Stewart Gavin, Cox Emma, Le Duc Mike, Pakeman Robin, Pullin Andrew, Marrs Rob
Centre for Evidence-Based Conservation, School of the Environment & Natural Resources, Bangor University, Bangor, Gwynedd, LL57 2UW, UK.
Ann Bot. 2008 May;101(7):957-70. doi: 10.1093/aob/mcn020. Epub 2008 Mar 12.
A great deal of money is spent controlling invasive weeds as part of international and national policies. It is essential that the funded treatments work across the region in which the policies operate. We argue that experiments across multiple sites are required to validate these programs as results from single sites may be misleading. Here, the control of Pteridium aquilinum (bracken) is used as a test example to address the following four questions. (1) Does the effectiveness of P. aquilinum-control treatments vary across sites? (2) Is the best treatment identified in previous research (cutting twice per year) consistent at all sites, and if not why not? (3) Is treatment performance related to P. aquilinum rhizome mass, litter cover or litter depth at the various sites? (4) Does successful P. aquilinum control influence species richness?
Pteridium aquilinum-control treatments were monitored for 10 years using six replicated experiments and analysed using meta-analysis. Meta-regressions were used to explore heterogeneity between sites.
The effectiveness of treatments varied between sites depending on the measure used to assess P. aquilinum performance. In general, cutting twice per year was the most successful treatment but on some sites other, less expensive treatments were as good. The effectiveness of treatments at different sites was not related to rhizome mass, but the effectiveness of most applied treatments were inversely related to post-control litter. Effective treatment was also associated with high species richness.
It is concluded that successful development of national weed control programs requires multi-site experimental approaches. Here, meta-analyses demonstrate that variation in effectiveness between sites could be explained in part by pre-specified variables. Reliance on data from a single site for policy formulation is therefore clearly dangerous.
作为国际和国家政策的一部分，大量资金用于控制入侵杂草。至关重要的是，所资助的治理措施要在政策实施的整个区域内有效。我们认为需要进行多个地点的实验来验证这些项目，因为单个地点的结果可能会产生误导。在此，以蕨菜（欧洲蕨）的防治为例来回答以下四个问题。（1）蕨菜防治措施的效果在不同地点是否存在差异？（2）先前研究中确定的最佳措施（每年刈割两次）在所有地点是否一致，若不一致，原因何在？（3）治理效果与不同地点的蕨菜根茎质量、凋落物覆盖度或凋落物深度是否相关？（4）成功控制蕨菜是否会影响物种丰富度？
通过六个重复实验对蕨菜防治措施进行了10年的监测，并采用荟萃分析进行分析。使用元回归来探讨不同地点之间的异质性。
根据用于评估蕨菜表现的指标，治理效果在不同地点有所不同。一般来说，每年刈割两次是最成功的措施，但在一些地点，其他成本较低的措施效果也一样好。不同地点的治理效果与根茎质量无关，但大多数应用措施的效果与治理后的凋落物呈负相关。有效的治理措施也与高物种丰富度相关。
得出的结论是，国家杂草控制项目的成功开展需要多地点实验方法。在此，荟萃分析表明，不同地点之间效果的差异部分可以由预先设定的变量来解释。因此，仅依靠单个地点的数据来制定政策显然是危险的。
