Contrasting Diversity Patterns of Crenarchaeal, Bacterial and Fungal Soil Communities in an Alpine Landscape

Abstract

BackgroundThe advent of molecular techniques in microbial ecology has aroused interest in gaining an understanding about the spatial distribution of regional pools of soil microbes and the main drivers responsible of these spatial patterns. Here, we assessed the distribution of crenarcheal, bacterial and fungal communities in an alpine landscape displaying high turnover in plant species over short distances. Our aim is to determine the relative contribution of plant species composition, environmental conditions, and geographic isolation on microbial community distribution.Methodology/Principal FindingsEleven types of habitats that best represent the landscape heterogeneity were investigated. Crenarchaeal, bacterial and fungal communities were described by means of Single Strand Conformation Polymorphism. Relationships between microbial beta diversity patterns were examined by using Bray-Curtis dissimilarities and Principal Coordinate Analyses. Distance-based redundancy analyses and variation partitioning were used to estimate the relative contributions of different drivers on microbial beta diversity. Microbial communities tended to be habitat-specific and did not display significant spatial autocorrelation. Microbial beta diversity correlated with soil pH. Fungal beta-diversity was mainly related to soil organic matter. Though the effect of plant species composition was significant for all microbial groups, it was much stronger for Fungi. In contrast, geographic distances did not have any effect on microbial beta diversity.Conclusions/SignificanceMicrobial communities exhibit non-random spatial patterns of diversity in alpine landscapes. Crenarcheal, bacterial and fungal community turnover is high and associated with plant species composition through different set of soil variables, but is not caused by geographical isolation.

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

“…Here the average habitat similarity and average bacterial community similarity were significantly and positively correlated at the scale of the circular neighbourhoods, which was in agreement with the environmental selection hypothesis 2,16,36 . Nevertheless, the initial similarities of habitat and soil bacterial community were weakly but negatively correlated, suggesting that variations in community composition occur at small scales, even in homogeneous habitats.…”

Ecological succession reveals potential signatures of marine–terrestrial transition in salt marsh fungal communities

“…Thus, the natural dynamics of plant colonization along the salt marsh successional gradient is likely to modulate the belowground SOM, which is directly intertwined with shifts in soil fungal communities. The influence of SOM on soil fungal communities has been previously reported (Hartmann et al, 2009;Millard and Singh, 2010); not only the quantity but also the quality status and turnover rate of SOM were found to influence specific fungal populations along an ecosystem landscape (Zinger et al, 2011). Yet, in our study, it appeared that, at a local scale, the magnitude of the shifts in SOM quantity and quality did not exceed the effects imposed by the dominant vegetation, resulting in a lowered fungal turnover within sites.…”

Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps

“…This trend was also found in a number of other soil-related mountain bacterial studies in the Colorado Rockies, Tibetan Plateau, the European Alps, and the Gorbeia Natural Park in Spain (2,5,8,10,15,16). Other environmental drivers of importance to grassland soil bacterial communities in mountain ecosystems include annual radiation, mean annual temperature, soil ammonium content, litter C:N ratio, snow depth, and plant diversity (2, 5-8, 10, 17).…”

“…In pioneering studies, King and coworkers (2) analyzed the bacterial habitat distribution along a mountain slope. Most authors have studied soil grassland bacterial diversity on a single or a few mountain transects, notably to emphasize the elevation factor in mountain ecosystems (3)(4)(5)(6)(7)(8). However, alpine studies that span an important horizontal surface area, along with the vertical elevation gradient, are much fewer, despite that mountain ecosystems are composed of a large spectrum of different topographic, climatic, soil physical, and chemical conditions, interspersed with a wide range of microclimates occupied by varied vegetation and animal populations (2,(9)(10)(11)(12).…”