Data from: Testing sea-level rise impacts in tidal wetlands: a novel in situ approach

Predictions of coastal wetland loss depend on reliable estimations of sea-level rise (SLR) and biological feedbacks to geomorphology, yet it is difficult to manipulate SLR to generate empirical data of impacts on wetland processes. Typically, data have been generated through small-scale mesocosm experiments, an approach that may not fully capture biological responses to SLR. Using passive and active weirs, we manipulated inundation depths and times in situ and at larger spatial scales than possible in mesocosms. In June 2013, we simulated three flooding scenarios (low, intermediate and high) using passive weirs designed to increase mean low water (MLW) by approximately 8–9, 12–13 and 16–18 cm, respectively, relative to controls. In March 2014, we also conducted a proof-of-concept exercise to demonstrate that active weirs equipped with a pump can increase both MLW and mean high water (MHW), thereby achieving changes in both inundation depth and inundation time. When compared to controls for the three flooding scenarios, passive weirs increased MLW in the low marsh by 9.1 ± 0.8, 11.8 ± 1.1 and 15.65 ± 0.8 cm, respectively, and in the high marsh by 6.3 ± 3.0, 17.0 ± 4.6 and 8.3 ± 2.5 cm, respectively. Passive weirs increased inundation time in low marsh by 0.4 ± 0.0 hd−1 and 2.9 ± 0.0 hd−1 to 24 hd−1 in both weirs for low and intermediate flooding, respectively, but not for high flooding where the control and weirs were both inundated 24 hd−1. At greater elevations, however, passive weirs increased inundation time in high marsh by 0.9 ± 2.2, 5.1 ± 4.1 and 4.0 ± 0 hd−1, respectively. Weirs slowed drainage rates by 5.6 ± 1.4, 3.8 ± 1.4 and 6.1 ± 0.1 cmh−1, respectively. The active weir increased MLW by 25.4 cm, MHW by 10.5 cm and inundation time by 10.7 hd−1 and slowed the drainage rate by 9.6 cmh−1. Weirs can be used to increase inundation depths and times to study SLR impacts on tidal wetlands, and are advantageous because they minimize disturbance; allow for larger-scale studies within tidal wetlands; and can be maintained at little cost and effort, thereby providing more robust estimates of SLR impacts on tidal wetland processes.

海岸湿地丧失的预测依赖于对海平面上升（Sea-Level Rise, SLR）以及地貌生物反馈的可靠估算，但目前难以通过操控SLR来获取湿地过程受其影响的实证数据。以往通常通过小型中型生态系统实验（mesocosm）生成相关数据，但该方法或无法全面捕捉湿地生物对SLR的响应。本研究借助被动堰与主动堰，在原位且较中型生态系统实验更大的空间尺度上，调控了淹没深度与淹没时长。2013年6月，我们依托被动堰模拟了三种淹没情景（低、中、高），相较于对照组，其分别可使平均低潮位（Mean Low Water, MLW）提升约8~9 cm、12~13 cm与16~18 cm。2014年3月，我们还开展了概念验证实验，证明搭载水泵的主动堰可同时提升平均低潮位与平均高潮位（Mean High Water, MHW），进而实现淹没深度与淹没时长的双重调控。相较于三种淹没情景下的对照组，被动堰可使低潮滩的平均低潮位分别提升9.1±0.8 cm、11.8±1.1 cm与15.65±0.8 cm，使高潮滩的平均低潮位分别提升6.3±3.0 cm、17.0±4.6 cm与8.3±2.5 cm。对于低淹没与中淹没情景，被动堰可使低潮滩的每日淹没时长分别提升0.4±0.0 h·d⁻¹与2.9±0.0 h·d⁻¹，最终达到24 h·d⁻¹；但高淹没情景下，对照组与堰体区域的每日淹没时长均为24 h·d⁻¹，未出现显著提升。不过在高程更高的区域，被动堰可使高潮滩的每日淹没时长分别提升0.9±2.2 h·d⁻¹、5.1±4.1 h·d⁻¹与4.0±0 h·d⁻¹。堰体可使排水速率分别降低5.6±1.4 cm·h⁻¹、3.8±1.4 cm·h⁻¹与6.1±0.1 cm·h⁻¹。主动堰可使平均低潮位提升25.4 cm、平均高潮位提升10.5 cm，每日淹没时长增加10.7 h·d⁻¹，同时使排水速率降低9.6 cm·h⁻¹。堰体可通过提升淹没深度与时长，用于研究SLR对潮汐湿地的影响，其优势在于：可最大程度减少研究干扰，支持潮汐湿地内更大尺度的原位研究，且维护成本与人力投入极低，因此能够为SLR对潮汐湿地过程的影响提供更稳健的估算结果。