Key points are not available for this paper at this time.
O. L. Lange, A. Meyer, H. Zellner, U. Heber, Photosynthesis and Water Relations of Lichen Soil Crusts: Field Measurements in the Coastal Fog Zone of the Namib Desert, Functional Ecology, Vol. 8, No. 2 (Apr., 1994), pp. 253-264
Lange et al. (1994) studied this question.