镇江内江湿地不同演替阶段植物群落小气候日动态

Diurnal dynamics of microclimate at different succession stages of vegetation communities in inner-river wetland of Zhenjiang City.

2005年5月,选择镇江内江湿地具有代表性的裸地、虉草群落和芦苇群落,分别代表植被群落的不同演替阶段,测定不同群落、不同层次的光照强度、气温、土温和空气相对湿度,研究其植物群落小气候的日动态.结果表明,随演替由裸地到虉草群落到芦苇群落进行,群落内光照强度、气温和土壤温度均明显降低,日变幅减小.其中,日均光照强度由1204.7μmol.m-2.s-1降至141.28μmol.m-2.s-1,日均变幅由1126μmol.m-2.s-1降至265μmol.m-2.s-1;日均气温由32.2℃降至24.9℃,日均变幅由12.75℃降至4.8℃;日均土温由21.83℃降至19.47℃,日均变幅由4.5℃降至2.1℃.群落内空气相对湿度明显升高(由58.95%增至87.3%),变幅减小(由29.75%降至5.15%).生境具有早期的开放性和后期的封闭性,小气候环境朝着更为阴、凉、湿的环境变化,且波动性减弱,稳定性增强.各群落内的光强、气温、湿度及土温之间均存在一定相关,但不同演替阶段各因子间相关程度各异.

To study the diurnal dynamics of microclimate at different succession stages of vegetation communities in the inner-fiver wetland of Zhenjiang City, three typical communities were chosen, and the light intensity, air temperature, soil temperature, and air relative humidity were measured. The results showed that with the succession of barren land → Phalaris arundinacea → Phragmites communis, the diurnal mean values of light intensity, air temperature, and soil temperature decreased from 1 204. 7 μmol · m^-2 · s^-1 to 141.28 μmol · m^-2· s^-1 , 32. 2 ℃ to 24. 9 ℃, and 21.83 ℃ to 19.47 ℃, and their daily variations decreased from 1 126 μmol · m^ -2· s^-1 to 265 μmol · m^ -2 ·s ^-1, 12. 75 ℃ to 4. 8 ℃ , and 4. 5 ℃ to 2. 1 ℃ , respectively. The air relative humidity increased from 58. 95% to 87.3% , while its variation decreased from 29. 75% to 5. 15%. Habitats were open at early succession stage but more closed at late succession stage, microclimatic conditions developed towards much more cloudy, cold, and moist, and microcllmate had a less fluctuation. There were definite correlations among the light intensity, air temperature, soil temperature, and air relative humidity in the vegetation communities, but the correlation coefficients among the test factors were differed at different succession stages.