Biomass of Grazed, Burned, and Undisturbed Páramo Grasslands, Colombia. II. Root Mass and Aboveground : Belowground Ratio

Abstract

In a Neotropical alpine grassland (páramo) in the Colombian Central Cordillera, the root mass, root distribution, and aboveground : belowground (A:B) ratio were determined at four sites with different grazing and burning management. Compared to grasslands at other latitudes, páramos have a relatively low belowground biomass and, due to the combination with a high aboveground biomass, a high A:B ratio. This is attributed to a low productivity and a lack of seasonality. Effects of grazing disturbance on the root system could be observed at a site without burning history, where the tussock grass vegetation was transformed into ground covering mats. Here, belowground biomass increased from 1.2 to 2.1 kg m^–2, which was more concentrated in the upper 10 cm of the soil. An undisturbed and two other grazed sites did not show differences in root mass or distribution, in response to disturbance. Nevertheless, A:B ratios decreased clearly towards more managed sites, as a result of decreased aboveground biomass.