Agenda - Parks and Recreation Commission - 04/08/2021

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threatened species should be deemed sensitive. Conservation guides for these species detail just how critical habitat fragments are for these species: "The survival of the regal fritillary in Minnesota probably depends upon concentrations of remnants within the dispersal capabilities of adults that can collectively support larger populations"13 and "conservation of the rusty patched bumble bee will ultimately depend in part on connecting patches of high quality habitat."' Rivers' Bend Park's native prairie remnants offer the regal fritillary the only habitat it is able to survive in within Minnesota13'14 and is already listed as within the primary dispersal zone of the rusty patched bumble bee. Additionally, all three habitat features necessary for rusty patched bumble bees are present within Rivers' Bend Park: the duff layer of the riparian forest is key overwintering habitat, native bunch grasses in the woodlands and prairie as well as abandoned rodent tunnels in the prairie are potential nesting areas, and the abundant forbs of the prairie and spring ephemerals of the woodlands offer necessary floral resources.' Structures and Improvements In an effort to contribute to eastern bluebird (Sialia sialis) trails, bluebird houses were erected throughout the park to act as potential nesting sites within a habitat corridor. Encroaching shrub and understory growth has crowded out some of these houses. A large bat house is located on the west side of the park, near the shore of the oxbow lake. The site has seen a lot of human traffic with a well-worn footpath going underneath the house from the paved path to the oxbow lake shore and no apparent bat activity. Erosion Erosion has continued to affect the shore in front of the swing river outlook located on the east side of the park due to use for fishing. The dock on the east side of the park has also become uneven due to the river current causing erosion of the sediment underneath, creating a potential tripping hazard at the entrance to the dock. Boundary Issues Potential boundary issues for the site include noise pollution from the bordering roads, chemical pollution from salts used on roads and paths, and air pollution from passing traffic. A line of mature spruces has been planted along St. Francis and Bunker Lake Boulevards to provide some cover for noise pollution and aesthetic appeal within the park. Some deciduous trees are beginning to encroach on the area where the spruces are growing. MANAGEMENT RECOMMENDATIONS The following management recommendations are intended to offer the Ramsey Parks and Recreation Board potential strategies to address the park's primary areas of concern while accomplishing the desired management outcomes: Invasive Species Control In order to successfully increase native species biodiversity and improve ecological health of the native prairie and floodplain forest, all invasives present must be monitored to determine whether they reach a density that threatens the natural dynamics of the site. Due to the level of prominence of the woody invasive species, buckthorn, Tartarian honeysuckle, and Siberian elm must be eradicated. This process involves several elements: treatment of invasive species with herbicide, removal of undesirable woody biomass, and supplemental plantings if necessary. The 9