Intraspecific competitive ability declines towards the edge of the expanding range of the invasive vine Mikania micrantha
Intraspecific competitive ability declines towards the edge of the expanding range of the invasive vine Mikania micrantha
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DOI：
10.1007/s00442-015-3526-9
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发表时间：
2016-05-01
期刊：
影响因子：
2.7
通讯作者：
Peng, Shaolin
中科院分区：
文献类型：
--
作者：
Huang, Fangfang;Peng, Shaolin
竞争能力的进化在植物入侵中起着重要的作用。虽然许多入侵物种的进化研究比较了来自本地和入侵范围的种群在其性能方面，很少有人注意到入侵范围内的种内竞争能力在范围扩展过程中的演变。此外，入侵凋落物数量的比例变化是否会影响不同年龄入侵种群的种内竞争能力尚未得到研究。在这里，我们选择薇甘菊H.B.K.，一种在中国南方具有很好的入侵历史的高度入侵的藤本植物，作为研究物种。我们操纵不同年龄的种群之间的竞争，从核心的范围内的边缘下四个凋落物处理在一个共同的花园实验。我们发现，在其30年的入侵，种内竞争能力迅速选择对范围的边缘，这可能是由人口密度下降的部分驱动。然而，凋落物来源并不影响不同年龄种群之间竞争的结果，它更像是一种营养供应。我们建议，特定阶段的条件，如人口密度应纳入实验设计时，检查入侵植物的进化，特别是当入侵种群受到选择在一个小的地理范围内。这种方法可以减少采样偏差，从而提高推断入侵种群进化机制的能力。
The evolution of competitive ability plays an important role in plant invasions. While many studies of the evolution of invasive species have compared populations from native and invaded ranges in terms of their performance, little attention has been paid to the evolution of intraspecific competitive ability within the invaded range during range expansion. In addition, whether the proportional change in the amount of invasive litter influences the intraspecific competitive ability among invasive populations of different ages has not yet been investigated. Here we selected Mikania micrantha H.B.K., a highly invasive vine in south China with a well-documented invasion history, as the study species. We manipulated competition among populations of different ages from the core of the range to its edges under four litter treatments in a common garden experiment. We found that during its 30-year invasion, intraspecific competitive ability was rapidly selected against towards range edges, which may be driven partly by the decline in population density. However, litter source did not influence the outcome of the competition among populations of different ages; it instead functioned more like a supply of nutrients. We suggest that stage-specific conditions such as population density should be incorporated into the experimental design when examining the evolution of invasive plants, especially when invasive populations are subject to selection on a small geographic scale. This approach can reduce sampling bias and thus improve the ability to infer the mechanisms responsible for the evolution of invasive populations.