ABSTRACT. Aquatic vascular macrophytes from the drainage system of the Alto Valle de Río Negro, Patagonia (Argentina). The aim of this work was to characterize the floristic composition of the drainage system in the Upper Valley of Rio...
moreABSTRACT. Aquatic vascular macrophytes from the drainage system of the Alto Valle de Río Negro, Patagonia (Argentina). The aim of this work was to characterize the floristic composition of the drainage system in the Upper Valley of Rio Negro and to record taxonomic and biological aspects. The floristic listing was obtained from 150 vegetation censuses (Braun-Blanquet, 1979) which recorded species with coverage values. The aquatic vascular macrophytes surveyed were classified according to Sculthorpe (1967) and Schmidt-Mumm (1998). Drainage channels were classified as 'rural' and 'urban' according to their location and the origin of their effluents. Floristic and ecological differences between environments were evaluated by means of the alfa-diversity -calculated through richness (S)-, Shannon index (H), Pielou's evenness index (J), value of importance per species and beta-diversity through the Sørensen similarity index. The floristic catalog includes 45 species distributed in 32 genera corresponding to 23 families, the most representative of which are Poaceae, Cyperaceae and Typhaceae. The distribution area of eight species for Río Negro province is extended. Plants with perennial cycles, herbaceous habit, emerging type and helophytic biotype (82%) are predominant. In urban environments Stuckenia pectinata reaches the highest value of importance, while Nasturtium officinale and Azolla filiculoides are dominant in rural environments. This work lays the groundwork of basic information for further studies on the potential of aquatic vascular macrophytes as bioindicators and phytoremediators in this drainage system.
