Anotace:
Andean highland ecosystems (known as paramos) have a great potential to store water and organic carbon, which fulfill the inherent functions associated to the regulation of carbon and water cycles, characteristics linked to their parent material (volcanic ash). However, paramos are at high risk of degradation associated with land use dynamics that affect organic carbon quality in the surface soil. Changes in vegetation cover, with transition from natural forest to tillage and then pasture, make the soil vulnerable to degradation by compaction, erosion, and carbon dioxide emissions associated with increased anthropogenic activity. Despite this cover change, information on soil carbon dynamics in paramos is scarce, impeding conservation management strategies in these ecosystems. This study evaluates the impact of different soil uses within a transect in the Guerrero paramo estimated from soil organic carbon (SOC) stock in the upper meter and carbon condition (expressed as stratification ratio, SR) in the surface soil. Carbon storage varied from 165.2 to 721.9 t ha−1 in the upper meter of soil with SR1 (0–10/10–20cm) between 0.92 and 2.01 and SR2 (0–10/20–30cm) between 0.99 and 2.05. Results of this study highlighted that in the fragile ecosystems than Andean paramos, the geomorphological position in relation to soil uses and management practices conditioned soil carbon availability, affecting pedogenetic processes. SR of SOC associated to anthropogenic intervention activities it does not indicate by itself C sequestration. In future researches it is necessary include additional parameters than net primary productivity and historic vegetation.