5.10. SR 12-20-2004 - Laserfiche WebLink

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and spread of trees and shrubs, removing accumulated plant litter, warming the soil in spring, and returning nutrients to the soil. With the spread of agriculture and urban development, fires have been suppressed, leading to the spread of shrubs, trees, and exotic plants in prairie and savanna communities, and loss of diversity of native grasses and forbs The activities of large_and small mammals and insects also helped to maintain prairie communities by spreading seeds, burrowing to loosen soils, and pollinating prairie grasses and forbs. In addition to the suppression of fires, prairies and savannas have been degraded by inappropriate levels of grazing, which reduces forb diversity and encourages the dominance of clonal plants (such as golden rod) that are unpalatable to livestock. Other factors responsible for the decline of prairie and savanna communities include, development, ill-advised tree planting, plowing, and too frequent mowing. Less than one percent of the prairie and savanna landscapes that once existed In southeastern Minnesota remain. The goal for managing the remaining remnants should be to maintain or restore as much of the original diversity as possible, through re-establishing or mimicking the processes that helped to maintain these plant communities. Prairie and savanna management should consider the following actions, as appropriate for each site: . Remove exotic species with appropriate methods. Cutting and herbicide treatment are often most appropriate for tree and shrub. species such as black locust, sumac, and buckthorn. Repeated herbicide treatments or biological controls may be needed for other exotic species such as leafy spurge and reed canary grass. . Remedy disturbance problems where possible, by closing trails where erosion is occurring, or reduce/rotate grazing to maintain plant populations. . Use prescribed burns to control cool season grasses and other exotics, remove accumulated plant litter, encourage recruitment of prairie plants from the seed bed, and to maintain the health of the prairie for the long term. Burns may be scheduled annually at first, and reduced to every 3-4 years, depending on amount of litter available to successfully support a burn. Vary the burn regime over the long-term to include both fall and spring burns. Burn only a portion of a prairie at anyone time to conserve insect diversity. City of Elk River, MN - Natural Resouce Inventory Bonestroo Natural Resources, September 2004 57