The impact of multiple agricultural land uses in sustaining earthworm communities in agroecosystems - A global meta-analysis.

Abstract

The impact of agricultural land use on biodiversity has been extensively examined through efforts to synthesize available data. Nevertheless, there is still a lack of a thorough synthesis describing the earthworm response to agricultural land-use Our meta-analysis compared undisturbed ecosystems (i.e., undisturbed grassland, primary forest) as controls against agricultural land-use treatments, with data extracted from 113 publications across 44 countries, yielding 1040 pairwise comparisons of earthworm density and biomass, and 536 pairwise comparisons of earthworm diversity. We also evaluated how agricultural land use effects on earthworms depend on soil, climate, and management practices reported in the studies. Arable cropland had significantly lower earthworm density (-18%), biomass (-15%), and species richness (-27%) compared to undisturbed sites. Conversely, higher earthworm density, biomass and species richness were observed in pastures, sites under agroforestry, crop management with fallow periods and crop-livestock integration. In regions with continental climates characterized by cool summers, agricultural land use exhibited positive effects on earthworm density and biomass. In sites with higher soil bulk density and lower organic matter content the adverse effects of agricultural land use are exacerbated. However, highly heterogeneous earthworm responses cannot be explained by the individual evaluation of climatic, soil-related, or management factors. Our results guide future efforts to address the data limitations that enable us to enhance our understanding of the interactive effects of various factors on earthworm responses to agricultural land use, as well as evidence-based and management strategies targeted at promoting sustainable agricultural systems while preserving soil biodiversity.