DOI: 10.5061/dryad.4md0s64
title: Data from: Recommendations for assessing earthworm populations in Brazilian ecosystems

description: 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 (&gt;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 (&lt;50% of studies) than other
 environmental variables such as sampling date, altitude, temperature,
 precipitation, climate and soil type and land use (all &gt;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.
description: The database has missing
 values, that are represented as empty cells in the excel file. 
 References cited
 in the Methods section: ALVARES, C.A.; STAPE,
 J.L.; SENTELHAS, P.C.; GONÇALVES, J.L. DE M.; SPAROVEK, G. Köppen’s
 climate classification map for Brazil. <b>Meteorologische
 Zeitschrift</b>, v.22, p.711–728, 2013. DOI: 10.1127/0941-2948/2013/0507. ANDERSON, J.; INGRAM, J. <b>Tropical soil biology and fertility: A handbook of methods</b>. 2 ed. ed. Wallingford: CAB International, 1993. v.1 171p. FAO. <b>World reference base for soil resources 2014. International soil classification system for naming soils and creating legends for soil maps</b>. 3.ed. Rome - Italy: IUSS, 2015. 1–191p. IBGE. <b>Manual técnico de pedologia</b>. 2<sup>a</sup> ed. Rio de Janeiro - RJ: Instituto Brasileiro de Geografia e Estatística, 2007. 316p. IBGE. <b>Manual Técnico da Vegetação Brasileira</b>. 2.ed. Rio de Janeiro-RJ: Instituto Brasileiro de Geografia e Estatística, 2012. 1–271p. ISO. International Organization for Standardization. ISO 23611- 1:2018: Soil quality: sampling of soil invertebrates: Part 1 : Handsorting and extraction of earthworms. 2nd ed. [Brussels], 2018. SANTOS, H.G. DOS; JACOMINE, P.K.T.; ANJOS, L.H.C. DOS; OLIVEIRA, V.A. DE; LUMBRERAS, J.F.; COELHO, M.R.; ALMEIDA, J.A. DE; FILHO, J.C. DE A.; OLIVEIRA, J.B. DE; CUNHA, T.J.F. <b>Sistema Brasileiro de Classificação de Solos</b>. 5.ed. Brasílilia-DF: Embrapa Solos, 2018. 592p. VAN-RAIJ, B. <b>Avaliação da Fertilidade do Solo</b>. 3.ed. Piracicaba-SP: POTAFOS, 1987. 142p.
description: A dataset of earthworm abundance in Brazilian ecosystems was
 constructed using published literature on the topic. Published studies
 that evaluated earthworm populations in Brazilian ecosystems were searched
 in the literature from 1976 up to the year 2017. The literature review
 included searchable online databases such as Web of Science, Scielo,
 Lattes-CNPq Platform, Biblioteca Digital de Teses e Dissertações (BDTD-
 Brazilian digital library of theses and dissertations), Google Scholar and
 the Alice-Embrapa Repository. As we were aiming to review all studies
 available and determine which soil, environmental, earthworm and
 sampling-related factors were evaluated, we also included non-indexed
 journals, book chapters, and conference proceedings in soil science,
 zoology, ecology, agroecology and conservation agriculture. We also made
 personal contact with colleagues who work with earthworms and/or are
 members of the Brazilian CNPq research group “Biology, ecology and
 function of terrestrial Brazilian oligochaetes (earthworms and
 enchytraeids)”, in order to help us expand our data search. 
 The data on soil, environmental and earthworm sampling variables
 were extracted from each of the 124 publications and entered into an excel
 data file. Using the data for all sites, the number of publications with
 each environmental, earthworm and soil physical and chemical variables was
 quantified, as well as the corresponding number of points/sampling sites.
 The data contains information from 765 specific sites, representing over
 7300 earthworm samples, from a wide range of soils, vegetation types and
 management systems in 135 counties in Brazil. Additional environmental and
 soils data were also obtained from these sites and complemented with
 information from various sources (e.g. online climate data, municipal GPS
 coordinates, Köppen climate database), or calculated (e.g. CEC or Sum of
 bases, pH, H+Al, C:N) and included, when possible. Climate information was
 corrected also when needed, following the data of Alvares et al. (2013).
 When not provided, geographic position data used was for the county seats,
 and when found to be incorrect, the county or state
 information was corrected. The data thus includes 13 climate and
 vegetation-related environmental variables (Sampling date, Sampling
 season, Locality, County, State, Geographical coordinates, Altitude, Mean
 annual precipitation, Mean annual temperature, Köppen climate, Biome, Soil
 cover/Vegetation type, Type of native vegetation), 8 management-related
 variables (Crop type, Soil management, Years in current land use, Previous
 land use, Pesticide use, Pesticides type, Fertilizers, Fertilizer type),
 17 soil-related variables (Soil type, pH, H+Al, K, Ca , Mg, P , C, Sum of
 bases, CEC, Base saturation, N , C:N, Sand, Clay, Silt, Textural class),
 and 6 earthworm sampling-related variables (Size of holes dug, Number of
 holes, Depth, Density, Biomass, Species identification).
 Native vegetation types were classified according to standard
 categoreies (IBGE, 2012), while forest plantations were divided into four
 main types: <i>Eucalyptus</i> or <i>Pinus</i> spp.
 trees, <i>Araucaria angustifolia</i>, and Others
 (contemplating all other tree species). Pasture grasses were separated
 into only two categories, <i>Brachiaria</i> spp. pastures
 (some of which are currently in the <i>Urochloa</i> genus),
 and Others, including all other types or species of pasture grasses. Soil
 types information was obtained from the publications or using
 the Brazilian national or state maps available online and from Embrapa
 databases (IBGE; Santos et al., 2018). Soil were classified according to
 the Brazilian (Santos et al., 2018) and the FAO (2015) soil classification
 systems. Soil tillage was classified into four categories, according to
 decreasing intensity: conventional tillage (CT), minimum tillage (MT), no
 tillage (NT) and permanent crop with no tillage (PC). Similarly, pesticide
 and fertilizer use information were searched for in each publication,
 including types (herbicides, fungicides or insecticides and fertilizer
 formulation) and active ingredients.  The soil chemical
 (pH, H+Al, K, Ca, Mg, P, C, sum of Bases, CEC, Base saturation, N and C:N
 ratio) and physical (sand, clay and silt proportions) attributes included
 were those generally provided in routine soil fertility analyses in
 Brazilian soil analysis laboratories (van Raij, 1987), except for C and N
 by combustion (which are not routine in most laboratories). Soil pH values
 were transformed to equivalent of pH in CaCl<sub>2</sub> or
 KCl for all samples, using a conversion factor of 0.6 when measured in
 water (i.e., pH in water was considered to be 0.6 points higher than that
 estimated in CaCl<sub>2</sub> or KCl). Values obtained in
 CaCl<sub>2</sub> or KCl were maintained and considered of
 similar magnitude for these two methods. All values of H+Al, K, Ca, Mg,
 sum of Bases and CEC not in standard units (cmol<sub>c</sub>
 dm<sup>-3</sup>) were transformed. Phosphorus values were
 standardized to mg dm<sup>-3</sup> and only studies using the
 Mehlich-extraction method were included. Carbon and Nitrogen values were
 in g dm<sup>-3</sup> and based on analyses performed using
 combustion or Walkley-Black digestion. When OM values were given, C was
 estimated using the “Van Bemmelen” factor, dividing OM by 1.72. Total
 sand, clay and silt contents were all in g
 kg<sup>-1</sup>. Textural soil classes were based on the soil
 texture triangle of IBGE (2007), similar to that of FAO (2015). When
 several sources of data were available for the same collection site, or
 when it was sampled more than once (for example, at different times of the
 year, or different years), the mean values of chemical and physical
 attributes of soils were calculated.  Only studies
 performed using the standard method for collecting earthworms in tropical
 soil conditions, based on ISO (2018) and the Tropical Soil Biology and
 Fertility (TSBF) method (Anderson & Ingram, 1993) were included in
 the database. Information on the size of excavated area to collect the
 earthworms, the number of samples taken per site, and the depth of the
 sample were extracted from each publication. Mean
 earthworm density and biomass data (when available) were entered into the
 database as well as information on species identification (if performed or
 not). Earthworm data was entered as number of individuals per
 m<sup>2</sup> (no. indiv. m<sup>-2</sup>) and
 biomass expressed as fresh mass in g m<sup>-2</sup> (fresh
 weight in preservative liquid, including intestinal contents). When the
 data were not expressed in these units, they were obtained by using sample
 number and the size (area, in m<sup>2</sup>) at each date and
 site. When more than one source of data was available
 by the same authors for the same site, i.e., if it was sampled more than
 once (e.g., at different times of the year or different years), mean
 density and biomass values were calculated for each sample site or
 treatment evaluated, so that each individual treatment or site was
 represented by only one line in the database. A preliminary analysis of
 climate effects showed that earthworm abundance and biomass at the same
 site could be significantly affected by the sampling date, particularly at
 sites in climates with pronounced dry and wet seasons. For sites in these
 climates, dry season sample dates were excluded from the database, as they
 could not be compared with samples of earthworm populations taken in the
 wet season. For cases where multiple samples were taken during the wet
 season, data were combined and means calculated per sample site. For
 climate types where there is no dry season, data from all sampling dates,
 irrespective of season were combined and means calculated per
 site. All data is provided in excel format, and
 includes four tabs in the data file: Legend, Data base, count and
 References. The Legend tab provides a detailed explanation for each
 variable included in the Data base tab. The counts tab provides a table
 with the total number and percentage of times each variable was provided
 in the 124 publications used. The References tab gives the full
 bibliographic information on each of the 124 studies (148 publications)
 used, of which most (80%) are in Portuguese.