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.

本研究旨在探究淹水频次增加对健康（完好草皮状植被）与不健康（呈凹陷-丘状地形）的高潮滩栖息地的影响。

Brinson等人（1995）构建了一个模型，用以刻画岸带生态系统状态（或栖息地类型）随海平面上升引发的淹水加剧而发生的演替序列：从森林→高潮滩→低潮滩→潮间带泥滩。他们提出，生态系统状态向海方向的迁移很大程度上取决于局部坡度与沉积物供给量。

各生态系统状态与对应生境内的优势植被紧密相关。最靠海（海拔最低）的生境为潮间带泥滩，其频繁受潮水淹没，通常以藻类物种为优势植被。向陆方向的下一级生境为矿质型低潮滩，以互花米草（Spartina alterniflora）为优势类群，通常在高潮时被海水淹没，沉积物以矿质成分为主。继续向陆的生境为高潮滩，其优势植被包括Spartina patens、Distichlis spicata与Juncus roemerianus；该生境仅偶尔在高潮时被淹，土壤通常为有机质型。高潮滩与森林之间的过渡带优势植被通常为Iva frutescens、Baccharis hamifolia与Juniperus virginiana，仅在强烈风暴潮时才会被海水淹没。森林生态系统的优势植被可为松类或硬阔类，同样仅在风暴潮事件中被海水淹没。

研究目标：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。研究选取了弗吉尼亚东海岸沿线的17个样地，用于开展大陆与障壁岛的盐沼演化研究。这些样地可用于开展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。本项目的初始工作为建立各样地的基础特征参数。