Proposal of new syntaxa and series of Grey Willow forests of humid dunes slacks of the North-Atlantic coasts of Europe

This article aims to point out the recent emergence of willows within the dune slacks of the Atlantic coasts following land abandonment. Firstly, a new association present in Brittany is examined: the <i>Epipactido palustris – Salicetum atrocinereae ass. nova hoc loco</i> with a detailed description about its physiognomic, floral, and ecological characteristics. Related dynamico-catenal trajectories that follow the expression of those forests are also described. This survey highlights an original littoral forest formation that could constitute the head of a vegetation series. Elements of reflection are proposed as for the conservation of the dune slacks woodlands and should allow the managers to refine their strategies. Secondly, the existence of a similar association along the coasts of the Channel and the North Sea is reported (<i>Hydrocotylo vulgaris – Salicetum cinereae ass. nova</i>). A new alliance (<i>Carici flaccae – Salicion cinereae all. nova</i>) is proposed in order to regroup these Northwest-European willow forests of the dune slacks and to clarify their synsystematic status.

本文旨在阐明大西洋沿岸沙丘间洼地在土地撂荒后，柳林群落新近出现的现象。首先，对布列塔尼地区现存的一个全新群丛（association）展开研究：<i>沼生火烧兰-灰黑柳新群丛（Epipactido palustris – Salicetum atrocinereae ass. nova hoc loco）</i>，并对其外貌特征、花部特征与生态特性展开详细描述；同时还阐述了伴随该类森林发育的相关动态链状演替轨迹。本研究揭示了一种独特的沿岸森林群落类型，其可作为某一植被演替系列的起始环节。针对沙丘间洼地林地的保护工作，本文提出若干思考方向，可为管理者优化保护策略提供参考。其次，本文报道了在英吉利海峡与北海沿岸存在的另一类似群丛（association）：<i>普通天胡荽-灰柳新群丛（Hydrocotylo vulgaris – Salicetum cinereae ass. nova）</i>。为将上述分布于西北欧沙丘间洼地的柳林群落归并统一，并厘清其植物社会学系统地位，本文提出建立一个全新的群丛属（alliance）：<i>灰脉苔草-灰柳群丛属（Carici flaccae – Salicion cinereae all. nova）</i>。