Groundwater hydrology plays an important role in coastal marsh biogeochemical function, in part because groundwater dynamics drive the zonation of macrophyte community distribution. Changes that occur over time, such as sea level rise and shifts in habitat structure are likely altering groundwater dynamics and eco-hydrological zonation. We examined tidal flooding and marsh water table dynamics in 1999 and 2019 and mapped shifts in plant distributions over time, at Piermont Marsh, a brackish tidal marsh located along the Hudson River Estuary near New York City. We found evidence that the marsh surface was flooded more frequently in 2019 than 1999, and that tides were propagating further into the marsh in 2019, although marsh surface elevation gains were largely matching that of sea level rise. The changes in groundwater hydrology that we observed are likely due to the high tide rising at a rate that is greater than that of mean sea level. In addition, we report changes in plant cover by P. australis, which has displaced native marsh vegetation at Piermont Marsh. Although P. australis has increased in cover, wrack deposition and plant die off associated Superstorm Sandy allowed for native vegetation to rebound in part of our focus area. These results suggest that climate change and plant community composition may interact to shape ecohydrologic zonation. Considering these results, we recommend that habitat models consider tidal range expansion and groundwater hydrology as metrics when predicting the impact of sea level rise on marsh resilience.

地下水水文学在沿海沼泽生物地球化学功能中发挥着重要作用，部分原因是地下水动态驱动了大型植物群落分布的分区。随着时间的推移发生的变化，例如海平面上升和栖息地结构的变化，可能会改变地下水动态和生态水文分区。我们研究了 1999 年和 2019 年的潮汐洪水和沼泽地下水位动态，并绘制了皮尔蒙特沼泽植物分布随时间变化的变化图。皮尔蒙特沼泽是位于纽约市附近哈德逊河口的咸潮潮汐沼泽。我们发现的证据表明，2019 年沼泽地表被洪水淹没的频率比 1999 年更频繁，而且 2019 年潮汐进一步传播到沼泽地，尽管沼泽地表海拔的增加在很大程度上与海平面上升的情况相匹配。我们观察到的地下水水文变化可能是由于涨潮速度高于平均海平面的速度造成的。此外，我们还报告了P 植物覆盖的变化。 australis，它取代了皮尔蒙特沼泽的原生沼泽植被。虽然P. australis 的覆盖面积、残骸沉积和与超级风暴桑迪相关的植物死亡有所增加，使得我们重点区域的部分原生植被得以反弹。这些结果表明，气候变化和植物群落组成可能相互作用，形成生态水文分区。考虑到这些结果，我们建议栖息地模型在预测海平面上升对沼泽恢复力的影响时考虑潮差扩大和地下水水文作为指标。