Influence of adding small instream wood on fishes and hydraulic conditions in channelized agricultural headwater streams in central Ohio

Authors: GATES, ERIC - The Ohio State University; Smiley, Peter - Rocky

Submitted to: Fishes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2024
Publication Date: 7/27/2024
Citation: Gates, E., Smiley, P.C. 2024. Influence of adding small instream wood on fishes and hydraulic conditions in channelized agricultural headwater streams in central Ohio. Fishes. 9. Article 296. https://doi.org/10.3390/fishes9080296.
DOI: https://doi.org/10.3390/fishes9080296

Interpretive Summary: Instream wood, consisting of fallen branches and trees, is a critical habitat feature for fishes and other stream animals. Channelized agricultural headwater streams (drainage ditches) typically lack instream wood because it is likely to reduce drainage capacity. We evaluated the influence of adding small (less than 4 inches in diameter and less than 3 feet in length) instream wood on fishes and hydrology within agricultural headwater streams in central Ohio. Adding small instream wood did not benefit fish communities or hydrology. Our results highlight the importance of large instream wood as habitat for fishes in degraded agricultural headwater streams. This information can be used by state, federal, and private agencies responsible for managing agricultural watersheds and restoring streams. This information can also assist with climate change adaptation as it highlights the importance of large instream wood addition and the potential for this practice to assist with mitigating the effects of agriculture in the face of climate change.

Technical Abstract: Instream wood is important for fish in headwater streams because it promotes the development of pool habitat and provides cover from predators during periods of low flow. The benefits of large instream wood have been extensively documented, but little is known about the influence of small instream wood on fish communities and hydrology in channelized agricultural headwater streams in the Midwestern United States. Understanding the influence of small instream wood will provide information that can guide the development of management strategies for fishes within these degraded streams. We conducted a before-after-control-impact experiment in the summer of 2011 where we sampled fishes and hydrology before and after the addition of small instream wood to pools within channelized agricultural headwater streams in central Ohio. The amount of instream wood was greater in the treatment pools than the control pools after the small instream wood addition. No differences in fish community structure or hydrology occurred between control and treatment pools before or after the addition of small instream wood. Our results indicate that adding large instream wood might be needed to benefit fishes and that it is possible to add instream wood to degraded agricultural headwater streams without impacting drainage capacity.