Dataset: Soil Redox and Hydropattern control Soil Carbon Stocks across different habitats in Tidal Freshwater Wetlands in a Sub-estuary of the Chesapeake Bay

Wetlands contain spatial and temporal variations in hydrology that affect vegetation and soil processes. In this study different wetland habitats were identified in both a natural and restored wetland site that varied in hydropattern (level of surface or ground water over time), with the goal of understanding how inundation impacts redox conditions and soil organic matter. Tidal freshwater wetlands were selected in Maryland, USA along the Patuxent River, a Chesapeake Bay tributary. Five habitats (mudflat, low marsh, high marsh, swamp, and adjacent upland) were selected at Patuxent Wetland Park, a natural wetland, and four habitats (mudflat, low marsh, high marsh, and adjacent upland) were selected at Wootons Landing Wetland Park, a restored wetland. Within each habitat three randomly located plots were established, and a data logging water level recorders were installed at one plot per habitat in February 2014 to monitor water level at 10-minute intervals. Water level depth was also measured manually in two additional observation wells within plots every two weeks for one year from February 2014 to March 2015. Soil cores to a depth of 50 cm were collected and soil C stocks were calculated based on soil bulk density and C percentage. Natural wetland habitats had shallower groundwater than their restored counterparts. Mudflats in both sites were most frequently flooded, followed by marsh and swamp habitats in the natural site. The restored high marsh that was dominated by <i>Phragmites australis</i> had the highest soil redox measurements at 12.5 and 40 cm soil depth (273±27 and 252±33 mv, respectively). Soil C stocks were also significantly higher in the natural compared to the restored wetland (14.8±0.50 and 8.9±0.99, respectively, P &lt;0.0001). Restored mudflat and marsh habitats had similar hydrological regime compared to the natural counterparts, but they had lower soil C stocks. Monitoring of hydrology and vegetation in similar habitats in restored and reference sites may help improve restoration success in achieving specific structural or functional outcomes. Promoting the accumulation of soil organic matter in the restored wetland is not only controlled by the hydropattern, but also by the soil redox conditions that are impacted by the invasion of <i>Phragmites australis</i>.

湿地的水文学（hydrology）存在时空变化，这些变化会影响植被与土壤过程。本研究在自然湿地与恢复湿地中识别出不同的湿地生境，这些湿地的水文模式（hydropattern，即地表水或地下水随时间的水位变化）存在差异，旨在探究淹水如何影响氧化还原条件（redox conditions）与土壤有机质（soil organic matter）。研究选取了美国马里兰州切萨皮克湾支流帕图森特河沿岸的潮汐淡水湿地。在自然湿地帕图森特湿地公园（Patuxent Wetland Park）选取了5种生境（泥滩、低沼泽、高沼泽、沼泽及邻近高地），在恢复湿地伍顿斯登陆湿地公园（Wootons Landing Wetland Park）选取了4种生境（泥滩、低沼泽、高沼泽及邻近高地）。在每种生境内设置3个随机样地，并于2014年2月在每个生境的1个样地中安装数据记录式水位计（data logging water level recorder），以10分钟为间隔监测水位。2014年2月至2015年3月期间，还通过样地内另外2口观测井每两周手动测量一次水位深度，持续一年。采集了深度达50厘米的土壤芯样，并基于土壤容重与碳含量计算了土壤碳储量（soil C stocks）。自然湿地生境的地下水比恢复湿地的更浅。两个站点的泥滩淹水频率最高，其次是自然站点的沼泽与湿地生境。以芦苇（<i>Phragmites australis</i>）为主导的恢复高沼泽在12.5厘米和40厘米土壤深度处的氧化还原测量值最高，分别为273±27毫伏（mv）和252±33毫伏。自然湿地的土壤碳储量也显著高于恢复湿地（分别为14.8±0.50和8.9±0.99，P<0.0001）。恢复湿地的泥滩与沼泽生境的水文状况（hydrological regime）与自然湿地相似，但土壤碳储量更低。对恢复站点与参考站点中相似生境的水文学特征及植被进行监测，可能有助于提升恢复工程在实现特定结构或功能目标方面的成功率。促进恢复湿地中土壤有机质的积累不仅受水文模式调控，还受芦苇（<i>Phragmites australis</i>）入侵影响的氧化还原条件所控制。