Richness, not evenness, of invasive plant species promotes invasion success into native plant communities via selection effects

Native plant communities are often invaded by multiple alien species. It is still unclear how increasing diversity of alien invasive species suppresses the growth of native species and thus contributes to invasion success. In the subtropical monsoon region of Southeast China, we experimentally created a native plant community with 18 herbaceous species. One week later, we let it be invaded by either zero (controls without invasion), one, two, four or eight alien plant species, with either high or low species evenness. After a four-month growth period we harvested the aboveground biomass of each species. We found that increasing invasive species richness significantly increased invasive plant biomass, the biomass of all invasive and native plant species within the community, and invasion success (the ratio of invasive plant biomass to the biomass of all native and invasive plants), but it did not significantly reduce native plant biomass. Experimentally manipulating invasive species even...

本地植物群落常遭多种外来物种入侵。目前尚不清楚外来入侵物种多样性的增加如何抑制本地物种生长，进而助力入侵成功。在我国东南亚热带季风区，我们通过实验构建了含18种草本植物的本地植物群落。一周后，我们使该群落分别遭受0种（无入侵对照）、1种、2种、4种或8种外来植物入侵，并设置了高物种均匀度与低物种均匀度两种处理。经过四个月的生长期后，我们收获了各物种的地上生物量。研究发现，入侵物种丰富度的增加显著提升了入侵植物生物量、群落内所有入侵与本地植物的总生物量，以及入侵成功率（入侵植物生物量与群落内所有本地及入侵植物生物量的比值），但并未显著降低本地植物生物量。对入侵物种均匀度的实验调控...