Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA.
Ecology. 2011 Dec;92(12):2208-13. doi: 10.1890/11-0518.1.
The greater abundance of some exotic plants in their nonnative ranges might be explained in part by biogeographic differences in the strength of competition, but these competitive effects have not been experimentally examined in the field. We compared the effects of neighbors on the growth and reproduction of spotted knapweed (Centaurea stoebe) in Europe, where it is native, and in Montana, where it is invasive. There were strong negative competitive effects of neighboring vegetation on C. stoebe growth and reproduction in Europe. In contrast, identical experiments in Montana resulted in insignificant impacts on C. stoebe. Although the mechanisms that produce this dramatic biogeographic difference in competitive outcome remain unknown, our results indicate that differences in net competitive interactions between ranges may contribute to the striking dominance of C. stoebe in parts of North America.
一些外来植物在非原生范围内更为丰富，部分原因可以用竞争强度的生物地理差异来解释，但这些竞争效应尚未在野外进行过实验检验。我们比较了欧洲（其原生地）和蒙大拿州（其入侵地）邻居对斑点矢车菊（Centaurea stoebe）生长和繁殖的影响。在欧洲，与植被相邻对 C. stoebe 的生长和繁殖有强烈的负向竞争作用。相比之下，蒙大拿州的相同实验对 C. stoebe 几乎没有影响。尽管产生这种竞争结果显著生物地理差异的机制尚不清楚，但我们的结果表明，范围之间净竞争相互作用的差异可能导致 C. stoebe 在北美的部分地区显著占优势。
