Amphibian population responses to mitigation: Relative importance of wetland age and design

•Amphibians occupy created wetlands at lower rates than reference wetlands.•Amphibians occupy impacted and reference wetlands at similar rates.•Amphibian occupancy changes over time in created wetlands.•Wetland design is important in mitigation wetland creation. Wetland creation is a common practice to mitigate for the loss of natural wetlands. However, there is still uncertainty about how effectively created wetlands replace habitat provided by natural wetlands. This uncertainty is due in part because post-construction monitoring of biological communities, and vertebrates especially, is rare and typically short-term (