Made available in DSpace on 2014-06-11T19:22:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-28Bitstream added on 2014-06-13T20:49:35Z : No. of bitstreams: 1 goncalvessouza_t_me_sjrp.pdf: 528020 bytes, checksum: c517fa0c7acfebb2b1d0502c18e30b48 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A complexidade arquitetural de plantas é frequentemente reconhecida como um dos fatores que melhor prediz a distribuição de artrópodes sobre a vegetação. Basendose na hipótese da heterogeneidade ambiental plantas estruturalmente mais complexas possuem maior abundância e riqueza de artrópodes. Porém, não se sabe como a variação arquitetural e a distribuição espacial de grupos específicos, como as bromélias, afetam a riqueza e composição de espécies de aranhas. Neste trabalho nosso objetivo foi responder as seguintes questões: 1) espécies de bromélias com características arquiteturais similares possuem subconjuntos não-aleatórios da comunidade de aranhas bromelícolas? 2) a complexidade arquitetural das bromélias aumenta a abundância e a riqueza de espécies de aranhas? 3) espécies de bromélias com distribuição vertical mais ampla possuem maior riqueza de espécies de aranhas? Amostramos aranhas em 39 espécies de bromélias que apresentam diferenças de complexidade arquitetural e distribuição vertical em uma área de Mata Atlântica na região sudeste do Brasil. Usamos uma análise de equação estrutural para testar os efeitos da complexidade arquitetural e da distribuição vertical de bromélias sobre a abundância e riqueza de aranhas. Ao contrário do esperado, a arquitetura de bromélias não afetou a composição de espécies de aranhas. A complexidade arquitetural (i.e., número de folhas) e a distribuição vertical (amplitude de ocupação do estrato vertical por uma espécie de bromélia) correlacionaram-se positivamente com a abundância e a riqueza de aranhas. Nossos resultados corroboram a hipótese da heterogeneidade ambiental e sugerem que, além da estrutura da planta, a distribuição espacial das mesmas pode ser um forte determinante do aumento da diversidade de animais / Although bromeliads can be important in the organization of invertebrate communities in Neotropical forests, there are few studies supporting this assumption. Bromeliads possess a three-dimensional architecture and rosette grouped leaves that provide associated animals with a good place for foraging, reproduction and egg laying, as well as shelter against desiccation and natural enemies. In this work we collected spiders from an area of the Atlantic Forest, southeastern Brazil, through manual inspection in bromeliads, beating trays in herbaceous+shrubby vegetation and pitfall traps in the soil, to test if: (1) species subsets that make up the spider Neotropical forest community are compartmentalized in different habitat types (i.e., bromeliads, soil, vegetation) and amplify spider beta diversity, (2) bromeliads are important elements that structure spider communities and thus generate different patterns of abundance distributions and species composition. There were subsets of spider species compartmentalized into the three habitat types. The presence of bromeliads represented 41% of increase in total spider richness, and contributed mostly to explain the high beta diversity values among habitats. Pattern of abundance distribution of spider community differed among habitats. These results indicate that bromeliads are key elements in structuring spider community and highlight the importance of Bromeliaceae as biodiversity amplifiers in Neotropical ecosystems

Orientador: Gustavo Quevedo Romero / Banca: Paulo Enrique Cardoso Peixoto / Banca: Lilian Casatti / Resumo: A complexidade arquitetural de plantas é frequentemente reconhecida como um dos fatores que melhor prediz a distribuição de artrópodes sobre a vegetação. Basendose na hipótese da heterogeneidade ambiental plantas estruturalmente mais complexas possuem maior abundância e riqueza de artrópodes. Porém, não se sabe como a variação arquitetural e a distribuição espacial de grupos específicos, como as bromélias, afetam a riqueza e composição de espécies de aranhas. Neste trabalho nosso objetivo foi responder as seguintes questões: 1) espécies de bromélias com características arquiteturais similares possuem subconjuntos não-aleatórios da comunidade de aranhas bromelícolas? 2) a complexidade arquitetural das bromélias aumenta a abundância e a riqueza de espécies de aranhas? 3) espécies de bromélias com distribuição vertical mais ampla possuem maior riqueza de espécies de aranhas? Amostramos aranhas em 39 espécies de bromélias que apresentam diferenças de complexidade arquitetural e distribuição vertical em uma área de Mata Atlântica na região sudeste do Brasil. Usamos uma análise de equação estrutural para testar os efeitos da complexidade arquitetural e da distribuição vertical de bromélias sobre a abundância e riqueza de aranhas. Ao contrário do esperado, a arquitetura de bromélias não afetou a composição de espécies de aranhas. A complexidade arquitetural (i.e., número de folhas) e a distribuição vertical (amplitude de ocupação do estrato vertical por uma espécie de bromélia) correlacionaram-se positivamente com a abundância e a riqueza de aranhas. Nossos resultados corroboram a hipótese da heterogeneidade ambiental e sugerem que, além da estrutura da planta, a distribuição espacial das mesmas pode ser um forte determinante do aumento da diversidade de animais / Abstract: Although bromeliads can be important in the organization of invertebrate communities in Neotropical forests, there are few studies supporting this assumption. Bromeliads possess a three-dimensional architecture and rosette grouped leaves that provide associated animals with a good place for foraging, reproduction and egg laying, as well as shelter against desiccation and natural enemies. In this work we collected spiders from an area of the Atlantic Forest, southeastern Brazil, through manual inspection in bromeliads, beating trays in herbaceous+shrubby vegetation and pitfall traps in the soil, to test if: (1) species subsets that make up the spider Neotropical forest community are compartmentalized in different habitat types (i.e., bromeliads, soil, vegetation) and amplify spider beta diversity, (2) bromeliads are important elements that structure spider communities and thus generate different patterns of abundance distributions and species composition. There were subsets of spider species compartmentalized into the three habitat types. The presence of bromeliads represented 41% of increase in total spider richness, and contributed mostly to explain the high beta diversity values among habitats. Pattern of abundance distribution of spider community differed among habitats. These results indicate that bromeliads are key elements in structuring spider community and highlight the importance of Bromeliaceae as biodiversity amplifiers in Neotropical ecosystems / Mestre

When multiple predators foraging together have different individual consumption rates than predators foraging in isolation, they exhibit non-independent multiple predator effects on prey. I examined multiple predator effects in a system consisting of invasive green crabs (Carcinus maenas L.), native rock crabs (Cancer irroratus Say) and benthic macrofauna prey. First, I examined multiple predator effects when green crabs and rock crabs forage on soft-shell clams (Mya arenaria L.) in different habitat types (sand, sand with artificial seagrass) and assessed the behavioural mechanisms responsible for the observed predation effects. Independent multiple predator effects on prey were detected for most conspecific and heterospecific pairs in both habitat types. In general, crab foraging behaviours were not affected by the presence of another predator. Interactions between predators did not influence foraging behaviours because encounters were infrequent, short in duration and predominantly non-aggressive. A non-independent multiple predator effect on prey (marginally significant) was observed when green crabs foraged with rock crabs in artificial seagrass. This effect, however, could not be explained by the observed crab behaviours. Second, I investigated multiple predator effects when green crabs and rock crabs forage on a soft-sediment macrofauna community. Because crabs did not have significant predation effects on the community throughout the experiment, I did not evaluate multiple predator effects on prey. It is possible that crab predation was not important in regulating the macrofauna community, in which case multiple predator effects were non-existent. Predation may have been suppressed due to a combination of factors, including interactions between predators, harsh environmental conditions or a sub-optimal prey field. Alternatively, my ability to detect significant predation effects may have been hindered because of prey movement in and out of cages or low statistical power. Overall, results from this thesis demonstrate that multiple predator effects on prey may differ with habitat and highlights the importance of conducting behavioural observations to better understand interactions between predators and the resulting consequences for prey. Multiple predator effects on a soft-sediment community should be re-evaluated to assess the importance of these crab species in regulating benthic macrofauna under natural conditions.

There are number of future projections of species' geographic ranges developed under conditions of ongoing climate change. However, only a few studies have assessed what are the characteristics of species explaining interspecific variability in the projected range shifts. Examination of such relationships is important for development of effective conservation strategies mitigating the effects of climatic changes. For this purpose, I calculated the predicted shifts of European ranges in Czech birds based on maps in A Climatic Atlas of European Breeding Birds and explored relationships between these predicted shifts and several ecological traits. We found significant effects of the type of European distribution and habitat requirements. Concerning the type of European distribution, the largest shift is predicted in the central species and the northern species compared to widespread and southern species. According to the habitat type, the largest shift showed forest birds in contrast to the urban species which will shift slightly. The former pattern is probably attributable to spatial constrains different among these specific groups (central species are less limited compared to widespread species). The latter pattern could be explained by higher sensitivity of forest species to climatic changes...