PERFORMANCE OF NATIVE AND EXOTIC BENTHIC MACROINVERTEBRATES UNDER EXTREME CLIMATE SCENARIOS IN THE SEMI-ARID REGION

PERFORMANCE OF NATIVE AND EXOTIC BENTHIC MACROINVERTEBRATES UNDER EXTREME CLIMATE SCENARIOS IN THE SEMI-ARID REGION

• Autor
• Dalescka Barbosa de Melo
• Co-autores
• Franciely Ferreira Paiva , Lívia Maria Osório de Sousa , Joseline Molozzi
• Resumo

• Precipitation has a direct influence on the survival of species, especially in freshwater aquatic ecosystems, which are dependent on rainwater for maintenance. Climate change scenarios tend to favour severe changes in global precipitation rates, which leads to changes in water volume level, the ecological quality of aquatic ecosystems, and consequently implications for species diversity and functionality. In this sense, we aimed to assess how changes in water volume levels caused by extreme drought affect exotic and native benthic macroinvertebrates in semi-arid reservoirs. To this end, benthic macroinvertebrates were sampled at 256 points of the reservoirs of two river basins, the Paraíba River (Cordeiro, Sumé and Poções) and Piranhas-Açu River (Cruzeta, Sabugí and Passagem das Traíras) located in Northeast Brazil’ semi-arid region in 2014, 2015 and 2019. This was the period of the most extreme drought which occurred in last 50 years in the Brazilian semi-arid region. Water volume data of the reservoirs were obtained in platforms online and categorized in three categories: 1) water volume < 10%; 2) water volume between 10 to 20%, and 3) water volume > 20%. To assess differences in the benthic macroinvertebrate’s abundance (exotic and native) between the water volume categories a PERMANOVA was performed. Also, to assess the change abundance and frequency of exotic and native organisms in relation to the water volume gradient a TITAN was performed. As a result, a total of 23408 benthic macroinvertebrates were found, with 8079 native individuals of the Chironomidae family and 15329 exotic individuals of the specie Melanoides tuberculata. However, significant differences were observed in native abundance between water volume categories (F_2.196 = 7.24; p= 0.0001), but not significant for the exotic (F_2.163 = 0.35; p= 0.8885). The TITAN analysis showed that the exotic species M. tuberculata had a higher occurrence in water volume < 20%, while some native taxa, were associated with water volume <10%, and only a few other native taxa, were associated with volume < 20%. In this sense, the high abundance of exotic species, as well as their persistence regardless of the water volume level are associated with severe environmental conditions of the reservoirs studied, because have a history of environmental impact. These conditions favour the high fecundity, density and dispersion rates of this species but some native organisms also can withstand low water volume levels as they are considered generalist species. The presence of some native species only at higher water volume indicates these species are more sensitive. Therefore, the differences in tolerance of benthic macroinvertebrates in reservoirs to volume decline directly affect the ecosystem dynamic, leading to the loss of native species and likely the loss ecosystem functions performed by these organisms. Consequently, this can lead to less resistant and/or resilient communities, especially when future predictions indicate a greater frequency of extreme drought in semi-arid regions in the face of climate change.

• Palavras-chave
• aquatic ecosystems, biodiversity, climate change, benthic fauna, precipitation
• Modalidade
• Comunicação oral
• Área Temática
• Ecologia (Invertebrados)

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