Divergent national-scale trends of microbial and animal biodiversity revealed across diverse temperate soil ecosystems

Abstract

Soil biota accounts for ~25% of global biodiversity and is vital to nutrient cycling and primary production. There is growing momentum to study total belowground biodiversity across large ecological scales to understand how habitat and soil properties shape belowground communities. Microbial and animal components of belowground communities follow divergent responses to soil properties and land use intensification; however, it is unclear whether this extends across heterogeneous ecosystems. Here, a national-scale metabarcoding analysis of 436 locations across 7 different temperate ecosystems shows that belowground animal and microbial (bacteria, archaea, fungi, and protists) richness follow divergent trends, whereas β-diversity does not. Animal richness is governed by intensive land use and unaffected by soil properties, while microbial richness was driven by environmental properties across land uses. Our findings demonstrate that established divergent patterns of belowground microbial and animal diversity are consistent across heterogeneous land uses and are detectable using a standardised metabarcoding approach.

Soil bacterial diversity mediated by microscale aqueous-phase processes across biomes

“…8a, b, respectively). Nonetheless, an inherent tradeoff between availability of nutrients and protection by spatial isolation appears to play an important role in the establishment and maintenance of high soil bacterial diversity 17,31,34 . In other words, the relation between bacterial abundance and diversity is only positive when the aqueous phase is fragmented and spatial isolation suppresses the dominance of few species.…”

“…Microbial diversity is manifested both at the scale of soil grains 8 and at very large scales across climatic regions and terrestrial biomes 2,13,14 . These observations often include variations in microbial biomass that responds to resource availability and affects bacterial diversity at all scales [15][16][17] . For example, wellestablished observations of microbial abundance variations with soil depth 18 could confound inferences of bacterial richness by promoting the detection of low abundant species in resource-rich environments.…”

“…Quantifying the roles of soil factors, such as soil texture, porosity and hydration conditions in relation to climate and vegetation cover, is an important step towards disentangling bacterial diversity and abundance as suggested by recent empirical evidence 17 . Soil chemical properties such as pH 2,14,17,19 and organic carbon content [15][16][17] together with climatic attributes, such as aridity index 15 , precipitation 2,17 and temperature 13 , have been identified as important explanatory variables. Yet, the rapid expansion of soil bacterial diversity datasets has not been met with similar development of predictive models for interpretation of the observed spatial patterns 20 .…”

“…Such endeavors invariably require development of mechanistic frameworks for systematic incorporation of the various factors that affect soil bacterial diversity. In this study, we capitalize on recent empirical 2,8,13,15,17,23 and theoretical developments 7,24,25 to generalize the role of soil aqueous microhabitat fragmentation and its nearly universal role in mediating bacterial diversity across soil types and climatic conditions. To characterize the average conditions in soils and facilitate long-term predictions, we define a soil climatic water content that combines rainfall patterns and volumetric soil water holding capacity into a well-defined attribute.…”

DNA metabarcoding in diet studies: Unveiling ecological aspects in aquatic and terrestrial ecosystems

“…Water, soil, and even air samples have been discussed to be suitable for eDNA studies (Brennan et al, ; George et al, ; Taberlet, Coissac, Hajibabaei, et al, ). Similarly, gut contents and scats have been highlighted as useful in describing regional biodiversity and used in eDNA‐like surveys (Boyer et al, ; Siegenthaler et al, ; Taberlet, Coissac, Pompanon, Brochmann, & Willerslev, ).…”