Pinus ponderosa alters nitrogen dynamics and diminishes the climate footprint in natural ecosystems of Patagonia

1. Evaluating climate effects on plant-soil interactions in terrestrial ecosystems remains challenging due to the fact that floristic composition co-varies with climate, particularly along rainfall gradients. It is difficult to separate effects of precipitation per se from those mediated indirectly through changes in species composition. As such, afforestation (the intentional planting of woody species) in terrestrial ecosystems provides an ecological opportunity to assess the relative importance of climate and vegetation controls on ecosystem processes. 2. We investigated the impacts of 35 years of afforestation on ecosystem N dynamics, in ecosystems ranging from arid shrub-steppe to closed-canopy forest in Patagonia, Argentina. Site of natural vegetation and adjacent sites planted with a single exotic species, Pinus ponderosa, were identified in five precipitation regimes along a continuous gradient of 250 to 2200 mm mean annual precipitation (MAP). We evaluated C and N parameters of ...