Marshlands and floodplains are generally characterized by a long history of human occupation and management, with strong impacts on biodiversity. In these landscapes, ditch networks often represent the last or most significant aquatic habitat, and significantly contribute to regional biodiversity. To determine the drivers of biodiversity in ditch networks, especially the importance of the water regime, we monitored vegetation in ditches in 11 sites (independent blocks of ditch networks) of an Atlantic marshland (the Marais poitevin, France) over a 4-year period, and a panel of local environmental conditions and landscape characteristics. Large differences in the species richness and composition of ditch plant communities were observed among sites. The water regime had a predominant effect on all descriptors of ditch plant communities. High water levels combined with strong temporal variability, including drying-out periods, were found associated to the communities with the highest species richness. By contrast, water quality parameters did not influence plant communities across sites. Among landscape variables, woodland cover combined with high hedge cover along the ditches significantly influenced plant composition and species richness. These results are discussed in terms of management actions that may promote the diversity and composition of ditch plant communities and address conservation challenges.

沼泽地和洪泛区通常以人类占领和管理的悠久历史为特征，对生物多样性产生重大影响。在这些景观中，沟渠网络通常代表着最后或最重要的水生生境，并为区域生物多样性做出了重要贡献。为了确定沟渠网络中生物多样性的驱动因素，尤其是水情的重要性，我们在4年的时间内对大西洋沼泽地（法国Marais poitevin）的11个地点（沟渠网络的独立区块）的沟渠中的植被进行了监测，以及一组当地环境条件和景观特征。地点之间的沟渠植物群落的物种丰富度和组成存在很大差异。水分制度对沟渠植物群落的所有特征都有主要影响。人们发现高水位加上强烈的时间变异性（包括干旱期）与物种丰富度最高的社区有关。相比之下，水质参数不会影响跨站点的植物群落。在景观变量中，林地的覆盖物和沿沟的高树篱覆盖物显着影响了植物组成和物种丰富度。在管理措施方面讨论了这些结果，这些管理措施可以促进沟渠植物群落的多样性和组成并应对保护挑战。林地的覆盖物和沿沟的高树篱覆盖物显着影响了植物的组成和物种丰富度。在管理措施方面讨论了这些结果，这些管理措施可以促进沟渠植物群落的多样性和组成并应对保护挑战。林地的覆盖物和沿沟的高树篱覆盖物显着影响了植物的组成和物种丰富度。在管理措施方面讨论了这些结果，这些管理措施可以促进沟渠植物群落的多样性和组成并应对保护挑战。