Predicting spatial patterns of soil bacteria under current and future environmental conditions

Abstract

Soil bacteria are largely missing from future biodiversity assessments hindering comprehensive forecasts of ecosystem changes. Soil bacterial communities are expected to be more strongly driven by pH and less by other edaphic and climatic factors. Thus, alkalinisation or acidification along with climate change may influence soil bacteria, with subsequent influences for example on nutrient cycling and vegetation. Future forecasts of soil bacteria are therefore needed. We applied species distribution modelling (SDM) to quantify the roles of environmental factors in governing spatial abundance distribution of soil bacterial OTUs and to predict how future changes in these factors may change bacterial communities in a temperate mountain area. Models indicated that factors related to soil (especially pH), climate and/or topography explain and predict part of the abundance distribution of most OTUs. This supports the expectations that microorganisms have specific environmental requirements (i.e., niches/envelopes) and that they should accordingly respond to environmental changes. Our predictions indicate a stronger role of pH over other predictors (e.g. climate) in governing distributions of bacteria, yet the predicted future changes in bacteria communities are smaller than their current variation across space. The extent of bacterial community change predictions varies as a function of elevation, but in general, deviations from neutral soil pH are expected to decrease abundances and diversity of bacteria. Our findings highlight the need to account for edaphic changes, along with climate changes, in future forecasts of soil bacteria.

The activity and functions of soil microbial communities in the Finnish sub-Arctic vary across vegetation types

“…Soil microorganisms are critical in C and nutrient cycling in terrestrial ecosystems (Falkowski et al 2008). Therefore, understanding soil microbial communities and how they correspond to local environmental variation is essential to predict the impacts of environmental change on ecosystem functioning (Buckeridge et al 2013, Mod et al 2021, Virkkala et al 2018).…”

The environmental niche of soil bacterial, archaeal, fungal and protist communities differ along edaphic and topoclimatic gradients in the Alps

“…Quantifying and comparing the niche properties of microorganisms has a wide range of potential uses, especially to model spatial distribution and evaluate the potential influence of climate and environmental change on taxa and communities [11,18,27,114]. Specialised taxa with limited niche breadth may be at greater risk of extinction as they benefit from homogeneous environments (in space and/or time).…”

“…Triplicate DNA extracts were pooled by sample for downstream analyses [50]. For bacterial and archaeal groups, the V5 region of the 16S rRNA gene was amplified for each DNA sample using the universal primers 784F-880R [27,50,52]. The protocol is described in detail in [50].…”

“…We opted for a standardized custom-made pipeline to avoid processing biases and allow for the best possible comparison among the groups, as described in [27]. In short, we demultiplexed the sequenced reads (of 16S and 18S), removed the barcodes, trimmed and merged the sequences.…”

“…Yet, microorganisms represent a large proportion of the global soil biodiversity and play essential roles in biogeochemical cycling, including carbon sequestration and soil fertility [23][24][25][26] and therefore, are essential for ecosystem functioning. Hence, understanding and quantifying the niche of microbial taxa and communities is a pressing need to help understand and forecast the influence of environmental change on microorganisms [27].…”