Table_5_Invertebrate communities of Bay of Fundy salt marsh pools: comparison of a natural and recovering marsh.xlsx

Disturbed salt marshes may recover with little additional management once tidal inundation is restored. We assessed the success of such recovery by comparing the invertebrate biota of Bay of Fundy salt marsh pools in a reference site at Dipper Harbour to that of Saints Rest marsh that had been drained for over a century and to which tidal flooding had been returned ~50 years prior to our study. The sediments and vegetation of salt marsh pools were sampled seasonally throughout one year. Average biomass of pool invertebrates ranged from 1.8 to 4.0 g dry wt m−2, depending on the amount of vegetation cover in the pools. The most abundant organisms of the pools were the gastropod Ecrobia truncata (=Hydrobia tottentei), Tubificidae (=Naididae) oligochaetes, and Chironomidae (=Chironomini). We compared overall abundance and biomass of the invertebrates in the pool communities, assessing the month of sampling, pool elevation, and source marsh as explanatory variables. Our analyses revealed that marsh origin of pools seldom explained a significant amount of variance, and when it did, the proportion of variance explained was usually lower than elevation of pools and month of sampling. Diversity of invertebrates found in all pools was higher at the recovering site with species richness >40% higher than in the reference site. We conclude that after an estimated 50 years since dyke failure and return of tidal flooding to Saints Rest marsh, that the ecosystem function represented by pools and their fauna has recovered.

受干扰的盐沼（salt marsh）在恢复潮汐淹没后，仅需少量额外管理即可实现自然恢复。本研究通过对比芬迪湾（Bay of Fundy）盐沼池的无脊椎动物（invertebrate）群落，与迪珀港（Dipper Harbour）参照位点的群落、以及已被排干一个多世纪、并在研究前约50年恢复潮汐淹没的圣茨雷斯特沼泽（Saints Rest marsh）的群落，评估了此类恢复的成效。

研究在一年内按季节对盐沼池的沉积物与植被开展了采样。池内无脊椎动物的平均生物量介于1.8至4.0克干重每平方米（g dry wt m−2），具体数值取决于池内植被覆盖占比。该池域中丰度最高的生物类群包括腹足类截截螺（Ecrobia truncata，原分类名为Hydrobia tottentei）、颤蚓科（Tubificidae，现归为Naididae）寡毛类动物，以及摇蚊科（Chironomidae，即Chironomini）昆虫。

我们对比了各盐沼池群落中无脊椎动物的总丰度与生物量，以采样月份、池体高程以及沼泽来源作为解释变量（explanatory variable）开展分析。结果显示，沼泽来源极少能解释群落组成的显著变异；即便能够解释，其解释的变异占比通常也低于池体高程与采样月份这两个因素。所有采样池中的无脊椎动物多样性在恢复位点均更高，物种丰富度（species richness）较参照位点高出40%以上。

综上，在堤坝溃决、圣茨雷斯特沼泽恢复潮汐淹没约50年后，该沼泽池域及其动物群落所代表的生态系统功能（ecosystem function）已完成恢复。