<p> Supplemental Material</p><p>Biological vs. geochemical control and environmental change drivers of the base</p><p> metal budgets of a tropical montane forest in Ecuador during 15 years</p><p>Wolfgang Wilcke • Andre Velescu • Sophia Leimer • Moritz Bigalke • Jens Boy • Carlos</p><p>Valarezo</p><p>Wolfgang Wilcke, Andre Velescu, Sophia Leimer</p><p>Karlsruhe Institute of Technology (KIT), Institute of Geography and Geoecology, Reinhard-</p><p>Baumeister-Platz 1, 76131 Karlsruhe Germany, e-mail: [email protected]</p><p>Moritz Bigalke </p><p>University of Bern, Institute of Geography, Hallerstrasse 12, 3012 Berne, Switzerland </p><p>Jens Boy</p><p>Leibniz University Hannover, Institute of Soil Science, Herrenhäuser Str. 2, 30419 Hannover,</p><p>Germany</p><p>Carlos Valarezo</p><p>National University of Loja, Research Directorate, Ciudadela Universitaria Guillermo Falconí, sector La Argelia, Loja, Ecuador </p><p>Supplemental Material includes Tables S1 and S2 and four references. Table S1 Mean (± standard deviation) base metal concentrations in parent rocks as determined with Roentgen Fluorescence analysis (see Stückrad et al. 2010 for a description of the method).</p><p>Ca K Mg Na ------[g kg-1] ------</p><p>Phyllite (n = 4) 1.3 ± 0.0 34 ± 0.39 11 ± 0.19 7.6± 0.10</p><p>Quartzite (n = 2) NDa 7.8±1.2 1.7±0.0 9.8±0.05 aND is not detected Table S2 Overview of the methods used to determine weathering rates.</p><p> a 1a TDi + Wi = STi + Bi ± OMi ± Xi ± Mi b 1b Wi = STi + TSPi – TDi</p><p> c 2 Wi = element export during baseflow + TSPi </p><p> d 3 Wi = (Ci/CNa)rock x (STNa + TSPNa) a W is weathering release from primary minerals,  is change, B is storage in biomass, OM is long-term storage in soil organic matter, X is the exchangeable pool and M is the secondary mineral pool. Equation taken from Likens (2013). b Simplification of Eq. 1a based on the assumptions that Bi , OMi and Xi equalled zero and Mi Total Suspended Particles (TSPi). </p><p>Justifications:</p><p>1) Bi does not change, because the studied forest is an old growth native forest in steady state;</p><p>2) OMi does not change because we did not find significant differences (t-test, p < 0.05) in (i) the thickness of the organic layer, (ii) the C concentrations and (iii) the C/N ratios of A and B horizons did not change between our two surveys in 1998 (Table 1) and 2007 (organic layer thickness: 12 ± 8.2 cm; C concentrations: 29 ± 16 and 10 ± 7.1 g kg-1 and C/N ratios: 14 ± 2.9 and 10 ± 3.3 in the A and B horizons, respectively; n = 20 soils of which 10 were in slope and 10 in valley bottom position).</p><p>3) Xi does not change because soil development (M) was assumed to equal the erosional loss of secondary minerals, which is measured as TSP. This assumption is based on the observation that the study soils were all shallow (usually hardly deeper than 0.5 m and rich in stones, Table 1) and did not show a further development than to the state of a Cambisol (IUSS Working Group WRB 2014) in spite of the tropical perhumid climate. We therefore assumed that continuous erosion kept the soils at a steady-state young development stage. c Element export during baseflow (including superdry flow) was 87 mg m-2 yr-1 Ca, 49 mg m-2 yr-1 K, 58 mg m-2 yr-1 Mg and 507 mg m-2 yr-1 Na (Boy et al. 2008b). Approach 2 is based on a suggestion of Stoorvogel et al. (1997). d (Ci/CNa)rock is the concentration ratio of element i to Na in the parent rocks. For the third approach, we assumed that the loss of Na can be entirely attributed to weathering, because Na is not an essential plant nutrient and because our study site is far away from the ocean in downwind (i.e., western) direction and that weathering resulted in a homogeneous complete dissolution of the parent rock (i.e. a stoichiometric release of Na and the other base metals). The third approach was used separately for phyllite and quartzite. References</p><p>Boy J, Valarezo C, Wilcke W (2008b) Water flow paths in soil control element exports in an </p><p>Andean tropical montane forest. Eur J Soil Sci 59:1209-1227</p><p>IUSS Working Group WRB (2014) World Reference Base for Soil Resources 2014. </p><p>International soil classification system for naming soils and creating legends for soil maps.</p><p>World Soil Resource Reports No. 106. FAO, Rome</p><p>Stoorvogel JJ, Janssen BH, Van Breemen N (1997) The nutrient budgets of a watershed and</p><p> its forest ecosystem in the Taï National Park in Côte d’Ivoire. Biogeochemistry 37:159-172</p><p>Stückrad S, Sabel K-F, Wilcke W (2010) Contributions of different parent materials in soils</p><p> developed from periglacial cover beds. Eur. J. Soil Sci. 61:844-853</p>