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INVESTIGATOR: Suseela, V.

PERFORMING INSTITUTION:
CLEMSON UNIVERSITY
CLEMSON, SOUTH CAROLINA 29634

INVESTIGATING THE PLANT-SOIL FEEDBACKS THAT MAINTAIN THE LEGACY EFFECT IN INVADED ECOSYSTEMS TO FORMULATE KNOWLEDGE BASED RESTORATION PRACTICES

NON-TECHNICAL SUMMARY: NON-TECHNICAL SUMMARYInvasive plant species pose a great threat to both agricultural and natural ecosystems leading to an estimated loss of $34 billion in the US, annually. Many invasive species create persistent changes in soil properties, which persists even after the removal of the invasive species (termed as the legacy effect). These changes in soil properties impedes the efforts to restore the invaded ecosystems. This is particularly true with invasive species that produce large quantities of biomass that contain chemical compounds different from that in the biomass of native species. These chemical compounds undergo microbial decomposition and are incorporated into soils leading to changes in the amount and chemistry of soil organic matter. Most of these invader-derived chemical compounds will persist in soil preventing the germination or growth of the native species even after the removal of the invasive species. The proposed research focuses on obtaining a detailed understanding of the mechanisms through which the tissue chemistry of invasive species creates the legacy effect in the invaded ecosystems. The influence of soil mineralogy in facilitating the creation and maintenance of the legacy effect will be evaluated at regional scales. Further the research team will test various management practices to successfully restore the invaded ecosystems to their pre-invasion status using various soil amendments. The study will utilize multiple invasive species that are prevalent in eastern United States that produces different litter chemistry. The proposed soil amendments would sequester the invader-derived compounds, and are environmentally sound methods that increase the soil health, which in turn would accelerating the natural recovery of the ecosystems in the invaded sites. The insight gained from this research would be instrumental in formulating knowledge-based management practices to remove the legacy effect of invasive species from invaded ecosystems.

OBJECTIVES: GOALS AND OBJECTIVESNon-native invasive plant species (NIPS) poses a serious threat to agricultural and forest ecosystems. The invasive species which are functionally and chemically different from the native species alter their biotic and abiotic (soil) environment through plant-soil feedbacks. The invasive species that input large quantities of chemically distinct litter that are rich in secondary metabolites have the potential to cause persistent changes in the chemistry of soil organic matter (SOM) in invaded ecosystems. The changes in SOM in invaded ecosystems can persist over longer time scales even after the removal of the invasive species (legacy effect). The proposed research will investigate the mechanisms through which NIPS induce persistent changes in SOM, which then would be used to formulate management practices that could reverse the legacy effect. The study will utilize multiple invasive species that are prevalent in eastern United States that produces different litter chemistry.The major goals of this project are 1) to test the plant secondary metabolite-mediated mechanisms through which NIPS engage in the creation of legacy effect by altering soil C cycling in invaded habitats; 2) to develop knowledge-based restoration practices to negate the effect of these chemical compounds, and successfully restore invaded habitats.Our specific objectives are to:Characterize the secondary metabolites in tissues of invasive plant species and their novelty in invaded ecosystems along eastern United States.Characterize the extractable and bulk soil carbon chemistry in soils invaded by the NIPS, and how it related to the tissue chemistry of the invader.Quantify the rate of nutrient mineralization, litter decomposability and enzyme activities in invaded and non-invaded soils across multiple sites across south eastern United States.Evaluate the role of soil minerology, specifically clay and Fe/Al oxide contents, in maintaining legacy effects at regional scales.Characterize the influence of NIPS in altering SOM in soils of different mineralogy classes across multiple sites that vary in the percent clay and Fe/Al oxide content.Evaluate the effectiveness of soil amendments to reverse the legacy effect by their ability to sequester or degrade the invader induced soil carbon compounds.