干旱荒漠草原型流域水文干旱和气象干旱关系

为了合理评估干旱对荒漠草原流域的影响程度,准确判断气象干旱与水文干旱之间的传播特征,以艾不盖河流域作为典型研究区,基于1965—2021年共57年的月降水和径流资料,计算三种不同时间尺度的SPI和SRI,分析了气象干旱和水文干旱的演变过程、趋势特征及相关性。研究结果表明：应用标准化降水指数SPI和标准化径流指数SRI能够很好地反映气象干旱和水文干旱变化状况;SPI值和SRI值对降水量和径流量的敏感性随着时间尺度的增加而降低,时间尺度越大,发生高等级气象干旱事件和水文干旱事件的频数越高;发生气象干旱事件和水文干旱事件的趋势增强,且发生水文干旱的程度和可能性较气象干旱更重;时间尺度越大,水文干旱与气象干旱相关性越好,同时水文干旱要滞后于气象干旱,滞时为0—1月。研究结果为荒漠草原流域抗旱减灾提供了有效的理论支撑。     

Responses of ephemeral plant germination and growth to water and heat conditions in the southern part of Gurbantunggut Desert

Ephemeral plants in the southern part of Gurbantunggut Desert were systematically monitored from 2002 to 2004 and the meteorological data and soil moisture during the same period were analyzed. The results show that the ephemeral plants germination and growth are sensitive to the changes of water and heat condition. The time for daily temperature over 0℃ in early spring in 2003 was delayed nearly 10 d compared with that in 2002, while the soil water changed little in the same period. Observation showed that there were 28 ephemeral species germinated in 2002, their life period was about 70 d in spring, and the maximum cover of ephemeral synusia reached 46.4%. However, only 17 ephemeral species germinated in 2003, their life period was about 50 d in spring, and their maximum cover was only 20.8%. The height of ephemeral plants was significantly higher in 2002 than that in 2003. It can be seen that ephemeral plant germination and growth in spring are strongly dependent on temperature. The changes of water conditions can affect ephemerals germination and growth as well. Because no heavy precipitation occurred during summer in 2002, only a few ephemerophytes were observed in autumn after ephemerals completed their life circle in early spring. However, about 60 mm precipitation was recorded from July to August both in 2003 and in 2004. Some ephemerals such as Erodium oxyrrhynchum and Carex physodes, etc. covered the dune surface rapidly with a cover 〉10%. Therefore, the ephemerals not only germinate in autumn after the early spring, some species may germinate in summer if adequate rainfall occurs. The study on responses of ephemerals growth to water and heat conditions not only has a certain ecological significance but also contributes a better understanding to the effect of climate changes on the desert surface stability.     

植物水势系数及其应用实例

本文提出了植物水势系数的概念与计测公式，即植物水势系数是植物水势占大气水势和土壤水势对植物水势产生直接影响力那部分水势之和的比值。并对在塔克拉玛干沙漠生长的沙生柽柳进行了应用实例的验证。结果表明，在自然状态下，植物水势系数可作为衡量植物对环境胁迫反应强弱的一个指标。     

遥感、GIS支持下的浑善达克沙漠化土地最新特征分析

通过对浑善达克沙地土地沙漠化的遥感调查发现,2000年沙地沙漠化土地面积达318．54万hm^2,占沙地总面积的58．84％。其中,轻度沙漠化土地占沙漠化土地的52.34%之多,是浑善达克沙地沙漠化土地的主体。在空间分布上,除了沙地北部的锡林浩特市之外,其余旗县都有大面积的沙漠化土地分布。从作业区的分析情况来看,沙漠化态势比较严重的是阿巴嘎旗和正蓝旗。与1995年对比分析表明,5年来浑善达克沙地在整体上基本稳定,沙漠化土地面积没有太大的扩展,但部分旗县仍以沙漠化的加重为主,区域差异很大。     

艾比湖地区主要荒漠植被防风固沙功能研究

在艾比湖保护区内多个样地风速测点选择荒漠植被,开展防风防沙研究。在实地测量的基础上通过比照不同地形、不同植被类型以及不同植被覆盖率防风及输沙率的影响,分析在不同风速范围的效果,对干旱地区防治风蚀及沙尘暴提供理论依据,课题研究对艾比湖国家湿地自然保护区生态恢复有着极其重要的意义。     

巴丹吉林沙漠沉积物的地球化学特征

在第四纪沉积物研究中,特别是现代沉积环境的研究中,沉积物的地球化学特征在分析物源和重建古环境等方面发挥积极的作用.通过采集了巴丹吉林沙漠不同区域、不同类型沙丘、不同地貌部位的沙样,分析了巴丹吉林沙漠沉积物的地球化学特征,得出巴丹吉林沙漠沉积物在矿物学上和沉积学上的成熟度较低,但是具有很好的均质性的结论.这一结论对于推断巴丹吉林沙漠沉积物的物源有很好的指示意义,同时对于研究巴丹吉林沙漠高大沙山的成因也有一定的线索意义.     

Arbuscular mycorrhizal fungi infection in desert riparian forest and its environmental implications: A case study in the lower reach of Tarim River

This study was conducted on the desert riparian forest along the lower reach of the inland Tarim River, which is located in the arid region of Northwest China. Fifteen plant species in 10 families were collected from five monitoring sections, and examined for the infection ofarbuscular mycorrhizal fungi （AMF）. The impact of different soil factors on AMF infection rate and intensity was compared using the principal component analysis （PCA） method. The results indicate that 11 species are AM and only 4 are non-AM plants. The estimated capacity of AMF infection depends on families of plants and also the parameters （infection rate, infection intensity, fungal spore density） used. The density of fungal spores was relatively higher in Phragmites communis and Populus euphratica in Graminaceae and Salicaceae families, respectively. The infection rate was above 50% in all the AM plants, except Calligonumjunceum. The highest infection rate appeared in Alhagi sparsifolia （97%） and Glycyrrhizainflata （92%）. However, when compared by AMF infection intensity, Tamarix spp. became the top one, followed by Alhagi sparsifolia, and Glycyrrhiza inflata was in the middle range of all the species. The PCA has identified that soil total salt, moisture, organic matter, total nitrogen, total P, available K and pH were closely associated with the AMF infection.     

晚新生代塔里木盆地中西部地区磁性地层与环境演化

报道了塔克拉玛干沙漠腹地塔格山剖面的磁性地层和古环境记录的研究结果.结果表明:塔里木海湾消亡、副特提斯海最终退出塔里木盆地发生在4.2 Ma以前;3.4 Ma塔里木盆地首次出现大型流动沙丘,塔克拉玛干沙漠开始形成;2.6 Ma塔里木盆地干旱化程度进一步加剧,沙漠的规模进一步扩大,形成了当今极度干旱的大型沙漠环境.     

Late Pleistocene／Holocene wetland events recorded in southeast Tengger Desert lake sediments, NW China

The area along the eastern and southeastern margins of the Tengger Desert, NW China, which is sensitive to the summer monsoon variations, was selected for studying the environmental conditions surrounding the transition between Paleolithic foragers and Neolithic farmer/pastoral-ists. Short cores were obtained from four lake basins in the southwestern Tengger using a hand-driven piston coringdevice. Proxies from these cores were supplemented by ra-diocarbon ages obtained from lake sediment cores, shoreline features and spring mound deposits. Together these records provide evidence of millennial-scale climate change eventsfrom the Pleistocene-Holocene transition to the present.Lake/wetland events, representing periods of more intensive summer monsoon, occur in the records at-12.7-11.6,-10.1, -9.3, -8.0, -5.4, -1.5, and -0.8 ka BP. They do suggest that century- to miliennial-seale climatic cycles are characteristic of the Holocene in the southeastern Tengger Desert although the chronology must be considered extremely tentative.     

Topographical changes of ground surface affected by the Tarim Desert Highway

The Tarim Desert Highway is the longest highway crossing the mobile desert in the world. The highway and its sand protection system were established in 1995. This great project must have significant effect on the aeolian environment in its neighborhoods. In 2004, we investigated the topographic changes of ground surface within the sand protection system and its external adjacent area in the hinterland of the Taklimakan Desert. The results showed that （i） the original topographic patterns of ground surface were greatly changed, and erosion as well as deposition was distributed clearly on the ground surface, affected by the road and its sand protection system; （ii） sediment deposited in the sand protection system gradually heightened the ground surface, but each part in the system changed differently： in the sand-blocking belt, a transverse sand ridge was formed in the same direction as the upright sand barrier; in the sand-binding belt, sediment was aggraded on the original surface in a certain thickness; at the initial stages since the establishment of the sand protection system, erosion had taken place in the un-stabilized area named by the deposition belt between the sand-blocking belt and the sand-binding belt, the inner of sand-binding belt, the windward slope of dunes in the sand-binding belt, and the neighboring leeward area of the sand protection system.