古尔班通古特沙漠固定沙丘上白梭梭和梭梭的空间分布及种间关联性

Spatial distribution and interspecific correlation of Haloxylon persicum and H.ammodendron on fixed dunes of the Gurbantunggut Desert,China

为了探讨沙漠中固沙灌木种群共存和演替机制,本文基于古尔班通古特沙漠东南缘固定沙丘上白梭梭(Haloxylon persicum)和梭梭(H.ammodendron)种群的地理位置和生长发育阶段信息(幼株、营养株、生殖株和死株),采用点格局分析方法(g(r)函数)及Monte-Carlo随机模拟检验和零模型选取的方法,分析了固沙灌木白梭梭和梭梭种群不同生长发育阶段在0-20 m尺度内的空间分布格局及种间关联性。结果表明:(1)两个种群在研究尺度范围内呈聚集分布,随着尺度的增大,其聚集强度逐渐减弱;(2)两个种群整体上呈负关联关系,尺度越大负关联关系越显著;(3)白梭梭种群生长发育阶段相差越大,个体间正关联关系越显著;梭梭种群生长发育阶段越接近,个体间正关联关系越显著;(4)两个种群中龄级较大的个体(如营养株、生殖株和死株)会对对方种群中龄级较小的幼株产生一定的抑制作用;同时,随着两个种群中个体的成长,双方受到的抑制作用逐渐减弱,主要表现为正关联和无关联。总体而言,古尔班通古特沙漠固定沙丘白梭梭和梭梭种群的分布格局整体上为聚集分布,随龄级增加聚集性减弱,受生境异质性和扩散限制的影响明显。种间关系多为负相关,种内不同生长发育阶段之间均为正关联关系。

Aims The aim of this study is to explore the coexistence and succession mechanism of sand-fixing shrubs population in the desert.Methods Based on the current literature on the geographical location and developmental stages(young,nutrition,reproductive and dead plant)of Haloxylon persicum and H.ammodendron populations on fixed dunes in the southeastern edge of the Gurbantunggut Desert,this paper adopted the methods of point pattern analysis g(r)function,Monte-Carlo random simulation test,and zero model selection.The spatial distribution pattern and interspecific correlation of H.persicum and H.ammodendron populations at different developmental stages in the scale of 0-20 m were analyzed.Results(1)The two populations demonstrated aggregated distribution in the range of the study scale,and the aggregation intensity decreased as the scale increased.(2)There is a negative correlation between the two populations,and the larger the scale,the more significant the negative correlation.(3)The greater the difference between developmental stages of H.persicum population,the more significant the positive correlation amongst individuals,and the closer the developmental stages of H.ammodendron population,the more significant the positive correlation amongst individuals.(4)The older individuals in the two populations(e.g.,the stages of nutrition,reproductive and dead plant)could inhibit growth of the smaller young plants in the other populations.At the same time,with the development of individuals in both populations,the inhibition in both species gradually weakened,exhibiting both positive correlation and non-correlation.Conclusion The distribution pattern of H.persicumand H.ammodendron population in fixed dunes of the Gurbantunggut Desert has an aggregated distribution.As the age class of each population increases,the aggregate distribution weakens.Habitat heterogeneity and diffusion are the two main factors.There is a negatively correlated interspecific relationship between both species,and the intraspecific developmental stages are positively correlated.