Ecomorfologia trófica de Hypostomus ancistroides (Pisces: Hypostominae) ao longo do gradiente urbano-rural de um ribeirão subtropical

Abstract

With the accelerated growth of urbanization, changes in land use are becoming increasingly impactful on river basins, which directly reflect human interventions in their surroundings. Disorganized occupation tends to compromise hydrological dynamics, intensifies pollution, and profoundly affects local ecosystems. This monograph addresses two points in the Ribeirão Cambé Basin, one urban and one rural, relating land use and occupation to the ecology of *Hypostomus ancistroides*, using limnological data, aerial records obtained with drones and satellites, and morphological and dietary data collected in the field, in order to evaluate the influence of urbanization on the landscape and fish ecology. To assess land use, land use and occupation maps, digital surface models, and orthophotos were generated, in addition to percentage graphs of the same, in order to characterize and analyze the landscape. To assess the ecology of *Hypostomus ancistroides*, tables with morphological measurements and stomach contents, their quantities and volumes, were generated, as well as relevance indices calculated and statistical relationship graphs generated. Statistical analyses were performed, applying PCA to the morphological indices in relation to the individuals at each point. Point 2 indicated the greatest ecomorphological influence, with compressed bodies. The food resources found in the intestines of *Hypostomus ancistroides* were identified from their phylogeny and the IRI was calculated, which showed greater importance for phytoplankton, specifically *Fragilaria capucina* for point 1, and also showed nematodes of importance specifically for point 2, as well as filamentous algae for both. PCoA was also applied to food resources, which showed greater heterogeneity in feeding at point 1. Then, PLS-CA was applied to morphological indices and food resources, which indicated a main relationship between the mouth, head, and peduncle with plant debris and the mouth with filamentous algae, indicating greater resources at point 1. At point 2, there was a relationship between the peduncle, head, and mouth with algae, larvae, and plant debris, indicating displacement, as well as a relationship between the compression index and plant debris, indicating greater current. Finally, RDA was applied to land use and occupation data, limnological variables, morphological indices, and food resources. Point 1 showed a primary relationship with phytoplankton, larvae, paved impermeable area, water depth, grassy vegetation cover, temperature at 10 m, and solar radiation, while point 2 showed a primary positive relationship with detritus, nematodes, plant remains, relative mouth height, agricultural planting, tree vegetation cover, relative humidity, and electrical conductivity. Thus, this study demonstrated that the ecomorphology and feeding habits of *Hypostomus ancistroides* in a stream along an urban or rural gradient vary according to the surrounding land use and occupation, riparian vegetation, and water quality.