退化天坑倒石堆阴坡植物群落垂直分布特征——以云南沾益深陷塘为例

Taking the plant community of the arbor and shrub layers on the shady slope of the talus in the degraded sinkhole of Shenxiantang as the object, the variation characteristics of species diversity at different slope positions of the talus and its main influencing factors were studied. The results showed that there were 21 species belonging to 17 genera and 13 families in the arbor layer on the south side of Shenxiantang, and 20 species belonging to 20 genera and 14 families in the shrub layer. The community belonged to the subtropical humid coniferous and broad-leaved mixed forest type; The microclimate environment made the vegetation at the sinkhole entrance and on the slope of the sinkhole significantly different. The secondary collapse on the talus enabled the middle slope position to conserve more water and provided a high-quality niche for water-demanding plants. All α -diversity indices reached the maximum at the slope position at the edge of the sinkhole bottom. The Margalef richness index, Shannon index, Simpson index, and Pielou evenness index were 3.58, 2.47, 0.79, and 0.86 respectively, but the overall difference was small, and the coefficient of variation was only 0.226 at the highest; The β -diversity index fluctuated greatly. Along the sinkhole entrance, the slope of the sinkhole, and the edge of the sinkhole bottom, the Routledge index and the Whilson - Shmida index both showed a trend of decreasing - increasing - decreasing, with their maximum values being 15.95 and 1.20 respectively. The species replacement rate generally showed an upward trend, and the number of common species gradually decreased. Soil was the most important influencing factor for the differences among various slope positions. The plant diversity on each slope position was mainly related to the contents of total nitrogen, total phosphorus, available phosphorus, and organic carbon in the soil.

以深陷塘退化天坑倒石堆阴坡乔灌层植物群落为对象,研究倒石堆不同坡位的物种多样性变化特征及其主要影响因子。结果表明:深陷塘南侧乔木层物种有13科17属21种,灌木层物种有14科20属20种,群落属于亚热带湿润针阔混交林类型;微气候环境使坑口与坑坡植被差异明显,倒石堆上的二次崩塌使中坡位能够涵养更多的水分,为需水性植物提供了优质的生态位。各α多样性指数均在坑底边缘坡位达到最大值,Margalef丰富度指数、Shannon指数、Simpson指数、Pielou均匀度指数分别为3.58、2.47、0.79、0.86,但整体上差异较小,变异系数最高仅为0.226;β多样性指数波动较大,沿坑口、坑坡和坑底边缘间,Routledge指数、Whilson-Shmida指数均呈现减小-增大-减小趋势,其最大值分别为15.95、1.20,物种更替率总体呈上升趋势,共有种的数量逐渐减少。土壤是各坡位间差异最主要的影响因子,各坡位上植物多样性主要与土壤全氮、全磷、有效磷、有机碳含量有关。