Global distribution of soil fauna functional groups and their estimated litter consumption across biomes

Abstract

Soil invertebrates (i.e., soil fauna) are important drivers of many key processes in soils including soil aggregate formation, water retention, and soil organic matter transformation. Many soil fauna groups directly or indirectly participate in litter consumption. However, the quantity of litter consumed by major faunal groups across biomes remains unknown. To estimate this quantity, we reviewed > 1000 observations from 70 studies that determined the biomass of soil fauna across various biomes and 200 observations from 44 studies on litter consumption by soil fauna. To compare litter consumption with annual litterfall, we analyzed 692 observations from 24 litterfall studies and 183 observations from 28 litter stock studies. The biomass of faunal groups was highest in temperate grasslands and then decreased in the following order: boreal forest > temperate forest > tropical grassland > tundra > tropical forest > Mediterranean ecosystems > desert and semidesert. Tropical grasslands, desert biomes, and Mediterranean ecosystems were dominated by termites. Temperate grasslands were dominated by omnivores, while temperate forests were dominated by earthworms. On average, estimated litter consumption (relative to total litter input) ranged from a low of 14.9% in deserts to a high of 100.4% in temperate grassland. Litter consumption by soil fauna was greater in grasslands than in forests. This is the first study to estimate the effect of different soil fauna groups on litter consumption and related processes at global scale.

Effects of land use and soil properties on taxon richness and abundance of soil assemblages

“…In another strong contrast to the first global model of PREDICTS data, soil organisms in pasture attain similar taxon richness and abundance as in primary vegetation. This agrees with other studies that found high soil fauna biomass in temperate grasslands (Heděnec et al, 2022). Pastoral management practices cause less physical disruption of the soil structure than many arable farming practices (Aksoy et al, 2017).…”

The pervasive impact of global climate change on plant-nematode interaction continuum

“…Greater amount of nematode herbivory reduces the plant biomass in general, and changes the biomass allocation pattern as seen in grasslands ( Brinkman et al., 2015 ; Franco et al., 2020 ). The nematodes also help to shape the vegetation community aboveground ( Hedenec et al., 2022 ). As seen in the coastal dune grasslands, the specialist PPNs play pivotal role in natural succession by bringing the end of dominant plant species followed by the non-host plant establishment ( van der Putten et al., 1993 ).…”

Soil invertebrates are the key drivers of litter decomposition in tropical forests

“…mites and collembolas) and macrofauna (e.g. earthworms, isopods and millepedes) are also important contributors to litter decomposition (Anderson 1978;Korboulewskyet al 2016;Heděnec et al 2022). The quality and palatability of plant-derived resources affect soil invertebrate diversity (Cebrian 1999;Kurokawa et al 2010;Bastida et al 2020).…”