Sensitivity of tropical trees to drought stress and the implications of the responses of tropical forest to climate change

Abstract

Tropical Species are expected to be adversely affected by the increased frequency in drought due to climate change.While being a hotspot for biodiversity as well as impact of climate change, the flora of tropical India is underrepresented in the literature and not much is known about its response to drought stress to understand and predict the sensitivity to future changes in climate. In this study stem and leaf hydraulic traits of 20 tree species from a moist deciduous forest in south western ghats were measured. Xylem vulnerability to embolism agreed with reports from studies on similar ecosystems across the world, if not slightly shifted towards higher resistance to embolism. Leaf and stem hydraulic traits showed a broad range. While xylem vulnerability to cavitation and leaf re-hydration capacity had a positive correlation with leaf and wood functional traits like Leaf mass per area (LMA), Leaf dry matter content(LDMC) and Wood density (WD), with more resistant species having a higher structural investment, species with a resistant chlorophyll response to drought showed lower structural investment. Both these observations are in agreement with the existing leaf economy and slow-fast resource acquisition spectrum. Xylem vulnerability analysis also hinted at the contribution of non structural features like presence of latex and resin to resist embolism formation in xylem.