Pflanzengesellschaften und Lebensformen des Superpáramo des Parque Nacional Sierra Nevada de Mérida in Venezuela
Berg, Alexander L.
The vegetation of the superparamo of the "Sierra Nevada de Mérida" National Park, Venezuela, was analysed using phytosociological methods. Thirteen plant communities are described, each with its characteristic floristic and life form composition, structure, ecology and distribution. A new graphic presentation of the abundance and the percentage of life forms in each community is applied. The zonal communities, belonging to the Draba empetroides-Luzula racemosa-community-group are dominated by tussock-grasses or giant rosette plants and seem to be confined to Venezuela. The most common ones are the Espeletia schultzii-Aciachne acicularis-community (up to 4150 m) and the Coespeletia moritziana-Festuca tolucensis-community (4150-4500 m). The Festuca fragilis-Oritrophium paramense-community and the Coespeletia timotensis-community occur between 4500 and 4600 m. The azonal communities, referred to the Gentiana sedifolia-Carex amicta-community-group and the Aciachnetum pulvinatae, are dominated by cushion grasses, rosette plants or cushion plants and have a wide distribution along the Andes. The Aciachnetum pulvinatae is characteristic of former lakelets. The Carex bonplandii-Lachemilla sprucei-community (Marchantio-Epilobietalia) and the Wernerion-community (Wernerietalia) are characteristic vegetation types of mires, cushion bogs and meadows. Above 4600 up to the snow-level at 4850 m discrete communities are lacking; isolated individuals of Festuca fragilis, Poa pauciflora, Draba empetroides and Draba racemosa, among others, occur in protected places. The study revealed, that the diversity of the vegetation is related to an altitudinal gradient and the soil-humidity.