Quantifying the effects of projected urban growth on connectivity among wetlands in the Great Plains (USA)

Abstract

Urban wetlands often have prolonged hydroperiods relative to non-urban ones, so they may play an outsized, positive role for wildlife. Ecological studies of urban wetlands have typically focused on large metropolitan areas, but non-traditional urbanizing areas such as the towns of the Great Plains of North America are projected to experience land-use and climate changes that will alter connectivity among the freshwater wetlands along a continental-scale migratory wildlife corridor. We used seven graph theory metrics to quantify connectivity among 89,798 of these wetlands under landscape-change forecasts from two models built for three climate-change and development scenarios, projected to the year 2050. We compared outcomes from models that differed in focal variable (impervious surface or developed land use). Overall, models with impervious surface projections resulted in the most wetlands affected, whereas models featuring developed land use projections resulted in the largest spatial distribution of effect. There were differences in how many and which wetlands were forecast to become urbanized by model and scenario, resulting in different wetland network topologies and differences in the connectivity roles of individual wetlands. A consensus network was therefore developed based on the wetlands that were projected to increase in impervious surface and exist within developed land use by 2050. These 126 wetlands can be prioritized for urban ecological studies or management because they are highly likely to be affected regardless of model or scenario. Lastly, our study highlights the utility of considering a range of developmental futures when planning urban wetland management in non-traditional urbanizing areas.