Grandes hidrelétricas em sistemas de água doce: a perda subestimada de espécies e os impactos na pesca artesanal
Year: 2022
Type: dissertation
Abstract: The presence of large power plants in tropical rivers favors the loss of provisioning ecosystem services, such as fishing. Therefore, the consequent transformations of the rivers for the generation of energy directly affect the economy and the local subsistence. When we think about subsistence fishing in tropical environments affected by the installation of large plants, it is possible to identify a subsequent chain of impacts. The reproduction of fish species, which may be limited by habitat demands or environmental triggers, imposes limitations on the occupation of the river, such as reservoirs. The species that remain in these places, due to their reproductive plasticity, reconfigure the ichthyological fauna. This reorganization of species implies the distribution of the sizes of fish that are caught and, consequently, the vulnerability and profitability of fishing. When access to fisheries resources is hampered, food sovereignty is at risk. Here we use pre- and post-operation fishery catch data between the upstream and downstream regions of the Xingu River to assess the impacts on fish cooccurrence networks in artisanal fisheries in the Amazon. We hypothesized that the replacement of species that co-occur in fisheries between different regions of influence of the plant would be observed over time. The data used in this study come from the monitoring of subsistence fisheries carried out between the municipalities of Altamira and Porto de Moz, Pará, Brazil. The analyzes of the co-occurrence models were based on graph theory applied to network analysis, considering the power plant influence regions and periods. The resulting models from the 2016-2020 period were used to design new networks with removal of the core species groups. As a result, we saw that the species groups vary between the areas of influence, with the largest number being downstream of the power plant. Among the periods, the one that presented more groups of species was the one before the operation of the HPP. The projections showed significant alterations in the conformation of the co-occurrence networks, mainly for the low flow stretch. In summary, our study shows that the plant reflects on the loss of species in subsistence fisheries. Understanding how this impact translates into the region's communities and ecosystem ecology will be critical to planning and implementing mitigation and control strategies.
Author: Oliveira, Nathália Napole de
Language: Portuguese
Subfield: Nature and Landscape Conservation
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7120738800