茂兰喀斯特森林不同林窗中灌木对幼苗层光资源分配的影响  

Effects of Shrub Shading on Light Resource Allocation in Seedling Layers under Different Forest Gaps in Maolan Karst Forests

作　　者：李羽翎 张广奇 臧丽鹏 刘庆福 隋明浈 陈丹梅 谢加琪 李雍 Li Yuling;Zhang Guangqi;Zang Lipeng;Liu Qingfu;Sui Mingzhen;Chen Danmei;Xie Jiaqi;Li Yong(Fanjingshan National Nature Reserve Management Bureau in Guizhou,Tongren 554400,Guizhou,China;College of Forestry,Guizhou University,Guiyang 550025,Guizhou,China)

机构地区：[1]贵州梵净山国家级自然保护区管理局,贵州铜仁554400 [2]贵州大学林学院,贵州贵阳550025

出　　处：《山地农业生物学报》2024年第6期8-14,共7页Journal of Mountain Agriculture and Biology

基　　金：国家自然科学基金委员会-贵州省人民政府喀斯特科学研究中心项目(U1812401);贵州省科技支撑项目(黔科合支撑[2019]2874);贵州省基础研究计划项目(黔科合基础[2020]1Y124)。

摘　　要：林窗形成后光照显著增强是造成林窗与林下环境异质性及物种更新差异性的主要原因,但林窗内先建植的灌木层植物对光照具有再分配作用,导致幼苗层的光环境复杂多样。本研究以茂兰国家级自然保护区内常绿落叶阔叶混交林林窗为研究对象,测定林窗大小,获取不同林窗内灌木层和幼苗层的光环境参数(开阔度、直接辐射、散射辐射与总辐射),建立不同林窗内灌木层光环境与开阔度的关系、幼苗层光环境与灌木层开阔度的关系,并分析它们在不同林窗内的显著差异性,探究林窗内光资源再分配对幼苗层光环境的影响。结果表明:中、小林窗的开阔度与灌木层光环境参数均呈极显著正相关关系(P<0.01),且在不同林窗大小间存在显著差异(P<0.05);不同林窗内幼苗层的开阔度与幼苗层光环境参数均呈极显著正相关关系(P<0.01),在林窗大小间没有显著差异。不同林窗内灌木层光环境与幼苗层光环境显著不同,且灌木层光环境各参数的值显著大于幼苗层光环境各参数的值(P<0.05)。幼苗层的开阔度(灌木遮阴)对幼苗层直接辐射的解释率为62.6%,对散射辐射的解释率为91.5%,对总辐射的解释率为83.3%。说明灌木层对林窗内光资源进行的再次分配是喀斯特森林林窗内幼苗层光环境的主要影响因素。该研究结果为探究林窗内幼苗更新机制与促进退化喀斯特森林的恢复及更新提供依据。The significant increase in light availability following the formation of a forest gap is the primary driver of heterogeneity between the forest gap and understory environments,thereby influencing species regeneration.However,pre-existing shrub layer vegetation within the gap redistributed the light,creating a complex and diverse light environment for seedling growth.In this study,we measured gap sizes and obtained the light characteristic parameters of the shrub layer under various gap sizes,as well as the light characteristic parameters of the seedling layer under different levels of shrub shading conditions within the evergreen deciduous broad-leaved mixed forest at Maolan National Nature Reserve.This study established the relationship between the light environment and the openness of the shrub layer,as well as the light conditions in the seedling laye racross various gap sizes.An analysis was conducted to compare the light conditions in the seedling layer and the openness of the shrub layer,and investigated how the redistribution of light resources in the forest gap impacts the light environment of the seedling layer.The results indicated a highly significant positive correlation between openness and light characteristic parameters of the shrub layer in middle and small gap sizes(P<0.01),with a significant variation observed among different gap sizes(P<0.05).A significant positive correlation was observed between the shrub layer openness and the light parameters of the seedling layer in different gap sizes(P<0.01),with no significant variance observed among different gap sizes.The light environment in the shrub layer varied significantly from those in the seedling layer in different gap sizes.The light environment parameters in the shrub layer were significantly higher than those in the seedling layer(P<0.05).The shading effect of the shrub layer accounted for 62.6%of direct transmittance,91.5%of diffuse transmittance,and 83.3%of total transmittance.The shrub layer in Karst forests played a significant role i

关 键 词：喀斯特森林 林窗大小 灌木遮阴 幼苗层 光资源分配 

分 类 号：S754.1[农业科学—森林经理学]