Climatic affinities of Neotropical species of Capparaceae: an approach from ecological niche modelling and numerical ecology

Abstract

Abstract In the Neotropics, the distribution of Capparaceae has been historically associated with seasonally dry forest (NSDF), but recent taxonomic studies have questioned this assumption. Given the environmental co-occurrence of species and the need to understand their relationships with the ecosystem, we use ecological niche modelling and numerical ecology methods to better describe the distribution patterns of Capparaceae and their climatic affinities with NSDF. We used the Maxent algorithm to model the ecological niches of 104 species of Capparaceae, which gave maximum values of the response curves for climatic suitability. These values were used to carry out multivariate statistical analyses [principal components analysis (PCA), non-metric multidimensional scaling (NMDS) and discriminant analysis (DA)] to identify ecological associations based on climatic similitude among species. Both PCA and NMDS showed that annual precipitation, precipitation of the wettest quarter and precipitation of the driest quarter were the most important climatic variables shaping distributions of species and their associations with NSDF, moist tropical forest (MTF) and wet tropical forest (WTF). Although we found 72 species associated with NSDF as previously reported, DA revealed an overlapping pattern among the three ecological/climatic assemblages (NSDF, MTF and WTF). This confirms the existence of transition zones and species with wider niches. Our results provide an important biogeographical framework of ecological patterns for species associated with NSDF, opening new lines of research on the reconstruction of distribution in future climatic scenarios or palaeo-distributions.