摘要
运用扩散系数、聚集指数、平均拥挤度、聚块指数、Cassie指数、Moristia指数、聚集强度等7项指标,对腾格里沙漠南缘天然植被群落演替进程中半固定沙地、半固定-固定沙地过渡带、固定沙地3个不同演替恢复阶段优势种群的空间分布格局及格局变化过程进行了研究。各项指标的分析结果基本一致,各演替阶段的优势种群均表现出显著聚集分布的空间格局,且C和PI分别都通过了t检验和X2拟合检验,与预期假设呈显著差异,测定结果较好。引起腾格里沙漠南缘天然植被恢复初期优势种群呈显著聚集分布的主要原因有植物种本身的繁殖特性带来的空间局限性,风大沙多的外部环境以及土壤水分和养分强烈的空间异质性。优势种群空间分布格局强度的变化,与群落的空间异质性以及群落演替逐渐进行的生态学过程相对应,演替初期,优势种个体数量较少,处于侵入繁殖的阶段,群落物种数量相对较丰富,较强的空间异质性促进较强聚集分布的形成,随着群落演替的不断推进,优势种完全占据了空间资源,聚集强度下降,群落空间异质性逐渐降低,群落更加稳定,植被逐渐得以恢复,目前形成了以油蒿为主要优势种群的天然植被格局。
The spatial patterns and variations of the dominant populations occurring in southern margin area of Tenggeli Desert in different recovering successions （semi-fixed sand, half semi-fixed sand and fixed sand- y transitional zone,fixed sandy） were investigated with 8 indices,including dispersion index （C）, clump in- dex （It）,mean crowding intensity （m＊）,patch index （M1）,Cassie index （Ca）,Moristia index （Iδ） and the clump intensity index（PI） ,the spatial distribution pattern among the species of dominant populations were analyzed. The result was basically identical with all indices, also dispersion index and clump intensity index respectively through the t and X2 test, there were significant differences between result and expectation. The result showed that all of the spatial distribution pattern of main species in the study area were clump. The spatial limitationthat clue to reproductive characteristics of plants itself, the external environment of more windy and dusty, and strongly spatial heterogeneity of soil water and nutrient were main cause for significant clump distribution model in early succession stage. The change of spatial pattern was accordancewith spatial heterogeneity of community structure and process of ecology, in early succession stage, the quantity of main species was relatively lack,this was very helpful for promoting population invasion and in- habitation, rather the quantity of species number was relatively rich, strongly spatial heterogeneity of com- munity structure was promoted formation of clump distribution. With the further succession, the dominant species occupied absolutely space advantage, the intensity of clump distribution pattern and the spatial het- erogeneity of community structure were all declined, the structure of community more stabilization, this was helpful for promoting vegetation restoration. Now,Artemisia desertorum was mainly constructive spe- cies in study area, the natural vegetation gradually development in the direction of singlen
作者
李亚
胡小柯
魏怀东
苏万红
纪永福
周兰萍
LI Ya HU Xiao-ke WEI Huai-dong SU Wan-hong JI Yong-fu ZHOU Lan-ping(Gansu Desert Control Research Institute/ State Key Laboratory Breeding Base of Desertification and Aralian Sand Disaster Combating, Lanzhou, Gansu 730070, China Jingtai County Forestry Bureau, Jingtai, Gansu 730040, China)
出处
《西北林学院学报》
CSCD
北大核心
2017年第2期67-72,共6页
Journal of Northwest Forestry University
基金
甘肃省基础研究创新群体(145RJIA335)
甘肃省自然科学基金(1506RJZA137)
甘肃省技术研究与开发专项(1004TCYA011)
国家自然科学基金(31360204)
关键词
腾格里沙漠南缘
优势种群
空间分布格局
聚集分布
空间异质性
in the south fringe area of Tenggeli desert
dominant species
spatial distribution pattern
clump distribution
spatial heterogeneity
