End of Year Biomass at Surface Elevation Table plots in Upper Phillips Creek marsh 1999-2017

Background: 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. Brinson, M.M., R.R. Christian, and L.K. Blum. 1995. Multiple states in the sea-level induced transition from terrestrial forest to estuary. Estuaries 18:648-659.背景：布林森（Brinson）等于1995年提出了一个模型，用以表征海岸带（shorezone）生态系统状态（ecosystem state，或生境类型habitat type）随海平面上升（rising sea-level）引发的淹没（inundation）程度加剧而发生的变化，其变化序列为森林→高潮盐沼（high marsh）→低潮盐沼（low marsh）→泥滩（mud flat）。该研究团队指出，生态系统状态的向海迁移（seaward shift）主要取决于局地坡度（local slope）与沉积物供给（sediment supply）。各类生境均与其中分布的优势植被（dominant vegetation）紧密相关。海拔最低、最靠海的生境为泥滩，其频繁受潮汐（tide）淹没，通常以藻类物种（algal species）为优势植被。向陆一侧的次级生境为矿质型低潮盐沼（mineral low marsh），该生境以互花米草（Spartina alterniflora）为优势种，通常在高潮时段被海水淹没，其沉积物主要由矿物组分构成。再向陆一侧的生境为高潮盐沼，其优势植被可能为S. patens、Distichlis spicata与Juncus roemerianus。该生境仅偶尔在高潮时被海水淹没，其土壤多为有机质土壤。高潮盐沼与森林之间的过渡带通常以Iva frutescens、Baccharis hamifolia和Juniperus virginiana为优势植被，仅在强烈风暴潮（storm surges）发生时才会被海水淹没。森林生态系统的优势植被可为针叶林（pines）或阔叶林（hardwoods），同样仅会在风暴潮事件中被海水浸渍。布林森, M.M., 克里斯琴, R.R., 布卢姆, L.K. 1995. 海平面上升诱导的陆地森林向河口过渡的多稳态现象. Estuaries 18:648-659.