Climate change reshapes the global distribution of wild barley relatives: integrating life-history traits and ecological niche modeling

Abstract

Introduction Wild Hordeum species are crucial genetic resources for climate‑resilient crop breeding. Clarifying their responses to climate change is essential for germplasm conservation and sustainable crop improvement. This study aims to elucidate the divergent climatic responses of wild Hordeum species and provide scientific evidence for germplasm protection and climate‑adaptive crop breeding. Methods This study was conducted at a global scale, covering the major distribution areas and diversity hotspots of wild barley. We combined life‑history traits, niche breadth, and interspecific habitat overlap, and adopted MaxEnt species distribution models with CMIP6 climate datasets to project the spatiotemporal dynamics of suitable habitats for 13 wild Hordeum species. The ENMeval package was used for systematic parameter calibration and sensitivity analysis to optimize model configurations and ensure reliable predictive performance. Results The model showed strong performance (mean AUC = 0.907 ± 0.029, TSS = 0.763 ± 0.064). Four global diversity hotspots were identified: southwest and central Asia, the Mediterranean region, western North America, and the Andes Mountains. Niche breadth and climate vulnerability are phylogenetically structured, with closely related species sharing similar ecological constraints and extinction risks. By 2100, wild Hordeum’s global suitable habitat is projected to contract by ~62%, with annual species suffering greater losses than perennials. Hordeum spontaneum will suffer the most severe range contraction (97.83% habitat loss, threatening wild population persistence), while Hordeum muticum shows moderate resilience (36.96% reduction) and Hordeum agriocrithon will expand by 34.84%. Habitat migration is primarily driven by precipitation gradient variation, and stable niche overlap among closely related species verifies the edge adaptation hypothesis. Discussion Wild Hordeum species exhibit divergent climate change responses. These contrasting habitat change trajectories signal divergent conservation urgency: extreme contractions threaten genetic erosion in crop wild relatives, whereas expanding ranges highlight potential donor species for climate‑adaptive breeding. High‑risk taxa such as Hordeum stenostachys require urgent coordinated in‑situ and ex‑situ conservation to prevent population decline and genetic erosion. In contrast, range‑expanding species (Hordeum agriocrithon) offer insights into adaptive mechanisms, with practical implications for climate‑resilient crop breeding. Notably, these projections reflect climatic suitability under a single climate model and should be interpreted cautiously given unmodeled biotic interactions and dispersal constraints.