Ecological inferences in Orchidaceae species from the Brazilian subtropical Atlantic Forest based on morphological and functional anatomical traits

Abstract

Ecological anatomy studies seek to link structural aspects to environmental pressures, improving knowledge about the occurrence and distribution of species. Orchidaceae is a group with high species richness and ecological diversity, well represented in the Brazilian Atlantic Forest, a biodiversity hotspot. The Iguaçu National Park (ParNa Iguaçu) is an important remnant of the southern Brazilian Atlantic Forest with a high richness of Orchidaceae. Given the family's diversity and the relevance of ecological anatomy studies for interpreting traits associated with the survival of plants in certain environments, we studied 38 species of Orchidaceae from ParNa Iguaçu, seeking to identify possible functional groups. For this, we surveyed 57 leaf morpho-anatomical characters and conducted histochemical and statistical tests. The morpho-anatomical traits group the species into two functional groups, with Cyclopogon congestus emerging isolated. In group A, xeromorphic morphoanatomical characters predominate, and group B combines members with meso/hygromorphic characteristics. We advocate the importance of understanding the ecological behavior of species, especially Orchidaceae, due to their important ecological role, in conservation actions in protected areas. Furthermore, our results highlight the morphological and anatomical diversity of the Orchidaceae found in ParNa Iguaçu, as well contributing to the development of better management practices for these plants, considering the threats posed by the opening of clearings and climate change.