Enhancing habitat and diversity in cattail-dominated shorelines

This project aims to quantify and clarify whether or not hybrid/narrowleaf cattail removal can increase plant diversity and benefit fish communities in nearshore lake ecosystems and how these effects vary regionally in Minnesota. To accomplish this, researchers will experimentally remove sections of cattail in up to 24 lakes across Minnesota’s major ecoregions and measure environmental, vegetation, and fish responses.

Objectives:
1) Understand the little known effects of hybrid/narrowleaf cattail on the ecological dynamics of nearshore lake communities across Minnesota.
2) Determine if small-scale cattail removal can increase plant diversity and heterogeneity and positively affect fish abundance and diversity.
3) Compare the regional effects of cattail removal on nearshore lake ecosystems.

Nearshore aquatic plants are an important source of biodiversity in Minnesota lakes and are critical to fish communities, including important game species (walleye, bass, pike, sunfish, etc.) and forage fishes (minnows, darters, etc.). Fishes using nearshore, vegetated habitat usually prefer a combination of emergent, floating-leaved, and submerged plants for spawning, rearing, refuge, and feeding habitat. In Minnesota, hybrid/narrowleaf cattail (hereafter cattail) have expanded in nearshore lake communities, altering environmental conditions and displacing other plant species. Cattail acts as an “ecosystem engineer” by replacing diverse wetland and aquatic plant communities with a more homogenous environment dominated by tall, dense, difficult-to-penetrate cattail and its litter (dead cattail). As plant diversity is reduced, research suggests that fish diversity may decline, though it is unknown if this occurs in cattail dominated, nearshore lake ecosystems in Minnesota. Despite the negative impacts of dense cattail in many habitats, in some Minnesota lakes (e.g. shallow southern lakes where other species struggle to survive), cattails play crucial roles by providing vegetated habitat and preventing erosion. Thus, the extent to which cattails are detrimental or beneficial to nearshore habitats is likely to vary across the state.

Project manager: Amy Schrank

Funded by: Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources

Project start date: Jan. 2021

Project end date: Dec. 2022

  

Invasive cattail