Integrating Spatially-Explicit and Genetic Analyses to Identify Conservation Priorities for Bufo eichwaldi (Amphibia: Anura) in the Hyrcanian Forest

Bufo eichwaldi (Amphibia: Anura) is a toad species endemic to the Hyrcanian forests of northern Iran and southeastern Azerbaijan, increasingly threatened by anthropogenic pressures, underscoring the urgent need for conservation measures. We assessed the genetic diversity, population structure, and potential distribution of B. eichwaldi using molecular analyses and Species Distribution Modeling in order to inform management plans for the species. We analyzed two mitochondrial gene fragments (16S rRNA and D-loop) and one nuclear gene (Recombination activating gene 1), totaling 1865 bp, in 23 individuals from four populations. Our genetic analyses revealed high haplotype diversity (0.984) and significant genetic differentiation (F_ST) among populations, with the Azerbaijan population showing a genetic distance of 1.85%–2.04% from Iranian populations in the D-loop gene fragment. Genetic results support the hypothesis that B. eichwaldi recently expanded into the Hyrcanian forests after the last glacial maximum (LGM). Species distribution models calibrated using maximum entropy (MaxEnt) under average current climatic conditions (1970–2000) were projected to the Mid-Holocene (6 Kya) and LGM (21 Kya), as well as on 256 time slices of 10 ky BP to assess historic habitat stability. Our models showed good predictive accuracy, with the most influential environmental variable being precipitation of the wettest month (50.1%), followed by temperature annual range (39.7%). Suitable habitats for B. eichwaldi have become increasingly available in the Hyrcanian region after the LGM, in agreement with genetic evidence of a recent range expansion into these forests. This study highlights the value of integrating genetic and ecological data to inform conservation strategies for B. eichwaldi.