van der Valk Arnold G, Volin John C, Wetzel Paul R
Ecology Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA,
Environ Manage. 2015 Apr;55(4):799-806. doi: 10.1007/s00267-014-0434-4. Epub 2015 Jan 8.
The number of dominant vegetation types (wet prairies, sawgrass flats, ridges and sloughs, sloughs, and tree islands) historically and currently found in the Everglades, FL, USA, as with other wetlands with standing water, appears to be primarily a function of the magnitude of interannual water-level fluctuations. Analyses of 40 years of water-depth data were used to estimate the magnitude of contemporary (baseline) water-level fluctuations in undisturbed ridge and slough landscapes. Baseline interannual water-level fluctuations above the soil surface were at least 1.5 m. Predicted changes in interannual water-level fluctuations in 2060 were examined for seven climate change scenarios. When rainfall is predicted to increase by 10 %, the wettest scenario, the interannual range of water-level fluctuation increases to 1.8 m above the soil surface in sloughs. When rainfall is predicted to decrease by 10 % and temperatures to increase by 1.5 °C, the driest scenario, the range of interannual range of water-level fluctuations is predicted to decrease to 1.2 m above the soil surface in sloughs. A change of 25-30 cm in interannual water-level fluctuations is needed to change the number of vegetation types in a wetland. This suggests that the two most extreme climate change scenarios could have a significant impact on the overall structure of wetland vegetation, i.e., the number of vegetation types or zones, found in the Everglades.
美国佛罗里达州大沼泽地历史上和当前存在的优势植被类型（湿草原、锯齿草滩、高地和泥沼、泥沼以及树岛），与其他有积水的湿地一样，似乎主要取决于年际水位波动的幅度。利用40年的水深数据进行分析，以估算未受干扰的高地和泥沼景观中当代（基线）水位波动的幅度。土壤表面以上的基线年际水位波动至少为1.5米。针对七种气候变化情景，研究了2060年年际水位波动的预测变化。在降雨预计增加10%（最湿润情景）时，泥沼中水位波动的年际范围增加到土壤表面以上1.8米。在降雨预计减少10%且气温预计升高1.5摄氏度（最干旱情景）时，泥沼中水位波动的年际范围预计减少到土壤表面以上1.2米。湿地中植被类型数量的变化需要年际水位波动有25 - 30厘米的变化。这表明，两种最极端的气候变化情景可能会对大沼泽地中湿地植被的整体结构，即植被类型或区域的数量，产生重大影响。
