Georg-August-University Göttingen, JF Blumenbach Institute of Zoology and Anthropology, Göttingen, Germany.
ISME J. 2011 Jul;5(7):1108-14. doi: 10.1038/ismej.2011.9. Epub 2011 Feb 24.
Biological invasions can lead to extinction events in resident communities and compromise ecosystem functioning. We tested the effect of two widespread biodiversity measurements, genotypic richness and genotypic dissimilarity on community invasibility. We manipulated the genetic structure of bacterial communities (Pseudomonas fluorescens) and submitted them to invasion by Serratia liquefaciens. We show that the two diversity measures impact on invasibility via distinct and additive mechanisms. Genotypic dissimilarity of the resident communities linearly increased productivity and in parallel decreased invasion success, indicating that high dissimilarity prevents invasion through niche pre-emption. By contrast, genotypic richness exerted a hump-shaped effect on invasion and was linked to the production of toxins antagonistic to the invader. This effect peaked at intermediate richness, suggesting that high richness levels may increase invasibility. Invasibility could be well predicted by the combination of these two mechanisms, documenting that both genotypic richness and dissimilarity need to be considered, if we are to understand the biotic properties determining the susceptibility of ecosystems to biological invasions.
生物入侵会导致当地社区物种灭绝，并破坏生态系统功能。我们检验了两种广泛应用的生物多样性测度指标——基因型丰富度和基因型差异度对群落可入侵性的影响。我们人为操纵细菌群落（荧光假单胞菌）的遗传结构，并让其受到液化沙雷氏菌的入侵。结果表明，这两种多样性测度指标通过不同的、累加的机制影响可入侵性。优势种群落的基因型差异度与生产力呈线性正相关，而与入侵成功呈负相关，表明高基因型差异度通过生态位占据阻止了入侵。相比之下，基因型丰富度对入侵的影响呈钟形曲线，且与产生对抗入侵种的毒素有关。该影响在中等丰富度时达到峰值，这表明高丰富度水平可能会增加入侵性。这两种机制的组合可以很好地预测入侵性，这表明如果我们要了解决定生态系统对生物入侵敏感性的生物特性，就需要同时考虑基因型丰富度和差异度。
