砒砂岩区人工油松林下草本植物的生态位特征

Niche Characteristics of Herbaceous Plants Under Artificial Pinus Tabuliformis Forest in Feldspathic Sandstone Region

[目的]探究砒砂岩区油松(Pinus tabuliformis)人工林下草本植物生态位特征,为当地油松人工林维护生物多样性和群落稳定提供基础数据。[方法]选取长势良好的油松林地,实地调查记录各样地草本植物的类型及数量、平均株高及盖度等基本情况;基于调查数据,采用Shannon和Levins生态位宽度指数、Levins生态位重叠指数及生态响应,分析油松人工林下草本层植物生态位特征。[结果]①砒砂岩区油松人工林草本层植物共计35种,其中本氏针茅的生态位宽度指数最大,表现出较强的适应性,明显处于群落优势地位。②整体生态位宽度及生态位重叠指数普遍不高,林下草本物种存在分化现象。③林下草本物种有37.15%的物种为发展物种,62.86%的物种为衰退性物种,14种优势物种中,11类属于发展性物种,其中资源占有量较大的物种为本氏针茅(0.1885)、阿尔泰狗娃花(0.0531)、糙隐子草(0.0379)。[结论]砒砂岩区油松人工林下草本植物种间竞争微弱,群落物种对资源环境的利用能力欠佳。主要优势草本物种绝大部分处于发展阶段,表明现阶段油松人工林群落趋于相对稳定状态。

[Objective]The niche characteristics of understory herbaceous plants in Pinus tabuliformis plantation forests in the feldspathic sandstone area were explored in order to provide basic data for local Pinus tabuliformis plantations to maintain biodiversity and community stability.[Methods]The types,quantity,average plant height,and coverage of various herbaceous plants were recorded by field investigation in a well-growing P.tabulaeformis forest area.Based on the survey data,the Shannon and Levins niche breadth index,Levins niche overlap index,and ecological response were used to analyze the niche characteristics of understory herbaceous plants.[Results]①There were 35 species of herbaceous plants in the P.tabulaeformis plantation forest in the arsenic area.Among them,Stipa bungeiensis had the largest niche breadth indexes with better performance.Because of this species’s strong adaptability,its community was in an obviously advantageous position.②The overall niche width and niche overlap index were generally not high,and understory herbaceous species were differentiated.③37.15%of understory herbaceous species were developing species,and 62.86%of species were declining species.Among the 14 dominant species,11 were developing species.The developing species with the largest resource occupancies were S.bungeana(0.1885),Heteropappus altaicus(0.0531),and Cleistogenes squarrosa(0.0379).[Conclusion]Competition among understory herbaceous plants in P.tabulaeformis plantations in the arsenic area was weak,and the community species had poor utilization of resources and environment.Most of the dominant herbaceous species were in the developing stage,indicating that the P.tabulaeformis plantation community tended to be relatively stable at this stage.