Abstract
Abstract Fish ecomorphology and diet can help us to understand species response to impacts and coexistence patterns. Thus, we developed a comparative analysis of ecomorphology and diet of Inpaichthys kerri and Hyphessobrycon vilmae and tested for environmental variables that explain their abundance in headwater streams. We sampled streams from the Aripuanã River basin, Mato Grosso State, Brazil. We sampled environmental variables following a standardized protocol and used 30 and 80 individuals from each species to obtain ecomorphological attributes and feeding index, respectively. To identify environmental variables that influence species abundance, we developed generalized additive mixed models. Inpaichthys kerri presented broader and deeper caudal peduncles, more dorsal eyes, and larger fins, besides the lower consumption of aquatic insects, algae, and detritus when compared to H. vilmae. Inpaichthys kerri was more abundant in fast waters with little amounts of marginal grasses, conditions associated with more forested streams, while H. vilmae was more in streams with more abundant marginal grasses from pasture. Deforestation in the Aripuanã basin threatens the persistence of I. kerri, since its optimal environmental conditions tend to be replaced by H. vilmae optimal conditions. Natural history helps us to understand species occurrence and represents a substantial contribution for more effective conservation measures.
Highlights
Headwater streams are small and open ecosystems highly interconnected to the terrestrial environment (Allan, 2004)
We developed a comparative analysis of ecomorphology and diet of I. kerri and H. vilmae and tested for environmental variables that can explain the abundance of these species in the set of streams where they occur
Despite the similar consumption of aquatic insects and 55% of niche overlap, species showed different trophic patterns, with I. kerri feeding upon a lower proportion of aquatic insects, filamentous algae, and detritus and a higher proportion of terrestrial insects when compared to H. vilmae
Summary
Headwater streams are small and open ecosystems highly interconnected to the terrestrial environment (Allan, 2004). Agriculture expansion over Tropical Rainforest biomes (e.g., Amazon) has changed the energetic balance in streams by altering resource availability, since it shifts predominant resources from allochthonous (e.g., terrestrial insects and plants) to autochthonous (e.g., aquatic insects and algae) (Zeni, Casatti, 2014). These changes caused by human activities have the potential to influence several aspects related to the occurrence and persistence of fish assemblages, such as habitat use and trophic ecology (Chua et al, 2020). Chua et al (2020) found that morphological traits can mediate fish occurrence in streams under deforestation, since fish with superior mouths and small body mass were associated with marginal grasses and ni.bio.br | scielo.br/ni
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
