摘要
【目的】详细刻画和分析树种空间优势度,为关键树种保护和森林群落物种多样性维持提供理论依据。【方法】基于林木空间优势度指数(大小比数和双曲正切指数)构造标记二阶特征函数,通过模拟数据检验标记二阶特征函数的有效性以及同种空间聚集对树种空间优势度的影响,在此基础上以雅长自然保护区1.6 hm2实测样地为研究对象,详细分析样地中主要树种空间优势度在不同空间尺度上的变化,探究树种空间优势度与树种混交之间的关系。【结果】1)研究森林群落属老龄林,结构多样性丰富,共记录木本植物35科61属86种,断面积49.81 m2·hm-2。群落中不同树种具有不同胸径分布范围,其中以较大径级树种如多花杜鹃、枫香树等为主要建群种,较小径级树种如细齿柃、榕叶冬青等个体数量较多,在林分中占有一定地位,不同树种的大小比数和双曲正切指数表明,树种平均胸径与其优势度存在显著正相关关系。2)群落中主要树种在小尺度范围内均存在吸引相似大小林木的趋势,较大径级树种空间优势度低于期望值和零模型模拟的随机区间,较小径级树种空间优势度显著高于期望值,随着尺度距离增加,树种空间优势度趋于期望值。3)同种空间聚集可增加或减小树种空间优势度,对枫香等大径级树种而言,同种聚集导致其空间优势度降低,而对榕叶冬青等小径级树种则相反。【结论】标记大小比数和双曲正切指数二阶特征函数能够精细刻画不同空间尺度上树种空间优势度;树种间“空间隔离”效应可减轻优势树种对劣势树种的竞争排除作用,有利于维持物种共存,提高森林群落物种多样性。
【Objective】Detailed analysis of spatial dominance of individual tree species was carried out in order to provide a theoretical basis for the protection of key species and the maintenance of species diversity in forest communities.【Method】In this study,based on the spatial dominance indices(tree size dominance and hyperbolic tangent indices),we constructed marked second-order characteristic functions to investigate the changes of spatial dominance of main tree species at different spatial scales.We simulated dependent,spatial marked point patterns to test the effectiveness of the constructed marked second-order functions and to analyze the influences of spatial aggregation of conspecifics on the spatial dominance of focused tree species.We investigated the changes of spatial dominance of the main tree species at different spatial scales in a 1.6 hm2 forest plot in Yachang nature reserve and explored the relationships between tree dominance and species mingling.【Result】1)The studied forest community was an old-growth forest in which structural diversity was rich.A total of 86 species,61 genera and 35 families were recorded,and the basal area of this stand was 49.81 m2·hm-2.Different species in the community had different ranges of DBH distributions.Larger-sized tree species such as Rhododendron cavaleriei and Liquidambar formosana were the dominant tree species in the stand,and tree species of small-sized species,e.g.Ilex ficoidea and Eurya nitida,were also dominant in terms of their abundances.Size dominance and hyperbolic tangent index values of different tree species indicated that spatial dominance of tree species was associated with the population mean DBH.2)All the tree species had a tendency to attract trees of similar sizes at small scales,and generally,spatial dominance of large-sized tree species was lower than the expected value or simulation envelopes constructed from the null model.However,spatial dominance for small-sized tree species was significantly greater than the expected,and its value tended to approach the expected value with the increasing spatial distance.3)Spatial aggregation of conspecifics can increase or decrease the degree of species dominance.For large diameter tree species,such as L.formosana,conspecific aggregation resulted in the decrease of its spatial dominance;on the contrary,conspecific aggregation can increase species spatial dominance for small-sized tree species such as I.ficoidea.【Conclusion】Our analysis of both simulated and experimental plot data showed that mark dominance second-order functions can effectively describe the spatial dominance of tree species at different scales.The species spatial segregation effects might reduce the competitive exclusion of inferior species by dominant species,and thus can maintain species coexistence and improve the species diversity in forest communities.
作者
黄绍娴
王宏翔
彭辉
王耀仪
李远发
叶绍明
Huang Shaoxian;Wang Hongxiang;Peng Hui;Wang Yaoyi;Li Yuanfa;Ye Shaoming(College of Forestry, Guangxi University Nanning 530001;Fengyang Mountain Administration of Zhejiang Fengyang Mountain-Baishanzu National Nature Reserve,Longquan 323700)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2022年第4期128-140,共13页
Scientia Silvae Sinicae
基金
国家自然科学基金项目(32101520)
广西科技基地和人才专项(AD20297051)。
关键词
林分空间结构
树种空间优势度
二阶特征函数
空间隔离假说
物种多样性维持
stand spatial structure
spatial dominance of species
second-order characteristic function
spatial segregation hypothesis
maintenance of species diversity
