The dominance of aeolian processes in arid areas created a harsh environment in these regions for soil and vegetation where soil fertility, ecosystem productivity, air clarity, and human health is dependent to aeolian activities and rate of dust emission. Biological soil crusts (bio-crusts) are the communities of living organisms on the soil surface which play an important role in soil ecosystem services in arid land. Lichens are known as organisms that can accumulate certain elements or substances at high concentrations in the atmosphere. The relation between lichens species and soil geochemistry as well as dust capture in geomorphic zones in north- eastern Iran were studied. Different lichens species and soil particles were analyzed by a scanning electron microscopy (SEM-EDS). The results of XRF and XRD analysis showed lichen crusts affected soil mineralisation. By creating microtopography, indicated the lichens trapped dust. They also increased the amount of clay on the soil surface. The results indicted the significant role of lichens in soil ecosystem services dryland.

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