Soil organisms provide crucial ecosystem services that support human life. However, little is known about their diversity, distribution, and the threats affecting them. Here, we compiled a global dataset of 60 sampled earthworm communities from over 7000 sites in 56 countries to predict patterns in earthworm diversity, abundance, and biomass. We identify the environmental drivers shaping these patterns. Local species richness and abundance typically peaked at higher latitudes, while biomass peaked in the tropics, patterns opposite to those observed in aboveground organisms. Similar to many aboveground taxa, climate variables were more important in shaping earthworm communities than soil properties or habitat 65 cover. These findings highlight that, while the environmental drivers are similar, conservation strategies to conserve aboveground biodiversity might not be appropriate for earthworm diversity, especially in a changing climate.

To test whether invasion of exotic earthworms affects soil carbon (C) and nitrogen (N), we sampled the litter and upper mineral soil (to 30 cm) at a series of sites varying in their earthworm populations in an old-growth beech–maple forest at Mont St. Hilaire, southern Quebec. We measured earthworm abundance and biomass using hand-sorting and chemical extraction (allyl isothiocyanate) methods. They gave similar results, though there was evidence of size and species-specific biases. Abundance and biomass of the earthworms ranged from <10 to >100 earthworms·m–2 and from <10 to 125 g·m–2, respectively, and were correlated with distance from a nearby lake (negatively) and soil pH (positively). The presence of earthworms was associated with a decrease in the mass and thickness and an increase in the C/N quotient of the litter layer. There were no significant changes in C and N mass of the mineral soil between 0 and 10 cm, but the underlying layers (10–20 and 20–30 cm) in sites with >10 earthworms·m–2 showed significantly (p < 0.05) greater concentrations and masses of both C and N than did sites with <10 earthworms·m–2. The overall profile (litter plus soil to 30 cm) average C was 13.7 and 10.1 kg·m–2 with and without earthworms, respectively, and the equivalent figures for N were 1.01 and 0.68 kg·m–2. These results demonstrate that invasion of earthworms into deciduous forests affects both the litter and mineral soil, and sampling to a depth of 30 cm suggests that earthworm invasion (from <10 to >10 earthworms·m–2) may increase overall C and N.

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Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change.

Ecological economics arose as a normative transdiscipline aiming to generate knowledge and tools to help transition the economy toward a scale which is sustainable within the bounds of the earth system. Yet it remains unclear in practice how to legitimize its explicitly normative agenda. One potential means for legitimation can be found in deliberative social and political theory. We review how deliberative theory has informed ecological economics, pointing to three uses: first, to support valuation of non-market goods and services; second, to inform environmental decision-making more broadly; third, to ground alternative theories of development and wellbeing. We argue that deliberation has been used as problem-solving theory, but that its more radical implications have rarely been embraced. Embracing a deliberative foundation for ecological economics raises questions about the compatibility of deeply democratic practice and the normative discourses arguing for a sustainability transition. We highlight three potential mechanisms by which deliberation may contribute to a sustainability transition: preference formation; normative evaluation; and legitimation. We explore each in turn, demonstrating the theoretical possibility that deliberation may be conducive in and of itself to a sustainability transition. We point to a series of challenges facing the “scaling up” of deliberative systems that demand further empirical and theoretical work. These challenges constitute a research agenda for a deeply democratic sustainability transition and can inform the future development of ecological economics and other normative, critical transdisciplines.