Efeito das mudanças no clima e fragmentação de habitats sobre a distribuição de peixes migradores de interesse comercial da bacia Paraná-Paraguai.

Abstract

Biodiversity has suffered from unprecedented anthropogenic impacts that are often overlooked in aquatic ecosystems. In this scenario, climate change and fragmentation by dams have been identified as major impacting agents on the structure and functioning of aquatic communities. In this context, to support biodiversity conservation, the study aims to analyze the impact of climate change and fragmentation by reservoirs on the distribution of migratory fish of commercial value in the Paraná-Paraguay basin in the present and future. The potential distribution of species, predicted by the ecological niche modeling approach, revealed areas of greater suitability at present, mainly in the north-south axis of the Paraná-Paraguay basin. Forecasts for the future show a loss of suitability that will increase towards the end of the century in the pessimistic scenario, restricting suitability to the east of the lower portion of the Upper Paraná and east of the Middle Paraná. The habitat connectivity index of the Upper Paraná was higher in the regions of the Paraná River and its tributaries on the left and right banks, with emphasis on the Pardo River, the Ivinhema River and the Iguatemi River in Mato Grosso do Sul; the Ivaí River and the Piquiri River in Paraná. There are currently 233 dams in the Upper Paraná, with another 290 planned. The most impactful at present are Porto Primavera (Paraná River) and São Simão (Paranaíba River), followed by Água Vermelha (Grande River), Rosana (Paranapanema River) and Três Irmãos (Tietê River). Among the dams planned for the future are Paiçandu (Ivaí River), Apertados and Ercilândia (Piquiri River), PCH Barreiro (Pardo River), Inocência (Sucuriú River) and Salto do Itapura (Tietê River). These dams, if built, will block access to areas of greater suitability in the future. The preservation of aquatic biodiversity increasingly depends on public policies supported by scientific knowledge and conservation initiatives based on ecological criteria.