1. Globally, invasive non‐native plants are an increasing threat to indigenous biodiversity and ecosystems, but management can be compromised by poor efficacy of control methods, harmful non‐target effects or secondary invasions by other non‐native plant species.
2. A 5‐year field trial compared two stakeholder‐selected control methods for heather, a European plant invading native ecosystems in and adjoining Tongariro National Park in New Zealand. The control methods were a selective herbicide (Pasture Kleen^®; 2,4‐D ester) and biocontrol with an introduced beetle Lochmaea suturalis (Coleoptera: Chrysomelidae).
3. Biocontrol reduced mean heather cover by 97%, slightly more than herbicide at 87%, compared with a 20% increase in heather under no management.
4. Cover of native dicots, the most species‐rich plant group, increased following biocontrol. In contrast, herbicide application had major non‐target effects on native dicots, reducing their percentage cover and species richness. Native monocot cover and species richness increased following both herbicide and biocontrol treatments.
5. A similar eightfold increase in non‐native monocots occurred following both biocontrol and herbicide treatments. Overall, secondary invasion was greatest with biocontrol because non‐native dicot cover also increased, whereas herbicide almost eliminated non‐native dicots.
6. Synthesis and applications. Biocontrol and herbicide treatments both controlled heather but herbicide application was associated with severe non‐target impacts on native dicots. Benefits to the native flora were consequently greatest in the biocontrol treatment, despite greater secondary invasion. Control strategies for management of widespread non‐native plants to optimize ecosystem outcomes should include more consideration of biocontrol.

中文翻译：

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比较生物防治和除草剂对入侵非本地植物的管理：功效，非目标效应和继发入侵

1. 在全球范围内，外来入侵植物对本地生物多样性和生态系统构成的威胁越来越大，但是控制方法的有效性低，有害的非目标作用或其他外来植物物种的二次入侵可能会损害管理。
2. 一项为期5年的现场试验比较了希瑟（Heather）的两种由利益相关者选择的控制方法，该希瑟是一种在新西兰汤加里罗国家公园（Tongariro National Park）并毗邻新西兰的欧洲植物，其入侵原生生态系统。所述控制方法是一种选择性的除草剂（草Kleen的^® ; 2,4-d酯）和生物防治与甲虫引入的Lochmaea蝽（鞘翅目：叶甲科）。
3. 生物防治措施使平均石楠覆盖率降低了97％，略高于除草剂的平均覆盖率（87％），而没有管理的石楠覆盖率增加了20％。
4. 生物防治后，物种最丰富的植物双子叶植物的覆盖率增加。相反，施用除草剂对天然双子叶植物具有主要的非靶向作用，从而降低了它们的覆盖率和物种丰富度。除草剂和生物防治后，原生单子叶植物的覆盖率和物种丰富度均增加。
5. 经过生物防治和除草剂处理后，非本地单子叶植物发生了类似的八倍增长。总体而言，生物防治对次生入侵的影响最大，因为非天然双子叶植物的覆盖率也增加了，而除草剂几乎消除了非天然双子叶植物。
6. 综合与应用。生物防治和除草剂处理均能控制石南花，但除草剂的施用与对天然双子叶植物的严重非目标影响有关。因此，尽管继发侵害增加，但在生物防治中对原生菌群的益处最大。管理广泛的非本地植物以优化生态系统成果的控制策略应更多地考虑生物控制。