Tree height, leaf thickness and seed size drive Caatinga plants' sensitivity to climate change

Abstract

AbstractAimThe Anthropocene climate crisis may shift the distribution range of various species. Global Climate Models predict an increase in temperature and changes in precipitation across the Brazilian tropical semiarid region. Based on the joint analysis of functional traits and plant distribution models, we aim to identify which functional traits define the vulnerability of plants to climate change.LocationCaatinga, Brazil.TaxonTrees‐shrub plants.MethodsWe selected 36 species common to at least 25% of the floristic and phytosociological surveys made in the Brazilian semiarid region. We modelled both the current and future spatial distribution of these species and investigated whether functional traits, such as plant height, leaf area, leaf thickness, specific leaf area, stem specific density, and seed size can explain the range shifts of these species.ResultsModels indicate that 58.4% of the species are expected to expand their distribution range in the future. These species tend to be shorter and produce large seeds and thin leaves, which confer higher hydraulic safety and resistance of seeds to prolonged droughts. Meanwhile, 41.6% of the species are expected to reduce their distribution ranges in the future. Most of these are characterized as tall individuals with thick leaves and small seeds.ConclusionSpecies with traits that confer resistance to drought are likely to increase distribution towards the coast and to areas where the Caatinga borders with other domains. Also, these species with low height, thin leaves and large seeds may expand their distribution to the slopes and plateaus. The retraction of taller plants and with thicker leaves may have profound implications for the structure and functioning of Brazilian semiarid ecosystems, given their role in ecosystem processes and carbon cycle. Retractions can result in a reduction in the number of local species, which will impact regional biodiversity.