Testing the effect of wetland spatiotemporal variability on amphibian occurrence across scales

Context Dynamic landscapes vary in both space and time, yielding a critical knowledge gap in landscape ecology: does spatiotemporally-variable habitat within a landscape increase species occurrence and abundance? Wetland landscapes are an excellent model system for addressing this question, as wetlands fluctuate in permanence across both space and time, providing habitat and supporting species with diverse life histories. Objectives We applied environmental DNA (eDNA) to evaluate the effect of variability in wetland permanence on amphibian occurrence and abundance across spatiotemporal scales. Methods We combined predictions of wetland permanence derived from remotely sensed imagery with eDNA to assess the occurrence and abundance of three amphibian species across the U.S. Plains and Prairie Pothole Region. We tested the effect of variability in wetland permanence on amphibian occurrence and abundance across four spatial–temporal scales: (i) wetland; (ii) landscape context; (iii) wetland across time, and (iv) landscape context across time. Results We found strong evidence that spatial and temporal fluctuations in wetland permanence yielded more amphibian species at higher abundances. Furthermore, we found that species’ responses to wetland variability aligned with a priori predictions based on their natural histories. Conclusions Habitat variability across spatial and temporal scales promotes species occurrence and abundance. Maintaining the historical range of spatial and temporal variability within landscapes is essential for retaining species variability, particularly under climate change. Integrating eDNA and spatial modeling approaches provide an effective approach for broad-scale biodiversity assessments and for testing ecological theory.