Quantifying the hidden biodiversity, conservation value and effectiveness of fine sediment detention ponds in agri-environment schemes

过多的细微沉积物(通常为2毫米颗粒)是水体未能达到欧盟水框架指令所规定的良好生态状态的主要原因之一，该指令对整个营养食物网的生态影响得到了广泛认可(Mathers等人，2017年)。尽管细颗粒泥沙的输入、输送和储存是河流功能的一个自然组成部分，但人为的改变导致当代的输入远远超过历史水平(Collins和Zhang，2016)。为应对这一问题，英国已经实施了多项举措，以减少向水体输入的细微沉积物，包括英国流域敏感农业交付倡议(投资2900万英镑)和北爱尔兰的“Interreg来源可利用”项目(490万英镑)。最近，2020年的农业法案将根据环境土地管理计划(Elm：gov.uk，2020)奖励英格兰农民和土地管理者的“公共产品”，如增强生物多样性、改善水质或减少洪水。在增加生物多样性的同时处理河流细沉积物的一种方法是安装沉积物捕集器和缓冲池(例如，见2021年基于集水区的方法)。尽管它们在农业环境方案中广泛存在，但人们对沉积物缓解方法对景观生物多样性的贡献或减少细沉积物污染对河流健康的有效性知之甚少。一些研究表明，小型水体，包括人工和独特的狭长水体(Biggs等人，2017年)，除了具有高保护价值的水生生物外，还可能支持大量的水生生物(Cerini等人，2020年)。该项目将与从事农业管理和监测的主要利益攸关方和项目合作伙伴合作，提供直接用于政策和现实世界环境管理的基本信息。该项目将力求：i)量化目前各种水基沉积物减缓方法的吸收和分布；ii)量化沉积物滞留池塘的生物多样性和养护价值；以及iii)评估沉积物滞留方法在减轻河流系统细颗粒沉积物压力方面的有效性。

Excessive fine sediment (typically particles <2mm) is one of the principal reasons for the failure of waterbodies to achieve good ecological status under the EU Water Framework Directive with widely acknowledged ecological effects for the entire trophic food web (Mathers et al., 2017). Although the input, transport, and storage of fine sediment is a natural component of river function, anthropogenic modifications have resulted in contemporary inputs far exceeding historic levels (Collins and Zhang, 2016). To combat this, a number of UK initiatives have been implemented to reduce fine sediment inputs to waterbodies including the English Catchment Sensitive Farming Delivery Initiative (£29M invested) and the 'Interreg project source to tap' in Northern Ireland (£4.9M). More recently, the Agricultural bill in 2020, will reward farmers and land managers in England for 'public goods' such as enhancing biodiversity, improving water quality or reducing flooding under the Environmental Land Management Scheme (ELM: Gov.UK, 2020). One means of tackling riverine fine sediment whilst also enhancing biodiversity is the installation of sediment traps and buffer ponds (e.g. see Catchment Based Approach, 2021).Despite their wide occurrence in agri-environment schemes, little is known about the contribution of sediment mitigation methods to landscape biodiversity or their efficacy for reducing fine sediment pollution for riverine health. Some research has suggested that small water bodies including artificial and unique lentic waterbodies (Biggs et al., 2017) may support high numbers of aquatic organisms in addition to those with high conservation value (Cerini et al., 2020). This project will work with leading stakeholders and project partners engaged in agricultural management and monitoring to provide essential information that will feed directly into policy and real-world environmental management. The project will seek to: i) quantify the current uptake and distribution of the various aquatic-based sediment mitigation methods; ii) quantify the biodiversity and conservation value of sediment retention ponds; and iii) assess the effectiveness of sediment retention methods in mitigating fine sediment pressures for riverine systems.