Variation in patterns of fish assemblage and their environmental correlates in a tropical river basin from the Gulf of Mexico slope

Abstract

Understanding patterns of freshwater fish assemblage structure is key to protect them from ongoing human-induced threats to aquatic biodiversity. Yet, studies on associations between fish assemblages and habitat are lacking from many areas of high diversity in Middle America. We assessed fish assemblage structure and environmental associations from a portion of the Lacantún River sub-basin (Usumacinta River, Chiapas, Mexico). Based on environmental data and 17,462 individuals (56 species, 46 genera, and 22 families) captured from 13 sites sampled between 2017–2019, we found that stream order, distance to the Usumacinta, forest cover, temperature, and dissolved oxygen are key to explaining assemblage composition. Four clusters were found via multivariate regression tree analysis, with stream order and dissolved oxygen as defining variables. Our findings suggest that fish communities remain spatially structured even at small scales, in association to environmental gradients among habitats.

Caracterización y uso de los atributos funcionales de los peces para el estudio de sus comunidades en la cuenca del río Lacantún, Chiapas

“…Pese a ello, el contraste en la diversidad funcional ofrece interesantes perspectivas sobre cómo se estructuran las comunidades y se identificaron diferencias funcionales importantes con los otros sitios estudiados. De manera similar, es importante apuntar que aunque la temporada del año puede no ser un factor en la estructura de estas comunidades (Larre-Campuzano et al, 2023), la diversidad funcional podría variar en muestreos obtenidos en diferentes periodos, por lo que estudios posteriores deben considerar la temporalidad en sus muestreos para contextualizar las inferencias que se pueden lograr a partir de los análisis funcionales (Rodiles-Hernández et al, 1999).…”