LETG-Angers, UMR 6554 CNRS, Université d'Angers, Angers, France.
REHABS International Research Laboratory, CNRS-Université Lyon 1-Nelson Mandela University, George, South Africa.
PLoS One. 2021 Apr 8;16(4):e0249904. doi: 10.1371/journal.pone.0249904. eCollection 2021.
Two aquatic invasive alien rodents, the coypu (Myocastor coypus) and muskrat (Ondatra zibethicus), have taken over a significant amount of wetlands in France. Pays de la Loire is an administrative region of about 32 000 km2 in the Western France with 6.3% of its area in wetlands (excluding the Loire River). Populations of coypus and muskrats are established and a permanent control programme has been set to reduce their impacts. The control plan is based on few professional trappers and many volunteers which makes this programme unique compared to other programme relying on professionals only. The aim of this study is to analyse the temporal and spatial dynamics of coypu and muskrat captures during the last 10 years to evaluate their effectiveness. The number of rodents removed per year increased by 50% in 10 years and reached about 288 000 individuals in 2016 with about 80% of them being coypus. During the same time length, the number of trappers involved in the programme also increased by 50% to reach 3 000 people in 2016. Although the raise of coypus and muskrats trapped can possibly be explained by an increase of the number of trappers, the number of coypus removed per trapper per year increased by 22%. Despite the outstanding number of individuals removed per year, our results suggest that the programme does not limit the population dynamics of coypus. Finally, since 2017, the number of data gathered from municipalities decreased, as did the total number of individuals trapped. Indeed, although rewards are crucial to recruit new volunteers, subsidies from local and regional authorities are declining. Decision makers and financers should be encouraged to fund this programme from the perspectives of the direct or indirect costs related to the presence of aquatic invasive alien rodents in wetlands.
两种水生入侵外来啮齿动物，海狸鼠（Myocastor coypus）和麝鼠（Ondatra zibethicus），已经占据了法国相当多的湿地。卢瓦尔河地区是法国西部一个约 32000 平方公里的行政区，其湿地面积占 6.3%（不包括卢瓦尔河）。海狸鼠和麝鼠的种群已经建立起来，并制定了一个永久性的控制计划，以减少它们的影响。该控制计划依靠少数专业捕鼠者和许多志愿者，这使得该计划与其他仅依靠专业人员的计划相比具有独特性。本研究的目的是分析过去 10 年中海狸鼠和麝鼠捕获的时间和空间动态，以评估其效果。每年移除的啮齿动物数量在 10 年内增加了 50%，到 2016 年达到约 288000 只，其中 80% 是海狸鼠。在同一时间段内，参与该计划的捕鼠者人数也增加了 50%，到 2016 年达到 3000 人。尽管被捕的海狸鼠和麝鼠数量的增加可能是由于捕鼠者数量的增加，但每个捕鼠者每年捕获的海狸鼠数量增加了 22%。尽管每年移除的个体数量惊人，但我们的研究结果表明，该计划并没有限制海狸鼠的种群动态。最后，自 2017 年以来，从市政府收集的数据数量减少了，被捕的个体总数也减少了。事实上，尽管奖励对于招募新的志愿者至关重要，但地方和地区当局的补贴正在减少。决策者和资助者应该鼓励从与湿地中水生入侵外来啮齿动物有关的直接或间接成本的角度来资助该计划。
