皖江湿地及其开垦为稻田后土壤种子库结构比较

Comparison of soil seed bank structure in natural wetlands and their corresponding reclaimed paddy fields at lower reaches of Yangtze River in Anhui,China

运用镜检法对皖江2处天然湿地（十八索和升金湖）及其开垦的稻田表层土壤（0～10cm）种子库物种进行了鉴定，分析天然湿地开垦为稻田后土壤种子库群落结构及多样性的变化。结果表明：天然湿地种子库密度为83499～109141粒·m^-2，而开垦为稻田30～50年后种子库密度为9140～47452粒·m^-2；天然湿地的土壤种子库物种数为16～30种，以蓼科．莎草科或莎草科．蓼科为优势种，开垦为稻田后物种数下降为7～16种，且趋向于以禾本科为单一优势种；此外，与十八索湿地相比，升金湖湿地有较高的土壤种子库物种数、丰富度和多样性，而开垦年限为30年的十八索稻田土壤种子库物种数和丰富度显著高于开垦年限为50年的升金湖稻田。湿地开垦为稻田后，土壤种子库密度和物种数的急剧减少，人为管理生态系统生物多样性受到强烈干扰。因此，湿地保护对于维持长江流域的生物多样性及其流域生态功能具有重要意义。

By the method of microscopic examination, the soil seed bank structure and diversity of two natural wetlands （ Shibasuo Lake and Shengjin Lake） and their corresponding reclaimed paddy fields at the lower reaches of Yangtze River in Anhui, China were investigated. The total seed storage in topsoil （0-10 cm） was 83 499-109 141 ind · m^-2 for natural wetlands and 9140 - 47452 ind · m^-2 for reclaimed paddy fields. In natural wetlands, the seeds were of 16-30 grass plant species, being dominant with Polygonaceae and Cyperaceae or Cyperaceae and Gramineae; while in reclaimed paddy fields, the seeds were of 7-16 grass plant species, with the dominant of Gramineae. The seed storage and species numbers were greater in Shengjin Lake than in Shibasuo Lake. Higher seed bank storage and more species were observed in the paddy fields from Shibasuo wetland with 30 years of cultivation than from the Shengjin Lake wetland with over 50 years of cultivation. The shift of paddy fields from natural wetlands reduced the seed bank storage and the seed species number markedly, indicating that biodiversity was strongly disturbed when the ecosystem was managed by human. Therefore, conservation of natural wetlands is of significance in sustaining the biodiversity and eco-function of Yangtze River basin.