Stagg Camille LaFosse, Laurenzano Claudia, Vervaeke William C, Krauss Ken W, McKee Karen L
U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, LA 70506, USA.
Cherokee Nation System Solutions, Contractor to the U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, LA 70506, USA.
Plants (Basel). 2022 May 6;11(9):1259. doi: 10.3390/plants11091259.
Coastal wetlands are dynamic ecosystems that exist along a landscape continuum that can range from freshwater forested wetlands to tidal marsh to mudflat communities. Climate-driven stressors, such as sea-level rise, can cause shifts among these communities, resulting in changes to ecological functions and services. While a growing body of research has characterized the landscape-scale impacts of individual climate-driven stressors, little is known about how multiple stressors and their potential interactions will affect ecological functioning of these ecosystems. How will coastal wetlands respond to discrete climate disturbances, such as hurricane sediment deposition events, under future conditions of elevated atmospheric CO? Will these responses vary among the different wetland communities? We conducted experimental greenhouse manipulations to simulate sediment deposition from a land-falling hurricane under future elevated atmospheric CO concentrations (720 ppm CO). We measured responses of net primary production, decomposition, and elevation change in mesocosms representing four communities along a coastal wetland landscape gradient: freshwater forested wetland, forest/marsh mix, marsh, and mudflat. When was present, above- and belowground biomass production was highest, decomposition rates were lowest, and wetland elevation gain was greatest, regardless of CO and sediment deposition treatments. Sediment addition initially increased elevation capital in all communities, but post-deposition rates of elevation gain were lower than in mesocosms without added sediment. Together these results indicate that encroachment of oligohaline marshes into freshwater forested wetlands can enhance belowground biomass accumulation and resilience to sea-level rise, and these plant-mediated ecosystem services will be augmented by periodic sediment pulses from storms and restoration efforts.
沿海湿地是动态生态系统，存在于一个景观连续体中，范围从淡水森林湿地到潮汐沼泽再到泥滩群落。气候驱动的压力因素，如海平面上升，可导致这些群落之间的转变，从而改变生态功能和服务。虽然越来越多的研究已经描述了单个气候驱动压力因素对景观尺度的影响，但对于多种压力因素及其潜在相互作用将如何影响这些生态系统的生态功能却知之甚少。在未来大气CO浓度升高的情况下，沿海湿地将如何应对离散的气候干扰，如飓风沉积物沉积事件？这些反应在不同的湿地群落中会有所不同吗？我们进行了实验性温室操作，以模拟在未来大气CO浓度升高（720 ppm CO）的情况下，登陆飓风带来的沉积物沉积。我们测量了代表沿海湿地景观梯度上四个群落的中宇宙中净初级生产、分解和海拔变化的反应：淡水森林湿地、森林/沼泽混合地、沼泽和泥滩。当存在时，无论CO和沉积物沉积处理如何，地上和地下生物量生产最高，分解率最低，湿地海拔增加最大。添加沉积物最初增加了所有群落的海拔资本，但沉积后海拔增加率低于未添加沉积物的中宇宙。这些结果共同表明，低盐沼泽向淡水森林湿地的侵蚀可以增强地下生物量积累以及对海平面上升的恢复力，并且这些植物介导的生态系统服务将因风暴和恢复努力带来的周期性沉积物脉冲而得到增强。
