Monday, November 13, 2006

Plant-Soil Feedback of Two Native and Two Invasive Plant Species Shifts Soil Microbial Community Composition and Functions.

Shen Yu1, Joan Ehrenfeld1, Torsten Vor2, and Kenneth Elgersma1. (1) Rutgers, 14 College Farm Rd, New Brunswick, NJ 08901, (2) Institute of Silviculture, Univ of Gottingen, Busgenweg 1, Gottingen, Germany

The soil microbial community and its ecological functions are key components of plant-soil feedback. Effects of both live and decaying plant roots on soil microbial community composition and microbially-mediated processes can feed back to successive plants’ growth. This feedback can also apply to the process of exotic plant invasion, influencing the outcome of plant invasion and the resilience of native communities after invasive plant removal. A two-year greenhouse experiment was set up to explore 1) the influences of former plant growth on soil microbial community composition and enzyme activities; and, 2) the legacy effect of the former plant’s roots on altering soil microbial community composition and enzyme activities, which affects the next generation success. Two native woody shrubs, Vaccinium angustifolium and Viburnum dentatum, one invasive woody shrub, Berberis thunbergii, and an invasive grass, Microstegium vimineum, were planted in pots with an uninvaded soil. After one year, soil microbial community composition was only slightly shifted by plant species. Soil enzyme activities (acid phosphatase, phenol oxidase, and urease) were only slightly changed as well though b-glucosidase activity showed a significantly species-driven change. The aboveground portion of each species was cut and the pots were randomly assigned into four groups, in which one of the four species was transplanted as the second generation a year later. The former plants’ decaying roots significantly altered soil microbial community composition and urease activity whereas the growth of the second-generation plants also significantly shifted soil microbial community composition and all soil enzyme activities except acid phosphatase. These results reveal that although the species-specific influences on soil microbially-mediated processes (enzyme activities) from the second-generation plant growth are more important than the influences from the first-generation plants’ decaying roots, the legacy of the former plants should be considered for the success of plant invasion and resilience of native communities.

Handout (.pdf format, 166.0 kb)