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Urban buried streams: Abrupt transitions in habitat and biodiversity
Citation:
Hintz, C., M. Booth, Tamara Newcomer Johnson, K. Fritz, AND I. Buffam. Urban buried streams: Abrupt transitions in habitat and biodiversity. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 819:153050, (2022). https://doi.org/10.1016/j.scitotenv.2022.153050
Impact/Purpose:
The burial of streams in culverts is a common practice in densely populated urban areas. In this study, we address the ecological impact of stream burial in two urban streams that include long (>100 m) culvert reaches in Cincinnati, OH. While our work focuses on urban streams, this work is of general interest because this work demonstrates how different stream ecosystem parameters transition in response to abrupt changes within the stream channel and adds to the body of work regarding how streams respond to changes in surrounding land use. This is the first study to longitudinally characterize the impacts of culverts, and the study has management implications which could inform current stream monitoring and future stream restoration work.
Description:
Stream burial, the rerouting of streams into underground culverts, is common in industrialized and densely populated urban areas. While stream burial is common in urban environments, direct characterization of the within-culvert environment is rare and it is unclear if buried reaches reflect neighboring open reaches regarding habitat, biota, and water chemistry. Additionally, for a buried stream, the entrance and exit of the culvert are abrupt habitat transitions within the stream channel, and it is unknown if these transitions lead to similarly abrupt responses in biotic and abiotic characteristics or if responses are gradual. Quantifying the within-culvert environment and transitions upon entering/exiting the culvert has rarely been done but can help inform management practices regarding how these systems are impacted and establish a baseline for evaluating daylighting or stream restoration projects. To understand how culverts affect longitudinal biotic and abiotic characteristics of urban streams, we evaluated longitudinal patterns of physical habitat characteristics, stream water physiochemistry, periphyton biomass, and macroinvertebrate density and diversity in two urban streams that included long (>100 m) culvert reaches. Abrupt transitions in a suite of abiotic and biotic variables were observed at the entrances and exits of the culverts whereas some variables showed no response to the culvert presence. Periphyton biomass and macroinvertebrate density were reduced by 98% and 92%, respectively, by culverts in the two streams. Within the culverts, we observed greater water depths (average of 10 cm outside vs 26 cm within the culvert), finer benthic substrate, and diversity of macroinvertebrates was reduced by 50%. Nutrient concentrations, in contrast, showed no response to the presence of a culvert. Within 60-90 m downstream of the culvert exits, most of the measured parameters returned to levels similar to those observed upstream of the culvert, suggesting that the ecosystem impacts of urban culverts, though dramatic, may be spatially constrained.
URLs/Downloads:
DOI: Urban buried streams: Abrupt transitions in habitat and biodiversity
https://pubmed.ncbi.nlm.nih.gov/35038529/