and water quality needs—these are called specialist species. Degraded, unhealthy, aquatic communities usually have just a few species with similar needs in feeding, spawning and shelter that are able to withstand poor water quality—these are called generalist species.
Stream health ratings, called aquatic community indicators, are used to make sense of how fish and macroinvertebrate communities are being affected by any imbalance in the five factors of stream health. Indicators are developed by comparing the fish and macroinvertebrate communities from the sampled stream with samples from the best remaining streams in the area, called reference streams. Reference streams represent what streams in the area should be like. Streams that have diverse communities of specialist species score high, but streams dominated by a few generalist or nonnative species score lower.
How Community Indicators Work
Sampling sites for health assessments are chosen at random from 17,507 miles of permanently flowing, but wadeable (generally less than chest deep) Missouri streams. Landowners are asked permission to access the streams, and sites are sampled twice, once in the summer and once in the fall. On the day of summer sampling, the crew arrives early and collects water samples before the site is disturbed. Then nets are set to block the upstream and downstream ends of the site, and the fish community is sampled by electrofishing and seining. Physical habitat features are measured after fish sampling is done. In the fall, the site is visited once more to sample the macroinvertebrate community with fine-mesh dip nets. During winter, fishes and macroinvertebrates are identified in the lab.
After the values are calculated for each site by comparing them to reference streams, the percentage of miles of stream in good, fair or poor health can be estimated. Sampling is rotated among three large regions (see sidebar) from year to year rather than sampling statewide each year. Samples from the three regions are combined into a statewide assessment about every five years. This way, a random sample of 48 miles of streams becomes a cost-effective way to estimate the health of the many miles of warm-water, wadeable streams in Missouri.
Missouri Streams Status
The RAM program has collected 396,699 fishes of 152 species at 450 locations to assess stream health across Missouri since 2004. The more common species were from the minnow, sucker, sunfish, perch, sculpin, gar and catfish families. Unusual species were from the bowfin, pickerel, pirate-perch, trout