Biogeographical patterns of soil molecular microbial biomass as influenced by soil characteristics and management

Abstract

Aim The spatial organization of soil microbial communities on large scales and the identification of environmental factors structuring their distribution have been little investigated. The overall objective of this study was to determine the spatial patterning of microbial biomass in soils over a wide extent and to rank the environmental filters most influencing this distribution.Location French territory using the French Soil Quality Monitoring Network. This network covers the entire French territory and soils were sampled at 2150 sites along a systematic grid. MethodsThe soil DNA extracted from all these soils was expressed in terms of soil molecular microbial biomass and related to other soil and land-use data over French territory. ResultsThis study provides the first extensive map of microbial biomass and reveals the heterogeneous and spatially structured distribution of this biomass on the scale of France. The main factors driving biomass distribution are the physicochemical properties of the soil (texture, pH and total organic carbon) as well as land use. Soils from land used for intensive agriculture, especially monoculture and vineyards, exhibited the smallest biomass pools. Interestingly, factors known to influence the large-scale distribution of macroorganisms, such as climatic factors, were not identified as important drivers for microbial communities.Main conclusions Microbial abundance is spatially structured and dependent on local filters such as soil characteristics and land use but is relatively independent of global filters such as climatic factors or the presence of natural barriers. Our study confirms that the biogeography of microorganisms differs fundamentally from the biogeography of 'macroorganisms' and that soil management can have significant large-scale effects.

Turnover of soil bacterial diversity driven by wide-scale environmental heterogeneity

“…Recent microbial biogeography studies have revealed that the main environmental filters shaping spatial microbial diversity distribution are soil physico-chemical characteristics, land use and plant cover, whereas climatic and geomorphologic filters are less important 9,11,15,37 . Similar filters were also reported to explain soil bacterial community distribution in contrasted ecological regions at the scale of France 27,34 .…”

“…In addition, DNA fingerprinting precludes consideration of the accumulation of new minor species ARTICLE with increasing distance, which may represent a large proportion of the total soil microbial species richness 33 and determine the slope of TAR 14,31 . The low z bacteria might also be related to the grain size of our sampling design (16 km  16 km: 256 km 2 ), which did not consider scales less than landscape, and smoothed significant local variations in soil microbial community composition that might potentially affect TAR 34 . In parallel, soil habitat was characterized by a multivariate analysis including pedoclimatic, geomorphologic and land-use data, and the HAR was calculated by transposing the TAR concept.…”

Soil organic carbon and soil structure are driving microbial abundance and community composition across the arid and semi-arid grasslands in northern China

“…Wakelin et al (2008) found that soil pH was the dominant driver of microbial community structure and function in a range of Australian agricultural soils. Despite the large number of studies focusing on the driving factors of microbial distribution under a specific environmental gradient at regional or local scale, studies of microbial biogeography at large spatial scales have only been initiated recently (Fierer and Jackson, 2006;Drenovsky et al, 2010;Griffiths et al, 2011;Dequiedt et al, 2011). A notable example was the investigation of bacterial biogeography in British soil (Griffiths et al, 2011).…”

Spatial variability of soil microbial biomass and its relationships with edaphic, vegetational and climatic factors in the Three-River Headwaters region on Qinghai-Tibetan Plateau

“…Many studies on soil MB have been conducted in the past few decades (Dempster et al, 2012;Kaschuk et al, 2010;Xu et al, 2013), and the focus has recently changed from site/ecosystem level Wright and Coleman, 2000;Zak et al, 1994) to regional (Dequiedt et al, 2011;Drenovsky et al, 2010) and global scales (Serna-Chavez et al, 2013;Xu et al, 2013). These large-scale studies examined microbial biomass storage and the mechanisms determining its spatial patterns.…”