Dukes Jeffrey S
Department of Biological Sciences, Stanford University, 94305-5020, Stanford, California, USA.
Oecologia. 2001 Feb;126(4):563-568. doi: 10.1007/s004420000549. Epub 2001 Feb 1.
In the years since Charles Elton proposed that more diverse communities should be less susceptible to invasion by exotic species, empirical studies have both supported and refuted Elton's hypothesis. Here, I use grassland community microcosms to test the effect of functional diversity on the success of an invasive annual weed (Centaurea solstitialis L.). I found that high functional diversity reduced the success of Centaurea by reducing resource availability. An equally important, but unstudied, question is whether diversity can buffer a community against the impacts of invasive species. In this experiment, although species diversity (independent of functional diversity) did not affect the success of the invader, the invader suppressed growth of species-poor communities more strongly. Invasion of Centaurea also increased summer evapotranspiration in species-poor communities. These results suggest that loss of species diversity alone does not affect community invasibility, but that communities with fewer species may be more likely to decline as a consequence of invasion.
自从查尔斯·埃尔顿提出更多样化的群落应该更不易受到外来物种入侵以来，实证研究既有支持埃尔顿假说的，也有反驳该假说的。在此，我利用草地群落微观世界来测试功能多样性对一种入侵性一年生杂草（一年生矢车菊）成功入侵的影响。我发现高功能多样性通过减少资源可利用性降低了矢车菊的入侵成功率。一个同样重要但尚未研究的问题是，多样性是否能缓冲群落免受入侵物种的影响。在这个实验中，虽然物种多样性（与功能多样性无关）并未影响入侵者的成功入侵，但入侵者对物种贫乏群落生长的抑制作用更强。矢车菊的入侵还增加了物种贫乏群落夏季的蒸散量。这些结果表明，仅物种多样性的丧失并不影响群落的可入侵性，但物种较少的群落可能更有可能因入侵而衰退。
