Interactions among native and invasive species may affect management outcomes and goals. We implemented different mowing regimes to control the invasive Solidago gigantea and restore natural diversity, and also examined interactions between Solidago and a European native competitor, Tanacetum vulgare in the context of these regimes. Experimentally planted Tanacetum suppressed Solidago by 79% without management, and a suite of mowing management regimes reduced the density of Solidago by 80–98% when Tanacetum was absent. But, when Tanacetum was added, the density of the invader was not reduced by mowing. Put another way, in mowed plots with Tanacetum, Solidago was twofold to over fivefold denser than in mowed plots without Tanacetum. It is not clear why the effect of Tanacetum shifted from competition in the absence of disturbance to facilitation with intense management-associated disturbance, but other studies suggest that Tanacetum may create plant–soil feedbacks that favor Solidago. Evidence shows similar shifts from competition to facilitation under mowing regimes for other species, but these are not mechanistically clear either. We speculate that mowing reduced competition from Tanacetum while leaving belowground facilitative effects unchanged, shifting the net effect of Tanacetum to facilitation. When single-year mowed plots were abandoned for just 1 year, Solidago was twofold denser than in the control, thus maintaining treatments over time was important for successful management. Our results indicate that mechanical control may substantially alter biotic resistance gained from native competition.

中文翻译：

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密集的割草管理抑制了入侵者，但将本地人的竞争抵抗转变为促进

本地物种和入侵物种之间的相互作用可能会影响管理结果和目标。我们实施了不同的割草制度来控制入侵的大一枝黄花并恢复自然多样性，并在这些体制的背景下检查了一枝黄花与欧洲本土竞争对手Tanacetum vulgare之间的相互作用。试验性种植的Tanacetum在没有管理的情况下将Solidago抑制了 79%，而一套割草管理制度在Tanacetum不存在时将Solidago的密度降低了80-98% 。但是，当Tanacetum添加后，入侵者的密度不会因割草而降低。换句话说，在使用Tanacetum的割地中，Solidago的密度是没有Tanacetum的割地的两倍至五倍以上。目前尚不清楚为什么Tanacetum的作用从没有干扰的竞争转变为具有强烈管理相关干扰的促进，但其他研究表明，Tanacetum可能会产生有利于一枝黄花的植物-土壤反馈。有证据表明，在其他物种的割草制度下，从竞争到促进的类似转变，但这些在机械上也不是很清楚。我们推测割草减少了来自Tanacetum的竞争在保持地下促进效应不变的同时，将Tanacetum的净效应转变为促进效应。当一年割草的地块被废弃仅 1 年时，Solidago的密度是对照的两倍，因此随着时间的推移保持处理对于成功管理很重要。我们的结果表明，机械控制可能会大大改变从天然竞争中获得的生物抗性。