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Ordination and classification of vegetation along an altitudinal gradient in the Venezuelan páramos

Abstract

By means of ordination and classification techniques, the relationships between climate, soils, human activities and vegetation along an altitudinal gradient of the Venezuelan páramos are analyzed and interpreted. The altitudinal gradient chosen is characterized by decrease of temperature, precipitation, soil fertility, soil water-holding capacity, and plant cover as altitude increases. The ordination results suggest vegetation changes to be primarily related to environmental changes occurring with altitude, and secondly to disturbances caused mainly by grazing. Some results point toward a disjunction in the vegetational gradient occurring at ca. 3 500 m.a.s.l. and separating low and high páramo. This disjunction might have been caused by the glacial history of the páramos and the occurrence of frequent night-frosts.

The soil samples were kindly analyzed by the Laboratorio de Edafologia, Centro Nacional de Investigaciones Agropecuarias. Help in plant identification was generously obtained from the specialists of Instituto Botánico, Instituto Nacional de Parques, Caracas.

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Nomenclature follows Vareschi (1970).

Acknowledgements: This work was supported by the Decanato de Investigaciones, Universidad Simón Bolivar. I wish to thank A. Pacheco for help in the field sampling. Dr O. Arenas help was invaluable in the mathematical treatment of the data. Drs A. Vivas and J. M. B. Smith provided useful criticism to an earlier version of this work.

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Baruch, Z. Ordination and classification of vegetation along an altitudinal gradient in the Venezuelan páramos. Vegetatio 55, 115–126 (1984). https://doi.org/10.1007/BF00037333

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  • DOI: https://doi.org/10.1007/BF00037333

Keywords

  • Altitudinal gradient
  • Classification
  • Ordination
  • Páramo
  • Venezuela