Predictor variables for model averaging procedure

Litter mass, plant species richness, soil pH and litter carbon to element ratios for N, P, K, Ca, Mg, Na, and S measured on the core sites of the EFForTS project (http://www.uni-goettingen.de/en/310995.html) in the Jambi Province on Sumatra, Indonesia in 2012. Sites are coded as landscape-land use system-replicate (two landscapes: Bukit Duabelas (B) and Harapan (H); four land-use systems: Forest (F), Jungle rubber (J), Rubber (R), Oil palm (O); four replicates). Litter_mass gives the dry litter mass per ground area in g cm-2 (Krashevska et al., Biol. Fertil. Soils, 2015). Plant_rich gives the species richness of all trees with a diameter equal to or larger than 10 cm at breast height as well as all vascular plants per site. Soil pH, analysed in a 1:4 soil-to-water ratio, was taken from Allen et al. (PLoS ONE, 2015). Elemental ratios (CX) were calculated based on mg per g dry weight of the analysed leaf litter material. To obtain these site-averaged ratios, ratios of single leaf samples were weighted according to their relative importance in local leaf litter at each site (Jochum et al., The American Naturalist, 2017). Note that prior to analyses, predictor variables were transformed and standardized (see main article).