Human-created surface waters facilitate habitat suitability and connectivity for river otters (Lontra canadensis) in Texas

I evaluated whether the spatial distribution of human-created surface waters is associated with higher predicted habitat suitability and lower modeled resistance between watersheds for river otters (Lontra canadensis) in Texas, and quantified the marginal contribution of anthropogenic water features using a paired-scenario sensitivity analysis. River otters are known to use reservoirs, canals, and other human-modified water bodies, but the extent to which these features influence habitat suitability and connectivity at broad spatial scales remains unclear. Two prediction surfaces were generated from the fitted model: contemporary hydrology and a “natural-only” sensitivity scenario in which anthropogenic-water density was set to zero. Predicted suitable habitat increased from 104,747.5 km² under the natural-only scenario to 418,219.7 km² under contemporary hydrology (Δ = 313,472.1 km²; +299.3%), with gains concentrated across central Texas basins including the middle Brazos, upper Colorado, and San Antonio–Guadalupe. Anthropogenic-water density contributed non-redundant structure in the fitted model (Σ|β| = 5.20) relative to natural-water density (Σ|β| = 1.14), and resistance surfaces derived from contemporary predictions produced substantially lower inter-basin movement costs than the natural-only scenario, yielding broad low-resistance pathways across central Texas. These results indicate that human-created surface waters are associated with large increases in predicted habitat suitability and basin-to-basin permeability for L. canadensis, and the scenario contrasts identify basins and candidate corridors for targeted verification surveys and telemetry to test whether predicted pathways correspond to realized dispersal and recolonization dynamics.