Ecological niche comparison among closely related tree species of Lauraceae using climatic and edaphic data

Abstract

Edaphic specialization is considered to promote ecological differentiation among closely related species of Damburneya (Lauraceae) occurring in sympatry. However, little is known about the effects of soil and other key environmental factors like climate on the ecological niche and distribution of these tree species. Here, we assessed the role of climate and soil on niche divergence and potential distribution of four Damburneya species whose distributions span Central America and Mexico. We performed ecological niche modeling with MaxEnt using three sets of environmental data: climatic-only, edaphic-only, and a combination of both, to characterize species niches and suitable distribution areas. Niche overlap was quantified, and niche similarity was tested to assess niche differentiation among species. Climate and soil determined species’ potential distribution. While climatic niches were mostly similar, edaphic niches tended to differ. Warm and moist tropical forests with no water deficit and low seasonality in precipitation are the most suitable environments for the four species. This study supports previous reports of wide ecological plasticity of Damburneya salicifolia based on its distribution and leaf trait variation, as it occurred in drier environments with wider temperature and soil pH ranges than the other species. The observed patterns of niche similarity did not reflect the phylogenetic relationships between species, suggesting that the modeled niches do not necessarily reflect past evolutionary processes but rather the current environmental variation across the geographical ranges of the species. The results suggest that the studied species are similarly constrained by climate and tolerate wide edaphic variation, supporting a potential role for soils on ecological divergence within the genus. On the other hand, performance and predictions varied between models built with different datasets. This research supports the utility of including climate and soil data in ecological niche models to comprehensively analyze the niche and distribution of plant species.