A Contribution to Pollen Rain Characterization in Forest-Savanna Mosaics of the Venezuelan Guayana and Its Use in Vegetation Reconstructions from Sedimentary RecordsReportar como inadecuado




A Contribution to Pollen Rain Characterization in Forest-Savanna Mosaics of the Venezuelan Guayana and Its Use in Vegetation Reconstructions from Sedimentary Records - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

The main results of a study of pollenrepresentation in surface soils from different plant communities in the uplandsavannas of Guayana were presented. The representation of savanna herb pollen mainly belonging to thePoaceae and Cyperaceae was high in open communities such asfernlands, grasslands and Mauritia palm swamps, but decreased as vegetationstructure became more closed and woody; from savanna-forest borders tosecondary forests and lastly, evergreenmontane forests; mimicking the gradient of vegetation openness observed inliving plant communities. Thus, the proportion of savanna herb pollen inherbaceous communities: swamps, fernlands and grasslands, reached over 80% andarboreal pollen contributed less than 10%. This ratio changed in savanna-forestborders where savanna herb pollen decreased to 60% or less and the proportionof arboreal pollen rose to 30% or higher. Lastly, in forest soils, pollen abundancesfrom trees Dimorphandra, Protium, Schefflera, shrubs Miconia and other Melastomataceae and lianas contributed higher than 60% of the pollensum, even in open gallery forests and fallows. The lack of pollen from cassava, the main crop in the forests of the region, atthese sites was remarkable. The ordination of sediment samples from 4 recordsfrom the Late Holocene with respect to the soil surface samples studied, showedthat the characterization of pollen rain was useful for identifying long-termcompositional and structural changes in the sedimentary records, thus providingobjective indicators for the interpretation of past vegetation structure.

KEYWORDS

Pollen Representation; Savanna-Forest Dynamics; Upland Guayana; Gran Sabana; Poaceae Pollen

Cite this paper

L. Alejandra, B. Bibiana and B. Carlos -A Contribution to Pollen Rain Characterization in Forest-Savanna Mosaics of the Venezuelan Guayana and Its Use in Vegetation Reconstructions from Sedimentary Records,- American Journal of Plant Sciences, Vol. 4 No. 7A, 2013, pp. 33-52. doi: 10.4236-ajps.2013.47A1006.





Autor: Leal Alejandra, Bilbao Bibiana, Berrío Juan Carlos

Fuente: http://www.scirp.org/



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