Assessment of the greenbelt at Michigan Department of Natural Resources boat launches in Cheboygan and Emmet County, Michigan.

Abstract

Riparian zones are critical to the health of aquatic ecosystems. The riparian zone serves as a habitat for diverse plant and animal communities. These zones serve to protect the water from disturbances, control nutrient fluxes, and act as a buffer of vegetation to protect against anthropogenic erosion and pollution. Due to high moisture availability, riparian zones are well-suited for plant growth and nutrient uptake that facilitate a healthy aquatic system (Swanson et al. 1982). The part of the riparian zone referred to as the greenbelt is defined as the shoreline vegetation. Alterations to this vegetative buffer can result in degradation of water quality and the alteration of system ecology. Specifically, the removal of the greenbelt leads to a reduction of shade and allochthonous carbon input, in turn affecting the surrounding aquatic habitat (Naiman & Decamps 1997; Swanson et al. 1982). A healthy greenbelt contains a variety of different herbaceous and woody plant species. This diversity allows for the longterm success of the plant community (Hooper et al. 1997). Invasive species, such as knapweed (Centaurea maculosa) and the planting of turfgrass are a threat to this plant diversity. The presence of emergent vegetation is also important as this vegetation helps to reduce resuspension of sediment from erosion (Dieter 1990) as well as to prevent eutrophication and remove environmental contaminants (Qinghia et al. 2011). Finally, increased greenbelt density offers a large root network to stabilize erosion and buffer pollution (Shields et al. 1995). The deeper and more expansive the greenbelt, the greater these effects. Boat launches serve as one of the major threats to healthy greenbelts. For example, over-maintenance such as mowing and removal of native vegetation near the shoreline is common having potential negative effects on aquatic systems. The presence of a healthy greenbelt helps to drastically reduce the impact of boat launch pollutants.