End of Year Biomass for the 2nd UPC Inundation Experiment in Upper Phillips Creek marsh 1999-2008

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.