Although in Paraná some upper montane ecosystems are still in excellent conditions, imminent anthropogenic threats and the vulnerability of these environments have raised concern. The objectives of this study were: (1) to characterize representative soils of high altitude grasslands and upper montane rain forests in the Serra da Igreja; (2) identify the possible pedological factors underlying the different vegetation types and; (3) describe some of the environmental roles of the soils of these areas (carbon stock and water retention). The main soil types of the grasslands were fibric/sapric Folic and Haplic Histosols and the upper montane forests typic alitic Haplic Gleysols. Both soils are dystrophic, extremely acid, with high exchangeable Al saturation and very high levels of total organic C. The upper montane forests are mostly found in valleys influenced by morphogenetic processes that result in soils with mineral horizons. The grasslands are located on flat tops, where pedogenetic processes led to thicker histic horizons. This fact, combined with a great wind exposure, seem to prevent the normal expansion of tree species. Carbon stocks per unit area in the grassland soils are higher than those of the upper montane forests. Furthermore, C values in both areas are two- to threefold higher than those reported for soil ecosystems at low altitudes at the same latitude. Another important environmental feature of these soils is the high water retention capacity, due to the total porosity values in the histic horizons, which can retain water up to approximately 12 times their volume.
High altitude grasslands; montane tropical rain forest; soil carbon stocks; histosols; soil water retention
