青海湖流域的土地沙漠化一直是青海湖流域生态环境治理中最为严峻的问题之一。青海湖湖东沙地是在干旱气候条件下形成的风沙堆积区，对青海湖地区的生态平衡有严重的影响。自上世纪70年代开始，经过多年的人工植被恢复，青海湖东岸的沙漠化扩张趋势得到一定程度的遏制。但是，对于高寒沙地的不同类型人工植物群落，还没有一个系统的研究。因此，开展高寒沙地不同人工植被恢复措施下的人工植物群落的研究，探索高寒沙地人工群落与生态因子之间的关系，分析人工植物群落的功能性状特征与生态系统功能的关系是十分必要的。对治理高寒沙地因地制宜的选择人工植物种类和对人工植物群落更好的达到长期防风固沙的效果具有深远的意义。 本论文以位于青海湖湖东高寒沙地（简称湖东沙地）作为主要研究区域，以恢复生态学为理论基础，采用经典生态学野外实地调查方法，结合室内实验分析，通过对湖东沙地几块采取不同人工植被恢复措施的样地（恢复25年的沙棘固定沙丘ZG、恢复13年的沙棘半固定沙丘SJB、恢复6年的沙棘固定沙丘SHG、恢复6年的半固定沙丘SWB、恢复4年的乌柳复合半固定沙丘WLB）的人工植物群落，系统研究了不同恢复时间的人工植物群落的生态学特征以及不同人工植物群落对该区域沙地环境各生态因素（土壤、水分、风沙活动等）的影响，综合分析不同人工植物群落的物种多样性、群落功能多样性以及与生态系统功能之间的关系。希望研究能为高寒沙漠地区的植被重建与生态系统恢复提供理论支持，从而对高寒沙漠的防风固沙工程建设中的优质人工植物群落建立和资源优化配置等方面起到科学指导的作用。 主要的研究结果如下： （1）人工植物群落的建立有助于流动沙地表面的稳定，并促使自然植被的恢复，使得植物种类增加，其中以草本植物种类最多。青海湖湖东沙地的人工植物群落可划分为3个类型：“沙蒿—沙棘固定沙地群落”，“沙蒿—乌柳半固定沙地群落”和“沙棘—沙蒿半固定沙地群落”。“沙蒿—乌柳半固定沙地群落”的物种多样性要高于另外两个类型的群落，且生物多样性随恢复时间的增加而增加。“沙蒿—沙棘固定沙地群落”群落功能丰富度随恢复时间增加而增加；在“沙蒿—乌柳半固定沙地群落”，恢复4年的WLB样地的群落功能丰富度要高于恢复6年的SWB样地；“沙棘—沙蒿半固定沙地群落”的群落功能丰富度则远低于其他样地群落。“沙蒿—乌柳半固定沙地群落”的功能均匀度要高于其余两个类型的群落。湖东沙地的人工植物群落的物种多样性与功能多样性之间，存在相关的关系。 （2）湖东沙地的土壤沙质中以中砂为主，粒度特征参数与我国其他沙区存在着差异，沙地表层内几乎不含粘粒，仅在“沙蒿—沙棘固定沙地群落”的土壤表层少量含有。人工植物群落样地的分选系数表明：“沙蒿—沙棘固定沙地群落”样地抗风蚀的能力高于“沙蒿—乌柳半固定沙地群落”样地高于“沙棘—沙蒿半固定沙地群落”样地和流沙样地，且样地恢复时间越长的样地，表层土的风选系数就越大。各人工植物群落样地的土壤水分都不高，且上层沙土中的土壤水分随深度的增加而显著增加，下层沙土的土壤水分变化有不明显波动。各样地土壤中土壤有机质、氮、磷、钾的含量在整体上均呈现出ZG样地＞其他人工植被恢复样地＞LS流沙地的特点。湖东沙地的人工植物群落的物种多样性与土壤的生态功能性状之间，物种均匀度与土壤有机质含量之间存在线性负相关，其余特征指标间没有相关关系。人工植物群落的功能多样性与土壤的生态功能性状之间，功能均匀度分别与40~60 cm、80~100 cm的土壤水分之间存在线性负相关，功能离散度与80~100 cm的土壤水分之间存在线性负相关，其余特征指标间无相关关系。 （3）湖东沙地各人工植物群落样地的垂直梯度上的平均风速，可以与高度很好的拟合出各样地的风速廓线函数，并反映出区域内风速随高度呈现出指数函数的变化规律。WLB样地的拟合度最高，ZG样地次之，SWB样地的拟合度最低。“沙蒿—沙棘固定沙地群落”所在样地的地表粗糙度要高于“沙蒿—乌柳半固定沙地群落”所在的样地，更高于“沙棘—沙蒿半固定沙地群落”所在样地。不同样地防风作用随高度降低的幅度并不相同，其中ZG样地的变化幅度最大，而SWB样地的变化幅度最小。湖东沙地的人工植物群落的物种组成越丰富，对风速的影响就越大，防风作用也越强；群落的功能性状特征越丰富，1 m以下的防风作用就越强烈，1 m以下的各层平均风速也越低；群落的功能性状的多度越分散，近地面的防风作用就越弱，近地面平均风速也越强；群落的功能性状种类的分散程度越强，2 m处的防风作用就越强，2 m处的平均风速也越低。 （4）高寒湖东沙地的人工植物群落对局部近地面的气温和相对空气湿度均有一定的影响，对土壤温度的影响并不明显。人工植物群落内气温日变幅均高于流沙地，且气温的日变化呈现出“低—高—低”的趋势，各样地的植被对温度的升高和保持都有着不同程度的作用。人工植物群落样地的相对空气湿度日平均值均低于流动沙地。 综上所述，人工植被恢复改善了整个湖东沙地的生态环境，建立了多种类型的人工植物群落，起到了防风固沙的作用。恢复4年的复合式建群的人工植群落所在样地不仅在物种组成、群落物种多样性、群落功能性状等方面性接近湖东沙地恢复25年的单一种建群人工植物群落样地的恢复水平。

The desertification of the Qinghai Lake Basin has always been one of the most serious problems in the ecological environment management of the Qinghai Lake Basin. Since the 1970s, after years of artificial vegetation restoration, the desertification expansion trend on the eastern shore of Qinghai Lake has been suppressed to some extent. However, there is no systematic study of different types of artificial plant communities in alpine sand. Therefore, it is necessary to study the artificial plant community under the restoration measures of artificial vegetation in the alpine sandy land, explore the relationship between the artificial community and ecological factors in the alpine sandy land, and analyze the relationship between the functional characteristics of the artificial plant community and the ecosystem function. Only in this way, it has far-reaching significance for the selection of artificial plant species for the treatment of alpine sandy land and the better effect of long-term wind and sand fixation on artificial plant communities. This thesis is located in the eastern high-cold sand land of Qinghai Lake (referred to as Lake East Sand) as the main research area, based on the restoration of ecology as the theoretical basis, using the classical ecological field survey method, combined with indoor experimental analysis methods. Through the plots of artificial vegetation restoration measures in Lake East Sand (recovering 25 years of ZG Hippophae rhamnoides fixed sand land, recovering 13 years of SJB Hippophae rhamnoides semi-fixed sand land, recovering 6 years of SHG Hippophae rhamnoides fixed sand land, recovering 6 years of the artificial plant community of SWB Salix cheilophila semi-fixed sand land, and recovering 4 years of WLB Salix cheilophila compound semi-fixed sand land), the ecological characteristics of artificial plant communities with different recovery times and the influence of different artificial plant communities on ecological factors (soil, water, wind and sand activities, etc.) of sandy environment in this area were systematically studied. Major community and ecological studies that affect the impact of "and" communities on microclimates. Comprehensive analysis of species diversity, community functional diversity and relationship with ecosystem functions of different artificial plant communities. It is hoped that the research can provide theoretical support for vegetation reconstruction and ecosystem restoration in alpine desert regions, and thus play a scientific guiding role in the establishment of high-quality artificial plant communities and resource optimization in the construction of wind-fixing and sand-fixing projects in alpine deserts. The main findings are as follows: (1) The establishment of artificial plant community contributes to the stability of the surface of the flowing sand and promotes the restoration of natural vegetation, which increases the plant species, among which the herbaceous species are the most. The communities of artificial vegetation restoration in the Lake East Sand of eastern qinghai lake can be divided into three types: "fixed sandy land community of Artemisia desterorum & Hippophae rhamnoides", "semi-fixed sandy land community of Artemisia desterorum & Salix cheilophila" and "semi-fixed sandy land community of Hippophae rhamnoides & Artemisia desterorum ". The species diversity of "fixed sandy land community of Artemisia desterorum & Hippophae rhamnoides" was higher than that of the other two communities, and the biodiversity increased with the recovery time. The functional richness of "fixed sandy land community of Artemisia desterorum & Hippophae rhamnoides" increased with the recovery time. In the "semi-fixed sandy land community of Artemisia desterorum & Salix cheilophila", the community functional richness of WLB plot restored for 4 years was higher than that of SWB plot restored for 6 years. The functional richness of "semi-fixed sandy land community of Hippophae rhamnoides & Artemisia desterorum " was much lower than that of other land communities. The functional evenness of "semi-fixed sandy land community of Artemisia desterorum & Salix cheilophila" was higher than the other two communities. There is a correlation between species diversity and functional diversity of the artificial plant community in the Lake East Sand. (2) the Soil in the Lake East Sand is dominated by medium sand, and the characteristic parameters of grain size are different from other sandy areas in China. There is almost no clay in the surface layer of the sandy land, and only a small amount of it is contained in the "fixed sandy land community of Artemisia desterorum & Hippophae rhamnoides". The sorting coefficients of different artificial plant community plots indicated that the ability of the "fixed sandy land community of Artemisia desterorum & Hippophae rhamnoides" plot to resist wind erosion was higher than that of the "semi-fixed sandy land community of Artemisia desterorum & Salix cheilophila" plot higher than "semi-fixed sandy land community of Hippophae rhamnoides & Artemisia desterorum ". The plot of the semi-fixed sand community of Artemisia argyi and the quicksand plot, and the longer the plot recovery time, the greater the wind-selection coefficient of the topsoil. The soil moisture of each artificial plant community plot was not high, and the soil moisture in the upper sand soil increased significantly with the increase of depth, and the soil moisture change of the lower sand soil did not fluctuate significantly. The contents of soil organic matter, nitrogen, phosphorus and potassium in the soils of various plots showed the characteristics of ZG plots> other artificial vegetation restoration sites>LS sands. There is a linear negative correlation between species diversity and soil organic matter traits between the species diversity of artificial plant communities and soil ecological functional traits in Hudong sandy land, and there is no correlation between other characteristic indicators. The relationship between the functional diversity of the artificial plant community and the ecological functional properties of the soil indicated that there was a linear negative correlation between the functional uniformity and the soil moisture (40~60 cm), the functional uniformity and the soil moisture (80~100 cm), and the functional dispersion and the soil moisture (80~100 cm). There was no correlation among other characteristic indexes. (3) The average wind speed on the vertical gradient of the plots of each artificial plant community in the Lake East Sand can well fit the wind speed profile function of various lands with the height, and reflect that the wind speed in the region presents the change rule of exponential function with the height. The fitting degree of wind speed profile of WLB plot was the highest, followed by ZG lot and SWB plot. The surface roughness of the plot of "fixed sandy land community of Artemisia desterorum & Hippophae rhamnoides" was higher than that of "semi-fixed sandy land community of Artemisia desterorum & Salix cheilophila" and even higher than that of "semi-fixed sandy land community of Hippophae rhamnoides & Artemisia desterorum ". The wind resistance effect varies with the height, in which the ZG plot changes the most and the SWB plot changes the least. The richer the species composition of the artificial plant community in the Lake East Sand, the greater the influence on wind speed and the stronger the wind resistance effect. The richer the functional characteristics of the community were, the stronger the wind resistance effect was on the wind below 1 m, and the lower the average wind speed of each layer below 1 m was. The more dispersed the functional characters of the community were, the weaker the wind resistance effect near the ground would be and the stronger the average wind speed near the ground would be. The stronger the dispersion degree of functional characters in the community was, the stronger the wind resistance effect was at 2 m, and the lower the average wind speed was at 2 m. (4) the artificial plant community in the east alpine sandy land has a certain influence on the local near-surface temperature and relative air humidity, but has no obvious influence on the soil temperature. The diurnal variation of air temperature in the artificial plant community was higher than that in the quicksand, and the diurnal variation of air temperature showed a trend of "low-high-low". All kinds of vegetation have different effects on the increase and maintenance of temperature. The relative air humidity of the artificial plant community was lower than that of the flowing sand. In summary, the artificial vegetation restoration measures have improved the ecological environment of the whole east lake sandy land, established a variety of types of artificial plant communities, and played a role in preventing wind and fixing sand. The restoration level of the artificial plant community in the complex flora restored for 4 years was similar to that of the single artificial plant community restored for 25 years in terms of species composition, species diversity and community functional characters.