Trade-Offs and Synergies of Ecosystem Services in a Karst Peak Cluster Depression: Spatiotemporal Patterns and Driving Factors

Abstract

As geologically unique landforms characterized by extreme micro-topographic heterogeneity (peak-depression coupling) and intense human-land contradictions, karst peak-cluster depressions represent globally significant yet ecologically fragile landscapes fundamentally distinct from non-karst ecosystems in their water-soil-nutrient coupling processes. Understanding ecosystem service (ES) relationships in these geomorphologically complex regions is critical for optimizing ecological restoration. This study analyzed spatiotemporal dynamics and drivers of five ES (water yield, sediment retention, nitrogen export, carbon sequestration, and habitat quality) in a representative karst peak-cluster depression from 2005 to 2020. Results revealed pronounced temporal fluctuations in water yield and soil retention compared to stable carbon sequestration and habitat quality, alongside marked spatial heterogeneity governed by topography and land use. Significant trade-offs dominated between habitat quality and nitrogen export (56.14% pixel ratio)/sediment retention (54.02%), water yield and sediment retention (53.94%), and carbon sequestration and nitrogen export (53.09%), primarily in southern high-altitude and northern lowland regions. Conversely, synergies prevailed between sediment retention and nitrogen export (61.29%) and habitat quality and carbon sequestration (55.93%). Geodetector analysis identified annual precipitation, evaporation, and slope as primary drivers, with two-factor interactions (particularly precipitation-evaporation) exhibiting substantially stronger explanatory power (q-values up to 0.857) than individual factors. These findings highlight that ES relationships in karst depressions are shaped by coupled climatic-topographic controls rather than single determinants. We advocate spatially differentiated zoning strategies—including hydrogeological nitrogen interception, slope-threshold land-use planning, and climate-adaptive vegetation configuration—to balance inherent trade-offs between water yield and soil/carbon retention, thereby supporting sustainable development in vulnerable karst regions.