Evaluation of salt marsh restoration by means of self-regulating tidal gate – Avon estuary, South Devon, UK
Evaluation of salt marsh restoration by means of self-regulating tidal gate – Avon estuary, South Devon, UK
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DOI：
10.1016/j.ecoleng.2017.05.038
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发表时间：
2017-09
影响因子：
3.8
通讯作者：
G. Masselink;M. Hanley;Anissa C. Halwyn;W. Blake;K. Kingston;Thomas L. Newton;Mike Williams
中科院分区：
文献类型：
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作者：
G. Masselink;M. Hanley;Anissa C. Halwyn;W. Blake;K. Kingston;Thomas L. Newton;Mike Williams
盐沼提供重要的调节生态系统服务，包括自然防洪和碳固存，这增加了恢复和生物多样性抵消计划的价值。这项研究评估了在英格兰西南部使用受管制的潮汐交换（RTE）系统恢复盐沼的成功，即，一个自我调节的潮汐闸门（SRT），在控制1760年为农业开垦的14公顷前盐沼地区的部分盐水淹没。SRT投产后立即实施了（a）对水和沉积物通量的直接水动力监测和（B）重复调查相结合的方法，以评价5年期间的形态和生态（植物和有孔虫）变化。形态变化仅限于附近的SRT系统，由于有限的泥沙流入产生的沉积速率是一个数量级低于附近的天然沼泽。生态变化的一个短暂的盐沼群落后，5年的淹没周期，与延迟响应归因于（a）最初的有限潮汐淹没，由于保守的SRT设置，其次是（B）过度淹没，由于过多的降雨和反复出现的SRT失败，在一个开放的位置，以及（c）由（a）和（B）以及SRT系统中使用的相对狭窄的入口管引起的沉积物和繁殖体供应的缺乏。虽然最佳SRT设置下的生态响应是令人鼓舞的，缺乏多年生植物和有限的有孔虫丰度表明，沼泽是远远没有达到自然状态。我们推测，这主要是由于在潮汐周期中，淹没比排水更快，导致过度淹没。我们的研究表明，潮汐淹没方案的设计需要一个协同的理解核心生态和地貌的方法来评估可行性和成功。我们的结论是，SRT可以是一个有用的技术潮间带栖息地的创造有显着的网站限制（特别是洪水风险），但我们需要现实的期望，它可以实现在提供一个常年盐沼社区。
Salt marshes provide important regulating ecosystem services, including natural flood defence and carbon sequestration, which adds value to restoration and biodiversity offsetting schemes. This study evaluates the success of salt marsh restoration using a Regulated Tidal Exchange (RTE) system in SW England, i.e., a self-regulating tidal gate (SRT), in controlling the partial saline inundation of a 14-ha area of former salt marsh reclaimed for agriculture in 1760. A combination of (a) direct hydrodynamic monitoring of water and sediment flux and (b) repeat surveys to evaluate morphological and ecological (plants and foraminifera) changes over a 5-year period, was implemented immediately following SRT commissioning. Morphological changes were limited to the proximity of the SRT system due to limited sediment influx yielding sedimentation rates that were an order of magnitude below a nearby natural marsh. Ecological change to an ephemeral salt marsh community was only detected after 5 years of inundation cycles, with the delayed response attributed to (a) an initial limited tidal inundation due to conservative SRT settings, followed by (b) excessive inundation due to excessive rainfall and recurring SRT failure in an open position, and (c) a lack of sediment and propagule supply caused by (a) & (b) and the relatively narrow inlet pipe used in the SRT system. While the ecological response under optimum SRT settings was encouraging, the lack of perennial plants and limited foraminifera abundance demonstrated that the marsh was far from reaching natural status. We surmise that this is primarily due to inundation being more rapid than drainage leading to excessive submergence during a tidal cycle. Our study shows that the design of tidal inundation schemes requires a synergistic understanding of core ecological and geomorphological approaches to assess viability and success. We conclude that SRT can be a useful technique for intertidal habitat creation where there are significant site constraints (especially flood risk), but we need to be realistic in our expectations of what it can achieve in terms of delivering a perennial salt marsh community.