https://academic.oup.com/bioscience November 2019 / Vol. 69 No. 11 • BioScience 853 Comment on Havens and Colleagues (2019) Havens and colleagues (2019) concluded that “given the uncertain efficacy and the demonstrable risks of biocontrol, its use should be less frequent, better regulated, and better monitored.” In contrast, we argue that: (1) The frequency of implementation of biocontrol should continue based on records of specificity, safety and costeffective success. All examples of nontarget attack and impact cited by Havens and colleagues were from first-generation biocontrol programs and are not representative of current biocontrol practice (for a review, see Hinz et al. 2019). The authors have overlooked a large body of literature addressing economic impact assessments of weed biocontrol (e.g., Page and Lacey 2006, De Lange and van Wilgen 2010). Despite the “tremendous resources... invested in biological control programs.” these accounts show extremely advantageous cost:benefit ratios of up to 1:4000 (Culliney 2005). As Havens and colleagues correctly stated, “partial control of the plant populations can make other management efforts... more cost effective.” Therefore, statements such as “agents cannot be deemed successful unless population level impacts are apparent” are overly simplistic and incorrect. Some of the most successful integrated management programs against woody invaders in South Africa are based on a combination of physical removal of established trees and seed-feeding biocontrol agents (e.g., Hakea sericea; Esler et al. 2010). (2) Weed biocontrol is already well regulated. The current US review process for release of weed biocontrol agents includes a thorough consultation with stakeholders within and outside federal and tribal governments and takes at least 2–4 years. The review is focused entirely on the risks of biocontrol releases for individual species, thereby ignoring the significant risk to entire habitats of no management, and the potential benefits of biocontrol for those habitats. (3) Thorough and systematic postrelease monitoring, quantifying impact of biocontrol agents on target and nontarget species should continue to be the standard for biocontrol projects, as has been advocated previously in several papers. We agree that the study of plant demography at sites with or without the respective biocontrol agents can yield important information on success and safety (e.g., Catton et al. 2016). However, the authors’ decision to entirely exclude post-release studies lacking experimental controls ignores spatial and the extended temporal scales at which ecological systems including biocontrol operate. Controlled demographic studies by their intensive nature are typically limited to single or very few sites. As an alternative, long-term postrelease monitoring studies (longer than 10 years) over large spatial scales, even when lacking control sites, can estimate effects of biocontrol agents on weed population growth rates (e.g., Van Hezewijk et al. 2010). In addition, mechanistic modeling combined with model selection (e.g., Schooler et al. 2011, Weed and Schwarzländer 2014) provides an opportunity to simultaneously evaluate multiple hypotheses including individual and interactive effects of agent density, competition and climate to explain weed population dynamics. These approaches can provide valuable insights and should not be ignored. In summary, biocontrol should continue to be an important tool for invasive plant management, regulation should include benefit–risk analysis for all actions and inaction, and postrelease monitoring should consider all available data.

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评论 Havens 和同事 (2019)

https://academic.oup.com/bioscience 2019 年 11 月 / 卷。69 No. 11 • BioScience 853 Comment on Havens and Colleagues (2019) Havens 和同事 (2019) 得出结论，“鉴于生物防治的不确定性和可证明的风险，其使用频率应该降低，更好地监管和更好地监测。相比之下，我们认为： (1) 生物防治的实施频率应继续基于特异性、安全性和成本效益的成功记录。Havens 及其同事引用的所有非目标攻击和影响示例均来自第一代生物防治计划，并不代表当前的生物防治实践（有关评论，请参阅 Hinz 等人，2019 年）。作者忽略了大量关于杂草生物防治经济影响评估的文献（例如，Page 和 Lacey 2006，De Lange 和 van Wilgen 2010）。尽管“巨大的资源......投资于生物控制计划”。这些账户显示出极其有利的成本：收益比高达 1:4000 (Culliney 2005)。正如 Havens 及其同事正确指出的那样，“对植物种群的部分控制可以使其他管理工作......更具成本效益。” 因此，诸如“除非人口水平影响明显，否则不能认为代理人成功”之类的陈述过于简单化和不正确。南非针对木本入侵者的一些最成功的综合管理计划是基于物理清除已建树和以种子为食的生物防治剂的组合（例如，Hakea sericea；Esler 等人，2010 年）。(2) 杂草生物防治已经得到很好的监管。目前美国对释放杂草生物防治剂的审查过程包括与联邦和部落政府内外的利益相关者进行彻底协商，至少需要 2-4 年的时间。审查完全集中在单个物种的生物防治释放风险上，从而忽略了无管理对整个栖息地的重大风险，以及生物防治对这些栖息地的潜在好处。(3) 彻底和系统的释放后监测，量化生物防治剂对目标和非目标物种的影响应继续成为生物防治项目的标准，正如之前几篇论文所倡导的那样。我们同意在有或没有相应生物防治剂的地点进行植物人口学研究可以产生关于成功和安全的重要信息（例如，Catton 等人，2016 年）。然而，作者决定完全排除缺乏实验控制的释放后研究，忽略了包括生物控制在内的生态系统运作的空间和扩展的时间尺度。由于其密集性质，受控人口研究通常仅限于单个或很少的站点。作为替代方案，大空间尺度的长期释放后监测研究（超过 10 年），即使在缺乏控制点的情况下，也可以估计生物防治剂对杂草种群增长率的影响（例如，Van Hezewijk 等人，2010 年）。此外，机械建模与模型选择相结合（例如 Schooler et al. 2011, Weed and Schwarzländer 2014）提供了一个机会来同时评估多个假设，包括个体密度和交互效应，竞争和气候来解释杂草种群动态。这些方法可以提供有价值的见解，不应被忽视。总之，生物防治应继续成为入侵植物管理的重要工具，监管应包括对所有行动和不行动的收益-风险分析，放行后监测应考虑所有可用数据。