Test of the River Continuum Concept in Stream Orders of Varying Human Impact

Abstract:

The River Continuum Concept (RCC) describes the relationship between geomorphological characteristics of streams and their changes in dominant energy sources, resulting in varying distributions of macroinvertebrates. Particulate organic matter is refined the further it travels through streams of increasing size, which creates functionally distinct feeding groups of macroinvertebrates: shredders, collectors, filterers, scrapers, and predators. Macroinvertebrates are also commonly used as indicators of stream health due to their range in water pollution tolerance. Anthropogenic influences, such as agricultural runoff and urbanization, are of great concern for the RCC as they are known to pollute waterways and make them uninhabitable for macroinvertebrates. This experimental study aims to test if streams of varying order follow the functional feeding group trends proposed by the RCC when under healthy, low human impact conditions, compared to streams of similar order under unhealthy, high human impact conditions. A total of 6 field study sites were sampled over one month for general health parameters. Specifically, biological and chemical samples were collected from each site through habitat assessments, macroinvertebrate samples, algae samples, and water samples. Ongoing processing of each sample site will ultimately determine the level of impact at and will be further supported based on the diversity and abundance of pollution intolerant macroinvertebrates.