Upslope development of a tidal marsh as a function of upland land use
Upslope development of a tidal marsh as a function of upland land use
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DOI：
10.1111/gcb.13398
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发表时间：
2017-02-01
影响因子：
11.6
通讯作者：
Kemp, Andrew C.
中科院分区：
文献类型：
--
作者：
Anisfeld, Shimon C.;Cooper, Katharine R.;Kemp, Andrew C.
为了在海平面快速上升的时期茁壮成长，潮汐沼泽将需要向上迁移到邻近的高地。然而，人们对这一过程的机制知之甚少，特别是在城市化的河口，那里邻近的高地可能是修剪过的草坪，而不是树木繁茂的自然区域。我们研究了沼泽迁移在长岛湾盐沼使用详细的水文，土壤和生物采样沿着沼泽高地样带在树木繁茂和草坪环境。我们发现，沼泽发展的整体速度在很大程度上不受高地是否被入侵草坪或树木繁茂，但沼泽边缘植物群落，在这两种环境中发展是完全不同的，和一些指标（土壤盐度，有孔虫）似乎更容易迁移到草坪。此外，我们发现，不同方面的沼泽结构和功能迁移在不同的速度：湿地植被似乎是沼泽迁移的领先指标，而土壤特性，如氧化还原电位和表面盐度的发展过程中晚。我们定义了一个水文迁移区，由经历潮汐淹没的海拔高度组成，频率范围从20%到0.5%的高潮。这一水文界定的区域-延伸到高于最高天文潮汐基准面的高度-捕获了生物和土壤沼泽高地交错带。在这个迁移区的上边界的潮汐淹没是高度可变的，随着时间的推移，可能会更快地上升比平均海平面。我们的研究结果表明，土地管理措施在高地边缘的潮汐沼泽地可以促进或阻碍生态系统迁移，以应对海平面上升。这些发现适用于沿着美国大西洋海岸和其他城市化沿海地区的大面积潮汐沼泽。
To thrive in a time of rapid sea-level rise, tidal marshes will need to migrate upslope into adjacent uplands. Yet little is known about the mechanics of this process, especially in urbanized estuaries, where the adjacent upland is likely to be a mowed lawn rather than a wooded natural area. We studied marsh migration in a Long Island Sound salt marsh using detailed hydrologic, edaphic, and biotic sampling along marsh-to-upland transects in both wooded and lawn environments. We found that the overall pace of marsh development was largely unaffected by whether the upland being invaded was lawn or wooded, but the marsh-edge plant communities that developed in these two environments were quite different, and some indicators (soil salinity, foraminifera) appeared to migrate more easily into lawns. In addition, we found that different aspects of marsh structure and function migrated at different rates: Wetland vegetation appeared to be a leading indicator of marsh migration, while soil characteristics such as redox potential and surface salinity developed later in the process. We defined a hydrologic migration zone', consisting of elevations that experience tidal inundation with frequencies ranging from 20% to 0.5% of high tides. This hydrologically defined zone - which extended to an elevation higher than the highest astronomical tide datum - captured the biotic and edaphic marsh-upland ecotone. Tidal inundation at the upper border of this migration zone is highly variable over time and may be rising more rapidly than mean sea level. Our results indicate that land management practices at the upland periphery of tidal marshes can facilitate or impede ecosystem migration in response to rising sea level. These findings are applicable to large areas of tidal marsh along the U.S. Atlantic coast and in other urbanized coastal settings.