BUSCADOR RECOLECTA

Soil fauna play a key role in nutrient cycling and decomposition, and in recent years researchers have become more and more interested in this compartment of terrestrial ecosystems. In addition, soil fauna can act as ecosystem engineers by creating, modifying and maintaining the habitat for other organisms. Ecologists usually utilize alive catches in pitfalls traps as a standard method to study the activity of epigeic fauna in addition to relative abundance. Counts in pitfall traps can be used as estimates of relative activity to compare among experimental treatments. This requires taking independent estimates of abundance (e.g.: by sifting soil litter, mark-recapture), which can then be used as covariates in linear models to compare the levels of fauna activity (trap catches) among treatments. However, many studies show that the use of pitfall traps is not the most adequate method to estimate soil fauna relative abundances, and these concerns may be extensible to estimating activity. Here, we present two new types of traps devised to study activity in litter fauna, and which we call “cul-de-sac” and “basket traps” respectively. We experimentally show that, at least for litter dwellers, these new traps are more appropriate to estimate fauna activity than pitfall traps because: 1) Pitfall traps contain 3.5x more humidity than the surrounding environment, potentially attracting animals towards them when environmental conditions are relatively dry, 2) cul-de-sac and basket traps catch ca. 4x more both meso- and macrofauna than pitfall traps, suggesting that pitfall traps are underestimating activity; and 3) pitfall traps show a bias towards collecting 1.5x higher amounts of predators, which suggests that predation rates are higher within pitfall traps. We end with a protocol and recommendations for how to use these new traps in ecological experiments and surveys aiming at estimating soil arthropod activity., This work was funded by grants CGL2010-18602 and CGL2015-66192-R from the Spanish Ministerio de Economía y Competitividad (European funds FEDER), 020/2008 Spanish Organismo Autónomo de Parques Nacionales and P12-RNM-1521 from Junta de Andalucía (European funds FEDER), Peer reviewed

This study has been funded by Spanish Ministry of Science and Innovation grants CGL2010-18602, CGL2015-66192-R and Andalusian grant P12-RNM-1521-EEZA to J.M.L., the European Regional Development Fund, Agencia Nacional de la Promoción de Ciencia y Tecnología (PICT 2016-1780), Argentina to A.T.A. and FPI fellowship (BES-2011-043505) to N.M.R, Dos tablas de datos: Animal abundance y Decomposition data, Peer reviewed

This study was supported by the Office of Secretary of Public Education of Mexico through the program Further Education Programme for Teachers (UNICACH-110). Further support was provided by the Spanish Research Agency (grant CGL2017-84515-R to FIP and grant CGL2015-66192-R to JML). We thank the Cabo de Gata-Níjar Nature Park for support during field work (permit: 2016-101-657)., UV radiation UV radiation exposition with two levels: UV+ and UV- Biocides Exposition of biocides with two levels: biocides+ and biocides- Species Identity Leaf litter species identity with three levels: S. tenacissima, C. humilis and R. sphaerocarpa Mixtures Plant diversity treatments with four levels (three monospecific plus the mixture) Isopods Isopod presence with two levels: Isopods+ and Isopods- Mortality Total number of dead isopods after 80 days of experiment w_inic Litter initial dry weight (g) w_uv Litter mass after 200 days of UV exposition during the first stage of the experiment; dry weight (g) w_iso Litter mass after 80 days of exposition to isopods during second stage of the experiment; dry weight (g), Peer reviewed

Litter decomposition in field experiment. A total of 280 mesocosms were settled under and away of 20 individuals of Z. lotus. The litter boxes thus contained either one single species of litter (20 litter boxes for each species and position treatment), 2-sp mixtures (20 litter boxes for each 2-species combination and position treatment) or 3-sp mixtures (20 litter boxes with the 3-species mixture and position treatment)., This study was supported by the Office of Secretary of Public Education of Mexico though the program Further Education Programme for Teachers (UNICACH-110). Further support was provided by the Spanish Research Agency (grant CGL2017-84515-R to FIP and grant CGL2015-66192-R to JML). We thank the Cabo de Gata-Níjar Nature Park for support during field work (permit: 2016-101-657)., Date Date of collection (1 - 07/13/2017, 2 - 01/13/2018, 3 -08/30/2018) Plant Plant (Ziziphus lotus fertility island) ID utmx Geographic Longitude for each plant utmy Geographic Latitude for each plant Box Mesocosm ID Island Location of the mesocosm (Away or Under shrub) Mixtures Litter plant diversity (species richness 1, 2, 3) Species Identity of the litter plant species with three levels: S. tenacissima, C. humilis and R. sphaerocarpa w_inic Litter initial dry mass (g) w_end Litter dry mass (g) after 184, 367 and 597 days in the field, Peer reviewed

Litter decomposition in field experiment. A total of 280 mesocosms were settled under and away of 20 individuals of Z. lotus. The litter boxes thus contained either one single species of litter (20 litter boxes for each species and position treatment), 2-sp mixtures (20 litter boxes for each 2-species combination and position treatment) or 3-sp mixtures (20 litter boxes with the 3-species mixture and position treatment)., This study was supported by the Office of Secretary of Public Education of Mexico though the program Further Education Programme for Teachers (UNICACH-110). Further support was provided by the Spanish Research Agency (grant CGL2017-84515-R to FIP and grant CGL2015-66192-R to JML). We thank the Cabo de Gata-Níjar Nature Park for support during field work (permit: 2016-101-657)., Date Date of collection (1 - 07/13/2017, 2 - 01/13/2018, 3 -08/30/2018) Plant Plant (Ziziphus lotus fertility island) ID utmx Geographic Longitude for each plant utmy Geographic Latitude for each plant Box Mesocosm ID Island Location of the mesocosm (Away or Under shrub) Mixtures Litter plant diversity (species richness 1, 2, 3) Species Identity of the litter plant species with three levels: S. tenacissima, C. humilis and R. sphaerocarpa Predators Abundance of predators Decomposers Abundance of detritivores, Peer reviewed