Grazing and disturbance as management tools in coastal slacks: consequences for soil organic matter, biodiversity and functional resilience

沙丘湿地或湿地是生物多样性的栖息地，支持许多稀有的英国植物、无脊椎动物和脊椎动物物种。它们是欧洲自然保护的优先栖息地。放牧和干扰在沿海生境中对维持这种保护价值很重要，因为它们阻止了向灌木丛生境的演替，因此认识到它们更广泛的影响对于指导管理活动至关重要。我们对这些因素如何改变地上群落有很好的了解，但我们对这些系统中地下生物多样性的了解有限，特别是在植物与土壤成分之间的相互作用和对生物地球化学功能的影响方面。早期的工作以土壤有机质的积累为特征，并记录了其他土壤性质的变化(例如，Jones等人。2008年)。然而，很少有研究评估土壤微生物群落(Wasserstrom等人)。(2017年)和动物(Butt&Chamberlain，2007)可能会发展，以及地下生物多样性和植物-土壤相互作用的改变是否会推动土壤功能过程的变化。此外，迫切需要更好地了解这些变化可能如何与不同的放牧或干扰制度相互作用。利用已建立的长期实验和更广泛的研究地点网络，这项研究将测试有机质质量、土壤生物多样性和海岸系统功能弹性之间的联系，并提供独特的地下证据，以帮助优化保护管理策略。总而言之，本博士论文的目的是回答以下问题：1.放牧制度对沿海沙丘荒漠土壤中有机质质量、微生物和动物组成的长期影响是什么？2.土壤生物多样性的组成是否决定了生物地球化学功能的能力及其对气候和水文波动的恢复能力？3.能否确定优化植物群落、土壤生物多样性和功能恢复能力的管理策略？该项目将重点放在位于兰开夏郡东海岸的Ainsdale Sand Dunes国家级自然保护区的大片沙丘恢复系统上。该地点包括安斯代尔沙丘松弛长期实验(LTE)。这项放牧实验建立于1974年，是英国运行时间最长的沙丘湿地放牧实验，由绵羊和兔子组成。该提案将建立在米利特博士在安斯代尔所做的早期研究基础上(米利特和埃德蒙森，2013,2015)。

Sand dune wetlands or slacks are biodiverse habitats supporting many rare UK plant, invertebrate and vertebrate species. They are a priority habitat for nature conservation in Europe. Grazing and disturbance are important in coastal habitats for maintaining this conservation value because they prevent succession towards scrub habitat, so appreciating their wider impacts is essential for directing management activities. We have good understanding of how these factors can alter aboveground communities but our knowledge on belowground biodiversity in these systems is limited, particularly in the context of interactions between plants and soil components and consequences for biogeochemical functioning. Earlier work characterised the accumulation of soil organic matter with slack age and documented changes in other soil properties (e.g. Jones et al. 2008). Few studies, however, have evaluated how soil microbial communities (Wasserstrom et al. 2017) and fauna (Butt & Chamberlain 2007) may develop, and whether altered belowground biodiversity and plant-soil interactions may drive changes in functional soil processes. Furthermore, there is pressing need to better understand how these changes may interact with different grazing or disturbance regimes. Using an established long-term experiment and wider network of study sites, this research will test links between organic matter quality, soil biodiversity and functional resilience in coastal systems, and provide unique belowground evidence to help optimise conservation management strategies. In summary, the aim of this PhD is to answer the following questions:1. What are the long-term impacts of grazing regime on organic matter quality, microbial and faunal composition in coastal dune slack soils? 2. Does the composition of soil biodiversity determine the capacity for biogeochemical functioning and its' resilience to climatic and hydrological fluctuations?3. Can management strategies be identified which optimise for plant communities, soil biodiversity and functional resilience?The project will focus on extensive dune slack systems at Ainsdale Sand Dunes National Nature Reserve, on the east coast of Lancashire. This location contains the Ainsdale Dune Slacks Long Term Experiment (LTE). This grazing experiment was established in 1974 and is the longest running dune slack wetland grazing experiment in the UK, consisting of sheep and rabbit exclosures. The proposal will build on earlier research at Ainsdale by Dr Millett (Millett & Edmondson 2013, 2015).