小陇山自然保护区华山松群落8个主要种群的生态位研究

Ecological Niches of the Eight Major Populations of the Pinus armandii Community,Xiaolongshan Nature Reserve

小陇山国家级自然保护区是中国华山松的主要分布区之一。在野外大量调查基础上,运用Levins和Shan-non-Wiener生态位宽度、生态位重叠和生态位相似比例等指数,对林区华山松群落中8个主要种群生态位特征进行研究。结果表明,生态位宽度值大小依次为华山松、锐齿栎、披针叶忍冬、漆树、甘肃山楂、毛栗、辽东栎和少脉椴。华山松Shannon-Wiener生态位宽度值最大,为0.988 8,其次是锐齿栎,为0.877 6,少脉椴最小,为0.352 9。该群落种群间生态位重叠值普遍较低,表明多数种群间竞争较小。建群种华山松与其他种群间生态位重叠值较大,为0.079 1~0.101 3,而其他种群与华山松间生态位重叠值却较小,为0.015 4~0.069 0,华山松与毛栗的重叠值最大,为0.101 3,华山松与少脉椴的重叠值最小,为0.079 1。生态位相似比例在0.5以上的种群对有4对,占14.28%,分别是华山松-锐齿栎、华山松-披针叶忍冬、锐齿栎-披针叶忍冬和锐齿栎-漆树种群对,在0.5以下的有24对,占85.72%,表明群落中多数种群对资源利用的相似性程度较小。作为中国华山松的分布地之一,秦岭西段小陇山林区具有暖温带针叶林生态位的特征。

The Xiaolongshan Nature Reserve is one of the Pinus armandii distribution areas in China.Based on large number of field surveys,study was carried out on ecological niches of the eight major populations of the Pinus armandii community,which is located in Xiaolongshan,Gansu Province,using the indexes such as the Levins and Shannon-Wiener′s ecological niche breadth,niche overlap index,and niche proportional similarity.Results show that the ecological niche breadth of the 8 plant populations follow the order of Pinus armandiiQuercus aliena var.acuteserrataLonicera lanceolataRhus verniciflusCrataegus kansuensisCastanea mollissimaQuercus liaotungensisTilia paucicostata.The population of Pinus armandii is the highest in Shannon-Wiener niche breadth,being 0.988 8,that of Quercus aliena var.acuteserrata follows,being 0.877 6,and that of Tilia paucicostata the lowest,being 0.352 9 only.The values of niche overlap of the populations in the community are generally low,which demonstrates low competition between most populations,but the niche overlap values of the dominant population of Pinus armandii with the other populations are relatively high,ranging between 0.079 1 and 0.101 3,whereas those of the other populations with that of Pinus armandii are relatively low,being in the range between 0.015 4 and 0.069 0.The overlap value is the highest between Pinus armandii and Castanea mollissima,being 0.101 3 and the lowest between Pinus armandii and Tilia paucicostata,being 0.079 1.There are 4 pairs of populations that have niche proportional similarity higher than 0.5 in value,accounting for 14.28%.They are Pinus armandii and Quercus aliena var.acuteserrata,Pinus armandii and Lonicera lanceolata,Quercus aliena var.acuteserrata and Lonicera lanceolata,and Quercus aliena var.acuteserrata and Rhus verniciflus.And the remaining 24 pairs are lower than 0.5,accounting for 85.72%,which demonstrates that the populations are mostly low in similarity of resource utilization.As one of the most important distribution areas for Pinus armandii in China,Xiaolongshan,the western section of the Qinling Mountains,is characterized by the ecological niche of a warm temperate coniferous forest.