Tussock Grass
Páramo de sumapaz - vegetation - tussock grass - rainfall & groundwater & atmospheric water - soil
Overview of the three main vegetation assemblages in the high-altitude páramo ecosystem, with abundance of cushion-forming plants in topographic hollows and valley bottoms, tussock grasses along the hillsides, and forest in areas not easily accessible by humans.(Molina et al., 2024)
Within the Páramo ecosystem, elevation is the main driver for its vegetation, and this results in an internal vertical structure with three main Páramo vegetation belts: the sub-Páramo, the grass Páramo and supra-Páramo (Christmann and Oliveras, 2020). The summit and hillslopes feature well-drained soils covered by tussock grasses or bunch, constituting the grass Páramo. Whereas toeslopes and valley bottoms constitute permanently waterlogged areas covered by hard cushion-forming plants (Molina et al., 2024), such as sphagnum moss.
In undisturbed areas, tussock grasses may average 1-1.5 m tall with a coverage of up to 100%. Members of the grass and sedge families frequently form tufts or dense bunches of stems (culms) with rigid, pointed, tubular or inrolled leaves, providing good insulation for the buds and young leaves from cold temperatures, high radiation, evaporation, and high heat of fires to 500°C (Ramsay, 1992; Ramsay & Oxley, 1996).
Tussock grass vegetation exhibits significant rainfall interception capacity. Due to the low rainfall intensity and lack of climatic stability in Páramo, greater rainfall interception may still occur despite the tussock grasses are stunted (Ochoa-Sánchez, Crespo and Célleri, 2018). Moreover, the distinctive root system of tussock grass enables its vegetation belt to form a homogeneous system that regulates and transmits water evenly through all the soil horizons (Sebastián Páez-Bimos et al., 2023).
The tussock grass plant (RHS,2026)
Bibliography:
Christmann, T. and Oliveras, I. (2020). Nature of Alpine Ecosystems in Tropical Mountains of South America. Elsevier eBooks, pp.282–291. doi:https://doi.org/10.1016/b978-0-12-409548-9.12481-9.
Molina, A., Vanacker, V., Chadwick, O., Zhiminaicela, S., Corre, M. and Veldkamp, E. (2024). Vegetation patterns associated with nutrient availability and supply in high-elevation tropical Andean ecosystems. Biogeosciences, [online] 21(12), pp.3075–3091. doi:https://doi.org/10.5194/bg-21-3075-2024.
Ochoa-Sánchez, A., Crespo, P. and Célleri, R. (2018). Quantification of rainfall interception in the high Andean tussock grasslands. Ecohydrology, 11(3), p.e1946. doi:https://doi.org/10.1002/eco.1946.
Sebastián Páez-Bimos, Molina, A., Calispa, M., Delmelle, P., Braulio Lahuatte, Villacís, M., Muñoz, T. and Vanacker, V. (2023). Soil–vegetation–water interactions controlling solute flow and chemical weathering in volcanic ash soils of the high Andes. Hydrology and earth system sciences, [online] 27(7), pp.1507–1529. doi:https://doi.org/10.5194/hess-27-1507-2023.