Biocrust cover and successional stages influence soil bacterial composition and diversity in semiarid ecosystems
Identificadores
URI: https://hdl.handle.net/10481/87386Metadatos
Mostrar el registro completo del ítemEditorial
Elsevier
Fecha
2020Referencia bibliográfica
Science of the Total Environment 709: 134654
Resumen
Biocrusts are an important drylands landscape component, which enriches the upper millimeters of the
soil with organic matter and initiates biogeochemical cycles. However, little is known about the influence
of biocrusts on soil bacterial community structure and diversity. Different biocrust types representing a
successional gradient were studied. This gradient, from the earliest to the latest successional stages, consisted
of an incipient cyanobacterial biocrust < mature cyanobacterial biocrusts < biocrust dominated by
the Squamarina lentigera and Diploschistes diacapsis lichens < Biocrust characterized by the Lepraria isidiata
lichen. Moreover, in each biocrust type, four different percentages of biocrust cover were also
selected. Soil diversity gradually increased with biocrust successional stage and percentage of biocrust
cover. The biocrust cover had an important role in the total abundance of bacteria, generally increasing
in soils colonized by the highest percentages of cover. Biocrust successional stage was the most important
factor, significantly influencing 108 soil bacteria genera, whereas biocrust cover showed significant differences
in only 10 genera. Principal Component Analysis showed contrasting microbial composition
across the biocrust successional gradient. Some bacterial taxa were dominant in the soil colonized by different
biocrust types. Thus, Leptolyngbya, Rubrobacter, Solirubrobacter, Geodermatophilus, etc., were
more abundant in incipient cyanobacteria; Nostocales, Chroococcidiopsaceae, Coleofasciculaceae etc.,
under mature cyanobacterial biocrusts; Truepera, Sphingobacteriaceae, Actinophytocola, Kribella, etc.,
below the S. lentigera and D. diacapsis community, and Bryobacter, Ohtaekwangia, Opitutus,
Pedosphaeraceae, etc., in soils colonized by L. isidiata. Several soil bacteria taxa showed significant correlations
(p < 0.05) with chemical soil properties (pH, total nitrogen, total organic carbon, available phosphorous
and electrical conductivity). We discuss the role of biocrusts influencing these chemical soil
parameters, including the presence of certain metabolites secreted by biocrusts, and also their effects on soil moisture and several physical soil features, as well as their association with different microclimates,
all of which could favor a more selective environment for certain bacteria.