Modelling the contribution of ephemeral wetlands to landscape connectivity

Habitat loss and fragmentation continue to drive declines of amphibian populations. Maintaining connectivity between aquatic and terrestrial habitats and across wetlands is critical to amphibian conservation, particularly in regions where climate change may exacerbate habitat loss. Our objective was to study the impact of climate- and human-driven losses in ephemeral wetlands on functional connectivity for amphibians, using the endangered western tiger salamander (Ambystoma mavortium) in British Columbia, Canada as a case study. Land use data and dispersal characteristics for the western tiger salamander were used to develop a spatially-explicit individual-based model of amphibian movement. The model was configured to explore connectivity under three climate scenarios (a wet, average, and dry year), and a land management scenario in which only known breeding sites are conserved. We used a spatial network analysis to identify key ephemeral wetlands that connect otherwise isolated sub-networks across the landscape and probable movement paths between wetlands and the upland terrestrial habitat. Our results illustrate the importance of conserving ephemeral wetlands as stepping stones. We argue that a landscape approach to wetland conservation, rather than just conserving known breeding sites, is essential for retaining viable amphibian populations in a context of human induced habitat loss and climate change.