Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Variáveis climáticas determinam a composição funcional em florestas tropicais sazonalmente secas

Auteur : Gomes, D’Ávilla Ruama Fernandes Lopes

Université de soutenance : Universidade Estadual da Paraíba

Grade : Mestre em Ecologia e Conservação 2019

Résumé
In regions with a hot and semi-arid climate, such as Brazilian dry forests, vegetation exhibits morphological, anatomical and physiological strategies to promote efficiency in the use of available resources or their limitation. These environments act as environmental filters in selection of functional traits with ecological strategies that guarantee the survival of the vegetation. Among the functional traits, wood density and foliar phenology can be used to know the process of establishment and survival of vegetation in the most varied environments, also being used as stresses indicator, mainly water. In this context, the objective of this study was to evaluate the influence of climatic variables on the distribution of wood density and foliar phenology in Seasonally Dry Tropical Forests communities in Brazil based on a database compiled from 114 communities. For studied communities selection, floristic lists were searched in online databases. For data on the trait values, we also used a database of global wood density and literature on species foliar phenology. Climatic variables data were obtained from remote sensing based on raster available online. It was observed that high average values of wood density and the highest percentage of deciduous species were the dominant ecological strategies in dry forest communities. It has also been found that these strategies are related to places where rainfall rates are lower and still present high environmental stress. These results allow the understanding that seasonally dry tropical forests are ecosystems in which due to the environmental stress they are in, they select more conservative strategies to use the little available resource, with a strategy of resistance and/or tolerance to dry environment and arid region, with a higher dominance of deciduous species and higher wood density the greater stress. The results also allow us to predict how other ecosystems can behave (functionally) as a result of climatic changes that have been taking place

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