Detecting climate controls of available plant water in tropical catchments using xylem-water isotope measurements

Abstract:

Climate is one of the main factors influencing global biomes. However, there are only limited investigations on how various water sources including precipitation, groundwater and soil water in different seasons affect ecohydrological processes. In tropical regions, contrasting dry and wet seasons provide natural experiment settings for understanding plant responses associated with water availability. Using data from Puerto Rico, a multivariate Gaussian mixture model is developed for decomposing the probability distribution of xylem water observations. These model results can provide an indication of how source water proportions change in different seasons. Moreover, an environmental change detection framework for subtropical regions is developed based on the water isotope decomposition results. It has been widely hypothesised that the climate of subtropical regions will likely become more tropical based on observed increasing temperature trends in the late 20th century. The new research framework proposes approaches to comprehend changing environmental processes based on continuous stable water isotope monitoring.