Understanding how wetland species became rare or locally extinct using sedimentary DNA and stable isotopes - supporting future ecological restoration

湿地是全球经济、社会和生态最重要的生态系统之一，但由于人类活动导致湿地丧失和退化，湿地受到威胁（Hu et al., 2017）。在气候变化方面，湿地通过吸收二氧化碳和排放甲烷影响全球和局部气候（Hu et al., 2017; Russi, 2013）。此外，淡水湿地覆盖了地球表面的1%，却为世界上40%的物种提供了栖息地，使其成为生物多样性的重要贡献者（Mitra， S., Wassmann， R. and Vlek， P.L.G.（主编），2003）。湿地还通过补充地下水、调节水运动和净化水来促进水文循环（千年生态系统评估，2005年）。就人类健康而言，湿地提供了传统药物，世界上80%的人口依赖这些药物进行初级卫生保健，使其成为人类资源的绝对必需品（Hu等人，2017;Mitra， S., Wassmann， R.和Vlek， P.L.G.（主编），2003）。环境DNA和稳定同位素可以解释物种的摄食和饮食习惯，提供有关猎物类型及其相对重要性的关键信息（Oliveira, 2018）。此外，当营养资源是其分布和栖息地利用、生存和繁殖成功的限制因素时，它可以帮助解释种群动态，并允许采取适当的保护行动（Martin, 1987； Molina和Erwin, 2006; Newton, 1998； Toral等，2012）。了解湿地过去的营养水平可以帮助未来的管理和恢复项目，因为它可以帮助我们了解哪些物种是本地的，以及它们喜欢的环境。此外，观察特定历史阶段的气候和营养水平可以解释物种灭绝。反过来，这将确保物种不会被引入由于不适当的气候条件、竞争或人为压力而无法生存的地区。自20世纪70年代以来，世界上超过三分之一的湿地已经消失，83%的淡水物种正在减少（野禽和湿地信托基金，2022b）。2018年，英国政府制定了一项为期25年的环境计划，并规定以前所未有的规模恢复湿地，以减少洪水风险并提供宝贵的生态栖息地。重新引入湿地的指导方针要求了解哪些湿地物种是真正的本地物种，以及它们为什么会消失。这个项目将有助于这些指导方针，并提供一个本地物种及其可能消亡原因的数据库，从而创建本地湿地。此外，它将创造一种方法，可以应用于世界范围内的湿地恢复，并有可能估计以前物种减少的速度和原因，保护现有的野生动物。该项目旨在了解现代技术如何重建过去的生态系统，并解决湿地的生态问题。此外，它还努力填补在利用环境DNA （eDNA）和稳定同位素创建模型方面的研究空白，以估计湿地退化的速率和原因。实现这些目标将为野禽和湿地信托基金（WWT）等组织提供足够的信息，以遵守英国政府创建湿地的指导方针。

Wetlands represent one of the most critical ecosystems globally for economic, social and ecological purposes, yet they are threatened due to anthropogenic activities causing wetland loss and degradation (Hu et al., 2017). Regarding climate change, wetlands affect global and local climates by absorbing carbon dioxide and emitting methane (Hu et al., 2017; Russi, 2013). Furthermore, freshwater wetlands cover 1% of the earth's surface yet provide habitats for >40% of the world's species, making it a large contributor to biodiversity (Mitra, S., Wassmann, R. and Vlek, P.L.G. (eds.), 2003). Wetlands also contribute to the hydrological cycle by replenishing groundwater, regulating water movement and purifying water (Millennium Ecosystem Assessment, 2005). For human health, wetlands provide traditional medicines of which 80% of the world's population rely on for primary health care, making them an absolute necessity for humans regarding their resources (Hu et al., 2017; Mitra, S., Wassmann, R. and Vlek, P.L.G. (eds.), 2003). Environmental DNA and stable isotopes can explain species' feeding and diet habits, providing critical information about the types of prey consumed and their relative importance (Oliveira, 2018). Furthermore, it can aid in the interpretation of population dynamics and allow appropriate conservation actions when trophic resources are the limiting factor in their distribution and habitat use, survival and reproductive success (Martin, 1987; Molina and Erwin, 2006; Newton, 1998; Toral et al., 2012). Understanding past trophic levels within wetlands can aid in future management and restoration projects as it would provide insights into which species are native and their preferred environments. Furthermore, looking at the climate and trophic levels at certain historical stages could explain extinctions. In turn, this will ensure species are not introduced into areas where they could not survive due to inappropriate climatic conditions, competition, or anthropogenic pressures. Over a third of the world's wetlands have disappeared since the 1970s, with 83% of freshwater species declining (Wildfowl and Wetlands Trust, 2022b). In 2018 the UK Government created a 25-year Environment Plan and specified restoring wetlands on a never-before-seen scale to reduce flood risk and provide valuable ecological habitats. Reintroduction guidelines require an understanding of which wetland species are genuinely native and why they disappeared. This project would aid those guidelines and provide a database of native species and possible reasons for their demise, allowing native wetlands to be created. Furthermore, it would create a method that can be applied to the worldwide restoration of wetlands and can potentially estimate rates and causes of the decline of previous species, preserving current wildlife.This project aims to understand how modern technologies can reconstruct past ecosystems and solve ecological questions about wetlands. Furthermore, it endeavours to answer gaps in research with regards to using environmental DNA (eDNA) and stable isotopes to create models that can estimate rates and causes of decline in wetlands. Reaching these aims will provide enough information for organisations such as the Wildfowl and Wetlands Trust (WWT) to comply with the UK Government's guidelines to create wetlands.