塔里木盆地北缘绿洲-荒漠过渡带植被对土壤盐渍化的响应研究

Oasis and desert transition zone is the connecting strip of oasis ecosystem and desert ecosystem, it is habitat fragile, sensitive and easy to change, and it is of great significance in maintaining the stability of the ecosystem. In this project, the oasis-desert transitional zone as the research object, which is located the Weigan-Kuqa river delta oasis on the northern margin of the Tarim basin in Xinjiang. Based on ecology, soil science and geography etc multidisciplinary theories and research methods as the technical guidance, through “3S” spacial information technology and the wild fixed-point observation as the research method, in-depth study oasis - desert transitional zone classic vegetation patterns and characteristics of soil salinization. Actively explore the dynamic evolution law of soil salinization and vegetation cover in the study area, and further reveal the time series response processes and the interaction mechanism between vegetation distribution patterns and soil salinization, and by building a reasonable regional remote sensing monitoring model to evaluate quantitatively the evolution processes of soil salinization in the study area. By studying this project, when the natural environment of the study area has changed, we can systematically clarify the response of desert vegetation systems in the passive and active adaptation mechanisms. The research results of this project could be for the human rational protection and restoration of damaged desert vegetation,maintaining the stability and function of the oasis ecosystem and to promote agricultural production and regional sustainable development has important theoretical and practical significance.

绿洲-荒漠过渡带是绿洲生态系统与荒漠生态系统的连接地带，其生境脆弱、敏感、易变，对维持绿洲生态系统的稳定具有十分重要的意义。本项目以新疆塔里木盆地北缘渭干河—库车河三角洲绿洲-荒漠过渡带作为研究对象，基于生态学、土壤学以及地理学等多学科理论与方法为技术指导，以“3S”空间信息技术与野外定点观测为研究手段，对绿洲-荒漠过渡带典型植被格局与区域土壤盐渍化特征进行深入研究，积极探索该区域土壤盐渍化与植被覆盖的动态演变规律，进一步揭示植被分布格局与土壤盐渍化的时间序列响应过程及其相互作用机理，并通过构建合理的区域土壤盐渍化遥感监测模型对研究区土壤盐渍化演变过程进行定量评价。通过本项目的研究，可系统阐明研究区荒漠植被对自然环境改变的被动响应与主动适应机制，对人类合理保护与修复受损荒漠植被、维护绿洲生态系统的稳定和功能，以及促进农业生产与区域可持续发展具有重要的理论与现实意义。

本项目以塔里木盆地北缘绿洲-荒漠区为研究对象，基于多学科理论与研究方法，对植被空间格局与区域土壤盐渍化特征进行深入研究，积极探索该区域植被覆盖度与土壤盐渍化的动态演变规律，揭示植被空间分布格局与土壤盐渍化的响应关系，主要研究结论如下：.（1）2001-2019年间研究区的高植被覆盖度土地面积总体呈现出上升的趋势，中覆盖度面积呈现出先减后增的趋势，低覆盖度区域呈下降趋势；绿洲-荒漠过渡带的空间变动范围较大，绿洲呈扩增趋势，荒漠呈缩减趋势，在自然与人类活动的共同作用下，研究区绿洲化进程加快，过渡带植被得到一定的保护，区域内生态环境有所改善。.（2）研究区以柽柳、盐节木和盐穗木为主要物种的乔、灌木群落的丰富度指数、多样性指数均高于芦苇和骆驼刺等草本群落；乔、灌木群落的均匀度指数和优势度指数在不同区域上均呈现出相同的变化规律，而草本群落在不同区域上的变化较为复杂；平均地上生物量呈现出乔木>灌木>草本（分别为0.584kg/m²、0.406kg/m²、0.236kg/m²）。.（3）研究区乔、灌木植物群落的生物多样性特征较为稳定，草本群落则更易受水盐等生境条件的影响，各植物群落的物种多样性按低盐区＞中盐区＞高盐区的顺序依次递减；植被覆盖度与土壤含盐量呈显著的负相关关系（P<0.05），且总体趋势表现为植被覆盖度随土壤含盐量的升高而降低，土壤盐分在一定程度上抑制了植物生长。.（4）在2001-2019年间，研究区非盐渍地沿绿洲边缘呈扩张趋势，致使轻度盐渍地面积减少，中度盐渍地及重度盐渍地空间变动较大；区域内土壤盐渍化空间结构由复杂趋于简单，轻度盐渍地稳定性最强，其次是中度盐渍地，非盐渍地稳定性最弱，受人类活动及自然环境的共同影响，不同等级土壤盐渍化的稳定性均呈下降趋势。.通过构建合理的区域植被覆盖度估测模型与土壤盐渍化反演模型对研究区土地退化过程进行定量评价，揭示绿洲-荒漠过渡带植被空间格局分布与土壤盐渍化的响应关系，为选择耐盐植物进行盐渍地改良和生态修复提供科学依据。