基于CASA模型的长江口崇明东滩湿地植被净初级生产力与固碳潜力

湿地生态系统具有很强的储碳、固碳能力，在全球碳循环中占有重要地位。为了解盐沼的固碳能力，以崇明东滩南部典型盐沼潮沟体系为对象，结合实验观测与遥感影像解译，估算了盐沼湿地的净初级生产力，并探讨了环境变化下盐沼湿地固碳潜力的变化。结果表明：盐沼植物净初级生产力表现出显著的时空差异，时间差异体现在年际和季节差异，即2013年和2017年盐沼植物净初级生产力总量分别为245.70和257.75 t C·a^-1,呈现略微增长趋势；夏季植物净初级生产力(97.70±69.31 g C m^-2·month^-1)显著高于其他季节(P<0.05);空间差异表现为净初级生产力随高程降低而降低，其中芦苇群丛的净初级生产力(1079.64±168.34 g C·m^-2·a^-1)显著高于其他覆被类型(P<0.05);2017—2018年，研究区盐生植物固碳能力仍低于同一区域的陆地植被平均固碳水平，随崇明东滩盐沼逐渐成熟，固碳能力可进一步提高；在海平面上升背景下，盐沼植被的陆向演替，弥补了盐沼...

Net primary productivity and carbon sequestration potential of salt marsh vegetation in Chongming Dongtan of the Yangtze Estuary based on CASA model

Wetland ecosystems have strong carbon storage and sequestration abilities,playing an important role in global carbon cycle.To understand the carbon sequestration capacity of salt marsh wetlands,we estimated net pri-mary productivity based on field investigation and remote sensing in a typical tidal creek system in the southern Chongming Dongtan Wetland.The carbon sequestration potential of salt marsh wetlands under environmental change was also estimated.The results showed that net primary productivity of halophytes exhibited significant temporal and spatial variations.The temporal variations were mainly reflected in the inter-annual differences and seasonal differ-ences.The total net primary productivity of salt marsh in 2013 and 2017 was 245.70 and 257.75 t C·a^-1,respec-tively,showing a slight increase.The net primary productivity in summer(97.70±69.31 g C m^-2·month^-1)was significantly higher than that in other seasons(P<0.05).At the spatial scale,net primary productivity decreased with elevation and Phragmites australis cohorts(1079.64±168.34 g C m^-2·a^-1)had significantly higher net pri-mary productivity than other cover types(P<0.05).In 2017-2018,the carbon sequestration capacity of salt mar-shes in the study area was lower than the average level of carbon sequestration capacity of terrestrial vegetation in the same area.As the marsh matures gradually,carbon sequestration capacity can be further improved.Under the background of sea level rise,the positive succession of salt marsh vegetation compensates for the organic carbon loss caused by the erosion of salt marsh edge.The total carbon sequestration potential increased by 130.24-250.12 t·a^-1.The continuous rise of global temperature and the changes of estuarine environment,such as sea level rise,shoreline erosion,vegetation succession and human disturbance,increase the uncertainty of salt marsh carbon sequestration ability.Prediction of its contribution to carbon cycle will provide scientific support for carbon seques-tration and increasing carbon sinks.