Ecosociological studies in Ecuadorian bryophyte communities. V. Syntaxonomy, life forms and life strategies of the bryophyte vegetation on decaying wood and tree bases in S Ecuador
Parolly, Gerald; Kürschner, Harald
Decaying wood, tree bases and the trunks of tree ferns provide similar conditions in terms of water supply for a species assemblage classified here into the newly proposed Pyrrhobryo spiniformis-Riccardietalia amazonicae order within the epiphytic Taxilejeuneo-Prionodontetea fuscolutescentis Kürschner & Parolly 1998 class. Three ecologically well-differentiated communities, the Cyclodictyo albicantis-Symphyogynetum bogotensis (on permanently wet logs in ravine forest), the Micropterygietum trachyphylli (on decaying wood in montane rain forest) and the Bazzanietum spruceanae (in rain-sheltered places on tree bases, slanting trunks and hollows) from montane rain forests in southern Ecuador are described as new to science. The order was established after a revision of all neotropical data published related to these communities. The invalid names Lophocoleo martianae-Lejeunion flavae Ahmed & Frahm 2002, Hymenodontetalia aeruginosae Ahmed & Frahm 2002 and Syrrhopodetalia gaudichaudii Ahmed & Frahm 2002, whose communities chiefly dwell on trunks of tree ferns, are sunk in synonymy. An informal classification of the Pyrrhobryo spiniformis-Riccardietalia amazonicae is suggested, supporting a lowland and a highland group.Based upon the three communities from Ecuador, first symmorphological and synstrategical analyses are provided, unarbitrarily demonstrating common adaptive trends. Under the more or less stable climatic conditions of the montane forests with a predictable process of decay, weft and mat forming taxa prevail following a 'passive' and/or 'vegetative' perennial stayer strategy similar to trunk epiphytic communities. These 'functional types' characterise the widely distributed Micropterygietum trachyphylli. By contrast, dendroid and mat forming shuttle species with a strong achorous tendency and diaspore bank formation, as well as a high proportion of 'generative' species predominate in the Cyclodictyo-Symphyogynetum that underlies strong disturbance by floods. In the rain-sheltered Bazzanietum spruceanae, short turf-forming colonists, reflecting fairly dry site conditions, are frequent. Additionally, wefts dominate the shady sites, facilitating photosynthesis maintenance under the decreasing light conditions.