Assessing the effectiveness of protected areas and prioritizing conservation in fragmented Quercus brantii Lindl. and Q. macranthera Fisch. & C.A.Mey. ex Hohen. habitats in Iran under different climate change scenarios

Abstract Key message We evaluated the effectiveness of protected areas under climate change scenarios for two keystone Iranian oaks: Quercus brantii in Zagros semiarid forests and Q. macranthera in Hyrcanian temperate forests. Major habitat losses and upslope shifts are projected for both species. Conservation priority areas show limited overlap with existing protected networks, highlighting the need to improve their efficiency to ensure the long-term adaptation and persistence of these oaks across semiarid and humid regions. Context Q. brantii is the characteristic oak of the Zagros, and Q. macranthera of the Hyrcanian forests. Q. brantii is declining in the Zagros due to drought, fire, and land-use pressures, while Q. macranthera faces growing vulnerability in the Hyrcanian and Arasbaran regions. However, how past climates, future changes, and fragmentation may alter their distribution ranges, and how effectively current protected areas cover suitable habitats, remains unclear. Aims This study aimed to (i) reconstruct the potential distributions of Q. brantii and Q. macranthera under past, present, and future climates; (ii) identify refugial and habitats projected to remain relatively suitable over time; (iii) evaluate the overlap of suitable areas with the current protected area network; and (iv) propose priority regions for conservation expansion. Methods We used Maxent and morphological spatial pattern analysis to identify suitable areas and habitat patches under past, present, and future climates. The Zonation algorithm was then applied to evaluate the effectiveness of existing protected areas. Results Q. brantii may loose extensive habitat in the central Zagros, with stable refugia in the northwest. Q. macranthera will experience range contraction and upslope shifts in the Hyrcanian forests, retaining refugia, mainly in the western and eastern zones. Both species are expected to face increasing fragmentation and connectivity loss, particularly for Q. macranthera . More than 70% of climatically suitable habitats will occur outside the current protected areas . Conclusions Our findings highlight regions to which management resources should be allocated and suggest expanding and improving protected areas to ensure the long-term persistence of these oak species under climate change.