SPATIOTEMPORAL EVOLUTION OF THE MARGINS OF LAKE UBERABA, PANTANAL FLOODPLAIN (BRAZIL)

Résumé

Aquatic macrophytes are important components of wetland ecosystems, and studying them contributes to a better understanding of ecological succession in the Pantanal. The function and history of floating macrophytes on the shores of Lake Uberaba, located on the Paraguay River floodplain, were examined. A multitemporal analysis of Landsat satellite images in the years 1984-2015 was conducted. For the analysis, a land cover map was generated with three classes: water, aquatic macrophytes, and surroundings (undefined vegetation). The results revealed ~21.4% decrease in open water area of the lake over a period of 26 years (-4.7 km2/yr.). The expansion of vegetation helps explain the loss of open water and the recent shrinkage of Lake Uberaba. Macrophyte surface area along the lake margins grew by 1.4 km2/yr. Through ecological succession, the growth and decay of aquatic plants (r-strategists) along the lake shore likely provided the soil substrate needed for colonization by terrestrial plant assemblages (k-strategists). This hypothesis that we propose to describe the evolution of dynamic geomorphological processes in Lake Uberaba should be tested in other areas to verify its applicability to similar systems