Presence of riparian vegetation increases biotic condition of fish assemblages in two Brazilian reservoirs

A vegetação ripária aumenta a condição biótica da assembleia de peixes em dois reservatórios brasileiros

Abstract

The riparian vegetation in lakes and reservoirs is source of course wood structures such as trunks and branches and is used as sheltering, spawning and foraging habitats for fishes. The reduction of these submerged structures can thus, affect the composition and structure of fish assemblages in reservoirs.

Aim

To evaluate the influence of riparian vegetation on the biotic condition of fish assemblage by adapting the Reservoir Fish Assemblage Index (RFAI) to two reservoirs in the Upper Paranapanema river basin, São Paulo State, Brazil.

Methods

The RFAI was adapted from metrics related to the functional characteristics and composition of fish assemblages through a protocol of metric selection and validation, and to its response to the presence of riparian vegetation.

Results

The final RFAI was composed by nine metrics, been lower in sites without riparian vegetation as consequence of the predominance of larger individuals and the percent of piscivorous and detritivorous fishes.

Conclusions

These results suggest that increasing shore habitat complexity in reservoirs by maintaining riparian vegetation increases fish biotic integrity.

Keywords:
small hydropower plants; RFAI; habitat complexity; biotic integrity; high Paranapanema River Basin