川西周公山柳杉人工林林窗大小对土壤理化性质和物种多样性的影响

摘要

以川西周公山柳杉人工林林中5种不同大小(50～100、＞ 100～150、200～ 250、400～450、600～650 m2)的林窗为研究对象,通过对林窗内土壤pH值、有机质含量等指标和物种多样性的研究,探讨天然林窗的形成对土壤各理化指标以及物种多样性的影响.结果表明:(1)随着林窗面积的增大,群落各层次的物种数呈现出先升高后降低的趋势,灌木层、草本层的Shannon-Wiener多样性指数(H)、Simpson优势度指数(H')和Pielou均匀度指数(Jsw)均表现为林窗＞林下;(2)0～20 cm土壤速效钾含量表现为林窗＞林下;(3)各物种多样性指数变化与土壤理化指标存在一定相关性,草本层物种丰富度指数、Shannon-Wiener多样性指数及Simpson优势度指数与土壤pH值呈显著相关关系(P＜0.05),物种丰富度指数、Shannon-Wiener多样性指数与速效钾含量呈显著相关关系(P＜0.05).%Effects of size of gaps in a Cryptomeria fortunei plantation in the Zhougong Mountain,Southwest China on soil physicochemical propertis and species diversity were investigated.Soil samples and floral and faunal species were gathered from five gaps different in size,i.e.50-100,＞100-150,200-250,400-450 and 600-650 m2,for analysis of seil properties,like pH,organic matter content,and some others and species diversity.Results show:(1) With the gap increasing in size,the number of species in various layers of the community exhibits a parabolic curve,that is,rising first and then falling,while Shannon-Wiener index (H),Simpson index (H') and Pielou index (Jsw) of the shrub layer and herb layer are higher in the gaps than under closed canopy;(2) The content of soil available potassium in the 0-20 cm soil layer is on the same trend;(3) In the gaps,variation of species diversity is related to a various extent to soil physico-chemical properties for instance species richness index (D),H and H'of the herb layer are closely related to soil pH,and D and H to soil available potassium (P＜0.05),indicating that plant species diversity is closely related to soil pH and available potassium in the forest.