Endriss Stacy B, Nuzzo Victoria, Blossey Bernd
Department of Natural Resources and the Environment, Cornell University, Ithaca, New York, USA.
Department of Environmental Sciences and Center for Marine Science, University of North Carolina Wilmington, Wilmington, North Carolina, USA.
Ecol Appl. 2025 Jun;35(4):e70064. doi: 10.1002/eap.70064.
Spread of non-native species can be important drivers of biodiversity declines, leading to precautionary management based on assumptions that (1) non-native biota have negative impacts and are "guilty" of causing harm and (2) reducing a non-native species' abundance will reduce these negative impacts, in turn, benefiting native species. However, we frequently lack data to gauge both negative impacts of non-native species and success or failure of chosen management interventions to benefit native species. Addressing these knowledge gaps is critical to improving management outcomes for native species while maintaining public trust to sustain funding of management activities. Here, we investigated the response of Lythrum salicaria (purple loosestrife) and associated plant communities to implementation of biological control in more than 10 wetland sites in New York State for up to 28 years. Introduced to North America from Europe in the 1800s, L. salicaria is a prime example of a non-native species with a continent-wide distribution that could not be suppressed by mechanical and chemical treatments. In the 1980s, waterfowl biologists, wetland managers, and conservationists alike worried about the loss of diverse wetland plant communities associated with the rapid expansion of L. salicaria. In response, after careful assessments of safety, and potential costs and benefits, four highly host-specific insect herbivores were released in North America in the early 1990s to reduce L. salicaria abundance and its negative ecological impacts. In a companion paper, Blossey et al. documented reduced L. salicaria occupancy and stem densities following insect releases over time (i.e., biological success), irrespective of site-specific differences in starting plant communities or L. salicaria abundance. Here, we show that reduced abundance of L. salicaria leads to the ultimate goal of non-native plant management: increased cover, abundance, and diversity of species, often of native species (i.e., ecological success). We also conduct analyses to provide inference about which plant species are most sensitive to L. salicaria, including changes in L. salicaria stem density. Overall, we provide an important conservation success story: our findings emphasize that biocontrol of non-native plants can be effective and safe, allowing native species to recover as a dominant non-native species gradually declines.
非本土物种的扩散可能是生物多样性下降的重要驱动因素，这导致基于以下假设的预防性管理：（1）非本土生物群具有负面影响，并且是造成危害的“罪魁祸首”；（2）减少非本土物种的数量将减少这些负面影响，进而使本土物种受益。然而，我们常常缺乏数据来衡量非本土物种的负面影响以及所选管理干预措施对本土物种有益与否的成败。填补这些知识空白对于改善本土物种的管理成果，同时维持公众信任以确保管理活动的资金支持至关重要。在此，我们调查了在纽约州10多个湿地地点实施生物防治长达28年期间，千屈菜（紫千屈菜）及相关植物群落的反应。千屈菜于19世纪从欧洲引入北美，是一种分布于整个大陆的非本土物种的典型例子，机械和化学处理都无法抑制其生长。在20世纪80年代，水鸟生物学家、湿地管理者和自然资源保护主义者都担心与千屈菜迅速扩张相关的多样湿地植物群落的丧失。作为回应，在对安全性以及潜在成本和收益进行仔细评估后，20世纪90年代初在北美释放了四种高度寄主专一性的食草昆虫，以减少千屈菜的数量及其负面生态影响。在一篇配套论文中，布洛西等人记录了随着时间推移昆虫释放后千屈菜的占有率和茎密度降低（即生物防治成功），而与起始植物群落或千屈菜数量的特定地点差异无关。在此，我们表明千屈菜数量的减少导致了非本土植物管理的最终目标：物种（通常是本土物种）的覆盖度、数量和多样性增加（即生态成功）。我们还进行了分析，以推断哪些植物物种对千屈菜最敏感，包括千屈菜茎密度的变化。总体而言，我们提供了一个重要的保护成功案例：我们的研究结果强调，非本土植物的生物防治可以有效且安全，使本土物种能够随着一种占主导地位的非本土物种逐渐减少而恢复。
