Dippers (Cinclus cinclus) as bioindicators of health and resilience of freshwater ecosystems in the face of complex ecological change

面对复杂的生态变化，北斗七星（Cinclus cinclus）作为淡水生态系统健康和恢复力的生物指标

• 批准号: 2273240
• 金额: --
• 依托单位: University of Stirling
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2273240
• 关键词: Dippers; Cinclus; cinclus; bioindicators; health

Freshwater ecosystems are of critical importance because they integrate effects of environmental pressures across landscapes and catchments and are more than twice as important as other broad habitat types in terms of ecosystem service delivery per unit area (Natural Capital Asset Index). Monitoring freshwaters effectively and understanding their response to multiple environmental stressors is, however, challenging.Dippers are the quintessential river bird of Britain and, as a predator, are likely to provide a convenient and effective sentinel of the health of our riverine ecosystems and their response to various forms of environmental management. Dippers are proven sensitive indicators of anthropogenic pressures such as acidification from air pollution (e.g. Vickery, 1992). However, in the past 30 years, acid deposition has declined greatly following controls on emissions, while more environmentally benign forestry practices may have helped to mitigate impacts of conifer plantations on upland stream acidification. Water pollution from industrial and urban point sources has also been strictly regulated leading to improved water quality. The declines in dipper populations, and those of other riparian birds (e.g. grey wagtail, common sandpiper, goosander) revealed by Bird Atlas 2007-11, are therefore a conundrum.Dippers are predicted to be highly responsive to the changes in temperature and flow regimes that will arise from climate change over the 21st century (Saether et al., 2000). While Dippers are adversely affected by severe winters these have been eclipsed by mild wet winters in recent decades which are reflected in overall increases in river flow and variability, most notably in the west of the country. Water colour is generally increasing ('brownification') in upland freshwaters as the constraining effects of acidification on decomposition rates and solubility of organic carbon are lifted, alongside increasing precipitation and temperature (Battarbee et al., 2014). There is a growing case that effects of more variable river flow regimes and increased water colour on aquatic invertebrate prey and Dipper foraging efficiency may be affecting Dipper demographic rates (e.g. Taylor & O'Halloran, 2001), and thus contributing to declines in this and other river birds. Finally, while there is good evidence for chemical improvement of acidified upland freshwaters, most assessments suggest that biological recovery of acid-sensitive invertebrates and fish is lagging some way behind (Battarbee et al., 2014). The current status of Dippers may be an extension of this trend upon which other stressors have gradually been superimposed.Scotland has a rich archive of detailed climate projections, land cover maps, recent management histories, and high quality historical and current data on river flow, chemistry and invertebrate populations. Combined with the multiple detailed historical studies of Dipper ecology and demography from different parts of the country this provides a unique opportunity to test how the changing balance of environmental pressures on freshwaters is integrated in its impact on a charismatic and accessible bio-indicator species. It also presents an opportunity to explore if various local and catchment scale management interventions, ultimately intended to benefit biodiversity and ecosystem service delivery, are captured in improved Dipper performance. Native riparian tree planting and peatland restoration, for example, are measures that might be expected, via a range of mechanisms, to benefit Dippers.

淡水生态系统至关重要，因为它们综合了各种地貌和集水区的环境压力影响，就单位面积生态系统服务提供而言，其重要性是其他广泛生境类型的两倍以上（自然资本资产指数）。然而，有效地监测淡水并了解其对多种环境压力的反应是具有挑战性的。啄木鸟是英国典型的河鸟，作为捕食者，可能为我们的河流生态系统的健康及其对各种形式的环境管理的反应提供方便有效的哨兵。经证明，铲斗是人为压力的敏感指标，如空气污染造成的酸化（例如，Vickery，1992年）。然而，在过去的30年里，酸沉降大大减少后，控制排放量，而更环保的林业做法可能有助于减轻针叶树种植对高地流酸化的影响。工业和城市点源的水污染也受到严格管制，从而改善了水质。因此，Bird Atlas 2007-11揭示的杓鹬和其他河岸鸟类（如灰燕尾、普通矶鹬、鹅）数量的下降是一个难题。据预测，杓鹬对21世纪气候变化引起的温度和流动状况的变化反应灵敏（Saether et al.，2000）。虽然迪普人受到严冬的不利影响，但近几十年来，这些严冬已被温和潮湿的冬天所掩盖，这反映在河流流量和变化性的总体增加上，尤其是在该国西部。随着酸化对有机碳分解速率和溶解度的限制作用被解除，以及降水和温度的增加，高地淡水中的水色通常会增加（“褐变”）（Battarbee等人，2014年）。有越来越多的情况下，更多变的河流流量制度和增加水的颜色对水生无脊椎动物的猎物和北斗七星觅食效率的影响可能会影响北斗七星的人口率（例如泰勒和O 'Halloran，2001年），从而导致这种和其他河流鸟类的下降。最后，虽然有很好的证据表明酸化高地淡水的化学改善，但大多数评估表明，酸敏感无脊椎动物和鱼类的生物恢复落后了一些（Battarbee等人，2014年）。目前的状态可能是一个延伸的趋势，其他压力源已逐渐叠加。苏格兰有详细的气候预测，土地覆盖图，最近的管理历史，高质量的历史和当前数据的河流流量，化学和无脊椎动物种群丰富的档案。结合来自全国不同地区的北斗七星生态和人口统计学的多项详细历史研究，这提供了一个独特的机会来测试淡水环境压力的平衡变化如何整合到其对魅力和可访问的生物指示物种的影响中。它还提供了一个机会，以探讨各种地方和流域规模的管理干预措施，最终目的是有利于生物多样性和生态系统服务的提供，被捕获在改善北斗性能。例如，当地的河岸植树和泥炭地恢复是可能通过一系列机制使Dippers受益的措施。