中文摘要：

于新疆塔里木盆地荒漠绿洲过渡带设置3条样带（长900 m×宽50 m）进行植物群落调查,运用生态位测度指标和点格局法对种群空间格局、空间关联性及生态位特征进行研究。结果显示,胡杨（Populus euphratica Oliv.）、多枝柽柳（Tamarix ramosissima Ledeb.）和甘草（Glycyrrhiza inflate Bat.）具有较大的重要值和生态位宽度,对其它生态位较窄的物种具有资源竞争和扩张优势,生态适应能力强,对群落结构和环境变化起决定性作用;生态过渡带植物的种间生态位重叠普遍较高,尤其是草本植物间更明显,此分配格局反映出荒漠植物长期适应旱化生境而发生趋同适应,生态位分化程度低,种间资源竞争激烈;优势种群空间格局呈明显的空间变异性,0-25 m尺度内多枝柽柳和甘草分别呈随机分布和聚集分布,胡杨种群在≤5 m尺度内呈聚集分布,并随尺度增大转为随机分布;胡杨与多枝柽柳、胡杨与甘草、多枝柽柳与甘草分别在〈4 m、≤16 m和≤25 m尺度内呈显著空间负关联,种间相互排斥。表明在匮乏环境资源条件下植物趋同适应与资源竞争是驱动荒漠植物群落演替和限制物种共存的主要原因。

英文摘要：

Exploring the spatial patterns and niche characteristics of desert plant populations is helpful in elucidating the community dynamic mechanisms and vegetation restoration in desertoasis ecotones. Based on vegetation investigation data of three transects（ 50 m wide and900 m length）, the spatial distribution patterns, interspecific associations, and niche characteristics of the main plant populations in the desert-oasis ecotone of Tarim basin were analyzed using spatial point pattern analysis and niche indexes. Results showed that Populus euphratica Oliv., Tamarix ramosissima Ledeb., and Glycyrrhiza inflate Bat. had higher importance values and niche widths,indicating better ability to compete for resources against other species with narrow niches, stronger ecological adaptability, and dominance of community structure dynamics and the environment. The values of niche overlap among themain plant populations were generally high, especially among herbaceous species. The distribution pattern indicated that desert plants in drought habitats had convergent adaptation,a low tendency of niche differentiation and intense interspecific competition for resources. The spatial patterns of dominant populations were different; T. ramosissima and G. inflate populations showed random distribution and aggregation distribution at the 0- 25 m scale,respectively; P. euphratica populations showed an aggregated distribution at short distances（ ≤ 5 m） and random distribution with scale increase; P. euphratica vs T. ramosissima,P.euphratica vs G. inflate,and T. ramosissima vs G. inflate showed significantly negative spatial associations at the 4 m, ≤ 16 m,and ≤ 25 m scales,respectively,and interspecific competition exclusion was significant. Convergent adaptation and interspecific competition were the main driving factors for community succession and restricted species coexistence under the condition of scarce resources.