Abstract

Climate change, a global threat of utmost significance, has the potential to trigger shifts in biodiversity distribution and the emergence of novel ecological communities. For species with limited dispersal abilities or geographical barriers within their range, niche conservatism can further constrain their ability to colonize and thrive in future suitable habitats, rendering them more vulnerable to the effects of global climate change. In this study, an ensemble modeling framework and climatic niche dynamics analysis were employed to forecast the impact of climate change on climatic niche dimensions and transferability of two indicator species, namely, Ziziphus spina-christi and Ziziphus nummularia, in Iran. Our analysis revealed that, under optimistic and pessimistic climate change scenarios, the habitat suitability for Z. spina-christi will expand during 2041-2070 and 2071-2100, predominantly towards higher latitudes. In contrast, Z. nummularia is anticipated to experience a general decline in habitat suitability during the same periods and climate scenarios, resulting in the loss of portions of its southern range. Our examination of climatic niche dynamics unveiled a relatively low observed niche overlap between the two species. Randomization tests further underscored the adherence of these species to their historical niches, suggesting challenges in adapting to changing climatic conditions. The integration of predictive models and niche dynamics analysis indicates that these species may encounter difficulties migrating to the tracked niches in distant habitats due to their preserved niches. Given the high sensitivity of arid ecosystems to environmental disturbances and slow recovery rates, the repercussions for arid land biodiversity are indeed profound and irrevocable. Conservation and management measures, including identifying priority areas and creating artificial habitats, are crucial to protect these species' habitats.The study's conclusions are valuable for biodiversity conservation authorities, local stakeholders, and individuals dedicated to preserving Ziziphus habitats within the study area.