华西雨屏带马尾松人工林林窗大小对植物多样性与土壤理化性质的影响

Effects of Different Gap Sizes of Pinus massoniana Plantation on Plant Diversity and Soil Physicochemical Properties in the West China Rain Zone

【目的】旨在揭示马尾松人工林不同林窗大小下植物多样性与土壤理化性质之间的关系。【方法】以25年树龄的马尾松人工林内5种不同大小林窗(50~100、100~150、200~250、400~450、600~650 m^(2))为研究对象,以马尾松纯林为对照(CK),调查分析不同林窗下植被组成、物种多样性和土壤理化性质;使用冗余分析(RDA)研究了土壤因子与植物多样性的关系。【结果】(1)不同林窗内枹栎、青榨槭、柃木和野桐等乡土树种的重要值均位于前列;随着林窗面积的增加,耐荫物种数呈上升趋势,半耐荫物种数趋势平稳且占据重要地位。(2)G4(400~450 m^(2))林窗面积下呈最高的物种多样性,灌木层的物种丰富度和多样性与土壤理化性质存在极强正相关关系。(3)在G4林窗下土壤全钾(45.41 mg/kg)、速效钾(191.29 mg/kg)和有机质(68.42 mg/kg)的含量达到最高,速效钾含量显著高于其余林窗(P<0.05);土壤有机质、全氮和全钾是影响马尾松人工林林窗下植物分布的主要环境因子。【结论】G4林窗(400~450 m^(2))最有利于此地区植物群落的更新组成和土壤养分循环。

【Objective】This study aims to reveal the relationship between plant diversity and soil physicochemical properties in Pinus massoniana plantation under different gap sizes.【Method】In this study,five different gap sizes(50-100、100-150、200-250、400-450、600-650 m^(2))in a 25-year-old P.massoniana plantation were taken as research objects,were compared with pure stand of P.massoniana.This study investigated and analyzed the vegetation composition,species diversity and soil physicochemical properties under different gap sizes suing Redundancy analysis(RDA)to determine the relationship between soil factors and species diversity.【Result】(1)The important values of native tree species,such as Quercus serrata,Acer davidii,Eurya japonica,and Mallotus tenuifolius,were at the forefront in different forest gap sizes.The increase in the gap size led to an increase in the number of shade-tolerant species,while the number of semi-shade-tolerant species remained stable and occupied an important position.(2)The G4(400-450 m^(2))gap size showed the highest species diversity,and there was a strong positive correlation between species richness and diversity index of shrub layer and soil physicochemical properties.(3)The soil physicochemical properties under the middle and large forest gaps were obviously improved compared with those under the small forest gaps.The soil contents under G4 gap size showed of the highest content of total potassium(45.41 mg/kg),available potassium(191.29 mg/kg)and organic matter(68.42 mg/kg).The content of available potassium was significantly higher than that of other gaps(P0.05).Soil organic matter,soil total nitrogen and soil total potassium were the main environmental factors that affect the distribution of species under the forest gaps of P.massoniana plantation.【Conclusion】The results showed that plant diversity could sustain and even improve soil fertility,and G4 gap size(400-450 m^(2))was the most beneficial to plant community regeneration and soil nutrient cycling in this area.