What's a Healthy Stream?

Beep, Beep, Beep. Four biologists wielding dip nets and wearing funny looking backpacks stare intently into the waters of a small creek. Suddenly, silver flashes as small fishes are drawn toward the scientists by high voltage electricity. Four nets dart into the water in unison and come back to the surface with several species of fishes flipping inside. Great! The equipment is working and fish community sampling has started. It’s a typical scene from a day’s work with the Resource Assessment and Monitoring Program (RAM) field team.

The RAM Program

The goal of the RAM Program is to assess and monitor long-term trends in the health of Missouri’s warm-water streams. There are five factors that affect stream health, and each of these must be balanced for a stream to be healthy:

• Water quality,
• Stream flow,
• Physical habitat (channel shape, rock/soil makeup and vegetation in and around a stream),
• Stream system connectivity (how the watershed interacts with the surface and groundwater), and
• Biotic interactions (the way different species interact).

The RAM Program samples water quality and habitat and compares the information to healthy sites to determine benchmarks for restoration efforts. However, the program’s focus is on the living organisms in streams because their well-being is the ultimate goal of our stream conservation efforts. If we see improvement in animal and plant life, then we know our efforts are effective.

Fish and macroinvertebrates (animals that do not have a backbone, but are large enough to be seen with the naked eye, including worms, mollusks, crayfishes, mites and many kinds of insects) are affected differently by water quality and poor habitat, so it is important to sample a variety of organisms. Traumatic events such as toxic waste or sewage spills, or rain runoff contaminated with herbicides or pesticides, usually kill most fish and macroinvertebrates in an area. Long-term water flow changes and major habitat loss can also destroy these populations.

In a minor, or temporary disturbance, such as low-level chemical pollution, excessive sedimentation or nutrients, or increased flooding, fishes can swim away from the area and return when conditions improve. However, most macroinvertebrates cannot get away. When a community of macroinvertebrates is wiped out, recolonization may not occur until much later.

Healthy aquatic communities have an appropriate balance of species that use stream habitat efficiently. In these communities, there is a wide variety of species, and each tends to have specialized feeding, spawning, shelter 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 perch, trout and lamprey families. Some of these collections represent new locations for species in the state, some represent collections of species from river basins where they had not been recorded in more than 50 years, and others are collections of rare species. The vast majority of species were where they were expected to be.

Fifty-seven percent of fish communities sampled so far are in good health, being similar to reference stream communities. Forty-two percent are degraded to some degree, and just 1 percent are highly degraded. In general, most streams sampled in the Ozarks are in good health, but most streams in the Prairie portion of Missouri are somewhat degraded. The few highly degraded fish communities are associated with urban areas.

Macroinvertebrate community collections include 363,510 individuals of 568 different taxa. (The word “taxa” is used, instead of species, because many can only be identified to the level of family or genus. Taxa is a general term for the different levels of classification.) Six insect species have been collected that were not previously known from Missouri, including one that is a nonnative rice crop pest. Two species of rare snails have been found to inhabit watersheds where they were previously not known to occur.

Macroinvertebrate community health was similar to fish communities with 61 percent good, 20 percent degraded, and 19 percent highly degraded. Good, degraded and highly degraded macroinvertebrate communities are distributed evenly across the state without the distinct regional differences apparent in fish communities.

Information in Action

RAM Program data provide conservation benefits beyond a cost-effective estimate of the health of warm-water, wadeable streams statewide. The Conservation Department uses the information to make better decisions for conserving Missouri’s aquatic resources.

Aquatic community and aquatic species distribution information is used to prioritize and focus conservation efforts in watersheds across Missouri. Species distribution information is used to prioritize conservation efforts for sensitive or threatened species as well. Locations of sensitive species are used to assess potential impacts of development activities like power-line extension, bridge construction and impoundment construction. In the future, the Conservation Department will also be able to make better decisions for conserving Missouri’s aquatic resources based on the information we are collecting now.

Our partners also make use of RAM Program data. The RAM Program is a partnership with the Department of Natural Resources, and they use the data in their watershed planning, protection and reporting efforts. University students and professors use the information about aquatic communities to advance our understanding of connections between Missouri’s land and water resources. Missouri has contributed RAM Program data to federal agencies and national conservation organizations to help them assess the health of the nation’s waters and prioritize their national aquatic conservation efforts.

The Resource Assessment and Monitoring Program’s most important partners are Missouri’s citizens. Citizen concern about Missouri’s aquatic resources provides the reason and support for the RAM Program. The vast majority of wadeable streams in Missouri flow through private lands, and we thank the many landowners who have granted us permission to access their streams. Without access, we would never be able to do our stream health checkups!

Animal Life Regions

The Ozark Faunal Region (faunal refers to animal life) occupies the Ozarks of Missouri, an area found mostly south of the Missouri River. The Ozarks is a hilly area of thin, stony soil over granite, sandstone or limestone bedrock. Much of the area is forested. Ozark streams are generally clear, cool and have gravel bottoms. Submerged vegetation is often found in backwaters and side channels. Sixty-seven species of fishes have their range centered in the Ozark Faunal Region, and 20 of these species are found nowhere else in the world. Suckers, sunfishes, minnows and darters are the dominant groups of fishes found in Ozark streams.

The Prairie Faunal Region is found north and west of the Ozark Faunal Region and lies mostly north of the Missouri River. The Prairie is a flat or gently rolling area of deep soils. Most of the region was once prairie, but much is now row crop agriculture. Prairie streams tend to be turbid and have sand or silt bottoms, but many Prairie streams in west-central and northeast Missouri have gravel bottoms. Eighteen fish species have their range centered in the Prairie. Carpsuckers, suckers and minnows are the dominant groups of fishes in Prairie streams.

The Lowland Faunal Region lies in southeast Missouri, south of the Ozarks. The lowlands are a flat alluvial plain once covered by swamps and forests. The Lowlands have been extensively ditched for drainage and converted to row crop agriculture. Most of the aquatic habitat left in the Lowlands is ditches rather than streams. Ditches generally have soft bottoms, lots of vegetation, and may be turbid or clear. Twenty-three Missouri fish species have their ranges centered in the Lowlands. Minnow and darters are common in the Lowlands, but no groups of fishes really dominate lowland communities.