京西九龙山林下植被物种多样性及其空间分异研究

Research on species diversity and spatial distribution of undergrowth in Jiulong Mountain west of Beijing

基于北京九龙山植物群落的样地调查数据,采用Shannon-Wiener多样性指数指标对九龙山林下植物物种多样性及其空间分异做相关研究。结果表明,该研究区域物种多样性较低,基本维持在0~3.62,均值为2.40,乔木人工林林下物种多样性高于天然灌丛;九龙山林下物种多样性存在明显的垂直及水平分异,其中垂直分异主要表现为:南山随着海拔升高林下植被物种多样性降低,中山随着海拔升高林下物种多样性呈“V”型变化,北山海拔300 m以下随着海拔升高林下物种多样性降低,海拔300~400 m林下物种多样性波动较大,650 m以上林下物种多样性较高且随着海拔的升高而增高;水平分异主要表现为:在海拔400 m以下地区,林下物种多样性表现为油松>侧柏>黄栌>侧柏-元宝枫混交林;海拔400~650 m地区为天然灌丛物种多样性最高,元宝枫最低;海拔650 m以上地区,华北落叶松林林下物种多样性最高,荆条林最低。京西九龙山人工林林下植被物种多样性存在明显的空间分异,而造林树种、立地条件、人为干扰强度是影响该地区林下物种多样性及其空间分异的主要原因。

Based on the sample-plot survey of plant community in Jiulong Mountain of Beijing,research on species diversity and spatial distribution of undergrowth in Jiulong Mountain by applying the Shannon-Wiener diversity index.The result show that,the study area is low species diversity,basically maintained at 0~3.62 and the mean value is 2.40.Species diversity which in undergrowth of tree plantations higher than natural shrub.There is an obvious vertical and horizontal differentiation in species diversity of undergrowth in Jiulong Mountain.Vertical differentiation mainly show that,the species diversity of undergrowth is decreasing as the altitude increasing in south mountain,with the altitude increasing the species diversity of undergrowth shows a“V”-type in middle mountain,with the altitude increasing the species diversity of undergrowth is decreasing below 300 m in north mountain,between 300 m and 400 m,the species diversity of undergrowth is wave,above 650 m,with the altitude increasing the species diversity of undergrowth is increasing.Horizontal differentiation mainly show that,below 400 m,species diversity of undergrowth performance for Pinus tabuliformis forestry>Platycladus orientalis forestry>Cotinus coggygria forestry>Platycladus orientalis-Acer truncatum forestry.Between 400 m and 650 m,the species diversity of natural shrub is the highest and the Acer truncatum forestry is the lowest.Above 650 m,the species diversity of Larix principis-rupprechtii forestry is the highest and the Vitex negundo var.heterophylla is the lowest.There is obvious spatial differentiation of Species diversity of undergrowth vegetation in Jiulong Mountain,western Beijing,and the afforestation tree species,site conditions and human disturbance intensity are the main reasons that affect the species diversity and its spatial differentiation under forests in this area.