Native and non-native grasses generate common types of plant-soil feedbacks by altering soil nutrients and microbial communities.

摘要

Soil conditioning occurs when plants alter features of their soil environment. When these alterations affect subsequent plant growth, it is a plant soil feedback. Plant-soil feedbacks are an important and understudied aspect of aboveground-belowground linkages in plant ecology that influence plant coexistence, invasion and restoration. Here, we examine plant-soil feedback dynamics of seven co-occurring native and non-native grass species to address the questions of how plants modify their soil environment, do those modifications inhibit or favor their own species relative to other species, and do non-natives exhibit different plant-soil feedback dynamics than natives. We used a two-phase design, wherein a first generation of plants was grown to induce species-specific changes in the soil and a second generation of plants was used as a bioassay to determine the effects of those changes. We also used path-analysis to examine the potential chain of effects of the first generation on soil nutrients and soil microbial composition and on bioassay plant performance. Our findings show species-specific (rather than consistent within groups of natives and non-natives) soil conditioning effects on both soil nutrients and the soil microbial community by plants. Additionally, native species produced plant-soil feedback types that benefit other species more than themselves and non-native invasive species tended to produce plant-soil feedback types that benefit themselves more than other species. These results, coupled with previous field observations, support hypotheses that plant-soil feedbacks may be a mechanism by which some non-native species increase their invasive potential and plant-soil feedbacks may influence the vulnerability of a site to invasion.Digital Object Identifier http://dx.doi.org/10.1111/j.1600-0706.2012.20592.x