Biological Soil Crusts (BSC): Numees


Introduction

Biological Soil Crusts (BSC) occur in all biomes along the BIOTA-South transect except for the Fynbos. They can be classified into different types depending on the developmental time and the organism composition: three developmental stages of cyanobacterial crusts, mostly associated with green algae (ranging from initial to well developed crusts), lichen crusts (differentiated in cyanolichen and green algal lichen crusts), bryophyte and liverworth crusts, and the hypolithic crust type (community of photosynthetic organisms existing on sides and underneath translucent stones, e.g. quartz) occurring specifically in quartz gravel pavements (e.g. Knersvlakte - observatories Flaminkvlakte and Luiperskop, Namib Desert - observatory Wlotzkasbaken) but also underneath single quartz rocks of different sizes in other regions and biomes (e.g. observatory Ovitoto). Driving forces of such spatial variability of BSC types are climatic, topographic, pedogenetic and land use differences (as in observatory pairs such as Narais and Duruchaus) in different biomes along the transect.


 Dominant Crust Type

well developed cyanobacteria crust with lichens; and hypolithic crust (quartz pebbles)

 Biological Soil Crust Biomass (chlorophyll)

no data

BSC Biomass ranking (from BSC chlorophyll a+b values [mg/m2] )
very low <= 10
low = 11 to 50
medium = 51 to 100
high = 101 to 200
very high > 200



 Main cyanobacteria genera


 no data



 Main green algae genera


no data