基于树叶凋落物分解速率的溪流生态系统健康评价——以广东横石水河为例

Stream ecosystem health assessment based on the measurement of leaf litter breakdown:A case study in Hengshishui River of Guangdong Province

用Gessner等提出的树叶凋落物分解模式对横石水河的功能完整性和生态系统健康进行评价,对比了藜蒴和荷木2个树种的树叶凋落物在横石水河各污染样点和未受污染样点的分解速率.结果表明:藜蒴和荷木树叶凋落物在研究区污染样点的分解速率均显著低于清洁样点(P<0.05);根据Gessner模式,各污染样点的环境得分均为0,而各清洁样点的环境得分均为2,表明横石水河污染河段的健康状态已受到严重破坏.研究区生态系统健康的生物学评价与水质分析结果一致,表明树叶凋落物分解模式是一个合适的评价河流状态的指数.

Based on the Gessner＇ s model of leaf litter breakdown, the functional integrity and ecosystem health of Hengshishui River in Guangdong Province were assessed, and the breakdown rates of Castanopsis fissa and Schima superba leaf litters at the sites unpolluted and polluted by acid mine drainage were compared. The leaf litters of the two tree species had a significantly lower breakdown rate at polluted than at unpolluted sites （P 〈 0. 05 ）. According the Gessner＇ s model, all polluted sites had an ecosystem health score 0, while all unpolluted sites had a score 2, indicating that the health status of polluted river reaches were severely damaged. The biological assessment of stream ecosystem heahh was consistent with the results of water quality analysis, indicating that the leaf litter breakdown model was a suitable index of stream status.