Vegetation und Ökologie tropischer Hochgebirgsmoore in den Anden Nord-Chiles
The vegetation and ecology of the high Andean mires from northern Chile between 18 and 22° southern latitude are described. They are dominated by the cushion-plant species Distichia muscoides, D. filamentosa, Oxychloe andina (Juncaceae) and Scirpus s. l. (Cyperaceae). Especially Distichia muscoides but also most of its herbaceous accompanying flora have tropical Andean distribution areas, which reach their southwestern limits in northern Chile. From a comparison with the Andean mire vegetation from Peru, Bolivia and northwestern Argentina follows clearly that the dominating plant communities of the high Andean mires of northern Chile can be included in the fitosociological class of the Plantagini rigidae-Distichietea muscoidis Rivas Martinez et Tovar 1982. It is suggested to adjoin the Oxychloetum andinae to an own alliance, the Oxychloion andinae all. nov., because its geographical range reaches much farther south in the Chilean and Argentine Andes, where the accompanying tropical Andean flora is completely missing. The occurrence of Distichia muscoides in contrast to that of Oxychloe andina is linked to mire sites infiltrated by seepage waters from springs and rivulets poor in mineral constituents, which neither tend to accumulate salts on top during dry periods. Oxychloe andina has thereto a much wider ecological range. The influence of pasturing wild and domestic animals upon the vegetation of the Andean mires is very great and favours the extension of the cushion-plant species on account of the more damaged grasses and rushes. Observations on the vegetative and generative propagation ecology as well as a general geographical comparison of the high Andean flora of the mire sites confirms the impression, that there cannot exist any effective distribution barriers for these species and that their actual occurrence reveals their ecological demands and limitations.