|其他摘要||Five species of Calligonum L. in Tarim Basin, Calligonum roborovskii A. Los., Calligonum kurlaense Z. M. Mao, Calligonum yengisaricum Z. M. Mao, Calligonum juochiangense Liou f. and Calligonum taklimakanense B. R. Pan et G. M. Shen were chosen as research materials. Their distribution range, population spatial distribution patterns, and interspecific associations were confirmed by field population survey, combined with consulting specimen and relevant literature information. The associations between the five species’ distribution with their climatic and soil characteristics were explored through the mean variance analysis and the principal component analysis. The MaxEnt model was used to predict the potential distribution of the five species. All these results could supply theoretical basis for the protection, revegetation, and reasonable utilization of Calligonum L. The results of the study were as follows:
1. Survey of five species’ wild populations of Calligonum L. showed that C. roborovskii was widely distributed in Tarim Basin, but C. kurlaense, C. yengisaricum, C. juochiangense and C. taklimakanense presented narrow distribution. The most north distribution boundary of C. roborovskii was kumishi town of Tuokexun county (88.81°E，42.34°N), the most south distribution boundary was Nuer village of Cele county (81.01°E，36.30°N), the most west distribution boundary was Wupaer village of Shufu county (75.19°E，39.25°N), the most east distribution boundary was Kuruketag Mountain in the east of Lop Nur (92.42°E，40.40°N). C. kurlaense mainly distributed in Kuerle, Luntai and so on. C. yengisaricum just distributed in Yingjisha, Yecheng, Shache and so on. C. juochiangense just distributed in Ruoqiang. C. taklimakanense distributed in Middle Taklimakan (83.87°E，38.87°N，1107.3m). Besides, the analysis of the connectivity between each species showed that, the distribution of C. roborovskii with that of C. kurlaense, C. yengisaricum and C. juochiangense were significantly negative correlation respectively. They maybe replace each other in the future.
2. The analysis of population distribution pattern showed that C. roborovskii, C. kurlaense, C. yengisaricum and C. taklimakanense were all aggregated distribution at both scales 10m×10m and 20m×20m. C. juochiangense presented aggregated distribution at the larger scale of 20m×20m, but tended to uniform distribution at the smaller scale of 10m×10m. And the aggregated strength of the five species of Calligonum L. were lower, they were C. kurlaense, C. roborovskii, C. yengisaricum, C. juochiangense and C. taklimakanense in the order from great to small.
3. Five species’ warm index were all between 85~180℃·mon, so they were all belong to the warm temperate zone. The adaptability of C. roborovskii to moisture was larger. The annual precipitation of its distribution area was from 7.1mm to 88.7mm, and the optimum range was from 25.3mm to 74.2mm. The habitat of C. juochiangense and C. taklimakanense were more arid than that of C. kurlaense and C. yengisaricum, the two formers had stronger drought tolerance than the two latters. The soil type of the five species main was brown desert soil with high salinity. Its pH was alkaline (8.0). It had lower content of organic matter (1.2~8.0g·kg-1) in the top soil, and higher salinity content (1.2~10g·kg-1). Besises, comparative analysis supported that low temperature factor, moisture factor, saline and alkaline were the main reasons leading to the independent distribution of C. kurlaense, C. yengisaricum, C. juochiangense and C. taklimakanense. The principal component analysis showed that, the main factors limiting the distribution range of the five species were high temperature factor and moisture factor, followed by soil properties. For C. juochiangense and C. taklimakanense, the limit strength of moisture factor was stronger than temperature.
4. The potential distribution areas of C. roborovskii were located in Tarim Basin and some regions of Gansu, Inner Mongolia, and Qinghai, which was consistent with the collection areas of its specimens and the history distribution points. The potential distribution areas of C. juochiangense were still located in Ruoqiang, Qiemo and Turban regions, which had little difference with its original distribution areas (Ruoqiang). However, the potential distribution areas of C. kurlaense were Karamay of nortern Xinjiang, Turban and Camul of eastern Xinjiang, and Korla, Kashgar and Hotan of sorthern Xinjiang, which had larger difference with its original distribution areas (Korla). The potential distribution areas of C. yengisaricum were Jinghe of northern Xinjiang, Turban of eastern Xinjiang, Kashgar and Hotan of sorthern Xinjiang, which also had larger difference with its original distribution areas (Yingjisha, Shache, Yecheng of Korla). MaxEnt couldn’t figure out the potential distribution areas of C. taklimakanense, for it only distributed in the place of type specimen. Moisture factor was identified to be the key factor of the potential distribution areas of Calligonum L.|