The highly invasive knotweeds (Reynoutria spp.) are still infrequent in mountain regions. Despite their current low abundance, they may represent a significant threat for high elevation ecosystems if their population dynamics remain as aggressive as in lowlands during their range expansion to higher elevation. The aim of this study is to assess the knotweed’s invasion potential in mountainous regions by studying patch dynamics along an elevational gradient (between 787 and 1666 m a.s.l.) and by reviewing existing literature on their presence and performance in mountains. The outlines of 48 knotweed patches located in the French Alps were measured in 2008 and in 2015 along with biotic, abiotic and management variables. Based on these variables, knotweed’s cover changes and patch density were predicted using mixed models. Results showed that elevation has no effect on knotweeds dynamics along the studied elevational gradient. It appeared that the local expansion of knotweed patches is essentially controlled by the patches’ initial size and the distance to roads and rivers, i.e. to obstacles and sources of disturbance. Shade and patches’ size also impact knotweed patch density, probably through an effect on the species’ clonal reproduction and foraging strategies. Interestingly, patches seemed insensitive to the gradient of mowing frequency sampled in this study (between zero and five times per year). All evidences indicate that the knotweed complex is able to colonize and thrive in mountains areas. However, due to the particularities of its spatial dynamics, adequate and timely actions could easily be undertaken to prevent further invasion and associated impacts and reduce management costs.

中文翻译：

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虎杖能侵入其所介绍范围内的山脉吗？沿海拔梯度的斑块动力学分析

高侵入性虎杖（Reynoutria spp。）在山区仍然很少见。尽管目前种群数量不多，但如果其种群动态向低海拔扩展时，其种群动态仍然像低地那样具有侵略性，则可能对高海拔生态系统构成重大威胁。这项研究的目的是通过研究沿海拔梯度（在787和1666 m asl之间的斑块动力学）并回顾有关山区中虎杖的存在和表现的现有文献来评估虎杖在山区的入侵潜力。在2008年和2015年对位于法国阿尔卑斯山的48个虎杖斑块的轮廓以及生物，非生物和管理变量进行了测量。基于这些变量，使用混合模型预测了虎杖的覆盖率变化和斑块密度。结果表明，海拔高度对沿所研究海拔梯度的虎杖动力学没有影响。看来，虎杖斑块的局部扩展基本上由斑块的初始大小和与道路和河流的距离（即与障碍物和干扰源的距离）控制。阴影和斑块的大小也会影响虎杖斑块的密度，可能是通过影响物种的克隆繁殖和觅食策略来实现的。有趣的是，在本研究中，斑块似乎对割草频率的梯度不敏感（每年零次至五次）。所有证据表明虎杖复合体能够在山区定居和繁衍。但是，由于其空间动力学的特殊性，