Drivers of soil respiration in response to nitrogen addition in a Mediterranean mountain forests

We investigated the effects of soil N enrichment on soil respiration in the ecotone between Scots pine and Pyrenean oak forests (Mediterranean mountain, Central Spain) and whether these effects were mediated by changes on selected soil chemical and biological properties. Two N deposition rates were simulated –10 (medium) and 40 kg N ha^-1 a^-1 (high)– over the background deposition (control), in two neighbouring forests in which tree species (oak or pine) shapes soil stoichiometry and microbial communities. Manipulation of N deposition rates was carried out at three-month intervals throughout three years. Soil respiration was monitored during 2014-2017 time period, and soil samples were collected annually.