Testando o conservadorismo de nicho entre clados proximamente relacionados de espécies neotropicais e afrotropicais do gênero Amauropelta Kunze

Abstract

Ferns are plants with a high capacity for long-distance dispersal, being less limited by geographic barriers. Some studies showed disjunction patterns in fern species that occur between the Neotropics and Africa. One of the processes that can influence disjunctions is phylogenetic niche conservatism, where descendant species tend to retain the ancestral niche. The genus Amauropelta (Thelypteridaceae) is one of the groups that presented disjunction patterns, being the largest genus of the family Thelypteridaceae, having a wide distribution, with about 200 neotropical species and 12 paleotropical species. The objective of this work was to test hypothesis of niche conservation among closely related clades of neotropical and African species of Amauropelta using niche modeling in a comparative phylogenetic context. Thirty- nine species distributed among the clades Oligocarpa, Africa, Heteroclita, Germaniana, and Steyermarkii were selected. The models were built using the MaxEnt algorithm, based on records obtained from the GBIF repository, along with environmental variables from online databases. The models were binarized and compared using a calculated pairwise niche overlap. Pairwise matrices of niche overlap and patristic phylogenetic distance were built, and the correlation between the matrices was obtained using a Mantel test. The results show that the niches are similar in some aspects. However, most closely related species had niches that indicate divergence, which reflects the great dispersal capacity of ferns or may indicate other processes, such as competition. The few results that indicate the niche of conservatism were between species that occur sympatrically. The relationship between niche overlap and phylogenetic distance shows that only 10% of the observed niche overlap can be explained by phylogenetic distance, which indicates that other factors may influence niche overlap in the studied Amauropelta species.