Factors controlling litter decomposition in Mediterranean holm oak (Quercus ilex L.) forests

Abstract

Mediterranean holm oak (Quercus ilex L.) forests are suffering extensive forest dieback. This may affect plant-soil interactions and in turn, litter decomposition. Here, we propose a study to investigate which factors (climate, litter quality, and soil microbiota and fauna) affect litter decomposition at different scales, and how forest dieback, through changes in litter quality and forest environmental conditions, is affecting litter decomposition. Specifically we will run five experiments to study: 1) Climate effect on litter decomposition in eight Iberian holm oak forests along a climate gradient. 2) In one forest (Cabañeros), the role and contribution of photodegradation to litter decomposition in holm oak and 3) the effects of soil fauna (classified by body size) on litter decomposition. 4) In URJC, a climate manipulation experiment to investigate the effect of increased temperature (open top chambers) and decreased precipitation (rainfall shelters) on biotic and abiotic processes of litter decomposition. 5) A laboratory experiment under controlled conditions, to determine the relative contribution of abiotic (photodegradation and thermal degradation) and biotic (microbial degradation) processes, and their interactions on grass litter decomposition. The results of these experiments will be useful to incorporate new emerging factors and mechanisms of litter decomposition into current models.