Biological soil crusts, Southern Spain

Biological soil crusts play vital roles in dryland regions that cover over 35% of the Earth´s land mass, including 24% of Europe. They provide important ecosystem services such as limitation of soil erosion, retention of water, improving soil fertility and nitrogen and carbon fixation.生物土壤结皮（Biological soil crusts）在占地球陆地总面积逾35%的干旱区中发挥着至关重要的作用，这类干旱区覆盖了欧洲24%的陆地面积。它们可提供诸多关键的生态系统服务，包括抑制土壤侵蚀、涵养水分、提升土壤肥力以及固氮与固碳。