Tolerancia al estrés osmótico en dos anuros Neotropicales: efectos de la salinidad en el crecimiento y desarrollo larvario

Federico Marangoni; Valeria I. Gómez

doi:10.30972/fac.3619271

Authors

Federico Marangoni Grupo de Investigación en Anfibios y Reptiles de la Facultad de Ciencias Exactas y Naturales y Agrimensura (FaCENA, UNNE), CONICET. Corrientes, Corrientes, Argentina. https://orcid.org/0000-0001-6242-9222
Valeria I. Gómez Laboratorio de Ecología y Diversidad de Anfibios y Reptiles del NEA, Centro de Ecología Aplicada del Litoral (LEDAR), UNNE, CONICET. Corrientes, Corrientes, Argentina. https://orcid.org/0000-0002-8875-7010

DOI:

https://doi.org/10.30972/fac.3619271

Keywords:

Amphibians, Rhinella dorbignyi, Leptodactylus macrosternum, Salinity, Stress, Argentina

Abstract

Freshwater ecosystems are increasingly threatened by salinization driven by human activities and climate change, with major consequences for aquatic biodiversity. Amphibians are particularly vulnerable due to permeable skin and aquatic-dependent early life stages, yet Neotropical responses remain poorly understood. We evaluated lethal and sublethal effects of salinity on embryos and larvae of Rhinella dorbignyi and Leptodactylus macrosternum. Laboratory dose–response experiments using NaCl gradients (0–12 g/l) estimated LC₅₀, and larval assays under sublethal salinity (0–8 g/l) assessed survival, growth, and development. Individuals from syntopic populations were reared under controlled conditions. Salinity increased mortality in both species at embryonic and larval stages, with LC₅₀ values ranging from 6–9.7 g/l in R. dorbignyi and 7.1–8.8 g/l in L. macrosternum. A time-dependent decline in tolerance was more evident in R. dorbignyi. In sublethal assays, survival decreased with increasing salinity, particularly in R. dorbignyi, while effects in L. macrosternum were weaker. Larval body mass, growth, and developmental rate were significantly reduced under salinity exposure in R. dorbignyi, whereas L. macrosternum showed limited or non-significant changes in growth and development. Overall, salinity acted as a strong selective pressure affecting early-life performance, with clear interspecific differences in sensitivity. These results indicate that even moderate salinity increases in temporary ponds can reduce recruitment and that exposure duration is a key driver of impact. We emphasize integrating lethal and sublethal endpoints in ecotoxicological assessments and highlight that future studies should incorporate multiple populations per species and broader taxonomic sampling, including tests of intraspecific variation in tolerance, to disentangle plasticity from local adaptation and improve predictions under environmental change

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