Trends in Methods for Assessing Freshwater Habitats

Habitat assessment is an important form of management for species conservation, mitigation planning, environmental regulation, and impact assessment. As part of an American Fisheries Society and U.S. Fish and Wildlife Service project, we surveyed state, provincial, federal, and private organizations to obtain documentation about methods being used to assess aquatic habitats in the inland waters of North America. We then used this information to characterize attributes of established methods. We found that most methods target habitats associated with flowing waters, but a significant number of methods deal exclusively with lakes and reservoirs. The survey showed that the dominant purpose for having an established method was to standardize measurements and data collection techniques. Methods for stream habitats included a wide array of measurements emphasizing channel structure, water movement, substrate, cover, and riparian zones. The lentic habitat methods emphasized the littoral zone, shallow‐water physical structure, and riparian areas. Data analyses were primarily numerical summaries and calculations of descriptive statistics usually presented using databases. Assessment methods focused on aquatic environmental quality—more so than fishery resource evaluations—although methods associated with fishery investigations remain prominent. The overall characteristics of currently used methods suggest that many or most agencies are actively advancing their practices, and rapid change can be expected in most methods.