Abstract:
The release of biological control agents has been an important means of controlling invasive species for over 150 years. While these releases have led to the sustainable control of over 250 invasive pest and weed species worldwide, a minority have caused environmental harm. A growing recognition of the risks of biological control led to a focus on risk assessment beginning in the 1990s along with a precipitous decline in releases. While this new focus greatly improved the safety of biological control, it came at the cost of lost opportunities to solve environmental problems associated with invasive species. A framework that incorporates benefits and risks of biological control is thus needed to understand the net environmental effects of biological control releases. We introduce such a framework, using native biodiversity as the common currency for both benefits and risks. The model is based on interactions among four categories of organisms: (1) the biological control agent, (2) the invasive species (pest or weed) targeted by the agent, (3) one or more native species that stand to benefit from the control of the target species, and (4) one or more native species that are at risk of being harmed by the released biological control agent. Conservation values of the potentially benefited and harmed native species are incorporated as well, and they are weighted according to three axes: vulnerability to extinction, the ecosystem services provided, and cultural significance. Further, we incorporate the potential for indirect risks to native species, which we consider will result mainly from the ecological process of agent enrichment that may occur if the agent exploits but does not control the target pest or weed. We illustrate the use of this framework by retrospectively analyzing the release of the vedalia beetle, Novius (= Rodolia) cardinalis, to control the cottony cushion scale, Icerya purchasi, in the Galapagos Islands. While the framework is particularly adaptable to biological control releases in natural areas, it can also be used in managed settings, where biological control protects native species through the reduction of pesticide use.
摘要:
150多年来,生物防治剂的释放一直是控制入侵物种的重要手段。虽然这些释放导致全球250多种入侵害虫和杂草物种的可持续控制,少数人造成了环境危害。对生物控制风险的日益认识导致从1990年代开始对风险评估的关注,同时释放量急剧下降。虽然这一新重点大大提高了生物防治的安全性,它以失去解决与入侵物种相关的环境问题的机会为代价。因此,需要一个包含生物控制利益和风险的框架来了解生物控制释放的净环境影响。我们引入这样一个框架,利用本地生物多样性作为利益和风险的共同货币。该模型基于四类生物之间的相互作用:(1)生物防治剂,(2)代理针对的入侵物种(害虫或杂草),(3)一个或多个从目标物种的控制中受益的本地物种,和(4)处于被释放的生物防治剂损害的风险中的一种或多种天然物种。潜在受益和受损的本地物种的保护价值也被纳入,它们根据三个轴加权:濒临灭绝的脆弱性,提供的生态系统服务,文化意义。Further,我们考虑了对本地物种的潜在间接风险,我们认为这将主要是由于药剂富集的生态过程,如果药剂利用但不控制目标害虫或杂草,则可能会发生这种情况。我们通过回顾性分析vedalia甲虫的释放来说明这个框架的使用,Novius(=Rodolia)红衣主教,为了控制棉垫秤,Iceryapurchasi,在加拉帕戈斯群岛.虽然该框架特别适用于自然区域的生物防治释放,它也可以在托管设置中使用,生物控制通过减少农药的使用来保护本地物种。