Effects of climate change on the distribution of Hoplias malabaricus and its ecto- and endoparasite species in South America

Parasites are facing a loss in biodiversity in a changing climate. In this context, the present study aimed to evaluate the influence of climate change on Hoplias malabaricus and its species of monogenetic and digenetic parasites. The models were developed for South America and the species occurrence data were obtained from databases and digital platforms. The bioclimatic, edaphic, elevation, and slope variables were obtained from specialized platforms. Thus, to generate species distribution models, Support Vector Machine, Random Forest and Generalized Linear Model algorithms were used. All predictions of the model for a species were combined to obtain its final model (Ensemble) for the present and future scenarios. As a result, definitive hosts of the parasites showed high climatic suitability. The broad niche of these species indicated that these organisms can show certain opportunistic and generalist characteristics. Unlike their parasites that revealed a more restricted distribution than their host. Also, in a future scenario, endoparasite species will generally reduce 99% of their populations, ectoparasites 93%, while some hosts will increase their populations. In conclusion, the study assumed that future climatic events can influence parasites and their hosts differently, whereas anthropization can influence parasite extinction even without directly affecting their hosts.