放牧对温带典型草原植物物种多样性及土壤养分的影响

为探讨放牧强度对植物多样性及土壤养分的影响，本文以内蒙古温带典型草原毛登牧场为研究对象，选取围封、中度放牧、重度放牧3个放牧强度的试验样地，运用方差分析法研究不同放牧强度下植物多样性和土壤养分含量的差异性，采用典范对应分析揭示植物多样性与土壤养分间的关系。结果表明，植物群落物种组成受放牧强度影响变化显著，部分优势种重要值降低；放牧强度增大对植物群落多样性指数影响不显著，围封样地植物群落Pielou均匀度指数显著大于中度放牧、重度放牧样地（P<0.05）；围封样地土壤全钾（0~20 cm）、土壤有机质（0~40 cm）含量显著（P<0.05）大于中度放牧、重度放牧样地，硝态氮、铵态氮、全磷含量在不同强度放牧样地间差异不显著。典范对应分析结果表明，放牧干扰下温带典型草原多年生禾本科草本植物多样性与全钾、土壤有机质、铵态氮含量呈正相关，多年生非禾本科草本植物多样性与硝态氮、全磷含量呈正相关。

Effects of Grazing on Plant Diversity and Soil Nutrients in Typical Temperate Steppe

This study selected the typical temperate steppe of Inner Mongolia as the research object. No grazing,moderate grazing and heavy grazing intensity were selected to investigate the effects of different grazing intensities on plant diversity and soil nutrients. The results were as follows:The plant species composition changed significantly under grazing interference. The important values of part dominant species decreased with the increase of grazing intensity. The diversity index of plant communities showed no response with the increasing of grazing intensity. The Pielou evenness index of plant community were significant difference (P<0.05) between the forbidden and grazing plots. The content of total kalium (0~20 cm) and organic matter (0~40 cm) in forbidden plots was significantly (P<0.05) higher than that in moderate grazing and heavy grazing plots,but soil nitrate nitrogen,ammonium nitrogen and total phosphorus contents were not significantly different. The results of canonical correspondence analysis showed that the diversity of perennial grass in typical temperate steppes had positive correlation with the content of total kalium (TK),ammonium nitrogen (NH₄⁺-N),and soil organic matter (SOM),and the diversity of perennial forbs had positive correlation with the content of nitrate nitrogen(NO₃^--N),total phosphorus (TP) under the grazing interference.