An Assessment of Urban Lakeshore Restorations in Minnesota

Abstract

As our understanding of the importance of natural lakeshores in providing wildlife habitat and water quality protection has grown, so too has interest in restoring degraded lakeshore. Advances in lakeshore restoration practice have been hindered by a lack of field-based evaluations to guide decisionmaking and by gaps in our knowledge of how to revegetate littoral and shoreline areas. To understand how the choices practitioners are making affect restoration outcomes, we surveyed 22 lakeshore restoration projects in the Minneapolis/St. Paul, Minnesota (USA), metropolitan area that ranged in age from 1 to 6 years. We conducted comprehensive, floristic surveys of the vegetation found on each site and investigated site maintenance practices. We found that 29% of species planted in the upland zone of the lakeshore reliably established; long-term protection of the site from adjacent land uses improved the likelihood that planted vegetation would endure. The greatest revegetation failure occurred along the shoreline; 44% of species planted did not establish at this land-water transitional zone. Approximately 30% of the aquatic zone restorations did not contain any planted vegetation, although ten aquatic plant species were found to establish dependably on at least some of the remaining sites. In aquatic and transition zones, vegetative composition was most clearly related to exposure to wave activity. This survey suggests two restoration practices that should be improved to increase the likelihood of lakeshore restoration success: 1) choosing plants so they match the prevailing light and flooding conditions within sites; and 2) providing both upland and aquatic protection.