Life at the edge: how environmental gradients affect an orchid species distributed along coastal vegetation?

Understanding the causes of species geographical distribution is a fundamental topic in ecology and evolution. In this context, the Center-Periphery Hypothesis (HCP) assumes that marginal populations must exhibit a series of ecological and evolutionary differences when compared to central populations. Restrictions such as low reproductive success and lower adaptive potential are expected for peripheral populations, compromising habitat occupation beyond their geographic range. A review of the topic found that only nine studies tested the HCP in South America, restricting our ability to understand how species in megadiverse regions have their geographical distribution shaped by the environment. In this sense, the objective of this project is to test the HCP using as model Epidendrum fulgens, an orchid found along the Brazilian coast. Different but complementary approaches will be used to analyze central and peripheral populations of E. fulgens in order to detect ecological and evolutionary differences along the environmental gradient occupied by the species. The following will be performed: a) analysis of reproductive success and functional traits linked to temperature variation and water availability; b) transcriptome analysis for detection of genes under selection; c) quantification of reproductive isolation among disjunct populations that occur in distinct habitats. We hope to obtain new data for the Neotropical region that strengthens our ability to predict how environmental gradients may affect species distribution in highly diverse environments vulnerable to the threats of climate change.