Hexaploid individuals of Senecio carniolicus (Asteraceae) predominantly occur in dense swards while diploids prevail in open vegetation. We test whether this habitat segregation is due to differential responses to competition. Linear regression models were used to relate biomass and maximum leaf length of adults to vegetation cover within radii of 20 cm around target individuals. Biomass differed between ploidy levels, but was independent from vegetation cover in both cytotypes. Maximum leaf length of diploids increased with vegetation cover, but remained constant in hexaploids. This suggests that at the adult stage diploids respond to increasing competition by changes in plant architecture rather than changes in resource utilization, while hexaploids are unaffected by competition. Consequently, other factors, such as competitive interactions at earlier life stages, likely are responsible for habitat segregation of diploid and hexaploid S. carniolicus.

中文翻译：

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没有证据表明成虫的竞争能力在导致二倍体和六倍体千里光（菊科）生境隔离中发挥作用。


千里光（菊科）的六倍体个体主要出现在茂密的草丛中，而二倍体则普遍存在于开阔的植被中。我们测试这种栖息地隔离是否是由于对竞争的不同反应造成的。使用线性回归模型将成虫的生物量和最大叶长与目标个体周围 20 厘米半径内的植被覆盖度联系起来。生物量在倍性水平之间存在差异，但与两种细胞类型的植被覆盖无关。二倍体的最大叶长随着植被覆盖而增加，但在六倍体中保持不变。这表明，在成虫阶段，二倍体通过植物结构的变化而不是资源利用的变化来应对日益激烈的竞争，而六倍体则不受竞争的影响。因此，其他因素，例如早期生命阶段的竞争性相互作用，可能是二倍体和六倍体S. carniolicus栖息地隔离的原因。