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.

h i g h l i g h t s• Ecological impacts of sun-grown cocoa farming in Côte d'Ivoire were assessed. • Biodiversity and soil properties were measured along a chronosequence. • Plant species richness and diversity markedly decreased from forest to cocoa stands. • Earthworm abundance and species richness increased due the appearance of species adapted to degraded lands. • Full-sun cocoa farming significantly deteriorated soil quality. a b s t r a c tFull-sun cocoa farming is currently the most widespread cocoa cultivation system in humid and sub-humid Côte d'Ivoire. Higher short-term yields from increasing surfaces under cultivation in this farming system have contributed to the country being ranked as top cocoa producer in the world. However the negative consequences including biodiversity loss, soil fertility depletion and soil quality degradation associated with this system, have incredibly received so less attention that the type and magnitude of such agro-ecological consequences within the current context of climate change are worth investigating. The present study was undertaken in the former cocoa belt of Central-Western Côte d'Ivoire, precisely in the Oumé Department. The main objective was to assess the impact of forest conversion to full-sun cocoa plantations on above and below-ground biodiversity along with soil quality by measuring chemical, physical and biological parameters along a chronosequence of different ages (5, 10 and 20 years). The results are summarized as follows: (i) the conversion of semi-deciduous forests to cocoa plantations resulted in plant diversity and species richness loss due to the disappearance of a huge number of native species while earthworm abundance and species richness increased due to the appearance of species adapted to degraded lands, (ii) soil quality was severely impaired by cocoa farming with the worse scenario being found under the 10-year-old cocoa plantations, * BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). 576J. E. Tondoh et al. / Global Ecology and Conservation 3 (2015) where SOC, total N, CEC contributed mostly to soil quality degradation. The contribution of these findings to devise options for sustainable tree-based cocoa farming is discussed.

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The aim of this study, which was conducted in a humid savannah zone of central Côte d'Ivoire, was to examine changes in the quality of soil cultivated with herbaceous legume cover crops as a function of initial soil characteristics. Mucuna pruriens var utilis and Pueraria phaseoloides were used in a two side-by-side location experiment: a shrubby savannah (the savannah site or ''SAV'') and a natural fallow dominated by Chromolaena odorata (the fallow site or ''FAL''). The latter was mainly characterized by higher organic matter [organic carbon (C) 10 vs. 7.5 mg kg -1 ; total nitrogen (N) 0.8 vs. 0.5 mg kg -1 ) and total phosphorus (P) (282.3 vs. 168.3 mg kg -1 ) contents in the upper soil layer (0-10 cm). After 8 months of growth, biomass production by M. pruriens was found to be 6.5 and 4.9 t dry matter (DM) ha -1 at FAL and SAV, respectively. For P. phaseoloides, the values were 7.2 and 6.4 t DM ha -1 , respectively, in approximately the same period. The quantities of nutrients released by decomposing legume litter were higher at FAL than at SAV. Between-site differences in soil quality improvement were most noticeable in terms of available P, microbial biomass carbon (MBC) and MBC:total carbon (TC) ratio. The FAL site experienced a faster improvement of soil parameters under both legume species: available P increased from 18 to 58 mg kg -1 under M. pruriens, and from 19 to 52 mg kg -1 under P. phaseoloides; MBC increased from 88 to 185 mg kg -1 under M. pruriens, and from 127 to 192 mg kg -1 under P. phaseoloides. In contrast, the parameters remained constant over time at SAV. Soil C and N contents as well as C mineralization showed similar trends at both sites. Based on these results, we conclude that soil quality

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.

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