Development and Application of a Method to Identify Salt Marsh Vulnerability to Sea Level Rise
Development and Application of a Method to Identify Salt Marsh Vulnerability to Sea Level Rise
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DOI：
10.1007/s12237-017-0219-0
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发表时间：
2017-05-01
影响因子：
2.7
通讯作者：
Watson, Elizabeth Burke
中科院分区：
文献类型：
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作者：
Ekberg, Marci L. Cole;Raposa, Kenneth B.;Watson, Elizabeth Burke
湿地生态条件和生物完整性的评估通常使用景观规模评估、快速评估协议和密集的生物和物理化学测量的三层框架。然而，海平面加速上升(SLR)导致的洪水增加正在对美国东北沿海湿地的潮汐沼泽生态系统功能产生负面影响，但对这种压力的相对脆弱性并未被纳入状况评估。本文评估了可用于测量沿海湿地对SLR的脆弱性的工具，包括作为传统快速条件评估(例如，植被群落、土壤强度)的一部分进行的测量、基于现场和遥感的海拔、VDatum和海平面影响沼泽模型(SLAMM)模型输出的测量。使用最近的沼泽植被损失率(1972-2011年)作为未来脆弱性的替代指标，对纳入这些工具的脆弱性指标进行了校准和验证。该指标包括海拔资本的补充指标，包括高沼泽植被与低沼泽植被的百分比、互花米草高度、海拔测量和Slamm产量，这些指标共同解释了近期沼泽植被损失率变异性的62%。逐步回归表明，所有三个要素(海拔高度、植被测量和Slamm输出)都解释了SLR脆弱性的重要且在很大程度上独特的组成部分，其中Slamm输出和海拔测量之间的重叠程度最大。虽然土壤强度随生境区域的变化是可预测的，但它对脆弱性度量的贡献并不显著。尽管确定平均海平面和平均高水位等关键潮汐基准线以上的湿地高程很重要，但我们警告说，VDatum在屏障后河口的表现很差。这一因素使得很难在潮差不同的沼泽地之间比较高程资本，并对需要准确潮汐基准的大范围建模工作提出了精度问题。鉴于发生在美国东北部和其他地方的沿海湿地溺水的普遍模式，我们主张汇编关于沼泽栖息地和受SLR影响的脆弱性的区域数据是至关重要的，因为这使各机构能够根据其脆弱性或生境的混合性来确定适应地点的目标，这有助于将地点与适当的干预措施相匹配，并为地点具体管理行动提供更广泛的区域背景。如果没有这些数据，就可能在不需要采取行动的地方采取适应行动，这对将错失成功适应机会的脆弱地点不利。
Wetlands are commonly assessed for ecological condition and biological integrity using a three-tiered framework of landscape-scale assessment, rapid assessment protocols, and intensive biological and physiochemical measurements. However, increased inundation resulting from accelerated sea level rise (SLR) is negatively impacting tidal marsh ecosystem functions for US Northeast coastal wetlands, yet relative vulnerability to this stressor is not incorporated in condition assessments. This article assesses tools available to measure coastal wetland vulnerability to SLR, including measurements made as part of traditional rapid condition assessments (e.g., vegetation communities, soil strength), field and remote sensing-based measurements of elevation, VDatum, and Sea Level Affecting Marshes Model (SLAMM) model outputs. A vulnerability metric that incorporates these tools was calibrated and validated using recent rates of marsh vegetation losses (1972-2011) as a surrogate for future vulnerability. The metric includes complementary measures of elevation capital, including the percentage of high vs. low marsh vegetation, Spartina alterniflora height, elevation measurements, and SLAMM outputs that collectively explained 62% of the variability in recent rates of marsh vegetation loss. Stepwise regression revealed that all three elements (elevation, vegetation measures, and SLAMM outputs) explained significant and largely unique components of vulnerability to SLR, with the greatest level of overlap found between SLAMM outputs and elevation metrics. While soil strength varied predictably with habitat zone, it did not contribute significantly to the vulnerability metric. Despite the importance of determining wetland elevation above key tidal datums of mean sea level and mean high water, we caution that VDatum was found to perform poorly in back-barrier estuaries. This factor makes it difficult to compare elevation capital among marshes that differ in tidal range and poses accuracy problems for broad-scale modeling efforts that require accurate tidal datums. Given the pervasive pattern of coastal wetland drowning occurring in the Northeastern USA and elsewhere, we advocate that compilation of regional data on marsh habitats and vulnerability to SLR is crucial as it permits agencies to target adaptation to sites based on their vulnerability or mixture of habitats, it helps match sites to appropriate interventions, and it provides a broader regional context to site-specific management actions. Without such data, adaptation actions may be implemented where action is not necessary and to the disadvantage of vulnerable sites where opportunities for successful adaptation will be missed.