Ecosystem type drives soil eukaryotic diversity and composition in Europe

Abstract

Soil eukaryotes play a crucial role in maintaining ecosystem functions and services, yet the factors driving their diversity and distribution remain poorly understood. While many studies focus on some eukaryotic groups (mostly fungi), they are limited in their spatial scale. Here, we analyzed an unprecedented amount of observational data of soil eukaryomes at continental scale (787 sites across Europe) to gain further insights into the impact of a wide range of environmental conditions (climatic and edaphic) on their community composition and structure. We found that the diversity of fungi, protists, rotifers, tardigrades, nematodes, arthropods, and annelids was predominantly shaped by ecosystem type (annual and permanent croplands, managed and unmanaged grasslands, coniferous and broadleaved woodlands), and higher diversity of fungi, protists, nematodes, arthropods, and annelids was observed in croplands than in less intensively managed systems, such as coniferous and broadleaved woodlands. Also in croplands, we found more specialized eukaryotes, while the composition between croplands was more homogeneous compared to the composition of other ecosystems. The observed high proportion of overlapping taxa between ecosystems also indicates that DNA has accumulated from previous land uses, hence mimicking the land transformations occurring in Europe in the last decades. This strong ecosystem‐type influence was linked to soil properties, and particularly, soil pH was driving the richness of fungi, rotifers, and annelids, while plant‐available phosphorus drove the richness of protists, tardigrades, and nematodes. Furthermore, the soil organic carbon to total nitrogen ratio crucially explained the richness of fungi, protists, nematodes, and arthropods, possibly linked to decades of agricultural inputs. Our results highlighted the importance of long‐term environmental variables rather than variables measured at the time of the sampling in shaping soil eukaryotic communities, which reinforces the need to include those variables in addition to ecosystem type in future monitoring programs and conservation efforts.

Effects of climate on the distribution and conservation of commonly observed European earthworms

“…We assessed drivers of 41 European earthworm species and predicted the current and future distributions of 19 highly recorded species. Soil pH, phosphorus, and temperature were identified previously as strong drivers of earthworm distribution (Köninger et al, 2023;Phillips et al, 2019;Ruiz et al, 2021); however, we found precipitation seasonality, agricultural land area, and soil texture similarly or even more important for predicting patterns of earthworm distribution and richness (Figure 2b, Supporting Information Appendices S6-S8). The majority of the species occurred in the west of central Europe (i.e., the British Isles, Germany, the Netherlands, and Belgium) (Figure 2a).…”

“…Although the identified drivers of and predicted distributions for the targeted species aligned with the relevant literature (Rutgers et al, 2016;Phillips et al, 2019;Köninger et al, 2023), evaluating the resulting potential distributions is more challenging and more prone to bias due to major geographic and taxonomic gaps (Guerra et al, 2020). More targeted and standardized sampling is needed especially in central and southern of Spain, southern of Portugal, Italy, and eastern European countries (Supporting Information Appendices S12 & S13) (Guerra et al, 2020).…”

“…To reach conservation goals, their design and management have to meet individual species and ecosystem needs and to consider future impacts of global change (Gaston et al., 2006; Leverington et al., 2010). Earthworms and many other soil‐dwelling organisms are currently underprotected and are not explicitly targeted in nature conservation policies and regulations (Köninger et al., 2022; Zeiss et al., 2022). One solution could be to expand species‐specific targets in protected areas (Loiseau et al.…”

“…As a result, protecting aboveground species does not necessarily provide protection to belowground organisms (Zeiss et al, 2022). Recent large-scale studies describe the main drivers of large taxonomic groups distributions (e.g., earth-worms, nematodes, fungi, bacteria) (Delgado-Baquerizo et al, 2018;Köninger et al, 2023;Phillips et al, 2019;Tedersoo et al, 2014;van den Hoogen et al, 2019) and highlight the effects of climate (in particular temperature and precipitation). Regional and local-scale studies confirm the generality of these main drivers of distribution (Orgiazzi et al, 2016;Desie et al, 2020).…”

Let's give a voice to young soil researchers

“…Regarding soil biodiversity, YSRs contributed to the first ever assessment of soil biodiversity across Europe. The analysis of the largest European soil DNA dataset (Orgiazzi et al, 2022) showed how soil microbial communities were mainly explained by soil properties, especially pH (bacteria), and by vegetation cover (fungi), while soil animals were more associated with historical conditions in terms of climate and land use (Köninger et al, 2023; Labouyrie et al, 2023). YSRs also explored the role of soil biodiversity in policy cycles (Köninger et al, 2022) and the interactions of manure and soil biodiversity (Köninger et al, 2021).…”