Abstract

KUTSCHKER, Adriana; BRAND, Cecilia  and  MISERENDINO, María Laura. Quality assessment of riparian corridors in streams of northwest Chubut affected by different land use. Ecol. austral [online]. 2009, vol.19, n.1, pp.19-34. ISSN 1667-782X.

The proper evaluation of the ecological status of rivers requires the study of the riparian conditions as a crucial tool for the integral assessment of watercourses. The goal of this paper was to assess the quality of the riparian ecosystems of northwestern Chubut rivers subjected to different land uses. We adapted the Riparian Quality Index (QBR) to the Andean Patagonian rivers (QBRp). This index integrates structural aspects of vegetation (cover, floristic composition, vertical structure), morphology of the riparian corridor and level of land modification (streams, terraces, dikes). It was applied to 24 mountain stream sites subjected to different human activities. The selected land uses were: grazing, logging practices in native forest, plantations of exotic species and urbanizations. Reference sites were included in native woody areas with no exploitation and upstream of urban areas. We documented the following characteristics of the vegetation: cover, vertical structure and complexity; we assessed bank morphology and the degree of human alteration of the fluvial channel. QBRp values differed among land use types and among sites. The most impacted sites were rivers downstream of urban areas and flowing through pasture sites while the best ecological status was recorded on reference native forest sites. No riparian corridors in a very bad condition were found. Rivers with forested banks, even those with plantations of exotics, showed the best quality conditions in the riparian corridor.

Keywords : Riparian ecosystem; Ecological quality; Patagonian streams; QBR.

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