Connecting the dots: regional assessment of landscape connectivity in amphibian communities in Central Spain

Abstract Context Habitat fragmentation and loss are major contributing factors in the global biodiversity crisis. This is especially concerning for low-dispersing organisms in anthropized areas, where artificial elements separating suitable habitat patches impede landscape connectivity, compromising long-term population viability. Robust comparative assessments of regional population connectivity can drive evidence-based conservation measures for biological communities, but require comprehensive field surveys to provide reliable inferences. Objectives We focused on amphibians, low-dispersing taxa with declining populations worldwide, primarily due to habitat loss and fragmentation. We assessed patterns of landscape connectivity in 16 native amphibian species grouped in four communities in the most populated region in Spain (Community of Madrid). Methods We surveyed 2303 water bodies across the entire region to characterize amphibian communities and developed whole-range distribution models relating species presence data and remote sensing covariates. Then, we projected predicted global distributions in the study region with high resolution and used landscape resistance models and clustering analyses to reconstruct connectivity networks of all species and identify potential ecological corridors and barriers contributing to population fragmentation. Results We recorded 18–866 breeding sites per species, and generated models with high statistical performance. Connectivity varied spatially and across communities and species, highlighting barriers to dispersal comprising natural (mountains, rivers) and artificial features (water reservoirs, dammed rivers, urban areas), and also ecological corridors, including peri-urban green areas, river valleys, moorlands and mountain passes. Conclusions Our work presents a novel methodological framework leveraging data from local (field surveys) and global (online databases) scales across multiple species, enabling robust assessment of community-level connectivity patterns to inform conservation planning.