Species distribution modeling and assessment of environmental drivers responsible for distribution and preferred niche of critically endangered and endemic ornamental freshwater fish species of the genus Sahyadria.

India has different bioclimatic zones and supports diverse aquatic habitats rich in biodiversity. For effective conservation of the endangered species in its habitat, it is essential to know the distribution of fish species in the environmental range, and for this, species distribution models are the efficient and innovative tools. The present study used the MaxEnt modeling technique for developing probability distribution models highlighting the distribution of fish species by analyzing the known occurrence records of Denison barb under genus Sahyadria (Sahyadria denisonii Day 1865 and Sahyadria chalakkudiensis (Menon et al., Rec Zool Surv India 97:61–63, 1999)) in relation to environmental variables typically incorporating seasonal and temporal variability. AUC of the models for Sahyadria species depicted good fitness. Both species were found sensitive to "solar radiation," "temperature seasonality," and "temperature annual range" and assessed as significant predictors. The sensitivity and distribution of both species to these environmental variables were found correlated with their breading and spawning seasons. "Precipitation" was determined as one of the significant climatic envelopes influencing the distribution of the species associated with river flow. The models showed the distribution of S. denisonii in the higher precipitation areas compared to S. chalakkudiensis. The probability distribution model with respect to the distribution of both species indicates a lineage barrier at Palghat Gap supporting the earlier studies. At the latitudinal scale, prediction of the suitable ecological habitat provides a detailed insight into the distribution of all genetic lineages of the genus Sahyadria. Evidently, the findings of this study can assist in determining ecological niches for endangered species of other areas and may aid in field surveys as well as developing conservation plans. [ABSTRACT FROM AUTHOR]