Soil resource heterogeneity can affect plant growth and competitive ability. However, little is known about how soil resource heterogeneity affects competitive interactions between invasive and native plants. We conducted an experiment with an invasive clonal plant Alternanthera philoxeroides and a coexisting native one Alternanthera sessilis. The experiment was a randomized design with three factors, i.e. two species (A. philoxeroides and A. sessilis), two interspecific competition treatments (with and without) and five soil treatments (three homogeneous treatments and two small-scale heterogeneous treatments consisting of two patches of 10 cm × 15 cm and with different initial planting positions). Irrespective of competition, increasing soil resource availability increased the growth of A. philoxeroides. Increasing soil resource availability also increased the growth of A. sessilis without competition, but had no impact with competition. Irrespective of competition, soil resource heterogeneity increased biomass and ramet production of A. philoxeroides, and such effects were independent of initial planting position. For A. sessilis, however, soil resource heterogeneity only increased ramet production when the initial plant was grown in the low-resource patch without competition. Our results suggest that both high soil resource availability and small-scale soil resource heterogeneity can increase the relative competitive ability of the invasive plant A. philoxeroides when grown with its native congener A. sessilis. These findings may partly explain the invasion success of this clonal species in area with high soil resource availability and heterogeneity caused by e.g. nitrogen deposition, fertilization and disturbance.

中文翻译：

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与本地植物相比，土壤资源异质性更有利于入侵性克隆植物。

土壤资源异质性会影响植物的生长和竞争能力。然而，关于土壤资源异质性如何影响外来入侵植物与本土植物之间竞争性相互作用的了解甚少。我们用一种入侵性克隆植物菲律宾楠和一种天然存在的南方楠一起进行了实验。该实验是一项具有三个因素的随机设计，即两个物种（A. philoxeroides和A. sessilis），两个种间竞争处理（有或没有）和五种土壤处理（三种同质处理和两种由两种组成的小规模异质处理） 10厘米×15厘米的小块，并且具有不同的初始种植位置）。不论竞争如何，增加土壤资源的利用量都会增加phil.eroeroides的生长。土壤资源可用性的增加也增加了无竞争的芝麻沙蒿的生长，但对竞争没有影响。不论竞争如何，土壤资源异质性提高了A. philoxeroides的生物量和分株产量，且这种影响与最初的种植位置无关。然而，对于芝麻（A. sessilis），当原始植物生长在资源贫乏的地方而没有竞争时，土壤资源异质性只会增加分株产量。我们的研究结果表明，高土壤资源利用率和小规模土壤资源异质性都可以提高入侵植物A. philoxeroides与本地同种A. sessilis一起生长时的相对竞争能力。