Optimising the long-term control of invasive American mink from catchment to coast: how many mink is too many?

外来入侵物种威胁着生物多样性、生态系统功能和服务，并给国家经济带来代价。全球正在进行管理努力，以减少这些影响，但很少有人注意到无法根除客栈的情况，因此减少人口和遏制人口是唯一可行的解决方案。在内地的情况下尤其如此，因为遣送最后一批人的费用往往高得令人望而却步，或者在技术上是不可行的。在这种情况下，有效的长期管理必须优化稀缺的可用资源，以便有效控制，以应对Inns的影响。至关重要的是，这需要了解受管理客栈的丰富度/密度与受威胁本土物种的持续存在之间的关系，以及在优先管理的地区恢复以前被大幅削减的本土物种种群之间的关系。然而，即使是对于长期的项目，Inns对本地物种的控制努力的结果也大多缺乏证据。该项目将通过整理和分析16年来客栈控制超过23,000平方公里的有价值的数据和有关本地物种恢复的新数据，为弥补这一全球知识鸿沟做出贡献。美国水貂在历史上逃离毛皮农场后入侵了英国的大部分地区。水貂入侵了所有的栖息地，特别是在海岸线上蓬勃发展，它们在那里捕食海洋和陆地的猎物。它们对河岸和沿海生物多样性不断升级的影响是有据可查的。英国和其他地方已经启动了多个水貂控制项目，其中许多项目的动机是保护水鼠，受到美国水貂捕食的严重影响。就像猎物天真地捕食新的捕食者一样，当水貂入侵河边的水鼠群体时，不会在当地共存；当地的灭绝总是随之而来的。当这个过程在空间和时间上重复时，集合种群逐渐崩溃。协调控制超过23,000平方公里的水貂数量大大减少了水貂的数量，但从边远地区重新入侵需要进行持续的管理。评估多少数量的水貂控制足以防止水貂数量下降，并以具有成本效益的方式恢复目标物种，是适应性管理的关键一步，适用于其他无法根除的Inns物种。在苏格兰大陆，水貂控制是通过动员志愿公民保护者的热情实现的，由当地渔业信托基金的少数工作人员协调。在这些努力的基础上，我们将把水貂控制强度与水鼠恢复程度的估计联系起来。我们的研究问题包括：1.怎样的控制努力才能让脆弱的本土猎物物种持续存在？以水鼠恢复程度衡量的水貂控制努力-水貂影响关系是什么形式的？是否需要在一段时间内加强对水貂的控制，以恢复依赖扩散的非平衡集合种群，以扩散到由于先前的水貂捕食而导致种群局部灭绝的栖息地？3.地形、土地覆盖和与不受控制的集水区的毗邻如何影响水貂控制努力的能力及其对本地猎物的影响？

Invasive Non-native Species (INNS) threaten biodiversity, ecosystem functions and services and impose costs to national economies. Management efforts are underway globally to reduce these impacts, but little attention has been paid to situations where INNS are impossible to eradicate, and therefore population reduction and containment are the only feasible solutions. This is particularly true in mainland situations where removal of the final individuals is often prohibitively expensive or technically not feasible. In such circumstances, effective long-term management must optimise scarce available resources for effective control to address INNS impacts. Critically, this requires knowledge of the relationship between the abundance/density of managed INNS and the continued presence of threatened native species, and recovery of previously decimated native species populations in areas prioritised for management. However, even for long-standing projects, the evidence for the outcome of INNS control efforts on native species is mostly lacking. This project will contribute to remedying this global knowledge gap by collating and analysing valuable data on 16 years of INNS control effort over 23,000 km2 and new data on native species recovery.The American mink has invaded most of the UK following historical escapes from fur farms. Mink have invaded all habitats, particularly thriving along coastlines where they exploit both marine and terrestrial prey. Their escalating impacts on riparian and coastal biodiversity is well documented. Multiple mink control projects have been initiated in the UK and beyond, many motivated by the desire to protect water voles, severely affected by American mink predation.As is often the case with prey naïve to a novel predator, there is no local coexistence when mink invade a riparian water vole colony; local extinction always ensues. When this process is repeated across space and time, metapopulation collapse gradually occurs. Coordinated mink control over 23,000 km2 delivered substantial reduction in mink abundance but reinvasion from outlying areas necessitates ongoing management. Evaluating what amount of mink control is sufficient to prevent declines and allow the recovery of target species in a cost-effective manner is a key step in adaptive management, with applications to other INNS species that cannot be eradicated.In mainland Scotland, mink control was achieved by mobilising the enthusiasm of volunteer citizen conservationists coordinated by a handful of local fisheries trusts' staff. Building on these efforts, we will relate mink control intensity to estimates of the extent of recovery of water voles. Colloquially, we can find out "how many mink is too many mink?"Our research questions include:1. What control effort allows the persistence of vulnerable native prey species? What is the shape of the mink control effort - mink impact relationship, as measured by the extent of water vole recovery.2. Is more intensive mink control required for a time to allow the recovery of non-equilibrium metapopulations that rely on dispersal for spread into habitats where populations are locally extinct due to prior mink predation?3. How do topography, land cover and adjacency to uncontrolled catchments impact the resilience of mink to control effort and their impact on native prey?