Comparison of the ecological niche of two closely related toads (Bufo bufo and Bufo verrucosissimus)

Understanding climatic variables to determine the ecological niche is crucial to explaining species distributions and revealing how sister species coexist within a geographic area. Here, we used ecological niche modeling to determine the ecological niche patterns of two toad species in Türkiye: Bufo bufo and Bufo verrucosissimus. Thus, we tested the ecological niche divergence and similarity between these species. In our results, the potential distribution of B. verrucosissimus showed high suitability throughout all Caucasus hotspots, and this suitability has been found even along the middle and western coast of Türkiye, but suitability was found to be very weak in the southern part of Türkiye. For B. bufo, the distribution pattern indicated high suitability along the Black Sea and Mediterranean coasts of Türkiye, but this suitability was low throughout Caucasus hotspots. Furthermore, we found that among B. bufo and B. verrucosissimus, the niches are not identical, but this situation is different in the background test. Therefore, we suggested that although there is niche conservatism between the two sister species, this pattern is caused by geographic barriers, not climatic parameters.