Understanding why alien species become dominant in recipient communities requires a biogeographical perspective comparing the ecology of native and introduced populations. The genus Centaurea (Asteraceae) is well-known in invasion ecology because several aggressive invaders, including Centaurea melitensis L., belong to this genus. We compared the competitive ability of C. melitensis individuals from Spain (native range) and Chile (invaded range) when competing against Helenium aromaticum (Hook.) L.H. Bailey, a native relative from Chile. We performed germination bioassays and common garden competition experiments to compare: (1) the germination capacities of C. melitensis (Spain and Chile) and H. aromaticum (2) the potential allelopathic effect of leaf lixiviates of C. melitensis (Spain and Chile) on the seed germination of H. aromaticum, (3) the ability of C. melitensis from both origins to reduce the growth of H. aromaticum. No significant differences in the capacity of seed germination were found among C. melitensis from Chile and Spain and the native H. aromaticum. However, the seed germination of H. aromaticum was inhibited by the presence of C. melitensis leaves from Chile and Spain. Also, the biomass of H. aromaticum was reduced in the presence of C. melitensis, regardless of their origin. Our results demonstrate the competitive superiority of the invasive C. melitensis over H. aromaticum, but we found no evidence of an evolutionary increase in the competitive ability of the invader populations. Therefore, at least part of the invasive potential of C. melitensis seems to be acquired by selective processes in their original range.

要了解为什么外来物种在接收者社区中占主导地位，需要从生物地理的角度比较本地和引进种群的生态。矢车菊属（菊科）在入侵生态学中是众所周知的，因为包括桑蚕（Centaurea melitensis L.）在内的几种侵略性入侵者都属于该属。我们比较的竞争能力C.羊种同台竞技当个人从西班牙（本土范围）和智利（入侵范围）土木香芳香（胡克）LH贝利，来自智利本地相对。我们进行了发芽生物测定和常见的花园竞争实验，以比较：（1）棉铃虫（西班牙和智利）的发芽能力和芳香H.（2）的叶lixiviates的潜在化感作用C.羊种上的种子萌发（西班牙和智利）H.芳香，（3）的能力C.羊种来自两个来源以减少的生长H.香气。在种子发芽的能力没有显著差异中发现C.羊种来自智利和西班牙本土H.芳香。然而，种子萌发H.芳香通过的存在抑制C.羊种的叶子从智利和西班牙。另外，生物量H.芳香在存在降低C.羊种，不论其来源。我们的研究结果证明了微创的竞争优势C.羊种以上H.芳香，但我们没有发现任何的入侵者人口的竞争能力的进化增加的证据。因此，似乎通过选择过程在其原始范围内获得了部分梭状芽胞杆菌的入侵潜力。