Trophic ecology of the Neotropical tolerant fish Corydoras paleatus under the influence of contrasting environmental conditions in a prairie stream

Abstract

Worldwide, land use changes and urbanization affect habitat and biota in streams, drastically disrupting environmental conditions and biotic interactions. We evaluated the trophic ecology of the tolerant fi sh Corydoras paleatus in a prairie stream with contrasting environmental conditions intimately aligned with different nearby land uses. Gut analyses was conducted at three stream reaches with contrasting ecological attributes regarding water quality, habitat structure and riparian condition. A total of 231 guts were analyzed and 15 prey items identifi ed. A signifi cant variation in composition and structure of the dietary assemblage, niche breadth and feeding patterns of C. paleatus under different environmental conditions was observed. Psychodidae prevailed in most deteriorated environmental conditions and Chironomidae, followed by nematodes, in stream reaches where environmental conditions improved. Maximum niche breadth and a larger proportion of generalist individuals were found at the most deteriorated site. Conversely, the proportions of specialized individuals were slightly higher at sites with better ecological conditions. Psychodidae and mineral fragments were positively correlated with the most detrimental conditions, while fi lamentous algae prevailed where these conditions improved. Overall, good evidence suggesting that trophic ecology of a tolerant species is affected by local environmental conditions in water quality, habitat structure and riparian corridor was observed.

Ensambles parasitarios de Corydoras paleatus en un arroyo pampeano con condiciones contrastantes de calidad de agua y hábitat

“…El arroyo Langueyú presenta un importante desarrollo urbano-industrial en sus cabeceras y un predominio de las actividades agrícolas y ganaderas en su recorrido por la llanura. Este escenario antrópico ha mostrado tener influencia sobre la ecología trófica de Corydoras paleatus (Jenyns, 1842) (Bertora et al, 2021b), una de las especies de mayor distribución en este sistema (Bertora et al, 2018). Se desconoce en qué otros aspectos de la autoecología de esta especie puedan influir la actividad del hombre en la cuenca.…”