The effect of road culverts on the benthic macroinvertebrate community in wadeable lotic ecosystems
Roads and lotic ecosystems intersect as their paths unfold across the landscape. At their intersections lotic ecosystems are often routed underneath a road through a culvert. Road culverts allow the transportation system and lotic ecosystem to coexist, but their presence can introduce physical stress on the local ecology. The purpose of this study was to investigate the effects of road culverts on the benthic macroinvertebrate community. I collected physical habitat, water quality, and benthic macroinvertebrate data from three sample units near the culverted sections of two lotic ecosystems. Sample units were positioned in a longitudinal configuration with a reference sample unit located above the road culvert, a study sample unit below the outlet, and a recovery sample unit further downstream. Non-metric Multi- Dimensional Scaling and Bray-Curtis distance showed an alteration of the benthic macroinvertebrate community at the study sample units when compared to reference conditions. In the study sample units, the benthic macroinvertebrate community was composed of a greater proportion of stressor-tolerant taxa, as assessed by the presence of Ephemeroptera, Plecoptera, and Trichoptera taxa. There was also an alteration of dominant feeding groups in the study sample units. This study shows a fundamental shift of the local lotic ecology below road culverts.
Faculty Mentor: Yangdong Pan