The soil microbiomics of intact, degraded and partially-restored semi-arid succulent thicket (Albany Subtropical Thicket)

• Published in: PeerJ (San Francisco, CA) Vol. 9; p. e12176
• Main Authors: Schagen, Micaela, Bosch, Jason, Johnson, Jenny, Duker, Robbert, Lebre, Pedro, Potts, Alastair J., Cowan, Don A.
• Format: Journal Article
• Language: English
• Published: San Diego PeerJ, Inc 06-10-2021; PeerJ Inc
• Subjects: Albany Subtropical Thicket; Bacteria; Browsing; Carbon; Climate change; Community composition; Ecology; Ecosystem restoration; Ecosystems; Environmental factors; Land area; Microbial ecology; Microbiology; Microbiomes; Microorganisms; Molecular Biology; Portulacaria afra; Precipitation; Retention; Soil; Soil density; Soil erosion; Soil fertility; Soil microorganisms; Soil Science; Succulent thicket; Vegetation; Eastern Cape South Africa; South Africa; Netherlands; United States > US
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.12176

This study examines the soil bacterial diversity in the
Portulacaria afra-
dominated succulent thicket vegetation of the Albany Subtropical Thicket biome; this biome is endemic to South Africa. The aim of the study was to compare the soil microbiomes between intact and degraded zones in the succulent thicket and identify environmental factors which could explain the community compositions. Bacterial diversity, using 16S amplicon sequencing, and soil physicochemistry were compared across three zones: intact (undisturbed and vegetated), degraded (near complete removal of vegetation due to browsing) and restored (a previously degraded area which was replanted approximately 11 years before sampling). Amplicon Sequence Variant (ASV) richness was similar across the three zones, however, the bacterial community composition and soil physicochemistry differed across the intact and degraded zones. We identified, via correlation, the potential drivers of microbial community composition as soil density, pH and the ratio of Ca to Mg. The restored zone was intermediate between the intact and degraded zones. The differences in the microbial communities appeared to be driven by the presence of plants, with plant-associated taxa more common in the intact zone. The dominant taxa in the degraded zone were cosmopolitan organisms, that have been reported globally in a wide variety of habitats. This study provides baseline information on the changes of the soil bacterial community of a spatially restricted and threatened biome. It also provides a starting point for further studies on community composition and function concerning the restoration of degraded succulent thicket ecosystems.