Ecosystem responses to a whole-reservoir coarse woody habitat addition

Abstract

The addition of coarse woody habitat (CWH) is often used to mitigate the loss of natural structure in aging waterbodies. Ecosystem-scale effects of large-scale CWH additions and their influence on fish productivity have been assessed in oligotrophic, natural lakes, but need to be assessed in more ecosystems. Therefore, we tested the effects of an ecosystem-scale addition of CWH to a eutrophic reservoir using a reference reservoir and data from 4 years before and 4 years after habitat enhancement. Zooplankton and benthic macroinvertebrates did not respond to the addition of CWH, but bluegill (Lepomis macrochirus) reproductive productivity and largemouth bass (Micropterus salmoides) size structure increased. Positive fish responses that contrasted with a lack of fish population-level responses after a similar CWH addition in an oligotrophic, natural lake highlight the importance of assessing the efficacy of CWH addition across diverse ecosystems.