摘要
土地利用/覆被变化对溪流生态系统的影响是溪流生态学研究的热点。生物完整性是诊断溪流生物学状况和生态健康的重要指标。目的是研究西苕溪流域内土地利用类型对大型底栖无脊椎动物完整性(B-IBI)的影响。利用2003年西苕溪TM数据和DEM模型计算了62个样点上游3种空间尺度下(亚流域、沿岸和局部)的土地利用类型。结果表明,耕地,民居和竹园在流域中的百分比与B-IBI负相关,耕地百分比对B-IBI的影响在亚流域(r=-0.527,p<0.001),河岸(r=-0.665,p<0.001)和局部(r=-0.696,p<0.001)尺度上均显著。针叶林,阔叶林和混交林百分比与B-IBI正相关。阔叶林百分比在亚流域(r=0.333,p<0.001),河岸(r=0.589,p<0.001)和局部尺度(r=0.618,p<0.001)与B-IBI显著相关。而针叶林百分比仅在亚流域尺度(r=0.366,p<0.001)与B-IBI显著相关。在研究流域内耕地百分比小于50%的情况下,B-IBI并非随着耕地百分比的增长而线性下降,而是在达到一定阀值后(亚流域尺度,27%;河岸尺度,57%;局部尺度,59%)耕地的影响逐渐趋缓。在耕地百分比小于阀值前,B-IBI在局部尺度上与耕地百分比的增长的关系最强(r=-0.808,p<0.001,n=46)。建议在沿岸区增加阔叶林,针叶林与混交林的占有率,或者建立耕地与溪流间的林地缓冲带,有助于保护和恢复西苕溪生态健康。
Changes of land-use and land-cover strongly influence stream ecosystems.In the present study we evaluate the effects of these changes on the biological condition of Upper Xitiaoxi watershed Zhejiang Province,China,using a benthic index of biotic integrity（B-IBI）.Benthic macroinvertebrate assemblages were sampled from 62 sites in first-to fourth-order streams in 2004 to 2005 to develop a B-IBI.The land covers for each site was estimated at sub-basin riparian-zone and local scales using 2003 satellite image and a Digital Elevation Model.We showed that B-IBI was negatively correlated with the percentages of croplands,bamboo forest,and the residential area.The percentage of croplands was strongly and negatively correlated with B-IBI at all three spatial scales,sub-basin（r=-0.527,p〈0.001）,riparian（r=-0.665,p〈0.001）,and local scales（r=-0.696,p〈0.001）.The percentages of coniferous forests,broad-leaved forests,and blend forests were positively correlated with the B-IBI.The percentage of the broad-leaved forests was strongly correlated with B-IBI at the local（r=0.618,p〈0.001）and riparian scales（r=0.589,p〈0.001）,and less so at the sub-basin scale（r= 0.333,p〈0.001）.However,the percentage of coniferous forests was significantly correlated only at the sub-basin scale（r=0.366,p〈0.001）.With croplands 〈 50% of the whole catachment,B-IBI declined linearly as the percentage of the cropland increased,however,the index leveled off when cropland reached 27% of the sub-basin,57% of riparian zone,or 59% at the local scales.Furthermore,the linear correlation of the percentage of the cropland at local scale with B-IBI was the strongest（r=-0.808,p〈0.001,n=46）.Our results suggested that a buffer with higher percentage of forest land cover between stream watercourse and cropland should help to maintain or improve the biological conditions of Upper Xitiaoxi watershed.
出处
《生态学报》
CAS
CSCD
北大核心
2008年第3期1183-1191,共9页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(40301047和30370252)~~
