Dr. Alexandra Konings - Spatial variability in plant water sensitivity and its drivers

Overview

Understanding how plants respond to meteorological water stress is necessary for predicting photosynthesis and transpiration in a changing climate. Many studies of plant responses to water stress have focused on differences between species, because of the large species-to-species differences in stomatal closure, xylem conductance, and root traits. However, several other factors also influence how meteorology affects plant water status, such as soil hydraulics, topography, intra-specific variability in plant traits, etc. This begs the question of whether the traditional focus on species-to-species differences is warranted for understanding large-scale spatial variations. In this talk, I will present research to understand the relative importance of species cover at regional scales in controlling plant responses to water stress. To address this, I will use satellite-derived estimate of live fuel moisture content, a measure of canopy wetness that reflects the dynamics of root water uptake and transpiration. These data can be used to estimate so-called 'plant water sensitivity' - a metric of drought response - and combined with known information about species cover from 21,455 measured plots in the U.S. Forest Service Forest Inventory and Analysis database across the western United States. I will discuss the degree to which species cover and other traits can explain observed variability of plant water sensitivity, and implications for species-specific studies of drought response.