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

Mowry, Katherine

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

Persistent URL

https://dspace.allegheny.edu/handle/10456/56781

Author(s)

Mowry, Katherine

Date Issued

April 3, 2023

Abstract

The River Continuum Concept (RCC) describes the relationship between geomorphological characteristics of streams and their changes in dominant energy sources, resulting in varying macroinvertebrate distribution. However, these relationships only account for streams under healthy conditions and might not predict how streams can be disrupted by anthropogenic influences, like agricultural runoff and urbanization. This experimental study aims to test if streams of varying order more closely follow the functional feeding group trends proposed by the RCC when under healthy, low human impact conditions, as compared to streams of similar order under unhealthy, high human impact conditions. Sample sites were located at first, fourth, and sixth order streams, each paired with a low and high impact site, creating a total of six field study sites within the French Creek Watershed in Crawford County, PA. At each site, data was collected for macroinvertebrate samples, chlorophyll a biomass, various water parameters, nitrogen concentration, and phosphate concentration. Statistical analysis showed a mix of support and contradiction to the proposed hypothesis. The first order pair showed no significant deviations from the RCC despite some stream health differences. The fourth order pair best supported the hypothesis with clear stream health differences affecting RCC adherence. The sixth order stream pair contradicted the hypothesis by having stream health differences which should have negatively impacted the high impact site, but ultimately resulted in that site better adhering to the RCC than the low impact site. These results indicate that human impact does have the potential to cause streams of varying order to deviate from projected trends in the RCC as a result of stream health degradation. However, the severity of deviation and the consistency of impact across stream orders varied between measurements. Further research is needed to solidify trends found and identify pollutants which are degrading these streams.

Major

Biology

Environmental Science

First Reader(s)

Venesky, Matthew D.