Work

Nonlinear thresholds in agricultural landscape fragmentation: A GWRF-SHAP diagnostic framework for differentiated rural land management

Year: 2026

Type: article

Abstract: Agricultural landscape fragmentation (ALF) is a critical ecological constraint on rural sustainability, but conventional linear models fail to capture the nonlinear thresholds governing its response to rural development. This study proposes a GWRF-SHAP diagnostic framework to identify spatially explicit nonlinear driver-response relationships and operational thresholds along rurality gradients. Using Hunan Province as the study area, we classified six agricultural landscape types and stratified five rurality levels ranging from extreme rural to extreme non-rural using a three-dimensional rurality index. The GWRF model quantified local nonlinear associations while SHAP values interpreted factor contributions and threshold inflection points. Results demonstrated semi-natural production landscapes exhibit a unimodal fragmentation pattern peaking in transitional rurality zones, whereas constructed landscapes consistently maintain a relatively stable level of fragmentation. The proportion of forest land (Pfl), nighttime light index (NTL), topographic wetness index (TWI), plot distance to town center (Pdtc), and plot distance to road (Pdr) emerged as the dominant drivers of spatial variation in ALF. Together, these factors explained the observed fragmentation patterns and exhibited pronounced nonlinear threshold effects. Specifically, Pfl exhibited threshold values ranging from 0.48 to 0.68. Below this range, scattered forest patches embedded within farmland intensified edge fragmentation, whereas above the threshold, forests became the dominant landscape matrix and farmland was transformed into embedded patches, resulting in reduced fragmentation of production landscapes but increased fragmentation of natural landscapes. NTL showed threshold values between 0.45 and 1.02, reflecting distinct fragmentation processes under different stages of urbanization. Thresholds associated with Pdtc (2.49-6.28km) further distinguished human-dominated from terrain-dominated fragmentation processes in natural landscapes and separated compact urban cores from dispersed peripheral construction landscapes. These findings demonstrate that agricultural landscape fragmentation is governed by nonlinear threshold responses to rural development and provide a scientific basis for differentiated agricultural landscape governance and sustainable rural planning.

Source: Ecological Indicators

DOI: 10.1016/j.ecolind.2026.115483