Tropical headwater streams and the role of non-native species on fish assemblage’s diversity

• Published in: Biological invasions 2023-10, Vol.25 (10), p.3103-3118
• Main Authors: Santos, Bruno R. B., Teresa, Fabrício B., Borges, Pedro P., Casatti, Lilian, Tejerina-Garro, Francisco L., Pompeu, Paulo S., Benedito, Evanilde, Carvalho, Fernando R., Cetra, Mauricio, Dias, Murilo S., Súarez, Yzel R., Santos, Thiago, Brejão, Gabriel, Carvalho, Rodrigo A.
• Format: Article
• Language: English
• Subjects: Biodiversity; Biomedical and Life Sciences; Biota; Developmental Biology; Ecology; Fish; Freshwater & Marine Ecology; Headwaters; Indigenous species; Introduced species; Land use; Life Sciences; Native species; Nonnative species; Original Paper; Plant Sciences; Predation; Redundancy; Species diversity; Species richness; Topography
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-023-03093-5

Non-native species cause several impacts on freshwater biodiversity, but studies focusing on the Neotropical stream’s biota are still incipient. We used a data set of 586 headwater stream’s fish assemblages from the Brazilian Upper Paraná ecoregion to test whether the presence/absence of non-native species affect: species richness (S), functional diversity (MPD) and taxonomic diversity (Δ+). We compared diversity patterns of fish assemblages formed only by native species against those of assemblages formed by native and non-native species (Scenario 1); then, we removed non-native species from their original assemblages and recalculated their diversity values to compare them with those of fish assemblages formed only by native species again (Scenario 2). We also investigated: (1) whether non-native’s fish assemblages are associated with land use, topographic and watercourse connectivity variables; (2) fish ecological traits-environment relationship. In Scenario 1, S was higher in assemblages with the presence of non-native species, while in Scenario 2, both S and MPD were higher in assemblages where non-native species were removed. Non-native species were not directly related to land use, topographic or connectivity variables and most of them had a similar response to the environment when compared with native species. Findings show that non-native fish species are related to high-rich assemblages in headwaters, and they increase species richness and the functional redundancy of assemblages, decreasing functional diversity. Moreover, in most cases, native and non-native species seem to respond similarly to the environmental influence on their occurrence.