Résumé
Earthworms are often related to fertile soils and frequently used as
environmental quality indicators. However, to optimize their use as
bioindicators, their populations must be evaluated together with
environmental and anthropogenic variables regulating earthworm
communities. In this review we identify the earthworm, soil chemical,
physical, environmental and management-related variables evaluated in 124
published studies that quantified earthworm abundance (>7300
samples) in 765 sites with different types of climate, soils, land use and
management systems in Brazil. Most soil chemical and physical attributes
(except pH) were less reported (<50% of studies) than other
environmental variables such as sampling date, altitude, temperature,
precipitation, climate and soil type and land use (all >50% of
studies). Earthworms were rarely identified (24%) and few studies (31%)
measured their biomass, although most provided adequate information on
sampling protocol. Based on the importance in regulating earthworm
populations, we propose a set of variables that should be evaluated when
studying earthworm communities and other macrofauna groups. This should
help guide future studies on earthworms in Brazil and other countries,
optimize data collection and replicability, allow comparisons between
different studies and promote the use of earthworms as soil quality
bioindicators.