Effects of Stream Restoration on Stream Habitat Structure and Biodiversity

Abstract

By Joseph Mangan, Biological Sciences; Colin Barrett, Biological Sciences; Jake Lawrence, Environmental Studies

Advisor: Kenneth Petren

Award: Excellence in Research Communication

Presentation ID: 68

Abstract: Urban streams are an integral part of our modern day ecosystems and health. These streams face a wide variety of problems including frequent large changes in water flow rate, increased chemical pollutants, loss of nutrients, overabundance of other nutrients, and alterations to stream morphology or structure. Restoration efforts aim to reverse these factors to increase the ecological health of urban streams. A common route for restoration is to create riffles, which are areas of large boulders to alter the flow of the stream, and create a wider diversity of habitats for fish and stream macroinvertebrates. Stream restoration success is not often quantified after completion because of the lack of funds. Our question was whether riffles installed nine years ago affect current levels of habitat structure and macroinvertebrate diversity of the restored stream. We tested this hypothesis at Twin Creek Preserve. The Mill Creek Alliance completed a stream restoration of the East Fork of the Mill Creek in 2012. We quantified the substrate of the streambed using standard methods to measure the relative amounts of different sized substrate materials. We compared stream habitat structure to macroinvertebrates collected, using standard methods. We sampled five sites, each with a riffled and non-riffled section, in a paired design. Preliminary results suggest that riffles are generally more rocky and accumulated more small cobble and pebbles, while non-riffle areas had more sand and silt. We test these patterns statistically and compare these data to measures of macroinvertebrate abundance.