Mangrove Trees Outperform Saltmarsh Grasses in Building Elevation but Collapse Rapidly Under High Rates of Sea‐Level Rise
Mangrove Trees Outperform Saltmarsh Grasses in Building Elevation but Collapse Rapidly Under High Rates of Sea‐Level Rise
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DOI：
10.1029/2022ef003202
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发表时间：
2023-04
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影响因子：
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通讯作者：
J. Morris;J. Langley;W. C. Vervaeke;N. Dix;I. Feller;P. Marcum;S. Chapman
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文献类型：
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作者：
J. Morris;J. Langley;W. C. Vervaeke;N. Dix;I. Feller;P. Marcum;S. Chapman
红树林正在入侵全球亚热带交错带的盐沼，但这种植被转变对生态系统可持续性的影响尚不清楚。使用海岸湿地平衡模型来模拟植被存活和泥沙积累，我们预测黑色红树林，白骨壤，可以使土壤高度增加8毫米−1，比相同地点的盐沼高4倍，这一发现与现场海拔变化的测量结果基本一致。红树林比盐沼更快地建立海拔，因为它在地下产生了更多活的和不稳定的生物量，但当红树林溺水时，它们突然失去了海拔，因为洪水导致的死亡导致了大量迅速分解的死尸。在某些条件下，幼龄红树林积累根质量的速度比成熟树快，因此上升速度更快，但无论是盐沼还是任何年龄的红树林，都没有在海平面上升100厘米的百年中幸存下来。沿海沼泽面临的海平面加速上升提出了如何优化管理沿海湿地的问题，这些结果为管理者提供了关于红树林与沼泽湿地建设能力的预测性信息。
Mangrove trees are invading saltmarshes at subtropical ecotones globally, but the consequences of this vegetation shift for ecosystem sustainability remain unknown. Using the Coastal Wetland Equilibrium Model (CWEM) to simulate vegetation survival and sediment accretion, we predict that black mangroves, Avicennia germinans, can build soil elevation by 8 mm yr−1, four times greater than saltmarshes at the same site, a finding that is broadly consistent with field measurements of elevation change. Mangroves build elevation more rapidly than saltmarshes by producing much greater live and labile belowground biomass, but when mangroves drown, they abruptly lose elevation due to the large volume of quickly decomposing necromass following flood‐induced mortality. Under certain conditions, young mangroves can accumulate root mass faster than mature trees and, therefore, gain elevation more rapidly, but neither saltmarshes nor mangroves of any age survived a centenary sea‐level increase of 100 cm. The acceleration of sea‐level rise that coastal marshes are encountering raises the question of how coastal wetlands should be optimally managed and these results provide managers with predictive information on wetland building capacity of mangroves versus marshes.