风沙流对生物土壤结皮分布格局的影响及其机制研究

The wide distribution of biological soil crust (BSC) in the surfaces of desert and sandy areas holds important roles in the maintenances of health and stability of theses ecosystems, but the distribution pattern of BSC exhibits great susceptibility to disturbances at temporal and spatial scales. Wind-sand flow is one of the most common disturbances that BSC suffers in nature, however, up to now, less is known regarding the effect and mechanism of wind-sand flow on BSC distribution pattern. Based on the previous research accumulation and through the combination of field investigation and wind tunnel stimulation, this program studies the effect of wind-sand flow on BSC distribution pattern by investigating the changes of cryptogam species composition, dominant species, constructive species, abundance, richness, coverage and biomass; explores the environmental mechanism of the influence of wind-sand flow on BSC distribution pattern via monitoring the variances of light, soil temperature, moisture, nutrition and physiochemical properties under the treatment of wind-sand flow; probes into the biological mechanism of the impact of wind-sand flow on BSC distribution pattern through analyzing the alterations of photosynthesis, respiration, nitrogen-fixing rate, osmotic regulation substances, activities of protective enzyme and regeneration potential of BSC after exposing to wind-sand flow. From above, this research project is aimed to provide scientific basis to deeply explore the ecological functions of BSC in the desert and sandy land ecosystems, and to fully understand, protect and utilize BSC resources.

生物土壤结皮(以下简称结皮)在荒漠及沙区地表的广泛分布对维持生态系统健康和稳定性具有重要作用，但其分布在时空尺度上对干扰活动表现出极大的敏感性。风沙流是结皮遭受的最常见的自然干扰之一，其是否会对结皮分布格局产生影响，机理如何？目前我们知道的很少。基于前期的研究积累，本研究采用野外调查和风洞模拟相结合的方法，通过对风沙流作用下隐花植物种类组成、优势种、丰富度、多度、盖度及生物量等时空变化规律的调查，分析风沙流对结皮分布格局的影响；通过对风沙流处理后光照强度、土壤温度、水分、养分含量和理化性质等结皮生境条件变化的连续监测，探讨风沙流影响结皮分布的环境机制；通过对结皮光合作用、呼吸作用、固氮速率、渗透调节物质、保护酶活性和繁殖潜力等对风沙流胁迫响应规律及耐受能力差异的动态分析，确定风沙流影响结皮分布的生物机制；为深入探讨结皮在荒漠和沙地生态系统中功能，为全面认知、保护和利用结皮资源提供科学依据。

生物土壤结皮(以下简称结皮)是沙区生态系统重要组成之一，对维持生态系统健康和稳定性具有重要作用，但其分布在时空尺度上对干扰活动表现出极大的敏感性，并影响了其生态功能的发挥。由于结皮特殊的地表生境及低矮结构特点，使得其对风沙流—沙区最常见的自然干扰—十分敏感，然而目前对于风沙流是否会影响结皮分布格局以及相关机理如何我们了解的还很少。本项目结合野外考察和控制模拟，并参考人工培养的不同结皮生物野外接种后形成结皮效果，获得了隐花植物种(属)耐风沙流胁迫能力顺序及其与时空分布格局的关系，阐明了风沙流对结皮层细菌和真菌群落分布格局的影响；基于不同风沙流强度下土壤水分、温度和结皮对凝结水捕获的变化规律，揭示了风沙流影响结皮分布格局的环境机制；根据不同风沙流强度下，不同结皮生物在形态结构、温室气体通量、生理生长、抗逆和繁殖能力等相关指标对风沙流胁迫的响应差异，阐明了风沙流影响结皮分布格局的生物机制。以上研究结果的取得为全面评估结皮在沙区生态系统中功能及其对环境干扰的响应程度和方式，为全面认知、保护和利用结皮资源，促进风沙危害区生态修复提供了科学依据。