Effects of vegetation on bacterial communities, carbon and nitrogen in dryland soil surfaces: implications for shrub encroachment in the southwest Kalahari
Name:
Publisher version
View Source
Access full-text PDFOpen Access
View Source
Check access options
Check access options
Name:
Lan et al STOTEN author final ...
Embargo:
2021-10-09
Size:
1.871Mb
Format:
PDF
Description:
main article, author final version
Affiliation
Aberystwyth University, AberystwythChinese Academy of Sciences, Wuhan
Wuhan University of Technology, Wuhan
University of Derby
Issue Date
2020-10-09
Metadata
Show full item recordAbstract
Shrub encroachment is occurring in many of the world's drylands, but its impacts on ecosystem structure and function are still poorly understood. In particular, it remains unclear how shrub encroachment affects dryland soil surfaces, including biological soil crust (biocrust) communities. In this study, soil surfaces (0–1 cm depth) were sampled from areas of Grewia flava shrubs and Eragrostis lehmanniana and Schmidtia kalahariensis grasses in the southwest Kalahari during two different seasons (March and November). Our hypothesis is that the presence of different vegetation cover types (shrubs versus grasses) alters the microbial composition of soil surfaces owing to their contrasting microenvironments. The results showed that more significant differences in microclimate (light, soil surface temperatures) and soil surface microbial communities were observed between shrubs and grasses than between sampling seasons. Based on high-throughput 16S rRNA gene sequencing, our findings showed that approximately one third (33.5%) of the operational taxonomic units (OTUs) occurred exclusively in soil surfaces beneath shrubs. Soil surfaces with biocrusts in grass areas were dominated by the cyanobacteria Microcoleus steenstrupii, whereas the soil surfaces beneath shrubs were dominated by the proteobacteria Microvirga flocculans. Soil surfaces beneath shrubs are associated with reduced cyanobacterial abundance but have higher total carbon and total nitrogen contents compared to biocrusts in grass areas. These findings infer changes in the relative contributions from different sources of carbon and nitrogen (e.g. cyanobacterial and non-cyanobacterial fixation, plant litter, animal activity). The distinctive microbial composition and higher carbon and nitrogen contents in soil surfaces beneath shrubs may provide a positive feedback mechanism promoting shrub encroachment, which helps to explain why the phenomenon is commonly observed to be irreversible.Citation
Lan, S., Thomas, A.D., Tooth, S., Wu, L. and Elliott, D.R., (2020). 'Effects of vegetation on bacterial communities, carbon and nitrogen in dryland soil surfaces: implications for shrub encroachment in the southwest Kalahari'. Science of The Total Environment, 142847, pp. 1-11.Publisher
ElsevierJournal
Science of The Total EnvironmentDOI
10.1016/j.scitotenv.2020.142847Additional Links
https://www.sciencedirect.com/science/article/pii/S0048969720363774Type
ArticleLanguage
enISSN
00489697ae974a485f413a2113503eed53cd6c53
10.1016/j.scitotenv.2020.142847