Macroinvertebrates comprise a highly diverse set of taxa with great potential as indicators of soil quality. Communities were sampled at 3,694 sites distributed world‐wide. We aimed to analyse the patterns of abundance, composition and network characteristics and their relationships to latitude, mean annual temperature and rainfall, land cover, soil texture and agricultural practices. Sites are distributed in 41 countries, ranging from 55° S to 57° N latitude, from 0 to 4,000 m in elevation, with annual rainfall ranging from 500 to >3,000 mm and mean temperatures of 5–32°C. 1980–2018. All soil macroinvertebrates: Haplotaxida; Coleoptera; Formicidae; Arachnida; Chilopoda; Diplopoda; Diptera; Isoptera; Isopoda; Homoptera; Hemiptera; Gastropoda; Blattaria; Orthoptera; Lepidoptera; Dermaptera; and “others”. Standard ISO 23611‐5 sampling protocol was applied at all sites. Data treatment used a set of multivariate analyses, principal components analysis (PCA) on macrofauna data transformed by Hellinger’s method, multiple correspondence analysis for environmental data (latitude, elevation, temperature and average annual rainfall, type of vegetation cover) transformed into discrete classes, coinertia analysis to compare these two data sets, and bias‐corrected and accelerated bootstrap tests to evaluate the part of the variance of the macrofauna data attributable to each of the environmental factors. Network analysis was performed. Each pairwise association of taxonomic units was tested against a null model considering local and regional scales, in order to avoid spurious correlations. Communities were separated into five clusters reflecting their densities and taxonomic richness. They were significantly influenced by climatic conditions, soil texture and vegetation cover. Abundance and diversity, highest in tropical forests (1,895 ± 234 individuals/m2) and savannahs (1,796 ± 72 individuals/m2), progressively decreased in tropical cropping systems (tree‐associated crops, 1,358 ± 120 individuals/m2; pastures, 1,178 ± 154 individuals/m2; and annual crops, 867 ± 62 individuals/m2), temperate grasslands (529 ± 60 individuals/m2), forests (232 ± 20 individuals/m2) and annual crops (231 ± 24 individuals/m2) and temperate dry forests and shrubs (195 ± 11 individuals/m2). Agricultural management decreased overall abundance by ≤54% in tropical areas and 64% in temperate areas. Connectivity varied with taxa, with dominant positive connections in litter transformers and negative connections with ecosystem engineers and Arachnida. Connectivity and modularity were higher in communities with low abundance and taxonomic richness. Soil macroinvertebrate communities respond to climatic, soil and land‐cover conditions. All taxa, except termites, are found everywhere, and communities from the five clusters cover a wide range of geographical and environmental conditions. Agricultural practices significantly decrease abundance, although the presence of tree components alleviates this effect.
Here we introduce the Soil BON Foodweb Team, a cross-continental collaborative network that aims to monitor soil animal communities and food webs using consistent methodology at a global scale. Soil animals support vital soil processes via soil structure modification, direct consumption of dead organic matter, and interactions with microbial and plant communities. Soil animal effects on ecosystem functions have been demonstrated by correlative analyses as well as in laboratory and field experiments, but these studies typically focus on selected animal groups or species at one or few sites with limited variation in environmental conditions. The lack of comprehensive harmonised large-scale soil animal community data including microfauna, mesofauna, and macrofauna, in conjunction with related soil functions, limits our understanding of biological interactions in soil communities and how these interactions affect ecosystem functioning. To provide such data, the Soil BON Foodweb Team invites researchers worldwide to use a common methodology to address six long-term goals: (1) to collect globally representative harmonised data on soil micro-, meso-, and macrofauna communities; (2) to describe key environmental drivers of soil animal communities and food webs; (3) to assess the efficiency of conservation approaches for the protection of soil animal communities; (4) to describe soil food webs and their association with soil functioning globally; (5) to establish a global research network for soil biodiversity monitoring and collaborative projects in related topics; (6) to reinforce local collaboration networks and expertise and support capacity building for soil animal research around the world. In this paper, we describe the vision of the global research network and the common sampling protocol to assess soil animal communities and advocate for the use of standard methodologies across observational and experimental soil animal studies. We will use this protocol to conduct soil animal assessments and reconstruct soil food webs on the sites included in the global soil biodiversity monitoring network, Soil BON, allowing us to assess linkages among soil biodiversity, vegetation, soil physico-chemical properties, and ecosystem functions. In the present paper, we call for researchers especially from countries and ecoregions that remain underrepresented in the majority of soil biodiversity assessments to join us. Together we will be able to provide science-based evidence to support soil biodiversity conservation and functioning of terrestrial ecosystems.
The soil macrofauna, including animals between 1–2 mm and 20–30 mm in size, uses soil differently from the mesofauna, which lives in cavities, or microfauna that inhabits water films. In some ecosystems, the macrofauna accounts for most of the total soil animal biomass and substantially contributes to soil food-web functioning. Additionally, the macrofauna can be among the most diverse groups in the soil environment. A few macrofaunal taxa (e.g. earthworms and termites) are considered to be ecosystem engineers attracting research focus, while studies on most other soil macrofauna remain scattered and uneven. An analysis of 80 publications conducted for this study showed inconsistent definitions of soil macrofauna by specialists. Further, a comparison of taxa listed among the soil macrofauna and mesofauna deduced that researchers allocate soil animals to either group by higher-level taxonomic categories and not by size. The main challenge in soil macrofaunal surveys is the extremely high diversity of species from widely different taxa, which require highly specialised taxonomists to identify them to species level. The abovementioned publication analysis showed that small taxa, mainly insects, are often not surveyed. In addition, animals of the same species at different ontogenetic stages that coinhabit the soil are not analysed separately. This tendency leads to an underestimation of the abundance and biomass of early larval stages. Hence, the soil macrofauna is seldom included in analyses of soil ecosystem functioning and modelling. Synchronised and unified studies across biomes could draw more attention to this size group and increase research focus and output from soil ecologists and other scientists.
Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide. A correction has been made for this article, which is freely available at https://science.sciencemag.org/content/369/6503/eabd9834
A high demand for food production has placed tremendous pressure on the finite land area and natural resources for agricultural production in different South America (SA) countries. Traditional agriculture in almost all SA countries places an emphasis on intensive tillage and monoculture, which has led to a severe environmental degradation and loss of soil productive capacity. This has led to declining crop performance and yield, which has created a risk to food security for future generations. The no-till (NT) farming system can bring a real opportunity to create a legacy of healthy farms and healthy, living soils that will form the base for future food security. The evaluation and history of soil and water management in different SA countries and the strategies developed by researchers, farmers, and organizations in order to test, validate, and promote the diffusion of the sustainable technologies that make up the NT system (NT, suitable machinery, cover crops, crop rotation, enhancing biological, physical and chemical soil attributes) are detailed in order to highlight the lessons and learning for other regions and countries.