End of Year Biomass for the 2nd UPC Inundation Experiment in Upper Phillips Creek marsh 1999-2010

The objective of this study is to determine the effect of increasing inundation on healthy (in-tack turf) and unhealthy (hollow and hummock topography) high marsh habitat.
Brinson et al. (1995) developed a model representing the change that occurs in ecosystem state (or habitat type) along the shorezone, from the forest -> high marsh -> low marsh -> mud flat, in response to the increased inundation caused by rising sea-level. They suggested that a seaward shift in ecosystem state is largely dependent on local slope and sediment supply. The states are associated with the dominant vegetation found within each. The most seaward (lowest in elevation) state is the mud flat. It is frequently inundated by tide and typically supports algal species. The next landward state is the mineral low marsh; it is dominated by Spartina alterniflora and is typically flooded at high tide. Sediments here may be largely mineral in origin. The next landward state is the high marsh; it may be dominated by S. patens, Distichlis spicata, and Juncus roemerianus. It is occasionally inundated by high tides and the soil is usually organic. The transition zone between the high marsh and the forest is typically dominated by Iva frutescens, Baccharis hamifolia, and Juniperus virginiana. It is only inundated during severe storm surges. The forest may be dominated by either pines or hardwoods and is again flooded with sea water only by storm surges. Goals: The goal of this long-term project is to evaluate how sea-level rise affects marsh evolution and ecosystem state change. Seventeen sites along Virginia's eastern shore have been selected to study marsh evolution on both the mainland and the barrier islands. These sites will be available for long-term seasonal to annual observations. Some sites will also be available for experimentation and short-term studies. The initial project is to establish initial site characteristics.

本研究旨在探究潮汐淹水频次增加对健康（完好草被（intact turf））与不健康（凹陷与丘状地形（hollow and hummock topography））的高潮滩（high marsh）生境的影响。Brinson等（1995）构建了一套模型，用以表征沿潮间带的生态系统状态（或生境类型）随海平面上升引发的淹水加剧而发生的变化序列：森林→高潮滩→低潮滩→潮间泥滩（mud flat）。他们提出，生态系统状态向海侧的迁移很大程度上取决于局地坡度与沉积物供给量。各类生境与其中的优势植被类群一一对应。海拔最低、最靠海的生境为潮间泥滩，其频繁受潮汐淹没，通常以藻类为优势物种。向陆侧依次为矿质型低潮滩（low marsh），该生境以互花米草（Spartina alterniflora）为优势类群，通常在涨潮时被淹没，沉积物多为矿质成因。再向陆侧为高潮滩，其优势物种可为长穗米草（Spartina patens）、盐草（Distichlis spicata）与罗氏灯心草（Juncus roemerianus）；该生境仅偶尔会被高潮水淹没，土壤多为有机质。高潮滩与森林之间的过渡带通常以海滨艾（Iva frutescens）、毛叶白酒草（Baccharis hamifolia）与北美圆柏（Juniperus virginiana）为优势类群，仅在强风暴潮时会被海水淹没。森林群落可由松类或阔叶树构成，同样仅在风暴潮事件中会被海水淹没。
本长期项目的核心目标为评估海平面上升对盐沼演化与生态系统状态转变的影响。研究团队选取了弗吉尼亚东海岸的17个样地，用于开展大陆与障壁岛的盐沼演化研究。这些样地可用于长期的季节至年度尺度观测，部分样地还可用于受控实验与短期研究。本项目的首要任务是明确各样地的初始特征。