Unraveling the Sensitivity and Response of Ecosystems to Rising Moisture Stress in India

Abstract

Moisture stress has increased substantially across the globe with significant impact on terrestrial ecosystems. Therefore, we examine the sensitivity and response of terrestrial ecosystems to rising moisture stress in India during recent decades (2000 to 2019). The Random Forest approach reveals that soil moisture (SM) is the major driver (31%) of ecosystem functioning and its health in India. Moisture availability in the atmosphere (Vapor Pressure Deficit [VPD], 25.8%) and on land (Climatic Water Deficit [CWD], 24.6%) also have major control on the ecosystem functioning. Terrestrial warming (1.8%) increases evapotranspiration (ET, 10.76%), depletes SM (2.45%), and rises CWD (3.37%) and VPD (1.8%), despite the increase in precipitation (P, 2.54%) in recent decade (2010 to 2019) as compared to previous decade (2000 to 2009). In response to the rising moisture stress, the Water Use Efficiency (WUE) is increasing in the eastern Indo-Gangetic Plain (IGP), Southern India (SI), and eastern Himalaya, but the Carbon Use Efficiency (CUE) is decreasing in these regions. The Resilience method reveals that IGP and Northwest are nonresilient to moisture stress in terms of CUE, whereas SI, the western Central India, eastern Himalaya, and Northeast are nonresilient in terms of WUE. Our results reveal that ecosystem functioning factors (CUE and WUE) are increasing (decreasing) in regions where they are nonresilient (resilient) to moisture stress. Therefore, there is a need of proper ecosystem planning, climate risk management and policies to mitigate the threats of climate change and food security by maintaining ecosystem resilience to moisture stress across the regions.