Spatiotemporal distribution and driving forces of ecological fragility in Chengde's transitional region from plateau to plain, China

Abstract

Assessing the spatial distribution and drivers of ecological vulnerability in the Chengde Plateau-to-Plains Transition Area is essential for effective ecological management and conservation strategies in this ecologically sensitive region. This study investigated the factors influencing ecological fragility across three counties: Longhua County, Fengning Manchu Autonomous County, and Weichang Manchu and Mongolian Autonomous County. Using the sensitivity-resilience-pressure (SRP) model as the analytical framework, we developed a comprehensive ecological fragility assessment system incorporating ten key indicators. The Ecological Fragility Index (EVI) for the period 2000-2020 was calculated using spatial principal component analysis, with results classified into five fragility levels and visualized spatially through ArcGIS software. Additionally, the Comprehensive Ecological Fragility Index (CEVI) was employed to quantify overall ecological fragility patterns. The geographic detector model was utilized to examine how individual factors and their interactions influenced the spatial distribution of ecological fragility. The results indicated that severe and moderate ecological fragility predominated throughout the study region from 2000 to 2020. Areas characterized by mild and slight fragility were primarily distributed in northern Weichang Manchu and Mongolian Autonomous County, while extremely and severely vulnerable areas were concentrated in southern Fengning Manchu Autonomous County and southern Longhua County. Land use analysis revealed that forestland exhibited predominantly low ecological fragility, whereas construction land demonstrated extremely high fragility levels. The spatial variation of ecological fragility in this region was primarily driven by mean annual temperature, altitude, and soil erosion severity. Notably, factor interactions exerted greater influence on fragility patterns than individual factors alone, providing valuable insights for environmental restoration and management strategies in plateau-to-plain transition zones.

Keywords: Driving mechanism; Ecological vulnerability; Geodetector model; Principal component analysis; SRP model; Spatiotemporal distribution.