鄱阳湖区土地利用的生态效应

Ecological effects of land use in Poyang Lake region

在构建鄱阳湖区土地利用地理数据库的基础上,利用区域生态质量指数与土地利用变化生态贡献率对鄱阳湖区土地利用生态效应进行了定量研究。结果表明,鄱阳湖区1990年区域生态质量指数平均值为7·60,2002年为7·62,总体生态质量介于灌木林地、疏林地等土地利用类型之间。1990—2002年鄱阳湖区区域生态质量指数上升的主要动力为水库坑塘、有林地和疏林地的扩大;生态质量指数下降的主要动力依次为水田、中覆盖度草地的减少。在土地利用转移贡献率上,水田转为有林地、旱地转为有林地、水田转为疏林地、水田转为水库坑塘的生态贡献率之和达52·96%,为主导土地利用的正向转移类型。有林地转为水田、有林地转为旱地、水田转为农村居民点的生态贡献率之和达39·89%,为主导土地利用的反向转移类型。

Supporting by land use geodatabase, and using regional ecological quality index and land use change ecological contribution index, a quantitative study was made on the ecological effects of land use in Poyang Lake region. The results indicated that in this region, the average regional ecological quality index was 7.60 in 1990 and 7.62 in 2002, and the overall ecological quality lay between those of shrubbery and sparse woods. From 1990 to 2002, the main driving forces leading to the improvement of regional ecological quality index were the expansion of pond and reservoir, forest, and sparse woods, while the main reasons for the degradation of regional ecological quality index were the shrinkage of paddy field and middle coverage grassland. As for the land use change ecological contribution index, the sum of the ecological contribution rates in the changes from paddy field to forest, upland to forest, paddy field to sparse woods, and paddy field to pond and reservoir was up to 52.96% of the total, which constituted the main land use change for the improvement of ecological environment, while the sum of the ecological contribution rates in the changes from forest to paddy field, forest to upland, and paddy field to rural residential area accounted for 39.89% of the total, which constituted the main land use change for the degradation of ecological environment.