Investigating the impact of climate change on trend shifts of vegetation growth in Gilgit Baltistan

Abstract

Climate change impacts on vegetation have far-reaching implications for environmental resource management, especially in regions with vulnerable ecosystems like Gilgit Baltistan (GB). Vegetation in GB plays a critical role in regional ecological security and the global carbon cycle. However, the nuanced influence of climate on vegetation growth, characterized by seasonal variations, plant functional type disparities, and altitudinal differences, remains uncertain. This study leverages remotely-sensed vegetation indices and observed meteorological data (1991–2020) to examine seasonal and annual vegetation growth trends. We assess vegetation responses to climatic variables at regional, zonal, altitudinal, and pixel scales, employing a multi-model approach (expanded paired-consecutive, linear least-square linear, and piecewise regression models) to evaluate vegetation changes and trend shifts across GB. Our analysis reveals an overall increase in GB's Normalized Difference Vegetation Index (NDVI) from 1991 through 2020, averaging a rate of 4.30×10−4 NDVI yr−1 (0.19% yr−1). We also find vegetation's stronger response to precipitation over temperature during summer and vice versa during spring at lower elevations. Additionally, winter precipitation influenced vegetation growth at these elevations more than at higher elevations. By enhancing our understanding of the climate–vegetation growth relationship in GB, this study offers valuable insights that can inform improvements in terrestrial ecosystem models for better predictions of future vegetation responses to climate change.