Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

The Nature of Savanna Heterogeneity in the Orinoco Basin

J. J. San Jose, R. Montes and M. Mazorra
Global Ecology and Biogeography Letters
Vol. 7, No. 6 (Nov., 1998), pp. 441-455
Published by: Wiley
DOI: 10.2307/2997714
Stable URL: http://www.jstor.org/stable/2997714
Page Count: 15
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
The Nature of Savanna Heterogeneity in the Orinoco Basin
Preview not available

Abstract

Detrended Canonical Correspondence Analysis (DCCA) was used to describe the relationship between savanna environments and vegetation community composition in the Orinoco Basin. TWINSPAN derived three major types of savanna vegetation, each with its own floristic and physiognomic features. The first group reflected a plant association with species of Trachypogon occurring in moderately infertile soils with low water availability and high bulk density. This group is distributed mostly on hilltops and dissected plains of the northern Orinoco savannas. The second group has the highest species diversity in habitats occurring in the northern Orinoco with extremely infertile soils. The third group, on the other hand, has a considerable number of species belonging to the Leguminosae and Cyperaceae families and linked to the habitats of the eastern Colombian savannas with the highest soil water availability, a shorter dry season and higher precipitation. The regional analysis of the Orinoco savannas suggests edaphic controls to be important. Changes in the underlying geology have affected topography and soil formation, which results in variation in water and nutrient status. The moisture regime and hydrological features are acting as the major regional determinants, while nutrient levels and distinctive surface soil properties provide the subregional determinants. The local boundary, at any given site, is strongly determined by nutrient shortage and acidity. Also, biogeographic and floristic considerations were taken into account to explain differences in species composition.

Page Thumbnails

  • Thumbnail: Page 
441
    441
  • Thumbnail: Page 
442
    442
  • Thumbnail: Page 
443
    443
  • Thumbnail: Page 
444
    444
  • Thumbnail: Page 
445
    445
  • Thumbnail: Page 
446
    446
  • Thumbnail: Page 
447
    447
  • Thumbnail: Page 
448
    448
  • Thumbnail: Page 
449
    449
  • Thumbnail: Page 
450
    450
  • Thumbnail: Page 
451
    451
  • Thumbnail: Page 
452
    452
  • Thumbnail: Page 
453
    453
  • Thumbnail: Page 
454
    454
  • Thumbnail: Page 
455
    455