陕北典型退耕还林区林下草本物种生态位研究

Niche Characteristics of Undergrowth Herbaceous in Typical Reforest Cultivated Land Area in North Shaanxi Province

基于样方法进行不同资源位的群落调查,并用群落物种多样性、生态位宽度、生态位重叠和生态位相似性比例分析了安塞县典型退耕区16种不同退耕模式及年限群落林下草本物种生态位特征。结果表明:乔木林下草本群落物种多样性高于灌木林。生态位宽度以达乌里胡枝子和阿尔泰狗娃花最大,它们的Shannon-Wiener(Bs-w,i)和Levins(Bl,i)指数分别为0.89、0.83和0.64、0.58。生态位宽度较大的种间生态位重叠程度大,如阿尔泰狗娃花、铁杆蒿、长芒草等。生态位宽度与生态位相似比例值并不一致。生态位相似性比例小于0.5的种对有174对,约占种群总对数的91.6%,说明种群对环境需求有较大的差异,各种群能较好地共生于群落中。

Based on a field plot sampling method to investigate community niche of undergrowth vegetation in typical lands use conversion from agricultural lands into forest lands.Species diversity indices,parameters of niche breadth,niche similarity and niche overlap were calculated to analyze niche characteristics in 16 different models and periods of land use conversion from agricultural lands into forest lands communities in Ansai country.The results showed that the species diversity indices in land use conversion from agricultural lands into forest are better than land use conversion from agricultural lands into shrubbery.Niche breadth of Lespedeza davurica and Heteropappus altaicus were larger than that of other species.With Shannon-Wiener（Bs-w,i） and Levins（Bl,i） values being 0.89,0.83 and 0.64,0.58.Niche overlap degree between species increased with niche breadth,which was shown in H.altaicus,Artemisia gmelinii,Stipa bungeana,etc.There was no obvious correlation between niche similarity and niche breadths.174 sets of species had niche similarity values greater than 0.5,accounting for 91.6%.Therefore,species had different requirements to environment,and species could harmonious exist in communities.