Microclimatic convergence of high‐elevation tropical páramo and temperate‐zone alpine environments

Abstract

Abstract. Plant microclimates of three tropical superpáramo sites at 4100–4600 m a.s.l. in Ecuador were monitored over a five‐month period and results were evaluated in local and biogeographical contexts. Soil temperatures tended to decrease with altitude, whereas quantum flux density (QFD) exhibited no consistent altitudinal pattern. Leaf temperatures of prostrate rosette and cushion plants exhibited diurnal amplitudes of 30 °C independent of altitude, while herbaceous perennials and woody shrubs, which were situated higher above the soil surface, had lower maxima and lower daily amplitudes as a result of aerodynamic coupling to the atmosphere. Long‐term growth measurements and an analysis of a stem cross‐section of the shrub Loricaria indicated that growth conditions at 4060 m a.s.l. were constant over a 4‐yr to > 25‐yr period.Means and frequency distributions of QFD as well as soil and leaf temperatures in the Ecuadorean Andes closely resemble growing season averages at high alpine sites in the European Central Alps at 2600 m a.s.l. Equivalent growth conditions in equatorial tropical páramo sites and seasonal temperate zone mountains extending to the arctic, suggest that, aside from the duration of the growing season, similar abiotic selection pressures operate on high elevation plants in humid mountain ecosystems, which are largely independent of latitude.