Seasonal fluctuations in taxonomic and functional diversity in assemblages of catfishes in the Venezuelan Arauca River Floodplain

ABSTRACT

The Arauca River harbors a considerable fish biodiversity, yet it remains poorly sampled and the knowledge about its fish communities is incomplete. We studied the taxonomic and functional composition and diversity of catfish assemblages in one lotic and one lentic habitat of a segment of this floodplain during one hydrological cycle, from August 2014 to August 2015, comprising six samplings using gillnets, and identified the relationships between catfish traits and the environment based on five limnological variables. The functional structure was studied through 11 morphological measures and the species diets. We identified 31 catfish species and nine trophic groups. There were significant differences in species composition and diversity between habitats and months, but the functional structure of the catfishes was only determined by the temporal variability. The functional structure of the catfish assemblages was ordered by morphological traits related to locomotion, habitat use, and trophic ecology and these traits were correlated with the limnological variables, supporting the existence of environmental filters. Integrating the taxonomic and functional perspectives can provide a more complete picture of the ecological patterns of freshwater fish assemblages in the Neotropics and can help us predict how these assemblages might change in response to anthropogenic alterations of the environment.

KEYWORDS:

• Fish composition variation
• morphological diversity
• fish trait–environment associations
• catfish trophic groups

Acknowledgments

INSOPESCA granted the scientific fish permits N°404442 and N°455934. The authors wish to thank Carlos Rodríguez for his hospitality in Hato Santa Luisa and the staff of this ranch for their invaluable assistance in the field, particularly Erson Romero.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The funds for this project were granted by The Rufford Small Grant and Neotropical Grassland Conservancy. Idea Wild donated part of the equipment necessary for carrying out the samplings. This work was supported by the Rufford Foundation [14179-1].