The vegetation of Reserva Biológica San Francisco, Zamora-Chinchipe, Southern Ecuador 145 The vegetation of Reserva Biológica San Francisco, Zamora-Chinchipe, Southern Ecuador – a phytosociological synthesis Rainer W. Bussmann Department of Plant Physiology, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany, Fax: [0049] (0)921 552642, e-mail:
[email protected] Abstract Few floristic inventories and even less syntaxonomical vegetation descriptions of tropical mountain forests exist. The author presents a syntaxonomical treatment of the vegetation of Reserva Biológica San Francisco at the northern limit of Podocarpus National Park, Ecuador. The “Lower Montane Forests” (1800-2150 m), grouped in the new order Alzateetalia verticillatae, have a very diverse, 20-35m tall, 2-3 storied Estrato arboreo, and are a typical mosaic-climax. They grow on Terric Haplosaprists and Aquic Dystrupepts, developed from old landslide material and extend up to 2300 m at the bottom of wind-protected riverine valleys. At altitudes from 2100 to 2650/2750 m, the forest structure and floristic composition change completely. The vegetation types belonging to this “Upper Montane Forest” form the new Purdiaeaetalia nutantis, growing on Histic Petraquepts. They represent a monotypic vegetation type, with only one Estrato arboreo, and stems between 5-10 m, sometimes up to 15 m tall. The canopy is completely dominated by the twisted stems of Purdiaea nutans (Cyrillaceae). The „Subalpine-elfin forest“ which closely resembles the Bolivian „Jalca“ forms the uppermost forest belt of the study area. Described as Clusio ellipticae – Weinmannion cochensis, this forest – more like an impenetrable bushland - grows on Humaqueptic Epiaquents and is closely dovetailed with the adjacent Páramo region.