论古尔班通古特沙漠植物多样性的一般特点

古尔斑通古特沙漠处于中亚荒漠与内亚（亚洲中部）荒漠之间的过渡，其气候虽以干旱少雨、蒸发强烈、多风、日照强、温度变化剧烈的大陆性荒漠气候为特点，但由于降水季节分配较均匀，冬春有一定雨雪，植被相对较为茂密，以固定和半固定沙漠为主，共采集记录到２０８种高等植物，１８个植物群落类型，ｌｌ类植物生活型。植物多样性还包括下列一般特点：区系地理成分多样，但中亚成分占优势；有少量古老种，特有现象微弱，黎科植物占明显优势；早生植物为主；长营养期１年生植物有一定比例；短命和类短命植物获得发育等。由于近几十年来的过牧（牲畜的“冬窝子”）和滥采滥挖燃料及有经济价值的植物，植物多样性受破坏严重。当前的紧迫任务是加强保护，对有些物种还须采取措施，进行抢救。

On the General Characteristics of Plant Diversity of Gurbantunggut Sandy Desert

The Gurbantunggut Sandy Desert is located at the transitional belt between Central Asia and Middle Asia. Though its climate is characterized by aridness with scarce precipitation, intense evapotranspiration, windy, strong sunshine and severe variation of temperature, and is a kind of continental desert climate, yet, because of the rather evenness of seasonal distribution of precipitation, with certain amount of rain and snow falling in winter and spring, its vegetation is relatively luxuriant. Most parts of the deserts are fixed or semi|fixed. The characteristic features of plant diversity of Gurbantunggut Sandy Desert may be summarized as follows: (1) The species richness is relatively high. Compared with other sandy deserts of Central Asia (Takilmakan, Qaidam, Alxa), the flora of Gurbantunggut is more rich than others. There has been collected and identified 208 species of higher plants in Gurbantunggut. Among them, Chenopodiaceae (53 species), Cruciferae (22 species) and Compositae (20 species) are the three most dominant families. (2) The floral|geographical elements are diverse. According to studies by predecessors, the geographical elements of the flora of Gurbantunggut Sandy Desert consist of Central|Asian element, Middle|Asian element, Mediterranean element, North|Eastern African|Central Asian element and Euro|Asian element, so it has transitional character, though, that of Middle|Asian is more abundant. (3) The endemism of this sandy desert is weak. Nevertheless, there are many plant species which distribute only in Gurbantunggut Sandy Desert within the territory of China. (4) The species of Chenopodiaeceae possesses obvious dominant position in the composition of plant diversity. There are 24 genera and 53 species of Chenopodiaeceae, which account for 19 5% and 25 5% respectively of the floral total of this sandy desert and much higher than that of the rest dominant families such as Cruciferae, Compositae, Leguminosae and Gramineae. Not only the species composition, their role in plant communities are also outstanding. Large areas are occupied by plant communities with edificators from Chenopodiaceae, such as Haloxylon persicum, H.ammodendron, Ceratoides latens, Salsola arbuscula, Anabasis brevifolia, A.aphylla and others. (5) The ecotypes mainly consist of xerophytes. (6) The life forms are diverse. 11 categories of plant life forms have been found in Gurbantunggut Sandy Desert. Among them, the dominant ones are ephemerals (55 species), annuals with long period of nourishment (42 species). This two categories come to 97 species, accounting for 47% of the total. Next are plants with axial roots (38), shrubs (29) and nanoshrubs (16). (7) Annuals with long period of nourishment make up relatively large proportion, as mentioned above. (8) Ephemerals and ephemeroides obtain certain development. There are 66 species of ephemerals and 11 species of ephemeroides. Both of them are short|living plants and mainly grow on sandy soils. (9) Types of plant communities are rich. Compared with other deserts of Central Asia, the plant communities of Gurbantunggut are richer. 18 communities have been recorded. Owing to the overgrazing (many sites of the desert, especially along its border, are livestocks wintering places) and over|collecting and digging of fuels, as well as economic plants, the plant diversity of Gurbantunggut has been severely damaged. It is urgent at present time to adopt measures to protect its plant diversity, and for some endangered species, even to rescue them.