Syntaxonomy, life forms, life strategies and ecomorphology of the subandean woodlands and Polylepis forests in Central Ecuador. Ecosociological studies in Ecuadorian bryophyte communities. VI
Parolly, Gerald Kürschner
published: Aug 12, 2005
The cryptogamic epiphyte vegetation of the highest elevations that still support arboreal vegetation was studied at three different localities in the N Andes of Central Ecuador phytosociologically, symmorphologically and with regard to life strategies. To accommodate the stands dwelling in Polylepis forests, woodlands and subpáramo thickets within the syntaxonomic system of the neotropical Taxilejeuneo-Prionodontetea, we newly established the Orthotrichion elongati alliance and the Herberto divergentis-Plagio-chilenalia compressulae suborder. These communities grow under harsh and versatile conditions with mean annual temperatures of 6 to 9 °C and precipitation varying between 800 and 1500 mm/a. Two ecologically distinct associations mark either the inner-Andean valleys and the foothills of the volcanoes which are subjected to drier seasons (Blepharolejeuneo securifoliae-Orthotrichetum trachymitrii) or the more humid, fog-exposed slopes or boggy Polylepis woodlands (Campylopodo albidovirentis-Lepyrodontetum tomentosi).Symmorphological and synstrategical analyses based on the two communities clearly demonstrate common 'functional types' that support the outlined pantropical adaptive trends. Drought-tolerant mat, short turf, tall turf and cushion forming 'generative' perennial stayers and perennial shuttle species predominate. Taxa with a reliance on asexual reproduction, however, are restricted to the Campylopodo albidovirentis-Lepyrodontetum tomentosi, typical of humid and fog-exposed slopes. Most of the species show ecomorphological adaptations such as the formation of an abundant rhizoid tomentum, papillae, or the development of an internal central strand for rapid water-uptake and water conduction. If compared to the montane and oreal bryophyte communities of S Ecuador, a total change of 'functional types' can be observed.