Subjects: Geosciences >> Geography submitted time 2024-06-12 Cooperative journals: 《干旱区研究》
Abstract： In the present study, clay sand barrier–artificial Haloxylon ammodendron plantations and a mobile sand site (control) in the Minqin desert area were used to investigate the plant species composition, species importance value, dominan t species characteristics, species diversity, and soil moisture content. This study explored the long term effects of clay sand barrier–artificial Haloxylon ammodendron plantation construction on regional plant community structure, species diversity, and soil moisture. In total, 12 species belonging to 12 genera and 6 families were recorded in the c lay sand barrier–artificial Haloxylon ammodendron plantations in the Minqin desert area, with Chenopodiaceae and Zygophyllaceae being the dominant families. The construction of the artificial sand control system significantly increased the number of plant species in the region (from 4 species to 5–8 species). With an increase in the installation period, the vegetation structure gradually evolved from Agriophyllum squarrosum and Haloxylon ammodendrine (dominant species) to Grubovia dasyphylla, Kali collinum,Limonium aureum, and Haloxylon ammodendrine (dominant species). The life forms also shifted from a single type dominated by annual herbaceous plants to a composite type consisting of annual herbaceous plants, perennial herbaceous plants, and shrubs. Regarding alpha diversity, species richness index, Shannon–Wiener index, Simpson index, Pielou index, and Alatalo index showed an overall unimodal trend, with the highest species number and most even species distribution observed in the 20-year installation site and the lowest species number and most uneven species distribution observed in the control sand site. The Jaccard index of plant community similarity between neighboring sites with various installation periods showed the following order: control sand site > 1-year installation site > 20-year and 40-year installation sites > 1-year and 5-year installation sites > 10-year and 20-year installation sites > 40-year and 60-year installation sites > 5-year and 10-year installation sites. The dissimilarity index and Cody index showed the opposite trend. The fluctuation pattern of the regional soil moisture content was consistent with the trend of plant community succession. Compared with deeper soil layers (40 –60 cm), the role of shallow soil layers (10–30 cm) in the natural succession process of regional plants was more pronounced.
Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： The biological soil crust is important for maintaining stability in desert ecosystems. Therefore, the useof sand barriers as auxiliary measures to promote the formation and development of biological soil crust in aridareas is of great significance. In this paper, the effects of sand fixation by sand barriers (straw checkerboard,nylon grids, and covered nets) on the formation and development of biological soil crusts were studied usingmicrobial high- throughput sequencing combined with soil physical and chemical properties determination. Theresults showed that the crust thickness under the covered nets was the thickest, although the colors of the crust inthe straw checkerboard and nylon grids were similar to that of the algae crust. The proportions of clay andpowder particles in the crust of the three types of sand barriers for sand fixation were significantly higher thanthat of the moving sand. The nutrition degree of the crust in the covered nets was the highest, indicating thehighest degree of soil formation. From the composition analysis of fungi, bacteria, and blue-green algae in crustsfrom the three types of sand barrier, it was found that the proportions of Cyanobacteria and Leptolyngbya in thecrust in the covered nets were higher than those in the crust in the straw checkerboard and nylon grids. Incontrast, the proportions of Dothedeomycotes and Microcolleus were lower, and the number of unique microbialOUT was highest. Based on the previous process of soil crust formation and microbial succession in arid areas, itwas inferred that the degree of crust development in the cover nets was likely higher than that in the strawcheckerboard and nylon grids and that their formation and development trajectory differ. Therefore, among thethree types of sand barriers, the covered nets for sand fixation were more suitable for biological soil crustformation and development.
Subjects: Geosciences >> Geography submitted time 2020-12-17 Cooperative journals: 《干旱区研究》
Abstract：在水分输入以小量级降水和凝结水为主导的干旱区，植物叶片吸收水分策略具有尤为重要的生态意义。以民勤地区20种荒漠植物为研究对象，测定叶片单位面积吸水量（LWUC）、含水量增加率（RW）、水分饱和亏（WSD）、比叶面积（SLA）、干物质含量（LDMC），分析植物各叶片性状的分布规律及其相互关系，并比较不同功能群植物叶片水分吸收性状的变异特征。结果表明：（1）叶片可以吸收水分，具有利用小量级降水的能力；叶片性状存在较大的种间差异。（2）叶片LWUC与LDMC呈极显著负相关（P＜0.01），RW与WSD呈极显著正相关（P＜0.01）。（3）不同生长型植物叶片LWUC、RW、WSD差异不显著（P＞0.05）。（4）不同质地植物叶片LWUC差异极显著（P＜0.01），其中，肉质多汁类型植物显著（P＜0.05）高于草质、革质类型植物，肉质多汁和叶片退化类型植物差异不显著（P＞0.05）。（5）不同叶面性状植物叶片LWUC差异不显著（P＞0.05），但覆毛类型植物叶片RW、WSD极显著（P＜0.01）高于光滑叶面平均值。总之，本研究可以加深对荒漠生态系统不同功能型植物利用水资源方式和策略的理解，增强对荒漠植物生态适应对策和荒漠植被格局变化的认识，并为其保护和恢复提供科学依据。
Hits
Hits
Downloads
Comment