Contributions of Landscape Structure and Environmental Gradients to Habitat Quality in Forest-Dominated Heterogeneous Landscapes
Abstract
Habitat quality reflects the combined influence of landscape structure and environmental conditions, yet their relative contributions remain insufficiently understood in heterogeneous forest landscapes. We evaluated the relative contributions of landscape composition, configuration, and environmental gradients across 519 landscape units by integrating InVEST habitat-quality estimates, landscape metrics, and environmental variables within a hierarchical spatial beta generalized additive modelling framework. Landscape composition accounted for most of the variation in habitat quality, while landscape configuration, nonlinear environmental responses, and spatial structure provided additional explanatory information. Spatially blocked cross-validation indicated high predictive performance (R² = 0.962, RMSE = 0.040, MAE = 0.023). Forest cover had the strongest positive composition effect, whereas artificial surfaces were negatively associated with habitat quality. Landscape configuration provided additional explanatory information after accounting for landscape composition, although its multivariate relationship cautions against interpreting individual fragmentation metrics in isolation. Among environmental predictors, NDVI showed the strongest response and a distinctly nonlinear relationship with habitat quality. Habitat- quality patterns were highly stable under alternative InVEST half-saturation constants and ±25% changes in threat-impact distances. These results showed that, even where landscape composition accounted for most habitat-quality variation, landscape configuration and nonlinear environmental gradients provided additional information after accounting for spatial dependence and parameter uncertainty. These findings clarified the relative contributions of landscape composition, spatial configuration, and environmental heterogeneity to modelled habitat-quality patterns in forest-dominated heterogeneous landscapes.