Biodiversity and belowground interactions mediate community invasion resistance against a tall herb invader

作者：Scherber Christoph^*; Mwangi Peter N; Schmitz Martin; Scherer Lorenzen Michael; Bessler Holger; Engels Christof; Eisenhauer Nico; Migunova Varvara D; Scheu Stefan; Weisser Wolfgang W; Schulze Ernst Detlef; Schmid Bernhard

来源：Journal of Plant Ecology-UK, 2010, 3(2): 99-108.

DOI：10.1093/jpe/rtq003

• aboveground competition
• competitive suppression
• belowground interactions
• root competition
• shoot exclusion
• species richness

Aims
Species-rich plant communities are hypothesized to be more resistant against plant invasions because they use resources in a more efficient way. However, the relative contributions of aboveground competition and belowground interactions for invasion resistance are still poorly understood.
Methods
We compared the performance of Knautia arvensis transplants growing in plots differing in plant diversity both under full competition and with shoots of neighbors tied back to determine the relative strength of aboveground competition in suppressing this test invader without the confounding effect of shading. In addition, we assessed the effects of belowground competition and soil-borne pathogens on transplant performance.
Important Findings
Both aboveground competition and plant species richness strongly and independently affected invader performance. Aboveground biomass, height, leaf mass per area and flowering of transplanted individuals of K. arvensis decreased with increasing species richness of the host community. Species-rich and species-poor communities both imposed equally strong aboveground competition on K. arvensis. However, belowground interactions (especially belowground root competition) had strong negative effects on transplant performance. In addition, the presence of grasses in a plant community further reduced the performance of K. arvensis. Our results suggest that belowground competition can render species-rich host communities more suppressive to newly arriving species, thus enhancing community invasion resistance.

• 出版日期2010-6