Salt marsh vegetation change during a half-century of experimental nutrient addition and climate-driven controls in Great Sippewissett Marsh
Salt marsh vegetation change during a half-century of experimental nutrient addition and climate-driven controls in Great Sippewissett Marsh
复制标题
大西佩威塞特沼泽半个世纪的实验性营养添加和气候驱动控制期间盐沼植被的变化
DOI：
10.1016/j.scitotenv.2023.161546
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发表时间：
2023
影响因子：
9.8
通讯作者：
Goehringer Toner, D.
中科院分区：
文献类型：
--
作者：
Valiela, I.;Chenoweth, K.;Lloret, J.;Teal, J.;Howes, B.;Goehringer Toner, D.
植被覆盖每年绘制，1976年至2022年，在大Sippewissett沼泽，科德角，美国的实验地块，长期施肥在不同的剂量，并受海平面和其他气候相关变量的变化。在较高海拔地区的地块内的优势种遵循不同的年代际轨迹：海平面上升减少盖ofSpartinapatens;较高的N供应增加盖ofDistichlis spicata。D. spicatato高氮供应意外地促进了平台的增加，这一特征持续了几十年，并导致了植被的进一步变化：D。作为一种有效的生态系统工程，具有长期的生态后果。灌木通常发现在沼泽的上部边缘扩展到D. spicata刺激了增生，然后被遮蔽和排斥D. spicata，但随后随着海平面持续上升而失去了掩护。增加N供应转换林ofSpartina互花米草，占主导地位的低沼泽物种，从短到高的生态表型;海平面上升对S的影响较小。互花米草，但在2019-2022年期间似乎达到了一个临界点，培养了更高的植物。alterniflora和裸露的空间，即使在未施肥的控制地块，并在大Sippewissett沼泽一般。模型的结果预计，尽管潜在的植被和生态系统工程的影响增强加积，将有高沼泽的损失，低沼泽的短暂增加，其次是低沼泽的损失，并最终转换为浅开放水域的世纪结束。可怕的当地预测与最近来自世界各地盐沼的大量报告相吻合。拟议的管理策略可能只会推迟不幸的结果，而不是保持湿地。协调一致地减少温室气体造成的变暖，以及降低氮负荷似乎是解决湿地即将到来的危机和许多其他环境威胁的必要条件。
Vegetative cover was mapped annually, 1976–2022, in experimental plots in Great Sippewissett Marsh, Cape Cod, USA, chronically fertilized at different doses, and subject to changes in sea level and other climate-related variables. Dominant species within areas of higher elevation in the plots followed different decadal trajectories: rise in sea level diminished cover ofSpartinapatens; higher N supplies increased cover ofDistichlis spicata. The opportunistic growth response ofD. spicatato high N supplies unexpectedly fostered increased platform accretion, a feature that persisted for succeeding decades and led to further changes in vegetation:D. spicatafunctioned as an effective ecosystem engineer with long-term ecological consequences. Shrubs usually found in upper marsh margins expanded into areas whereD. spicatahad stimulated accretion, then shaded and excludedD. spicata, but subsequently lost cover as sea level rise continued. Increased N supply converted stands ofSpartina alterniflora, the dominant low marsh species, from short to taller ecophenotypes; sea level rise had minor effects onS. alterniflora, but during 2019–2022 appeared to reach a tipping point that fostered tallerS. alternifloraand bare space even in un-fertilized control plots, and in Great Sippewissett Marsh in general. Model results anticipate that—in spite of potential accretion enhanced by vegetation and ecosystem engineer effects—there will be loss of high marsh, transient increases of low marsh, followed by loss of low marsh, and eventual conversion to shallow open water by the end of the century. Dire local projections match those of the plurality of recent reports from salt marshes around the world. Proposed management strategies may only delay unfortunate outcomes rather than maintain wetlands. Concerted reductions of warming from greenhouse gases, and lower N loads seem necessary to address the coming crises in wetlands—and many other environmental threats.