Migration barriers in ferns: the case of the neotropical genus Diplopterygium (Gleicheniaceae)

Abstract

ABSTRACT Background Despite the broad distribution of several species in Gleicheniaceae in the neotropical region, Diplopterygium is the only genus having a restricted distribution. Species of Gleicheniaceae occupy open (including anthropogenic) habitats and produce large amounts of wind-dispersed propagules – so why does Diplopterygium bancroftii, the only neotropical species in the genus, have a restricted distribution? Aims We investigated if the restricted distribution of Diplopterygium in the Neotropics reflected the absence of suitable areas for the establishment. Methods We used species distribution modelling to identify suitability areas during different periods of the Pleistocene (Last Glacial Maximum and Last Interglacial), the Holocene, and the present. Results The environmental suitability model at the present time corroborated the current distribution of D. bancroftii, and also evidenced additional suitable potential areas where the species has so far not been recorded, especially in eastern Brazil. In projections of the past, no connectivity was observed between suitable areas in the Andes and eastern Brazil. Conclusions As neither the dispersal ability nor the absence of suitable areas at the present time or in the past were limiting factors to the range expansion of Diplopterygium, we discuss possible migration barriers and propose a hypothesis for its colonisation history in the Neotropics.