PHYSIOGRAPHIC ELEMENTS FOR DELIMITING THE PANTANAL ECOSYSTEM: DISCUSSION AND PROPOSAL.

Abstract

Physiographic element associations used by several authors were reviewed, in order to identify the boundaries of the Pantanal and its sub regions. Preliminary research results are also presented. The objective of the study was to discuss characteristics and limits of these sub regions and also to call the public's attention to the need of establishing physiographic delimitations of this ecosystem, in a forum that legislators will recognize and adopt. Seven maps found in the literature were redrawn, to allow comparison on a similar scale. The Pantanal delimitation on a 1:250.000 scale is proposed in this paper. The proposal was based on interactions between physiographic elements (hydrology, geomorphology, pedology, vegetation, and altimetry), supported on Landsat 5-TM images and topographic charts. This characterization will be useful for scientists and legislators interested ill the regions who are aware of the need to be concile the process of development with preservation or conservation of the ecosystem. Preliminary results indicate that, depending on the sub region, a single physiographic clement is enough to define the boundaries. For some areas, however, information on two or more factors is needed. Results also indicative that from counties localizes in the adjacent high lands, only  15 have pan or their area within the Pantanal.