Understanding the impacts of hydroclimatic extremes on terrestrial and wetland ecosystems

Abstract

Building on this, a composite flash drought risk index was developed and applied across more than 615 KBAs, integrating hazard frequency, ecosystem vulnerability, and human exposure. Results show that 45.8 percent of KBAs fall under high-risk zones, particularly inland forests and freshwater habitats. Freshwater KBAs are notably exposed, with 73.8 percent facing moderate to high risk. Areas with extensive croplands and high population density are especially susceptible, underscoring the dual threat to biodiversity and agricultural productivity. October emerged as the most common onset month, and the average drought duration was found to be 34 days. To assess wetland hydrology under changing climate regimes, an automated mapping technique using Short-Wave Infrared (SWIR) thresholding on Landsat imagery was implemented to evaluate annual inundation trends from 1991 to 2020 across 89 Ramsar wetlands. The analysis identified that 43 wetlands showed declining inundation trends, with 12 experiencing statistically significant losses. High-altitude wetlands and those located in regions with less than 500 millimeters of annual rainfall were most prone to shrinkage. The Upper Ganga wetland exhibited the most drastic decline, losing nearly 59 percent of its inundated area over three decades.