Divergent Fates of Freshwater Fishes Under Climate Change: Endemic Vulnerability and Habitat Shifts in Iran's Central Zagros

ABSTRACT Freshwater ecosystems in biodiversity hotspots face unprecedented threats from climate change, yet endemic species—often the most vulnerable—remain understudied. Using species distribution models (MaxEnt), we project habitat shifts for 10 riverine fishes (six endemics) in Iran's Central Zagros, a critical freshwater biodiversity hotspot, under optimistic (RCP 2.6) and pessimistic (RCP 8.5) scenarios (2050–2080). Our results reveal stark disparities: While generalists like Sellal bleak Alburnus sellal may gain > 130% habitat, endemic taxa such as killifish Esmaeilius vladykovi and Large scale scraper Capoeta aculeata face near‐total losses (> 90%). Notably, the Near Threatened Capoeta ferdowsii (endemic) declines across all scenarios, underscoring the heightened risks for range‐restricted species. Temperature and land use emerged as dominant drivers, with endemic fishes disproportionately affected by climatic stressors. These findings challenge assumptions of uniform climate impacts and provide a replicable framework for prioritizing conservation in fragmented freshwater ecosystems. We highlight three actionable insights: urgent protection of thermal refugia for endemic species, habitat connectivity restoration to facilitate climate‐driven range shifts and integration of SDM projections into IUCN Red List assessments. By quantifying divergent fates—from expansion to collapse—our study equips conservationists with data to safeguard freshwater biodiversity in one of the Middle East's most vulnerable regions.