# Spatiotemporal Dynamics of Ecological Vulnerability to Climate Change in Northwestern Sichuan’s Terrestrial Ecosystems of China: Conservation Implications

## TL;DR

This study maps how climate change affects ecosystems in northwestern Sichuan, showing where and when vulnerability changes, and how to protect biodiversity.

## Contribution

The study reveals spatiotemporal patterns of ecological vulnerability in TENS, highlighting ecosystem-specific dynamics and migration trends.

## Key findings

- Vulnerability increases from south to north and forms a V-shape from west to east due to topography and climate.
- Wetlands are most vulnerable, while forests are more resilient, with distinct responses to temperature and precipitation.
- About 34.6% of the area shows fluctuating vulnerability trends, with recovery spreading from southwest to north.

## Abstract

Climate change is exerting mounting pressure on terrestrial ecosystems in Northwestern Sichuan (TENS) of China, where rugged topography and variable climate render them particularly vulnerable. Previous studies have subsumed TENS within the broader analyses of the Tibetan Plateau, thereby overlooking its dynamics and heterogeneities. Consequently, the spatiotemporal variations in TENS’ vulnerability remain poorly understood. This study aims to demonstrate how vulnerability varies across spaces and over time, identify ecosystem-specific vulnerabilities, phased interannual dynamics, trend conversions, and migration paths of vulnerability changing trends. Using data on vegetation growth, temperature, and precipitation, we found that vulnerability increases from south to north and forms a V-shape from west to east. Wetlands are the most vulnerable, while forests are more resilient. Over time, vulnerability dipped in cool, wet periods, rose during warmer, drier spells linked to weather events, and fell sharply with wetter conditions and anti-desert efforts. About a third of the area showed back-and-forth trends, with recovering spots spreading southwest to north and worsening ones moving northwest to the center, then north. These insights call for focused protection and tailored approaches for each ecosystem type, helping society build adaptive plans to safeguard biodiversity and support sustainable land use in similar vulnerable regions worldwide.

Climate change intensifies ecosystem vulnerability in mountainous regions, particularly in Northwestern Sichuan’s Terrestrial Ecosystems (TENS), where complex terrain amplifies impacts on biodiversity and carbon dynamics. This study assesses spatiotemporal ecological vulnerability using the IPCC exposure-sensitivity-resilience framework. We applied autoregressive modeling and a 5-year moving window to monthly NDVI, temperature, and precipitation data from 1983 to 2022. Results show vulnerability index (VI) increases latitudinally from south to north, driven by inverse temperature correlations. Longitudinally, VI forms a V-shaped pattern due to topographic and monsoon influences. Wetlands are most vulnerable (VI ≈ 0.48) from precipitation sensitivity, while forests show lowest vulnerability (VI ≈ 0.43) due to high resilience. Temporally, VI fluctuates nonlinearly with decline (1985–1994) under cool-humid conditions, increase (1994–2008) amid warmer-drier El Niño effects, and sharp decline (2008–2011) from La Niña and sand control initiatives. Spatially, 34.6% of areas exhibit decline-increase-decline-increase trends. Centroids of decreasing VI shift southwest-to-north, indicating recovery diffusion. Increasing VI centroids move northwest-central-north. These findings underscore ecosystem-specific adaptive management and conservation policies, especially in northern TENS, to mitigate accelerating climate pressures.