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Tropical mountainous ecosystems are recognized as providers of valuable ecological and hydrological services (Viviroli et al, 2007). In Central America, the P aramo, a high-elevation tropical grassland ecosystem, extends over ~ 200 km2 in Costa Rica and Panama, with ~50% of this area located within the Chirripo National Park between 3,100 and 3,820 m asl (-83.49deg, 9.46deg). Vegetation mostly consists of 0.5 to 2.5 m tall bamboo dominated (Chusquea subtessellata ) grasslands, covering up to 60% of the total Paramo area in Costa Rica (Fig.1a). The climate is controlled by the northeast trade winds, the latitudinal migration of the Intertropical Convergence Zone (ITCZ), cold continental outbreaks (i.e., northerly winds), and the seasonal influence of Caribbean cyclones. These circulation patterns produce two rainfall maxima on the Paci fic slope, one in June and one in September, which are interrupted by a relative minimum between July-August, known as the Mid-Summer Drought, due to intensi cation of trade winds over the Caribbean Sea (Magana et al., 1999; Waylen, 1996). The wettest season extends from May to November (contributing up to 89% of the annual precipitation), whereas the driest season is from December to April (Fig. 2a; Esquivel-Hernandez et al., 2018). The surface water system of Chirripo is characterized by a lake district which comprises approximately 30 lakes of glacial origin and streams owing down the Caribbean and Pacifi c slopes (Fig1b).
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