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. 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.
Progress
Environmental, fish, and plant sampling was completed in August of 2021. Researchers sampled paired sites at nine lakes: Rainy, Kabetogama, First Crow, Second Crow, Long, Belle Taine, Big Marine, Maud, and Coon lakes. In addition to finishing field sampling as scheduled, the team completed cattail removal at all planned sites in each lake. Analysis of the first summer of data is ongoing and the team is well prepared to return to the sites in summer 2022 to collect our post-cattail removal data. Cattails were removed at all of our study sites. Researchers were able to overcome the difficulty of site selection by persistence and the research team found suitable sampling sites despite drought conditions.
Phase I
We will 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, information that is currently unknown. To accomplish this, we will experimentally remove sections of cattail in up to 24 lakes across Minnesota’s major ecoregions and measure environmental, vegetation, and fish responses. 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. 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.
Objectives:
- Understand the little known effects of hybrid/narrowleaf cattail on the ecological dynamics of nearshore lake communities across Minnesota.
- Determine if small-scale cattail removal can increase plant diversity and heterogeneity and positively affect fish abundance and diversity.
- Compare the regional effects of cattail removal on nearshore lake ecosystems.