Relationships between environmental heterogeneity and fish beta diversity in a tropical bay

ABSTRACT

Estuarine shallow waters have many habitats favouring the colonization and establishment of different fish species. Our study investigated the variability in the composition of these communities by examining beta diversity and evaluated the relationship between fish beta diversity and environmental heterogeneity, which can be dependent on the level of human alteration to which an ecosystem is exposed. Our goal is to provide insights not only on the biodiversity, but also to help develop effective conservation measures. We sampled fish and environmental variables (physicochemical water variables and sediment nutrients and granulometry) in three zones (inner, middle and outer) of Sepetiba Bay, in Southeastern Brazil. The aims of our study were to compare fish communities in the different zones by using beta diversity and to investigate the relationship between environmental heterogeneity and beta diversity. Habitat conditions varied considerably among the zones. Relationships between species and environmental conditions were species-specific, and a weak positive correlation between environmental heterogeneity and beta diversity was found. The highest beta diversity was detected in the inner bay zone, suggesting that relatively more urbanized areas had greater environmental heterogeneity and, thus, higher beta diversity. Our results serve as a ‘caution’ to reduce the urbanization effects on these environments that sometimes can increase habitat heterogeneity and species richness. The ‘weak’ relationship suggest that the ecosystems may have been in the ‘early stages’ of human influences and managers should take into account that anthropogenic impacts would reduce beta diversity because continued degradation would lead to natural habitat reduction.

http://zoobank.org/urn:lsid:zoobank.org:pub:EBBEA81F-6D4D-4CB3-8796-7E2A578A8B03

KEYWORDS:

• Biodiversity
• habitat heterogeneity
• coastal fish
• estuarine areas

Acknowledgements

The authors thank technicians from the Laboratory of Fish Ecology for helping in fieldwork. We also thank Dr Roy Kropp and two anonymous reviewers for valuable comments that help to strength the quality of the manuscript. This study was supported by the Project Pesquisa Marinha e Pesqueira, a compensatory measure established by Conduct Adjustment Term responsibility of the PetroRio Company, conducted by the Federal Public Ministry – MPF/RJ, with the implementation of the Fundo Brasileiro para a Biodiversidade (FUNBIO, Proc. 016/2017). This research was conducted under SISBIO Collection of Species Permit number10707 issued by ICMBio, Brazilian Environmental Agency.

Ethical approval

All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted (Universidade Federal Rural do Rio de Janeiro, Brazil, Animal Care and Use Committee, Protocol # 11874).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was part of the Project Pesquisa Marinha e Pesqueira, a compensatory measure established by Conduct Adjustment Term responsibility of the PetroRio Company, conducted by the Federal Public Ministry – MPF/RJ, with the support of the Fundo Brasileiro para a Biodiversidade (FUNBIO, Proc. 016/2017).