Composição, estrutura da comunidade e rede de interações de epífitas vasculares na Serra Negra da Mantiqueira, Minas Gerais, Brasil

Abstract

Mountain ecosystems are under severe conditions, which select taxa capable of establishing themselves in these environments, resulting in high levels of biodiversity and endemism. The Serra da Mantiqueira region, in the Southeast Region of Brazil and part of the Atlantic Forest, is considered of “High Biological Importance”. Among the plant formations of this mountain range, the rare and threatened cloud forests stand out, represented by the frequent immersion in mists and the water availability, both characteristics of great relevance for the occurrence of vascular epiphytes. The present research involved two approaches aimed at studying the ecology of epiphytes and phorophytes and was carried out in the Chapadão da Serra Negra Private Natural Heritage Reserve, Zona da Mata in Minas Gerais. In the first chapter, we compared the epiphyte community established in candeias (Eremanthus erythropappus, Asteraceae) of the cloud shrubland (AN) with that found in the ecotone of cloud dwarf forests (ENN), neighboring environments, but with structure and microclimatic characteristics. For this, we identified and quantified the epiphytes in 40 phorophytes from each environment, and calculated richness, frequency, Shannon diversity index (H’), Pielou evenness index, and two taxonomic diversity indices (Δ+, Λ+). In the second chapter, we investigated patterns of interaction networks between vascular epiphytes and phorophytes in a cloud dwarf forest, evaluating metrics such as network size, connectance (C), nestedness (NODF), equality of interactions, specialization (H²), and indices of generality and vulnerability. We sampled three plots of 400m² 10each, identifying and quantifying the vascular epiphytes that occur in phorophytes with DBH ≥ 10cm. In the first approach, we observed the highest richness in ENN, and the species sampled in AN is almost a subset of those recorded in the ENN. We conclude that the different conditions found in the two sampled environments, mainly those microclimatic and water availability, implied the presence of environmental filters, selecting species adapted to each location. In the second approach, we recorded a total of 3327 epiphyte individuals (represented by 113 species, 55 genera, and 20 families), in 322 phorophytes of 92 different species. The investigated network showed a low level of interaction between epiphytes and phorophytes, confirming our hypothesis. However, unlike prediction, the network has low nesting