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

Authors: UNGER, IRENE - University Of Missouri; KREMER, ROBERT - University Of Missouri; Veum, Kristen; GOYNE, KEITH - Virginia Polytechnic Institution & State University

Submitted to: Soil Ecology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2021
Publication Date: 9/1/2022
Citation: Unger, I.M., Kremer, R.J., Veum, K.S., Goyne, K.W. 2022. Immediate and long-term effects of invasive plant species on soil characteristics. Soil Ecology Letters. 4(3):276–288. https://doi.org/10.1007/s42832-021-0104-4.
DOI: https://doi.org/10.1007/s42832-021-0104-4

Interpretive Summary: Restoring former agricultural land to native prairie ecosystems typically involves aboveground management of the plant community with a focus on control of invasive species. However, plant-soil interactions are important in the health of native and reconstructed ecosystems and should not be ignored. This study measured several chemical, physical, and biological soil health indicators in a native prairie, an old field site dominated by the invasive plant sericea lespedeza, and two recently restored (2-4 yr) prairie sites. Results showed that the native prairie soil was significantly different from all former agricultural sites, and no differences in soil properties were found between the old field site and the recently restored prairie sites. This study highlights the impact of agricultural activities on the soil and illustrates that restoration of soil function may take several years. Overall, this study benefits landowners and conservation programs that target restoration and management of former agricultural lands.

Technical Abstract: Research on invasive plant species has typically focused on characteristics of the organism and ignores interactions with the soil ecosystem. Often these plant species are superior competitors with greater resource acquisition capabilities and/or they exhibit more efficient resource utilization over native species. However, invasive species may also alter soil characteristics or interact with the soil microbial community to yield a competitive advantage. Our objectives were to determine: i) if invasive plant species alter soil physical, chemical, or biological properties; and ii) the short-term soil health benefits of invasive plant species removal in ecological restoration efforts. We focused on sericea lespedeza (Lespedeza cuneata), a plant that may be allelopathic. Soil samples were collected in 2015 from four locations in Central Missouri, USA: an old-field with abundant sericea lespedeza, two recently reconstructed sites (2 and 4 yr), and a remnant prairie that has never been plowed. At each site we collected four composite soil samples at two depths (0-5 cm and 5-10 cm). Soil health indictors were used to characterize the physical, chemical, and biological properties of the soils at these sites. Nearly all soil properties 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 site. These results suggest that soils at the reconstructed prairie site have not fully recovered. Although above ground traits, such as plant community structure, appear to be similar to the prairie, the soils still resemble that of an invaded old-field site, and indicate that more time may be needed for soil properties to fully recover following invasive plant removal.