Are we purveyors of wetland homogeneity? A model of degradation and restoration to improve wetland mitigation performance

The national goal of no net loss of wetland functions is not being met due to a variety of suboptimal policy and operational decisions. Based on data used to develop a conceptual model of wetland degradation and restoration, we address what can be done operationally to improve the prospects for replacing both the area and functions of mitigated wetlands. We use measures of hydrologic, soil, and biodiversity characteristics from reference standard sites, degraded wetlands, and created wetlands to support our premise. These data suggest that wetland diversity and variability often become more homogeneous when subjected to a set of stressors. The degradation process reduces the original heterogeneity of natural wetlands. In addition, soil characteristics and composition of biological communities of creation projects may mirror those of degraded wetlands. We recommend that scientists and managers use identical sampling protocols to collect data from reference wetlands that can be used to assess the condition of degraded wetlands and to improve the design and performance of mitigation projects.