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，并给国家经济带来成本。全球正在进行管理努力以减少这些影响，但很少注意到INNS无法根除的情况，因此人口减少和遏制是唯一可行的解决方案。在大陆的情况下尤其如此，因为遣返最后的个人往往费用高昂，或者在技术上不可行。在这种情况下，有效的长期管理必须优化稀缺的可用资源，以有效控制INNS的影响。至关重要的是，这需要了解所管理的INNS的丰度/密度与受威胁的本地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摧毁的本地物种种群。然而，即使是长期的项目，INNS对本地物种的控制努力的结果的证据大多是缺乏的。该项目将通过整理和分析16年来INNS在23，000平方公里范围内的控制工作的宝贵数据以及关于本地物种恢复的新数据，为弥补这一全球知识空白做出贡献。水貂已经入侵了所有的栖息地，特别是在沿着海岸线，它们利用海洋和陆地的猎物。它们对河岸和沿海生物多样性不断升级的影响已有详细记载。多个水貂控制项目已经在英国和其他地方启动，许多是出于保护水鼠的愿望，受到美国水貂捕食的严重影响。通常情况下，当水貂入侵河岸水鼠殖民地时，没有当地的共存;当地灭绝总是发生。当这个过程在空间和时间上重复时，集合种群的崩溃逐渐发生。对23 000平方公里的水貂进行协调控制，使水貂数量大幅减少，但需要对来自外围地区的水貂进行持续管理。评估水貂控制量足以防止减少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，并应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主义者的热情，并由少数当地渔业信托基金的工作人员协调实现的。在这些努力的基础上，我们将水貂控制强度与水鼠恢复程度的估计相关联。通俗地说，我们可以找出“多少貂是太多貂？“我们的研究问题包括：1.是什么样的控制努力使脆弱的本地猎物物种得以持续存在？水貂控制努力的形状-水貂的影响关系，如水鼠恢复的程度所衡量的。是否需要更密集的貂控制一段时间，以恢复非平衡集合种群，依靠扩散到栖息地，人口是当地灭绝，由于先前的貂捕食？3.地形、土地覆盖和邻近不受控制的集水区如何影响水貂的控制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?