From fresh to salty: exploring water salinity tolerance in Rhinella ornata (Anura, Bufonidae) tadpoles on Brazilian Atlantic Forest
DOI:
https://doi.org/10.14295/bjs.v4i5.727Keywords:
amphibian, brackish environments, latency, mortality, salt concentration, salt toleranceAbstract
Changes in salinity levels of aquatic environments may significantly affect the distribution and abundance of many species, including amphibians. Typically, amphibians inhabit environments with low salinity. However, tadpoles of Rhinella ornata can often be found in environments in which stochastic events, such as high tides, can dramatically modify the water salinity of ponds in coastal regions. Here, we test the hypothesis that elevated salinity negatively affects the survival and latency of tadpoles of Rhinella ornata. We exposed 32 tadpoles to different salinity levels (0, 10, 18, 30 parts per thousand or ppt) and measured the time of death and latency time in individuals of two body size classes. Mortality was significantly different between intermediate and high salinity levels (18 and 30 ppt) but did not depend on body size. These results show that tadpoles of Rhinella ornata seem to be intolerant of high salinity, regardless of size. However, there was no mortality at lower salinity levels (0 and 10 ppt) and no difference in latency period between the two lower levels, implying that these tadpoles can survive in low water salinity for a short period, enabling them to swim to less brackish environments. Overall, this trait seems to be important for Rhinella ornata to tolerate shoreline environments, which are vulnerable to stochastic events that dramatically increase pond salinities.
References
AmphibiaWeb. (2025). University of California, Berkeley, CA, USA. Available in: <https://amphibiaweb.org>. Accessed on: Apr 7, 2025.
Alexander, L.G., Lailvaux, S.P., Pechmann, J.H., and P.J. DeVries (2012). Effects of salinity on early life stages of the Gulf Coast toad, Incilius nebulifer (Anura: Bufonidae). Copeia, (1), 106-114. https://www.doi.org/10.1643/CP-09-206
Assis, M.A. (1999). Florística e caracterização das comunidades vegetais da Planície Costeira de Picinguaba, Ubatuba/SP. PhD Dissertation, State University of Campinas, Campinas, São Paulo, Brazil, 248 p.
Baldissera Jr., F. A. B., Caramaschi, U., & Haddad, C. F. (2004). Review of the Bufo crucifer species group, with descriptions of two new related species (Amphibia, Anura, Bufonidae). Arquivos do Museu Nacional, 62(3), 255-282. https://www.doi.org/10.5281/zenodo.13678146
Bentley, P. J. (2002). Endocrines and osmoregulation. A Comparative Account in Vertebrates. Springer-Verlag, Berlin Heidelberg, 308 pp. https://www.doi.org/10.1007/978-3-662-05014-9
Brasileiro, C. A., Sawaya, R. J., Kiefer, M. C., & Martins, M. (2005). Amphibians of an open cerrado fragment in southeastern Brazil. Biota Neotropica, 5(2), 93-109. https://doi.org/10.1590/S1676-06032005000300006
Brown, M. E., & Walls, S. C. (2013). Variation in salinity tolerance among larval anurans: Implications for community composition and the spread of an invasive, non-native species. Copeia 2013, 543-551. https://doi.org/10.1643/CH-12-159
Castro, P., & Huber, M. E. (2010). Marine Biology. 8 ed. New York: McGraw-Hill., 461 pp.
Chinathamby, K., Reina R. D., Bailey P. C. E., & Lees, B. K. (2006). Effects of salinity on the survival, growth and development of tadpoles of the Brown Tree Frog, Litoria ewingii. Australian Journal of Zoology, 54, 97-105. https://doi.org/10.1071/ZO06006
Collins, S.J., & R.W. Russell. 2009. Toxicity of road salt to Nova Scotia amphibians. Environmental Pollution, 157, 320-324. https://doi.org/10.1016/j.envpol.2008.06.032
Christy, M. T., and C.R. Dickman (2002). Effects of salinity on tadpoles of the green and golden bell frog (Litoria aurea). Amphibia-Reptilia, 23, 1-11. https://doi.org/10.1163/156853802320877582
Elliott, M. and McLusky, D.S. (2002). The need for definitions in understanding estuaries. Estuarine, Coastal and Shelf Science, 55(6), 815-827. https://doi.org/10.1006/ecss.2002.1031
Frost, Darrel R. (2024). Amphibian Species of the World: an Online Reference. Version 6.2 (Date of access). Electronic Database Available in: <https://amphibiansoftheworld.amnh.org/index.php>. American Museum of Natural History, New York, USA. Access on: February 20, 2025.
Gordon, M. S., & Tucker, V. A. (1965). Osmotic regulation in the tadpoles of the crab-eating frog (Rana cancrivora). Journal of Experimental Biology, 42(3), 437-445. https://doi.org/10.1242/jeb.42.3.437
Greenberg, R. (2012). The Ecology of Estuarine Wildlife, pp 357-380. In: Day, J. W., Hall C.A.S., Kemp W.M., Yañez-Arancibia, A (Eds), Estuarine ecology. John Wiley and Sons Publisher, New York. . https://doi.org/10.1002/9781118412787
Hua, J., & Pierce, B. A. (2013). Lethal and sublethal effects of salinity on three common Texas amphibians. Copeia 2013, 562-566. https://doi.org/10.1643/OT-12-126
IUCN. (2025). The IUCN Red List of Threatened Species. Version 2024-2. <https://www.iucnredlist.org>. Access on: February 20, 2025.
Karraker, N. E., Gibbs, J. P., & Vonesh, J. R. (2008). Impacts of road deicing salt on the demography of vernal pool-breeding amphibians. Ecological Applications, 18(3), 724-734. https://doi.org/10.1890/07-1644.1
Langhans, M., Peterson, B. P., Walker, A., Smith G. R., & Rettig, J. E. (2009). Effects of salinity on survivorship of wood frogs (Rana sylvatica) tadpoles. Journal of Freshwater Ecology 24(2), 335-338. https://doi.org/10.1080/02705060.2009.9664301
Lorrain-Soligon, L., Bizon, T., Robin, F., Jankovic, M., & Brischoux, F. (2024b). Variations of salinity during reproduction and development affect ontogenetic trajectories in a coastal amphibian. Environmental Science and Pollution Research, 31(8), 11735-11748. https://doi.org/10.1007/s11356-024-31886-1
Lorrain-Soligon, L., Koch, L., Kato, A., & Brischoux, F. (2024). Short-and medium-term exposure to salinity alters response to predation, activity and spatial movements in tadpoles. Animal Behaviour, 212, 63-72. https://doi.org/10.1016/j.anbehav.2024.03.023
Mcdiarmid, R.W., & Altig, R. (1999). Physiology: Coping with the Environment. Gordon R. Ultsch, David F. Bradford e Joseph Freda. In Tadpoles: The Biology of Anuran Larvae (R.W. McDiarmid, & R. Altig, eds.). University of Chicago Press, Chicago e London, 7-23 p.
Newman, M. C. (2013). Quantitative ecotoxicology (2ed.). CRC press. 570pp.
Nóbrega, G. A., Eisenlohr, P. V., Paciência, M. L. B., Prado, J., and Aidar, M. P. M. (2011). A composição florística e a diversidade de pteridófitas diferem entre a Floresta de Restinga e a Floresta Ombrófila Densa das Terras Baixas do Núcleo Picinguaba/PESM, Ubatuba/SP?. Biota Neotropica, 11, 153-164. https://doi.org/10.1590/S1676-06032011000200015
Peel, M. C., Finlayson, B. L., & McMahon, T. A. (2007). Updated world map of the Köppen-Geiger climate classification. Hydrology and Earth System Sciences Discussions, 11(5), 1633-1644. https://doi.org/10.5194/hess-11-1633-2007
Peña-Villalobos, I., Narváez, C., & Sabat, P. (2016). Metabolic cost of osmoregulation in a hypertonic environment in the invasive African clawed frog Xenopus laevis. Biology Open, 5(7), 955-961. https://doi.org/10.1242/bio.016543
R Core Team (2024). _R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. <https://www.R-project.org/>. Access on: February 20, 2025.
Rios-López, N. (2008). Effects of increased salinity on tadpoles of two anurans from a Caribbean coastal wetland in relation to their natural abundance. Amphibia-Reptillia, 29, 7-18. https://doi.org/10.1163/156853808783431451
Sabat, P. (2000). Aves en ambientes marinos y salinos: viviendo en hábitats secos. A Revista Chilena de Historia Natural, 73(3), 401-410. http://dx.doi.org/10.4067/S0716-078X2000000300004
Szeligowski, R. V., Scanley, J. A., Broadbridge, C. C., & Brady, S. P. (2022). Road salt compromises functional morphology of larval gills in populations of an amphibian. Environmental Pollution, 292, 118441. https://doi.org/10.1016/j.envpol.2021.118441
Toledo, L. F., Ribeiro, R. S., & Haddad, C. F. B. (2011). Anurans as prey: an exploratory analysis and size relationships between predators and their prey. Journal of Zoology, 285(4), 308-315. https://doi.org/10.1111/j.1469-7998.2006.00195.x
Uchiyama, M., & Yoshizawa, H. (1992). Salinity tolerance and structure of external and internal gills in tadpoles of the crab-eating frog, Rana cancrivora. Cell and Tissue Research, 267, 3544. https://doi.org/10.1007/BF00318689.
Wells, K. D. (2007). The ecology and behavior of amphibians. University of Chicago Press, Chicago, Illinois, USA.

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