Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
J Environ Manage. 2021 Jul 15;290:112545. doi: 10.1016/j.jenvman.2021.112545. Epub 2021 Apr 21.
Classical biocontrol is key for the successful management of invasive alien plants; yet, it is still relatively new in Europe. Although post-release monitoring is essential to evaluate the effectiveness of a biocontrol agent, it is often neglected. This study reports the detailed post-release monitoring of the first biocontrol agent intentionally introduced against an invasive plant in continental Europe. The Australian bud-galling wasp Trichilogaster acaciaelongifoliae (Frogatt) is used to control the invasive Acacia longifolia (Andr.) Willd., with a long history of success in South Africa. This biocontrol agent was first released in Europe in 2015 at several sites along the Portuguese coast. We monitored the establishment, spread and early impacts of T. acaciaelongifoliae on target-plants in Portugal, across 61 sites, from 2015 to 2020. Initial release of adults emerging from galls imported from South Africa and the subsequent releases from galls established in Portugal (2018 onwards) was compared, assessing the implications of the hemisphere shift. The impacts on the reproductive output and vegetative growth of A. longifolia were evaluated in more detail at three sites. From 2015 to 2019, 3567 T. acaciaelongifoliae were released at 61 sites, with establishment confirmed at 36 sites by 2020. The transfer of the wasp from the southern hemisphere limited its initial establishment, but increased rates of establishment followed with synchronization of its life cycle with northern hemisphere conditions. Therefore, after an initial moderate establishment, T. acaciaelongifoliae adapted to the northern hemisphere conditions and experienced an exponential growth (from 66 galls by 2016, to 24000 galls by 2018). Galled A. longifolia branches produced significantly fewer pods (-84.1%), seeds (-95.2%) and secondary branches (-33.3%) and had fewer phyllodes but increased growth of the main branch compared to ungalled branches. Trichilogaster acaciaelongifoliae successfully established in the northern hemisphere, despite the initial phenological mismatch and adverse weather conditions. To achieve this, it had to establish and synchronize its life cycle with the phenology of its host-plant, after which it developed exponentially and began to show significant impacts on the reproductive output of A. longifolia.
经典生物防治是成功管理入侵外来植物的关键；然而，它在欧洲仍然相对较新。尽管释放后监测对于评估生物防治剂的效果至关重要，但它经常被忽视。本研究报告了首例在欧洲大陆引入的入侵植物生物防治剂的详细释放后监测。澳大利亚芽瘿蜂 Trichilogaster acaciaelongifoliae (Frogatt) 用于控制具有悠久成功历史的南非入侵植物长叶相思 Acacia longifolia (Andr.) Willd. 。这种生物防治剂于 2015 年首次在欧洲葡萄牙沿海的几个地点释放。我们在 2015 年至 2020 年期间，在葡萄牙的 61 个地点监测了 T. acaciaelongifoliae 对目标植物的建立、传播和早期影响。比较了从南非进口的瘿中成虫的初始释放和随后从葡萄牙建立的瘿中的释放（2018 年以后），评估了半球转移的影响。在三个地点更详细地评估了对长叶相思生殖产量和营养生长的影响。2015 年至 2019 年，在 61 个地点释放了 3567 只 T. acaciaelongifoliae，到 2020 年，有 36 个地点确认建立。将黄蜂从南半球转移限制了其最初的建立，但随着其生命周期与北半球条件的同步，建立率增加。因此，在最初适度建立之后，T. acaciaelongifoliae 适应了北半球的条件，并经历了指数级增长（从 2016 年的 66 个瘿，到 2018 年的 24000 个瘿）。生瘿的长叶相思分枝产生的荚果数量减少了 84.1%，种子减少了 95.2%，二级分枝减少了 33.3%，叶状柄减少了，但主分枝的生长增加了。尽管最初存在物候学不匹配和不利的天气条件，T. acaciaelongifoliae 仍在北半球成功建立。为了实现这一目标，它必须在其宿主植物的物候学上建立并同步其生命周期，之后它呈指数级增长，并开始对长叶相思的生殖产量产生显著影响。
