【摘要】 【目的】阿拉善高原境内分布着超过20万km2典型的温带荒漠生态系统,这些荒漠生态系统对全球气候与土地利用类型的变化极其敏感,然而水分、能量与生境异质性对该区植物区域物种丰富度的相对影响,以及这种影响在不同生活型植物间的差异还没有得到系统研究。【方法】本文利用阿拉善高原大尺度植物区域物种丰富度数据,并结合相关的气候与生境异质性数据,尝试系统地探讨阿拉善高原植物区域物种丰富度地理格局及其潜在的影响因素。【结果】(1)阿拉善高原植物区域物种丰富度存在显著的经纬度格局,全部物种、草本植物与木本植物区域物种丰富度均呈现出沿经度的升高而增加,沿纬度的升高而递减的变化趋势。(2)方差分解结果显示,水分与能量因子共同解释了全部物种、草本植物与木本植物区域物种丰富度60.7%、62.5%及42.6%的空间变异;两者单独的解释率分别为15.2%～19.6%与2.8%～5.3%。生境异质性分别解释了3组植物区域物种丰富度17.2%、12.3%、29.3%的变异,其单独解释率分别为3.1%、1.0%和11.8%。气候因素与生境异质性对草本植物与木本植物区域物种丰富度的相对影响并不一致;草本植物物种丰富度主要由气候因素决定,而木本植物丰富度则受气候因素与生境异质性的共同控制。(3)气候与生境异质性三者共同解释了区域物种丰富度54.4%～63.8%的变异,但仍然有36.2%～45.6%的变异没有得到解释。【结论】阿拉善高原植物区域物种丰富度格局由水分与能量类气候因子共同决定,水资源可用性是阿拉善地区植物物种多样性维持最为关键的限制因子。生境异质性对阿拉善高原植物丰富度,尤其是木本植物丰富度有着不可忽略的作用,是干旱区植物多样性维持的重要影响因素。阿拉善高原不同生活型植物区域物种丰富度的影响因素可能并不一致,其他未知潜在因素对阿拉善植物区域物种丰富度亦存在着重要影响。更多还原

【Abstract】 [Objective] Desert ecosystem is characterized by extremely restricted water and nutrient availability, high precipitation and temperature variability. Alxa Plateau of northern China covers large-area typical temperate desert ecosystems, with a total area of more than 200,000 km2. These ecosystems are highly vulnerable to global environmental and land-use changes, whereas the relative influence of water,energy and habitat heterogeneity on plant regional species richness, and the associated difference among different functional groups, are still unclear. [Method] With the distributions of 811 native plants, plant regional species richness of three groups, climatic and habitat variables, we tried to explore the biogeographic patterns and the underlying dominant factors of overall, woody and herb plant regional species richness of Alxa Plateau. [Result](1) Both the overall, woody and herb plant regional species richness in Alxa Plateau showed obvious longitudinal and latitudinal gradients, which increased from northwest to southeast.(2) We found that both plant regional species richness of three groups were positively correlated with water variables, but were negatively correlated with energy variables. Water and energy factors together explained 60.7%, 62.5% and 42.6% of the variation in overall, herb and woody species richness, respectively; and both water and energy factors could individually explained 15.2%-19.6%and 2.8%-5.3% of the variation in plant regional species richness of three groups. Habitat heterogeneity significantly explained 12.3%-29.3% of the variation in overall, herb and woody species richness, and also could individually explain 3.1%, 1.0% and 11.8% of variation in species diversity of three groups. The relative role of climate and habitat factors differed between herb and woody species richness. Herb plant regional species richness was predominantly determined by water and energy factors, whereas the woody plant regional species biodiversity was controlled by water, energy and habitat heterogeneity, together.(3)Water, energy and habitat heterogeneity together explained 54.4%-63.8% of the variance overall, herb and woody plant regional species richness, while with 36.2%-45.6% of the variance explained by other unknown factors. [Conclusion] Our results propose that the plant regional species richness patterns are predominantly shaped by water and energy factors together; and water availability is the most key limited factors in shaping these plant regional species richness patterns. Habitat heterogeneity also play a nonnegligible role in regulating these regional species richness in Alxa Plateau. We highlight that the dominant factors of species diversity may differ markedly depending on the plant functional group, and other unknown factors such as soil, neutral factors and human disturbances may also greatly influence plant species richness in Alxa Plateau.更多还原