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- A review of the ecological role of aquatic macrophytes on freshwater fishPublication . Thomaz, Sidinei Magela; Cardozo, Ana Lúcia Paz; Quirino, Bárbara Angélio; Yofukuji, Katia; Aleixo, Matheus Henrique Ferreira; Fugi, RosemaraMacrophytes play a central role in the structure and functioning of aquatic ecosystems. In this paper, we review the role of macrophytes in shaping fish attributes. By acting as physical barri-ers, macrophytes modify the abiotic environment, creating conditions preferred by fish, such as higher oxygen concentrations and lower CO 2 concentrations, particularly in the case of submerged macrophytes. The habitat complexity provided by macrophytes of different life forms favors fish, providing protection from predation and serving as sites for reproduction, acting as spawning substrates and nursery habitats for larvae and juveniles. Moreover, macrophytes contribute to fish foraging dynamics by providing food resources (e.g., periphyton and attached invertebrates) within structurally complex habitats. Consequently, macrophytes foster increased fish diversity compared to open water. Beyond these indirect influences, macrophytes serve as direct feeding resources for some species of fish, both herbivorous and detritivorous. Additionally, macrophytes function as fish dispersal vectors, assisting migration and enhancing gene flow in diverse ecosystems. Despite positively affecting fish, at extremely high biomasses, macrophytes can impair fish by degrading water quality and hindering fish movement and feeding. Understanding these intricate relationships provides insights for future research and management strategies, supporting the conservation and sustainable management of aquatic ecosystems.
- Habitat complexity versus habitat heterogeneity: invertebrates prefer macrophyte stands with intermediate biomass and high functional diversityPublication . Aleixo, Matheus Henrique Ferreira; Possamai, Luana Caroliny; Castro, Karis Soares Pereira de; Yofukuji, Katia; Cardozo, Ana Lúcia Paz; Fugi, RosemaraAquatic macrophytes serve as shelter and a direct source of food for invertebrates, in addition to indirectly providing items such as algae, detritus, and microorganisms. Thus, aquatic macrophytes act as habitat structuring elements, requiring a distinction between habitat complexity (physical formations such as fractal dimensions, density and biomass) and habitat heterogeneity (diversity of these structures). Here we explore the effects of habitat complexity and habitat heterogeneity on the invertebrate community. We collected macrophytes and invertebrates from 28 sampling sites along a 13.7-km stretch of the Ba & iacute;a River in Brazil, and examined specific groups (insects, microcrustaceans, and other invertebrates). Environmental variables in the sites were also measured. We aimed to explore the effects of habitat complexity (measured by macrophyte biomass) and habitat heterogeneity (evaluated through macrophyte functional diversity) on the richness and abundance of invertebrates. We found that overall invertebrate richness was positively influenced solely by habitat heterogeneity. For invertebrate abundance, intermediate habitat complexity had more invertebrates, while habitat heterogeneity had a positive impact. Environmental variables influenced only the abundance. For specific groups, insect richness was positively influenced by habitat heterogeneity, while insect abundance decreased with high complexity and increased with high heterogeneity. Microcrustacean abundance was positively influenced by habitat complexity. Richness and abundance of other invertebrates was positively influenced by habitat heterogeneity. Invertebrates prefer macrophyte stands with intermediate complexity and high heterogeneity. Abundance is linked to structural complexity and heterogeneity, while species richness is more strongly associated with heterogeneity. Furthermore, the impact of these factors varies among invertebrate groups. These findings emphasise the importance of integrating a broad range of metrics, such as macrophyte biomass and functional diversity, to gain a thorough understanding of invertebrate community dynamics in future studies. Additionally, our study demonstrates that preserving macrophyte stands with high heterogeneity significantly enhances the diversity of associated invertebrate species.
- The effects of climate change on the potential distribution of a frugivorous fish in the Amazon basinPublication . Oliveira, Ana Carolina Farias de; Spirlandelli, Felipe Pacheco ; Seripieri, Vitor Henrique Mistro; Lino, André Luiz Ramos ; Azevedo, João C.; Yofukuji, Katia; Souza, Beatriz Cristina de Paula; Pontara, Vanessa; Bueno, Marcelo Leandro; Esser, Luiz Fernando; Graça, Weferson Júnio da; Ferreira, José Hilário Delconte; Ré, Reginaldo; Bailly, Dayani; Batista-Silva, Valéria FláviaWe assessed the effects of climate change on the geographic distribution of Piaractus brachypomus Cuvier (1818), a species of economic interest in the Amazon basin, using ecological niche models. We employed a set of five algorithms under the ensemble forecasting approach to predict the geographic distribution of the species in the present and in the future considering different carbon emission scenarios. The projections indicate that a large portion of the Amazon basin presents suitable areas for P. brachypomus, with moderate reduction of these areas in the near future. By 2090, under the pessimistic scenario, losses intensify, and the most drastic contractions are projected for the Branco, Japurá, Mamoré, Negro, and Purus sub-basins, while by the end of the century, suitable areas are predicted to occur mainly in rivers of the southwestern and central Amazon regions. The gain of suitable areas was smaller compared to the proportion of stable areas and losses. These results provide valuable information for the development of effective conservation plans with the intent of ensuring the ecological and economic benefits that P. brachypomus provides in the Amazon basin.