Abstract
The presence of different mesohabitats in freshwater systems can support higher local and regional fish richness. Thus, their suppression by dam-building represents a real threat to aquatic biodiversity. Our aims were: (1) to survey the fish fauna in two different mesohabitats in lower Preto River: a riffle indirectly threatened by dam-building and a run with different physical structure; and (2) to analyze and compare the fish community structure in these different mesohabitats. Six samplings were made during one year in two reaches (R1 and R2). We conducted a ‘one way’ ANOSIM to assess the differences in fish community structure between R1 and R2. Fifty-three species were recorded, with the occurrence of Aphyocheirodon hemigrammus and Myleus tiete, two Brazilian threatened species. The highest richness was observed in R2. Nevertheless, diversity and evenness were significantly higher in R1. Rheophilic species were more common and restricted to R1 and species typical of lentic environments were predominant in R2. Fish community structure was different between R1 and R2 (R = 1, p = 0.02). Our results demonstrated that mesohabitats mosaic through rivers can contribute to the maintenance of a diverse fish assemblage.
Highlights
Brazil is the richest country in the world concerning freshwater fish, with approximately 3,000 species recorded to date (ICMBio, 2014)
The reach 1 (R1), ‘Cachoeira de São Roberto’, near the confluence with the Turvo River (20°11’09.3’’S 49°41’06.4’’W), is characterized by high water velocity with some slope, substrate primarily composed of slab and basaltic boulders, and sparse riparian forest composed by few trees
The reach 2 (R2) is located 1.8 km upstream from R1, near the mouth of the Botelho stream (20°11’38.3’’S 49o41’30.1’’W), and it is characterized by low water velocity, sandy substrate with pebbles, and marginal vegetation consisting of grasses (Poaceae) (Figure 2)
Summary
Brazil is the richest country in the world concerning freshwater fish, with approximately 3,000 species recorded to date (ICMBio, 2014). Despite this great richness and diversity, several Brazilian lotic systems are under strong anthropogenic pressure, especially related to dam-building, which modifies running (lotic) into standing (lentic) water ecosystems. Biological Sciences river homogenization, since it replaces the natural physical heterogeneity of the river by a large reservoir (AGOSTINHO et al, 2005). Physical habitat can act as environmental filters by maximizing energy
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
