Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-11T12:09:26Z No. of bitstreams: 2 DISSERTAÇÃO Natália Ramos.pdf: 2640173 bytes, checksum: 9f07d7330704d938b4b8e5189745b57e (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T12:09:26Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Natália Ramos.pdf: 2640173 bytes, checksum: 9f07d7330704d938b4b8e5189745b57e (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014 / FACEPE / A dinâmica populacional e a produção secundária de Talorchestia tucurauna, um anfípode talitrídeo de zonas supralitorais de praias arenosas, foram estudadas nas praias de Catuama (7°40'48.45" S 34°49'56.22" O) e Enseada dos Golfinhos (7°42'1.94" S 34°49'52.46" O), do litoral norte de Pernambuco no período de Março de 2012 a Junho de 2013. A coleta foi feita na ‘linha do deixa’, no supralitoral, em 4 quadrados (1m²) separados em 30 metros. Em laboratório, os organismos foram separados dos detritos e analisados, assim como os ovos de fêmeas ovígeras. Os espécimes foram medidos em comprimento total e cefálico para as análises de crescimento. Para a estimativa da biomassa, 100 indivíduos de cada praia foram analisados. . A abundância de T. tucurauna foi muito maior na praia de Catuama, principalmente pelo grande aporte de Halodule wrightii presente nesta praia. As populações mostraram padrões de variação na densidade similares ao longo do ano, com maiores abundâncias nos meses chuvosos. Houve um predomínio de fêmeas ao longo do ano.Fêmeas ovígeras e juvenis estiveram presentes em todos os meses, indicando uma reprodução contínua. O recrutamento ocorreu com maior intensidade nos meses chuvosos. A fecundidade estimada foi de 5,5 + 2,3 e 5,5 + 2, nas praias de Catuama e Enseada dos Golfinhos, respectivamente. O comprimento corpóreo dos indivíduos variou entre as categorias sexuais, e os machos apresentaram maiores comprimentos do que as fêmeas. Devido à baixa abundância em Enseada dos Golfinhos, as análises de crescimento foram estimadas apenas para os indivíduos da praia de Catuama. A taxa de crescimento foi maior para machos (k=2,12) do que para as fêmeas (k=1,36) resultando em uma longevidade maior para fêmeas, estimada em 19 meses, e em 13 meses para os machos. As taxas de mortalidade anual e total foram maiores para machos. A produtividade total da praia de Catuama foi 827,19 mg.m -2.ano-1, a biomassa total foi de 586,95 mg.m -2.ano-1 e a razão P/B foi de 1,41. Em Enseada dos Golfinhos, a produtividade total foi de 15,97 mg.m -2.ano-1 ,a biomassa total foi de 20,54 mg.m -2.ano-1 e a razão P/B foi de 0,78. Os resultados aqui apresentados encontram suporte na literatura quanto à variação dos aspectos de história de vida de Talitridae, e contribuem com o estudo da espécie, visto que informações ecológicas e biológicas sobre a espécie são insuficientes.

Climatic envelope models focus on the climatic variables affecting species or species assemblages, and are important tools to investigate the effect of climate change on their geographical ranges. These models have largely been proposed in order to make successful predictions on species‘ persistence, determining which variables are likely to induce range expansion, contraction, or shifting. More recent models, including the ability and the cost for individuals to respond promptly to an environmental stimulus, have revealed that species may express phenotypic plasticity able to induce adaptation to the new environment. Consequently, understanding how species evolve to a changing climate is fundamental. From this perspective, investigating intraspecific responses to an environmental variable may contribute to better understanding and prediction of the effect of climate change on the geographical range and evolution of species, particularly in the case of widespread species. In this context, the present study aimed at establishing how environmental variables (focussing mainly on temperature) may have contributed to shape the spatial distribution, physiology, reproductive biology and connectivity of two species of Southern African sandhoppers (Talorchestia capensis and Africorchestia quadrispinosa, Amphipoda, Talitridae). Most of the work was carried out on T. capensis, due to its widespread spatial distribution. A first investigation of the biogeography of T. capensis and A. quadrispinosa, revealed that, for both species, spatial patterns of abundance, size and sex ratio were not explained by the Abundant Centre Hypothesis (greater abundance at the core of a spatial range), but rather guided by bio-physical forces. Precisely, the abundance of sandhoppers was driven by the morphodynamic state of the beach, salinity and temperatures, with strong differentiation among sites that reflected local environmental conditions. In support of these findings, strong population structure in the genetics of T. capensis was found (three main groups) when investigating its phylogeography and genetic connectivity. Although such defined structure may suggests cryptic speciation, the concomitant within-population variation in the COX1 region of mtDNA, also highlighted the importance of individual genetic variability. High individual variability was also found in the response of T. capensis to temperature, both in its physiology (thermal plasticity) and its reproductive biology (maternal effects). Since temperature is one of the main variables affecting the coastal marine systems of southern Africa and the metabolism of animals in general, its effect on the physiology and reproduction of T. capensis was therefore investigated. Thermal responses to increasing/decreasing temperatures were assessed for separated populations of T. capensis. Individual variability was reported in the oxygen consumption of T. capensis in response to temperature (high variation around the means, especially for increasing temperatures). Among population differences in thermal sensitivity were significantly correlated with air temperature variability experienced over the past 23 years, highlighting the importance of historical temperature fluctuations to the current thermal physiology of these sandhoppers. Temperature also had an important effect on the reproductive plasticity of T. capensis. Different temperatures induced mothers to adjust the size of their offspring (i.e. egg size), with larger eggs produced at lower temperatures. Interestingly, females showed strongly significant among individual variation in the size of the eggs. Given the importance of understanding rapid responses of organisms to climate change and considering the fundamental role played by phenotypic plasticity in evolution, the overall study revealed the significance of individual plasticity and variability in response to the environment and highlighted its importance. Particularly, studying the thermal physiology of separated populations and understanding within population reproductive plasticity in response to temperature, helped to clarify how differences among individual responses have important consequences at the population level, possibly explaining the widespread distribution of T. capensis.