Immediate and long-term effects of invasive plant species on soil characteristics

Invasive plant species may alter soil characteristics or interact with the soil microbial community resulting in a competitive advantage. Our objectives were to determine: i) if invasive plant species alter soil properties; and ii) the long-term effects of invasive plant species on soil properties and subsequent implications on ecological restoration efforts. We focused on Lespedeza cuneata, a plant that may be allelopathic. Soil samples were collected from four locations in Central Missouri, USA: an old-field with abundant L. cuneata, two reconstructed sites, and a remnant prairie that has never been plowed. Soil health indictors were used to characterize soil properties at these sites. Nearly every soil property differed significantly between the unplowed prairie reference site and the other three sites. The reconstructed sites, however, generally did not differ from the invaded old-field. These results indicate that the reconstructed prairies are not fully recovered. Although above-ground traits, such as the plant community structure, appear similar to the prairie, the soil microbial community structure still resembles that of an invaded old-field site. These results indicate that more time may be needed before soil microbial populations fully recover after invasive plant removal.