providing a more accurate prediction. I repeated the individual models in phases, from the initial post-release phase after the release of individuals onto a new reserve through to their „settled‟ phase, allowing me to explore the effect of habitat variables on different settling phases of translocated animals. The results indicate that all the rhinos‟ acclimation phase lasted no longer than 25 days and that to minimize disturbance to the settling process all individuals in a newly released cohort should be released within this period. This study as a whole provides conservation managers with a better ecological understanding of black rhino in conjunction with a number of management tools. This will enable conservation managers to better understand the way animals utilise and perceive their environment, allowing for better monitoring and analyses of animal movements. This will aid in the development of strategic management plans in the conservation of not only animal species but also the ecosystems that they reside in and the identification of suitable areas for future conservation of animal species. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

Thesis (M.S.)--University of Nevada, Reno, 2007. / "December, 2007." Includes bibliographical references. Online version available on the World Wide Web.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2005. / Härtill 5 uppsatser.

Thesis (Ph.D.)--University of Melbourne, Dept. of History and Philosophy of Science, 2005. / Typescript. Includes bibliographical references (leaves 229-245).

Thesis (PhD)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Thomas E. McMahon. Includes bibliographical references.

Thesis (Honors)--College of William and Mary, 2009. / Includes bibliographical references (leaves 70-72). Also available via the World Wide Web.

Made available in DSpace on 2014-06-11T19:35:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-10-20Bitstream added on 2014-06-13T18:47:13Z : No. of bitstreams: 1 santos_ef_dr_rcla.pdf: 1202781 bytes, checksum: 4d006c5b53b648271a9e037b99723339 (MD5) / As cutias (Dasyproc(a leporina), são roedores fmgívoros com hábitos escavadores de esconder e procurar reservas de sementes (Scatter-hoardings) em baixas quantidades em vários locais da sua área de vida, para uso futuro e subsistência durante a escassez de alimentos. Os objetivos deste trabalho foram capturar e marcar o maior número de animais através de tatuagem definitiva, avaliar o impacto que esses roedores exercem sobre a mata, observar vários aspectos da população de cutias, tais como a dieta, biometria, predação específica em plântulas, massa corporal e taxa de prenhez. O estudo foi desenvolvido em um parque público chamado Bosque dos Jequitibás (10 ha), situado na cidade de Campinas-SP. O clima da região é tropical de altitude com inverno seco e verão quente e chuvoso. A dieta das cutias, assim como o seu gasto de tempo diário foram estudados através de transectos totalizando 3600 horas de observações diretas. Atividades como farejar (36,88%) e comer (17,91%) totalizaram cerca de 54,79% das atividades, evidenciando que gastam grande pane do dia forrageando em busca de alimento, onde utilizam muito o olfato. Os principais recursos alimentares utilizados foram scmcntes (37,23%). frutos da mata (21,74%). frutos do zoológico (18,2 1%), alimentos oferecidos pelos visitantes (16%), outros itens (2,99%) e alimentos para gatos (2,72%). Os recursos antrópicos oferecidos totalizaram 39,92% da dieta, sendo um dos fatores que contribuem para a subsistência desta espécie no bosque. Foram capturados e marcados com tatuagens definitivas dezoito machos e dezessete fêmeas para coleta de seus padrões de biometria, onde houve diferença significativa entre a massa corporal dos machos (3.0 kg) e fêmeas (3,5 kg), o índice de gestação encontrado foi de (26,32%). mostnmdo uma alta taxa de prenhez entre as fêmeas. No sentido de avaliar o impacto da herbivoria que esses roedores... / Red-rumped agoutis are frugivorous rodents of excavating habits of hiding themseives and iooking for reserves of seeds, i.e. scatter-hoarding. of smail quantities in various spots of their Iiving arca, for further use and survivai during periods of lack of food. The objective of this work was to evaluate the impact that these rodents have over the woods where they inhabit, among several other aspects, such as their diet, their time usage, the biometry of the individuais, the specific predation in young individuais of Hymenaea courbaril, their corporeal mass, and their pregnancy rate. The study was deveioped in a ten-hectare city park caiied Bosque dos Jequitibás, located in the central arca of the ciLy of Campinas, So Paulo. The weather in Lhe piace is defined as tropical with dry winters and hot, wet summers. Transectos were used to study Lhe diet of the red-rumped agoutis as weil as their daily time consumption. The total time of direct observations was of 3,600 hours. Activities such as sniffing (36.88%) and eating (1791%) totaiized 54.97% of the daiiy activities of the animais, evidencing that they spend most part of the day foraging and in doing so using a iot of Lheir olfaction. The main dietary resources utilized were seeds (37.22%), wiid fruits (21.73%), zoo fruits (18.20%), food thrown by 100 visitors (16%), others (2.98%), and cat food (2.71%). The anthropic resources such as zoo fmits, fruits offered by visitors and cat food totalized 39.92% of the diet, which is one of the facts lhat contribute to the subsistence of lhe species in thc park. eighteen males and seventeen females were captured and tattooed for the coliection of the standards of biometry. which presented a significant difference between the corporeal masses of maies (3.0 kg) and females (3.5 kg). The pregnancy rate found was of 26.32%. Aiming to evaluate the impact of their herbivorous... (Complete abstract, click electronic address below)

Orientador: Gustavo Quevedo Romero / Banca: Adalberto José dos Santos / Banca: Maria Stela M. Castilho Noll / Resumo: Até dez espécies de aranhas do gênero Peucetia (Oxyopidae), incluindo duas espécies sul-americanas, P. flava e P. rubrolineata, vivem associadas a várias espécies de plantas com tricomas glandulares nas regiões Neotropical, Paleártica, Neártica e Afrotropical; estas associações provavelmente evoluíram porque insetos aderidos aos tricomas glandulares podem ser utilizados como fonte de alimento pelas aranhas. Na região noroeste do estado de São Paulo, indivíduos de P. flava ocorrem estritamente sobre a planta com tricomas glandulares Rhynchanthera dichotoma (Melastomataceae). Neste sistema nós desenvolvemos experimentos para testar quais os custos e benefícios de P. flava para R. dichotoma e se há condicionalidade nestas associações. Além disso, testamos o papel dos tricomas glandulares como mediadores destas associações aranhas-plantas. Nós observamos que estas aranhas atuam como guarda-costas das plantas e que este efeito é temporalmente condicional; forças base-topo minimizam os efeitos das aranhas durante o período chuvoso. Além disso, estas aranhas indiretamente aumentaram a aptidão da planta pela redução do número de botões inviáveis. Os tricomas glandulares podem ter uma função análoga ao de uma teia pela retenção de presas. As aranhas preferem plantas com tricomas glandulares intactos e permanecem mais tempo sobre estas do que em plantas com tricomas glandulares removidos. Análises isotópicas de 15N mostraram que estas aranhas podem se alimentar tanto de insetos vivos como de carcaças de insetos aderidos aos tricomas glandulares, exibindo hábitos carniceiros. Estes resultados demonstram que esta associação é um mutualismo facultativo. / Abstract: Up to ten species of the genus Peucetia (Oxyopidae), including two South American species, P. flava and P. rubrolineata, live strictly associated with many species of glandular plants in Neotropical, Palearctic, Afrotropical and Neartic regions; this associations probably evolved because insects adhered to these sticky structures may be used as prey by the spiders. In southeastern Brazil specimens of P. flava were reported to occur strictly on Rhynchanthera dichotoma (Melastomataceae), a glandular shrubby plant that typically inhabits swamps. In this system we used experiments to test the cost and benefit of these spiders to plants and also the role of glandular trichomes as mediators of this association. We found that these spiders act as plant body-guards and this function is temporally conditional; bottom-up forces mitigate the impact of spiders during the rainy season. Moreover, these spiders indirectly increase fitness of the host plant by reducing the number of unviable flower buds, without influence on the seed set. Glandular trichomes probably have an analogous function of a web by capture or prey retention. Spiders prefer plants with intact glandular trichomes, remaining much longer on these ones than on those with these structures removed. Isotopic analyses of 15N demonstrated that these spiders fed on live and dead prey adhered to glandular trichomes, exhibiting a scavenging behavior. These results demonstrate that this association is a facultative mutualism. / Mestre