Palaeoclimate explains a unique proportion of the global variation in soil bacterial communities

Abstract

The legacy impacts of past climates on the current distribution of soil microbial communities are largely unknown. Here, we used data from >1000 sites from five separate global and regional datasets to identify the importance of paleoclimatic conditions (Last Glacial Maximum and Mid-Holocene) in shaping the current structure of soil bacterial communities in natural and agricultural soils. We show that paleoclimate explained a greater amount of the variation in the richness and composition of bacterial communities than current climate. Moreover, paleoclimate accounted for a unique fraction of this variation that could not be predicted by geographic location, current climate, soil properties, or plant diversity. Climatic legacies (temperature and precipitation anomalies from the present to ~20k years ago) likely shape soil bacterial communities both directly and indirectly via shifts in soil properties and plant communities. The ability of both paleo-and current climate to predict the distribution of soil bacteria declined dramatically in agricultural soils, highlighting the fact that anthropogenic activities have a strong influence on soil bacterial diversity. We illustrate how climatic legacies can help explain the current distribution of soil bacteria in natural ecosystems, and advocate that climate legacies should be considered when predicting microbial responses to climate change.

Drought and its legacy modulate the post‐fire recovery of soil functionality and microbial community structure in a Mediterranean shrubland

“…To the best of our knowledge, the legacy effects of drought on soil biogeochemical processes and the microbial community after fire have not been investigated to date. Long‐term legacies were found in a number of sites across the world when comparing past and current climates (Averill, Waring, & Hawkes, ; Delgado‐Baquerizo et al, ; Hawkes, Waring, Rocca, & Kivlin, ). The legacy effects of changes in climate, including drought, on soil remain a topic of research.…”

Late Quaternary climate change explains soil fungal community composition rather than fungal richness in forest ecosystems

“…While there is a paucity of studies to compare this to, it has been shown that fungal richness in the sediment of two European lakes was not related to the past two millennia of paleoclimatic variations (Capo et al, 2016). This is different from the effect of Quaternary climate change on bacterial species richness in a global scale (Delgado-Baquerizo, Bissett, et al, 2017). This is different from the effect of Quaternary climate change on bacterial species richness in a global scale (Delgado-Baquerizo, Bissett, et al, 2017).…”

“…Previous studies found that a direct effect of paleoclimate on microbial communities might have occurred in the past (e.g., in response to a severe climatic event), but if the microbial communities response to past climatic change slowly which lead to the consequences of this compositional shift might still be detectable today (Capo et al, 2016;Delgado-Baquerizo, Bissett, et al, 2017). For example, Delgado-Baquerizo, Bissett, et al (2017) found that paleoclimate explained a unique proportion of the variation in soil bacterial richness and community composition across a global scale.…”

Effects of climate legacies on above‐ and belowground community assembly

“…Studies over the past two decades provide strong evidence that climatic changes, since the last glaciation about 10,000 years ago (Fordham et al., ), are partly responsible for the current distribution of plants, animals, and microbial communities in terrestrial ecosystems globally (Atkinson, Briffa, & Coope, ; Delgado‐Baquerizo et al., ; Lyons et al., ; Partel et al., ; Svenning, Eiserhardy, Normand, Ordenez, & Sandel, ). Recent studies have also provided solid evidence that a knowledge of climatic legacies can improve our predictions of the current distribution of specific groups of organisms including plants and microbes (Delgado‐Baquerizo et al., ; Partel et al., ; Schleuning et al., ). Much less is known on the role of climatic legacies in driving ecological networks of above‐ and belowground organisms.…”