准噶尔无叶豆的地理分布、群落学特征及生物生态学特性

准噶尔无叶豆(Eremosparton songoricum（Litv.）Vass.)是国家级保护植物。对该植物地理分布、群落特征及生物生态学特性进行的研究表明:①准噶尔无叶豆分布区和生态幅狭窄,在我国仅斑块状分布于新疆古尔班通古特沙漠腹地局部地段及沙漠东南缘的部分流动沙地上;②群落中包含植物14科33属37种,可划分为7个地理区系成分,其中,温带分布型属占75.76%。依据群落组成及外貌,划分为5个群丛,主要特点为:不表现为显著的景观植被,且小面积出现;结构简单,层次单调,植物组成均系适沙和耐沙的种类;整个群落以先锋性为特征。此外,群落不稳定,有逐步被其他类型的、相对稳定的群落所替代的趋势,具有时空分布的“暂时性”;③具有“花多果少”的果实产量格局,2005年结实率为(15.36±2.16) %。呈“水泡状”或“干瘪状”的种子比率达(16.2±2.31)％,虫蛀率达(16.92±2.69)%;④种子向幼苗转化率低。依靠超强的水平根茎克隆能力来扩展种群空间。经综合分析,认为准噶尔无叶豆对生境高度专一,人为干扰破坏所带来的生境丧失将使该种受胁状态加剧。对该物种进行保护首先应加强现有生境的就地保护,减少人为破坏;其次,积极开展迁地保护生物学研究,建立苗圃,营造人工种群。

Distribution and Bio-ecological Characteristics of Eremosparton songoricum, a Rare Plant in Gurbantunggut Desert

Eremosparton songoricum is a rare species in Gurrbantuggut Desert of China, and is listed in the China Red Data Book as a national protected plant. To assist in efforts to conserve and restore this species effectively, the geographic distribution, community structure and demographic characteristics of E. songoricum were studied through field investigation and statistical analysis. ①The distribution and ecological breadth of E. songoricum are narrow, in China, only found scattered in small fragments of the hinterland and sand dunes around the north-southern rim of Gurbantunggut Desert. ②In the E. songoricum community there are 37 plant species, belonging to 33 genera and 14 families. Among them, the temperate geographical elements are dominant and occupy 75.76%. The community can be divided into five associations. The habitat of the community is dry, and the coverage is relatively low. The structure of the community is simple and the species composition is dry-tolerant or sand-dependent. The community is unstable and may be replaced by other communities, such as Aristida pennata-Ephemeral plants community, showing the spatio-temporal temporality. ③E. songoricum has a pattern of low fruit and seed yield with many more flowers. The population seedling rate is (15.36±2.16)%. The seeds are often attacked by worms, the attacked rate is (16.92±2.69)%, and a relatively high proportion（16.2%±2.31%）of seeds are in irregular growth and can not ripen smoothly. ④Insufficient seeds and low survival rate from seed to seedling were the weak link. Clonal growth method with rhizome is the major strategy to maintain and spread populations. Due to highly dependence to aeolian and semi-fixing sand habitats and increasingly destroyed habitat in recent years, E. songoricum had been driven to endangered condition. In the future, in situ conservation should be considered as the most important management activity for this species. At the same time, the artificial populations should be expanded from seeds collected in years of high seed set.