Received in revised form

phosphorus, as a result of mineral weathering and leaching (Izquierdo et al., 2013). This phenomenon of ‘ecosystem retro-gression ’ (Peltzer et al., 2010; Wardle et al., 2004) is a topic of much ity, and vegetation arious parts of the le et al., 1997), but land management. Among the chro-coast of California l., 2010; Westman Mendocino is one of the best studied (Jenny et al., 1969). It is located in the Jug Handle State Natural Reserve and characterized by a succession of five uplifted marine terraces formed from the same parent material, with each terrace different in age from the next by approximately 100,000 years (Merritts et al., 1991). Soils range from young and relatively nutrient-rich near the coast to old andweathered podzols defined as spodosol at the top of the chronosequence, thus forming a natural soil fertility gradient (Izquierdo et al., 2013; White et al.