Populations at the edge: range dynamics and conservation of the Great Crested Newt under global change.

在人类活动的开发和环境的快速变化下，许多物种面临着新的生存环境的挑战，一些物种正在转移它们的活动范围，许多物种正在受到威胁或灭绝。物种分布范围边缘的种群是关键，而且往往是最脆弱的：它们规模小，支离破碎，联系较少；遗传多样性低，生境欠佳；经常面临多种人为压力，如栖息地的丧失和恶化。然而，处于范围领先边缘（朝向气候变化方向的边缘）的种群是物种成功转移范围的关键：它们已经占据了适应性将得到改善的位置，因此可能很容易扩大，并且可能拥有独特的和对当地有利的遗传变异。了解这些种群在生态和进化上如何应对环境变化，它们是否能够在多种自然和人为压力下持续存在，以及我们如何更好地帮助它们在这一过程中，对于全球变化下有效的物种保护至关重要。基于预测过程的模型，整合了形成物种生态和适应性反应的基本过程，如遗传变异、人口统计学和扩散，以及评估多种环境压力因素的影响，是更好地了解物种范围动态和更好地预测物种对未来环境变化的可能反应的有力工具。这些模型正在开发中，它们现在已经成熟，可以进行测试并应用于保护相关的应用。两栖动物在全球范围内正在减少，是生物多样性保护的重中之重。它们特别容易受到多种压力因素的影响，因为它们依赖湿地，而湿地是一个特别受到气候变化和栖息地丧失挑战的生态系统，并受到入侵物种、疾病和污染的威胁。在欧洲，大冠蝾螈是一个正在减少的物种。在英国，它是一种重要的湿地旗舰物种，近年来在本土两栖动物中呈现出最高的下降速度。在苏格兰，T. cristatus并不常见，分布范围有限且分散，重要的是，苏格兰代表了该物种世界范围的西北范围。重要的是，该物种在苏格兰的分布不一致，在Fife最北的地点和最南的高地地点之间有80公里的差距。已经确定了许多合适的未被占用的栖息地，预计将有更多的栖息地适合气候变化，为这些边缘种群扩大其范围创造了潜力。然而，由于城市化、农业变化和工业发展、干旱加剧、遗传多样性减少以及来自信号小龙虾和美洲水貂等非本地物种的捕食风险增加等多重威胁，使得这种扩张和持续存在的可能性变得极其不确定。因此，对于研究变暖范围边缘种群对环境变化的生态和适应反应，以及应用新的基于综合过程的方法来预测这些反应和指导保护干预措施，Cristatus是一个优秀的和重要的物种。该项目的总体目标是了解和预测在持续的气候变化和多种压力因素下苏格兰cristatus的持久性，以及其从边缘种群扩展的潜力，为保护管理提供信息，朝着积极主动的方向发展，而不是被动地管理全球变化下两栖动物数量下降。

Under anthropogenic exploitation and rapid environmental changes, many species are challenged with novel conditions, some are shifting their ranges moving to new suitable areas, and many are now threatened or extinct.Populations at the edges of species' range are key and often the most vulnerable: they are small, fragmented and less connected; harbour low genetic diversity and occupy suboptimal habitat; often face multiple anthropogenic stressors such as habitat loss and deterioration. However, populations that are at the range leading margin (the edge towards the direction of climate change) are key for successful species' range shifting: they already occupy locations where suitability will improve and thus could potentially readily expand, and might possess unique and locally favourable genetic variants. Understanding how these populations will respond to environmental change, both ecologically and evolutionarily, whether they will be able to persist under multiple natural and anthropogenic stressors, and how better we can assist them in this process, is crucial for effective species' conservation under global change.Predictive process-based models, that integrate the fundamental processes shaping species' ecology and adaptive responses, such as genetic variation, demography and dispersal, together with assessing impacts of multiple environmental stressors, are a powerful tool to both better understanding species' range dynamics and making better predictions of likely species' responses to future environmental change. These models are being developed, and they are now ripe for testing and for applications of conservation relevance.Amphibians are declining globally and are a high priority for biodiversity conservation. They are particularly vulnerable to multiple stressors as they rely on wetlands, an ecosystem particularly challenged by climate change and habitat loss, and are threatened by invasive species, diseases and pollution. The great crested newt Triturus cristatus is a declining species in Europe. In Britain it is an important wetland flagship species and has shown the highest rate of decline in recent years amongst native amphibians. In Scotland, T. cristatus is uncommon, with a restricted and fragmented range and, importantly, Scotland represents the north-west range of the species' world range. Critically, the species has a disjoint distribution in Scotland with an 80 km gap between the most northerly site in Fife and the most southerly Highland site. Much suitable unoccupied habitat has been identified and more is predicted to become suitable with climate change, creating potential for these edge populations to expand their range. However, multiple threats such has increasing habitat fragmentation, due to urbanization, agricultural changes and industrial developments, increasing drought, reduced genetic diversity, and increasing risk of predation from non-native species such as the signal crayfish and American mink, make it extremely uncertain whether this expansion and persistence will be at all possible.T. cristatus is thus an excellent and important species for investigating ecological and adaptive responses to environmental changes of populations at the warming range margins, and for applying new integrated process-based methods to predict these responses and guide conservation interventions.The overall aim of this project is to understand and predict the persistence of T. cristatus in Scotland under ongoing climate change and multiple stressors, and its potential expansion from marginal populations, to inform conservation management, moving towards a pro-active, rather than reactive, management of declining amphibians under global change.