USGS ecologists studied two post-mining restoration projects implemented on the same headwater stream to determine the ecological effects of two different restoration strategies and to elucidate potential mechanisms contributing to different ecological outcomes. One project simulated natural stream conditions by creating a complex channel with high habitat heterogeneity. A second project used a sand filter to reduce contaminants and sediment along a straight, armored channel, resulting in comparatively low habitat heterogeneity. Within two years, stream habitat parameters and community composition within the high heterogeneity reach were similar to those of reference reaches. In contrast, the low heterogeneity reach contained poor habitat conditions for tailed frog larvae, most macroinvertebrates, and fish, even 7–8 years after project completion. Stream communities can respond quickly to restoration of physical characteristics and increased heterogeneity, but “details matter” because interactions between habitats and species can be complex, unpredictable, and can influence restoration effectiveness. 

Arkle, R.S., Pilliod, D.S., 2021, Stream Restoration is Influenced by Details of Engineered Habitats at a Headwater Mine Site: Diversity, v. 13, no. 2, p. 48, https://doi.org/10.3390/d13020048