SciELO - Scientific Electronic Library Online

 
vol.35 issue2Morphological and anatomical characterization of the genus Stereocaulon Hoffmann (Lichenized Ascomycetes) in Colombia author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Journal

Article

Indicators

Related links

  • On index processCited by Google
  • Have no similar articlesSimilars in SciELO
  • On index processSimilars in Google

Share


Caldasia

Print version ISSN 0366-5232

Abstract

MONTES, RUBÉN ANTONIO; SAN-JOSE, JOSÉ  and  AYMARD, GERARDO ANTONIO. Characteristics of the Flora and vegetation of the Mesa high plain and the eolic plain at the Aguaro-Guariquito National Park, Guárico State, Venezuela. Caldasia [online]. 2013, vol.35, n.2, pp.219-240. ISSN 0366-5232.

We studied the relationships between vegetation and topography in two topo-sequences corresponding to the National Park Aguaro-Guariquito, Guárico State, Venezuela. The first is a high plain or Mesa landscape covered by a well-drained Savanna (site 1). In the dissected areas of this plateau geofractures occur with permanently saturated soils where the palm Mauritia flexuosa (morichals) grows (site 2). The other topo-sequence corresponds to an eolic plain with soils consisting of materials originating from the Mesa plateau and covered by wet savanna (site 3), which remains waterlogged for three months (June-August) with a water level of 0.25 ± 0.10 m. The most deprived areas in this topo-sequence feature temporary conditions of extreme flooding in which a community dominated by Acosmium nitens (congrial) occurs (site 4), and a vegetation characterized by the presence of Caraipa llanorum (saladillal) (Site 5). The congrial remains flooded for seven months(June-December), with a high water level of 1.02 ± 0.10 m. In contrast, the saladillal remains flooded for six months (June-November) and the water level reaches a height of 0.80 ± 0.10 m. Flooded communities (sites 2-5) are on more acidic soils (4.0 - 4.6 units) than those characteristic of the well-drained savanna (site 1; 5.0 units). The pH was associated with the aluminum concentration. The organic matter content was higher in flooded (8.59%) than in seasonally flooded and well-drained sites (0.7- 1.0 %). The flooded habitat restricts biodiversity. The congrial, saladillal, wet savanna and morichal featured 52, 52, 56 and 74 species, respectively. In contrast, well-drained Savanna has 114 species. The similarity between the saladillal and congrial was 56%. For other communities, similarity was less than 38%. The results indicate that life-forms of Teroculmi and Teroherbae (i.e., annual species of grasses, sedges and herbs) account for 43% of the average of the spectrum of biological forms.

Keywords : Central Venezuelan savannas; Caraipa llanorum; Acosmium nitens; topo-sequences.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )