Persistence of amphibian metapopulation occupancy in dynamic wetlandscapes

Context: Occupancy and persistence of amphibian populations in patchy wetland habitats is influenced by landscape heterogeneity, species traits, and hydroclimatic variability. Such information is helpful for understanding the key drivers for reported world-wide declines in amphibian populations over past decades. Objectives: The overarching goal of this study is to investigate how the combination of dynamic patch habitat attributes, as influenced by stochastic hydroclimatic forcing and landscape heterogeneity, and species traits drive long-term spatiotemporal patterns of wetland patch occupancy for amphibian metapopulations. Methods: We used a data-model synthesis approach, integrating a long-term record of monitoring for Rana pipiens with simulations using a dynamic stochastic patch occupancy model, which links parsimonious representations of ecohydrological dynamics. Analyzed data were collected over a 20-yr period at the Cottonwood Lake Study Area in the Prairie Pothole Region in North Dakota, USA. Results: The stability of the mean hydroclimatic forcing during the two decades of amphibian monitoring, and access to dense and diverse wetlands, contributed to persistence of the R. pipiens, despite seasonal spatiotemporal habitat dynamics. The amphibian occupancy pattern simulated for a larger domain surrounding the study area showed that the increased number of wetland habitats dampens variability in patch occupancy, contributing to persistence in the R. pipiens metapopulation. Conclusions: The proposed framework is useful for understanding how spatial heterogeneity in habitat attributes and temporal variability in hydroclimatic forcing could affect metapopulation persistence in dynamic wetlandscapes. This integrated perspective can then be used to guide monitoring and management strategies based on statistically representative areas of heterogeneous and dynamic wetlandscapes.