PRIORITIZING STREAMS FOR PROTECTION AND RESTORATION USING A HOUSE-NEIGHBORHOOD FRAMEWORK: A CASE STUDY IN COOK COUNTY, ILLINOIS

Restoration success can be limited by the availability of nearby dispersal sources. Recognizing this, Merovich et al. (2013) proposed a house-neighborhood approach to freshwater stream conservation: For restoration, they prioritized poor-quality stream reaches (“houses”) in good-quality watersheds (“neighborhoods”), and for protection, good-quality stream reaches in poor-quality watersheds. We modified this approach for streams in highly urbanized Cook County, Illinois. Using random forests regression with GIS-derived landscape explanatory variables, we predicted fish species richness (R2 = 0.30), mussel species richness (R2 = 0.49), and a fish-based index of biotic integrity (R2 = 0.40) for all inland stream reaches in the county. We then developed and applied three metrics to rank reaches according to their potential for (1) biodiversity protection, (2) dispersal source protection, and (3) restoration. The latter two metrics acknowledge the conservation importance of distance-dependent dispersal along dendritic stream networks by considering both the quality of a stream reach per se and the quality of its network neighbors. Ranking stream reaches with these metrics can help to identify sites at which conservation actions are likely to deliver the greatest results.