Browsing by Author "Zoubir, Zaineb"
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- Biodiversity and ecological quality of Angueira River (NE Portugal): effects of natural and anthropogenic impactsPublication . Zoubir, Zaineb; Teixeira, Amílcar; Yessef, MohamedFreshwater ecosystems are, at a global level, strongly threatened by several pressures, mostly of anthropic origin, with emphasis on water pollution and eutrophication, fragmentation and degradation of aquatic and riparian habitats, overexploitation of resources, introduction of exotic and invasive species and extreme hydrological changes resulting from climate change. The objective of the present study was to evaluate the biodiversity and ecological integrity of watercourses in the Angueira River basin, located in the northeast of Portugal, focusing on natural variability and anthropogenic impacts. In this way, several metrics were determined, during the spring of 2023 and 2024, in 14 sampling locations, using standardized methodologies within the scope of the European Water Framework Directive. Water quality, hydromorphology, biological communities, namely benthic macroinvertebrates and fish, were the main abiotic and biotic elements evaluated. The results revealed a decline in biodiversity and ecological quality in different areas along the river, mainly under the influence of physical barriers (weirs) and rural settlements. It was also observed that prolonged drought phenomena, particularly in smaller tributaries and in the final stretch of the Angueira River, contributed to the lower biodiversity and ecological quality of aquatic and riparian ecosystems. In contrast, in reference sites, mostly located in the upper reaches of the basin, diverse and native communities of macroinvertebrates and fish were found, although the presence of invasive alien species (e.g. red crayfish and signal crayfish, mosquitofish), widespread throughout the river network. In fact, the synergistic effects resulting from the dispersion of exotic species, water pollution, degradation of the riparian ecotone, the high presence of physical barriers and the prolonged droughts in recent years, had negative impacts affecting the ecological equilibrium of the Angueira River. In this context, the study highlights the need for conservation and management efforts to protect and restore the Angueira River basin. Priority recommendations include pollution control measures, invasive alien species control and aquatic and riparian habitat restoration to ensure long-term sustainability for both human well-being and for the aquatic and riparian environments.