毛乌素沙地南缘沙丘生物土壤结皮发育特征

Development Characteristics of Biological Soil Crusts on Sand Dune in Southern Mu Us Sandy Lands

生物土壤结皮广泛分布于干旱和半干旱区,它的形成和发育对荒漠生态系统生态修复过程产生重要的影响。采用野外调查、测定和室内分析相结合的方法,对毛乌素沙地南缘沙丘生物土壤结皮发育特征进行研究。结果表明:不同地貌部位生物土壤结皮的厚度、各类型结皮盖度、机械组成和结皮及其下层剖面土壤容重均发生不同程度的变化。生物土壤结皮的发育对不同地貌部位具有一定的选择性,丘顶微生物结皮少量分布,迎风坡以浅灰色的藻类结皮为主,背风坡以黑褐色的藻类结皮为主,丘间地以苔藓结皮为主。不同地貌部位结皮层微生物总数存在较大差异。不同发育阶段生物土壤结皮的优势成分不同,表现出明显的阶段性特点,其形成和发育是生物过程和非生物过程的统一。

Biological soil crust is developed broadly and has an ecological significance in arid and semiarid regions.Development characteristics of biological soil crusts on sand dune in southern Mu Us sandy lands were studied in this paper based on methods of field investigation,measurement and laboratory analysis.Results indicate that the thickness,bulk density,subsoil bulk density and thickness of biological soil crusts at different locations of sand dune varied differentially.Distribution of biological soil crusts has selective characteristics on different surface of sand dune.A little microorganism crusts distribute on the top of sand dune area,windward and leeward area of sand dune mainly covered by light and darker algae crusts respectively,mosses crusts mainly distribute on inter dune area.Quantitative characteristics of total culturable microorganism in biological soil crusts varied according to different location of sand dune.With development of biological soil crusts,its biotic component changed significantly,appeared an obvious phased character.Development and formation of biological soil crusts should be the interactions between biotic and abiotic processes.