Phylogeny and Ecological Modeling of Caspian Red Deer Cervus elaphus maral in Hyrcanian Forests

The Caspian red deer Cervus elaphus maral , a large mammal endemic to the Hyrcanian forests, is particularly susceptible to habitat fragmentation, reduced genetic diversity, and climate change. To assess the genetic structure and diversity of this species, 120 samples were collected non-invasively across habitats with varying population densities. A total of 58 D-loop sequences, supplemented with data from GenBank, were analyzed to construct phylogenetic trees and perform molecular analyses. Habitat suitability was modeled using 16 key environmental and climatic variables influencing red deer distribution. A total of 482 presence points, recorded between 2021 and 2022, informed five individual models and an ensemble model to predict current and future habitat suitability. Projections extending to the year 2100 were generated under both optimistic and pessimistic climate scenarios. Genetic analyses revealed two major genetic groups: a distinct population in the western Hyrcanian forests and eight subpopulations in the central and eastern regions. The western population appears to have experienced long-term habitat isolation. Ecological modeling indicated that forested regions with dense vegetation are expected to remain suitable habitats. Climate change projections indicate that by 2100, significant habitat loss will occur, particularly in low-lying areas near human settlements and at elevations above 2000 meters. The central forest is expected to remain stable, while the eastern and western edges may become more suitable in the future. Although many of the optimal habitats are currently protected, the findings underscore the urgent need for an integrated conservation network encompassing the entire Hyrcanian region.