• habitat;
  • macroalgae;
  • macrophytes;
  • mortality;
  • streams;
  • tethering

Abstract  Predation risk can impact population dynamics and ecosystem structure. Changes in key habitats, such as shifts between types of submersed aquatic vegetation, may affect predation risks experienced by certain organisms that use vegetation as a predation refuge. Relative predation risks experienced by Lucania parva (Baird & Girard) were assessed among three habitats in a Florida coastal stream using tethering experiments. Relative predation risks were highest in bare substrate, intermediate in a rooted macrophyte, Vallisneria americana Michx, and lowest in filamentous macroalgae. These results suggest that L. parva predation risk may decline following shifts from macrophytes to filamentous macroalgae, potentially leading to increased L. parva population size. These findings counter a widely held perception that such habitat shifts yield exclusively negative faunal effects, and are useful for assessing implications of habitat change and guiding restoration activities.