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Free keywords:
physical habitat; wetland; floodplain; large river; Pantanal; conservation
Abstract:
The Paraguay-Paraná river system forms an important ecological corridor across
South America. Here, we report the first description of the fluvial geomorphology
and the physical structure of aquatic habitats along the main channel a 200-km long
section of the Upper Paraguay River between Cáceres city and Taiama island (Mato
Grosso, Brazil). Four functional sets were identified: (a) main channel and
anabranches, (b) floodplain channel, (c) floodplain lake, and (d) aquatic-terrestrialtransition
zone. The diversity of functional units was higher in the meandering and
transitional sectors (Brillouin index 1.957 and 2.003) than in the straight and fluviolacustrine
sectors (Brillouin index 1.562 and 1.577, respectively). In the transversal
dimension, the relatively homogeneous habitats of the main channel contrasted
with the heterogeneous floodplain habitats. We attribute this morphological diversity
to changes in the hydrological connectivity, caused e.g. by drifting large macrophyte
mats or by multi-year periods of higher and lower inundation phases.
