Influence of climatic variables on CSR strategies of aquatic plants in a semiarid region

Abstract

Temporary pools in semiarid regions are influenced by climatic seasonality and the extremes of moisture/desiccation effects influence mechanisms for plant survival, which should be analyzed based on competitor (C), ruderal (R), or stress tolerator (S) strategies. The aim of the present study was to evaluate how aridity exerts an influence on CSR functional groups of aquatic plants in temporary pools. Aquatic plants were sampled from 27 temporary pools in areas with a climatic gradient of evaporation, precipitation, and temperature. The distribution of functional groups along the environmental gradient was analyzed through redundancy analysis and patterns of CSR strategies were analyzed using linear correlation. We found that assemblages of macrophyte ponds were composed mainly of intermediate R/CR strategies. Evaporation exerted a positive influence on the occurrence of species with larger specific leaf area and a negative influence on the occurrence of taller species. Moreover, ponds in regions with greater evaporation had greater species richness (r 2 = 0.2, P \0.01). The same was found for competitors (r 2 = 0.2, P\ 0.01) but not for ruderal or tolerant classes. In conclusion, climatic conditions influence CSR classes and exert a specific influence on the specific functional traits of species in temporary pools of semiarid regions.