干旱区生态环境知识资源中心

Biological soil crusts (BSCs) play a crucial role in counteracting desertification. Manmade biotic crusts (MBCs) could be established rapidly by inoculation of cyanobacterial strains Microcoleus vaginatus and Scytonema javanicum in Hobq Desert, Inner Mongolia of China. This study investigated the morphological and ecophysiological characteristics as well as microstructures of MBCs in a field setting. Based on their color and succession process, MBCs were sequentially divided into five stages as, light gray, gray-black, black, black-green and green crusts. Their compressive strength, thickness, species number of cyanobacteria and eukaryotic algae, photosynthetic efficiency as well as carbon-assimilation rates increased with the development of MBCs. In addition, among the five successional stages, green crusts had the highest contents of chlorophyll a; however, black crusts had the highest content of scytonemin. By ultrastructural observation, filamentous cyanobacteria were found closely bound to sand particles. The findings of this study have important theoretical implications for understanding the survival and developmental conditions of MBCs in the field. Furthermore, the results have also clearly demonstrated the feasibility of counteracting desertification by inoculation of MBCs in desert areas.