Relationships between plant community species richness, remnant area, and invasive leafy spurge cover in southeastern Minnesota bluff prairie habitats

摘要

Bluff prairies are extreme habitats centered on southwestern facing bluffs along major rivers in the driftless area of the upper Midwest. Characterized by steep slopes, thin soils, and intense exposure to sun and wind, bluff prairies harbor a much warmer, drier microclimate than is found elsewhere in the region. Such harsh conditions help preserve bluff prairie habitat for unique communities of plants and animals. However, like many prairie habitats, bluff prairies are shrinking in size and experiencing fragmentation, resulting in smaller prairie remnants rather than larger, intact prairies. This shrinking and fragmentation is likely a consequence of non-prairie and/or non-native plants encroaching from the edges. One prominent introduced invasive species, leafy spurge (Euphorbia esula), has the ability to spread quickly and displace native plants. During the summer of 2012, the native flowering plant communities (excluding grasses, rushes, and sedges), prairie remnant sizes, and invasive leafy spurge presence and cover were surveyed in 10 bluff prairies in southeastern Minnesota. It was found that native flowering plant species richness is positively correlated with prairie remnant area and negatively correlated with percent leafy spurge cover. The current study provides insight into the current habitat quality of southeastern Minnesota bluff prairies and enables future studies to monitor changes in prairie size and community composition over time.