Efecto del gradiente altitudinal sobre las reservas de carbono y nitrógeno del suelo en un matorral seco en Ecuador

The study of the distribution and reserves of carbon (C) and nitrogen (N) in the soil is of crucial importance for all terrestrial ecosystems, particularly in dry mountain areas where there is a high spatial heterogeneity due to the differences in soils, climate and vegetation along altitudinal gradients. The objective of this investigation was to determine if altitude affects the soil C and N reserves of a neotropical dry scrub ecosystem in the south of Ecuador. We selected an altitudinal transect ranging from 1200 to 1800 m a.s.l. where eight plots were sampled at two depths (0-10 and 10-20 cm). The results show that the reserves of C and N varied along the altitudinal gradient, with the highest values sampled at 1800 m a.s.l. and the lowest at 1200 m a.s.l. This variation in the reserves is mainly related to the decrease in temperature and the increase in precipitation with altitude, as at higher elevations decomposition rates of organic matter is usually slower. Our results suggest that elevation should be included in models and estimates of reserves of C and N at a local and regional scale in this type of ecosystem, which would allow identifying the most vulnerable areas to the effects of climate change. In addition, the information generated in this study could be useful to assign conservation priorities to this type of ecosystem. Overall, our results contribute and add information to the scarce literature found on the C and N in these arid ecosystems of Ecuador.