Recognition of wetland ecosystem services has led to substantial investment in wetland restoration in recent decades. Wetland restorations can be designed to meet numerous goals, among which reestablishing a diverse native wetland plant community is a common aim. In agricultural areas, where previously drained wetland basins can fill with eroded sediment from the surrounding landscape, restoration often includes excavation to expose buried seed banks. The extent to which excavation improves the diversity of wetland plant communities is unclear, particularly in terms of longer‐term outcomes. We examined plant species diversity and community composition in 24 restored agricultural wetlands across west‐central Minnesota, U.S.A. In all study wetlands, hydrology was restored by removing subsurface drainage and plugging drainage ditches, thus reestablishing groundwater connectivity and hydroperiod (“business as usual” treatment). In half of the wetlands, accumulated sediment was removed from the basin and redeposited on the surrounding landscape (“excavated” treatment). Initially, sediment removal significantly decreased invasive species cover, particularly of hybrid cattail (Typha × glauca) and reed canary grass (Phalaris arundinacea), and increased community diversity and evenness. Over time, the effects of sediment removal diminished, and eventually disappeared by approximately 6 years after restoration. While our results demonstrate that sediment removal improves initial restoration outcomes for plant communities, longer‐term benefits require sustained management, such as invasive species control or resetting of basins through additional excavation.

中文翻译：

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去除泥沙后恢复的农业湿地的植被轨迹

近几十年来，对湿地生态系统服务的认可导致了对湿地恢复的大量投资。可以设计湿地修复体来实现许多目标，其中一个常见的目标是重建多样化的原生湿地植物群落。在农业地区，以前排水的湿地盆地可能充满周围景观的侵蚀沉积物，恢复工作通常包括挖掘以露出埋藏的种子库。挖掘在多大程度上改善了湿地植物群落的多样性尚不清楚，特别是在长期成果方面。我们检查了美国明尼苏达州中西部24个恢复的农业湿地中的植物物种多样性和群落组成。在所有研究湿地中，通过去除地下排水和堵塞排水沟来恢复水文学，因此，重新建立了地下水连通性和水文周期（“一切照旧”处理）。在一半的湿地中，积聚的沉积物从盆地中移出并重新沉积在周围的景观上（“挖掘”处理）。最初，去除沉积物会大大降低入侵物种的覆盖率，尤其是杂种香蒲（香蒲×青冈）和草芦（草芦），以及增加社会多样性和均匀度。随着时间的流逝，去除泥沙的作用逐渐减弱，并在恢复后约6年最终消失。虽然我们的结果表明，泥沙清除可以改善植物群落的初始恢复效果，但长期利益则需要持续管理，例如侵入性物种控制或通过额外开挖对盆地进行复位。