Biological soil crusts of the Succulent Karoo: a review

Abstract

Biological soil crusts (biocrusts) form a regular soil surface community covering about 12% (~18 × 10 6 km 2) of the global terrestrial surface area mainly in dryland regions all over the world (Rodrίguez-Caballero et al. 2018a). They are composed of varying proportions of photosynthesizing cyanobacteria, lichens and bryophytes, which grow together with heterotrophic fungi, bacteria and archaea as well as microfauna such as protozoa, nematodes and microarthropods (

Diversity of Microorganisms in Biocrusts Surrounding Highly Saline Potash Tailing Piles in Germany

“…In general, the bacterial community in the biocrusts surrounding potash tailing piles was dominated by Proteobacteria (29% of total bacterial reads, 446 OTUs), Cyanobacteria (16% of total bacterial reads, 87 OTUs), Actinobacteria (15% of total bacterial reads, 255 OTUs), Planctomycetes (14% of total bacterial reads, 227 OTUs), Bacteroidetes (10% of total bacterial reads, 181 OTUs) and Chloroflexi (8% of total bacterial reads, 124 OTUs) ( Figure 2 a). Overall, the distribution of bacterial orders in the studied biocrusts was similar to those of other biocrusts around the world [ 27 , 30 , 31 , 32 ]. Besides, representatives of Bacteroidetes and Gammaproteobacteria were shown to be salt-tolerant in soils [ 33 ].…”

Effects of climate change and land use intensification on regional biological soil crust cover and composition in southern Africa

“…We hypothesize that i) NDVI will reflect the rapid response of biocrusts to variations in climatic factors, and ii) as a consequence, the NDVIbiocrust will be reduced in the future due to a predicted increase in aridity according to the IPCC predictions for the region (Weber et al, 2018). We further suggest that iii) the reduced NDVIbiocrust will be the result of changes in both biocrust coverage and composition.…”

“…Currently, biocrusts cover more than 25 % of the soil surface in the Succulent Karoo with cyanobacteria-dominated biocrusts forming the main crust type in areas where environmental conditions limit the establishment of more developed communities (Weber et al, 2018). Under good environmental conditions, light cyanobacteria-are quickly replaced by dark cyanobacteria-dominated biocrusts and at a later stage also the more developed lichen-and bryophyte-dominated biocrusts are formed (Büdel et al, 2009).…”

Ecology and responses to climate change of biocrust-forming mosses in drylands

“…In addition to their presence, the location of photoprotective compounds in the cells can be essential for their functionality. For example, Ceratodon purpureus , a cosmopolitan species that can persist and be dominant in arid ecosystems ( Weber et al , 2018 ), has a lower total quantity of photoprotective compounds than Bryum pseudotriquetrum , another cosmopolitan species more abundant in wetter areas ( Clarke and Robinson, 2008 ). However, Ceratodon has its ultraviolet screening compounds mainly located in the cell wall rather than inside the cells, which is why it has greater UV tolerance ( Clarke and Robinson, 2008 ).…”