Interação epífito-forófito: influência das variáveis ambientais e diversidade filogenética no gradiente de umidade mata de brejo – floresta estacional semidecídua – cerradão
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Data
2017-03-16
Autores
Joanitti, Sabrina Anselmo [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Epífitos vasculares são plantas autotróficas, que germinam, enraízam e crescem utilizando-se de outras plantas como suporte, e são independentes dos forófitos na obtenção de água e nutrientes. A maioria das pesquisas que abordaram a diversidade em epífitos se baseou em métodos tradicionais, como riqueza de espécies, a partir da contagem do número de espécies que ocorrem em um determinado local. Ao estimar a diversidade dessa maneira, espécies raras e comuns apresentam o mesmo peso nessa quantificação. Portanto, medidas de diversidade que incorporam informações filogenéticas sobre as espécies ou indivíduos são mais robustas do que aquelas que não o fazem. A diversidade de epífitos é determinada principalmente pelo clima, pela disponibilidade de água, pelo tamanho, pelas características da casca e pela arquitetura do forófito. A combinação de certas condições, estruturas e recursos ambientais criam microambientes que determinam a distribuição e abundância das espécies de epífitos. Nossos objetivos consistiram em compreender a importância das variáveis bióticas e abióticas na estrutura da comunidade de epífitos vasculares e a diversidade filogenética entre epífitos e forófitos em três formações vegetais: mata de brejo, floresta estacional semidecídua e cerradão, no município de Bauru, estado de São Paulo. A condição microclimática da mata de brejo explica a relação positiva entre a abundância de epífitos e o tamanho do forófito, padrão que não se repete no cerradão e na floresta estacional semidecídua. As variáveis ambientais desempenharam um papel dominante na determinação da riqueza e composição de espécies de epífitos vasculares nas três formações vegetais estudadas. Este resultado demonstra que a distribuição espacial dos epífitos vasculares e a sua diversidade são previsíveis em escalas espaciais em razão dessa condição microclimática. As espécies de epífitos vasculares são filogeneticamente próximas entre si em uma mesma formação vegetal, demonstrando a existência de um conservantismo filogenético entre as espécies. Sugerimos que na mata de brejo a competição é responsável por moldar a comunidade de epífitos vasculares. A maior diversidade filogenética de forófitos proporciona uma maior diversidade filogenética de epífitos, portanto, diferentes espécies de epífitos podem ter desenvolvido adaptações a diferentes espécies de forófitos. Além disso, as adaptações dos epífitos permanecem na sua filogenia, são passadas para os seus descendentes e estão diretamente relacionadas às características dos forófitos.
Vascular epiphytes are autotrophic plants that germinate, root, and grow using other plants as support, and are independent of phorophytes in obtaining water and nutrients. Most studies that have addressed epiphyte diversity were based on traditional methods, such as species richness, counting the number of species that occur in a specific location. Estimating diversity in this way, rare and common species have the same weight in this quantification. Therefore, diversity measures that incorporate phylogenetic information about species or individuals are more robust than those that do not. The diversity of epiphytes is determined mainly by climate, water availability, size, bark traits and architecture of phorophytes. The combination of certain environmental conditions, structures and resources create microenvironments that determine the distribution and abundance of epiphyte species. Our aims were to understand the importance of biotic and abiotic variables in the vascular epiphytes community structure, and the phylogenetic relationship between epiphytes and phorophytes in three plant formations: swamp forest, semideciduous seasonal forest and woodland savanna, in the municipality of Bauru, state of São Paulo. The swamp forest microclimatic condition explains the positive relationship between the abundance of epiphytes and the size of the phorophytes, a pattern which does not repeat in the woodland savanna and in the semideciduous seasonal forest. The environmental variables played a dominant role in determining the richness and composition of vascular epiphyte species in the three plant formations studied. This result demonstrates that the spatial distribution of vascular epiphytes and their diversity are predictable at spatial scales due to this microclimatic condition. Phylogenetically, vascular epiphyte species are closely related in the same plant formation, demonstrating the existence of a phylogenetic conservatism among species. We suggest that, in the swamp forest, competition is responsible for shaping the community of vascular epiphytes. The higher phylogenetic diversity of phorophytes provides a higher phylogenetic diversity of epiphytes. Therefore, different epiphytes species may have developed adaptations to different phorophytes species. Besides, epiphyte adaptations remain on their own phylogeny, are passed on to the descendants, and are directly related to the characteristics of phorophytes.
Vascular epiphytes are autotrophic plants that germinate, root, and grow using other plants as support, and are independent of phorophytes in obtaining water and nutrients. Most studies that have addressed epiphyte diversity were based on traditional methods, such as species richness, counting the number of species that occur in a specific location. Estimating diversity in this way, rare and common species have the same weight in this quantification. Therefore, diversity measures that incorporate phylogenetic information about species or individuals are more robust than those that do not. The diversity of epiphytes is determined mainly by climate, water availability, size, bark traits and architecture of phorophytes. The combination of certain environmental conditions, structures and resources create microenvironments that determine the distribution and abundance of epiphyte species. Our aims were to understand the importance of biotic and abiotic variables in the vascular epiphytes community structure, and the phylogenetic relationship between epiphytes and phorophytes in three plant formations: swamp forest, semideciduous seasonal forest and woodland savanna, in the municipality of Bauru, state of São Paulo. The swamp forest microclimatic condition explains the positive relationship between the abundance of epiphytes and the size of the phorophytes, a pattern which does not repeat in the woodland savanna and in the semideciduous seasonal forest. The environmental variables played a dominant role in determining the richness and composition of vascular epiphyte species in the three plant formations studied. This result demonstrates that the spatial distribution of vascular epiphytes and their diversity are predictable at spatial scales due to this microclimatic condition. Phylogenetically, vascular epiphyte species are closely related in the same plant formation, demonstrating the existence of a phylogenetic conservatism among species. We suggest that, in the swamp forest, competition is responsible for shaping the community of vascular epiphytes. The higher phylogenetic diversity of phorophytes provides a higher phylogenetic diversity of epiphytes. Therefore, different epiphytes species may have developed adaptations to different phorophytes species. Besides, epiphyte adaptations remain on their own phylogeny, are passed on to the descendants, and are directly related to the characteristics of phorophytes.
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Palavras-chave
Cerradão, Conservantismo filogenético, Fatores bióticos, Fatores abióticos, Filogenia, Floresta estacional semidecídua, Mata de brejo, Plantas hospedeiras