Species distribution modeling for honeycreepers on Kauaʻi, Hawaiʻi informs conservation action

Effective conservation requires aligning management actions with species' ecology, particularly under rapidly changing environmental conditions. However, traditional methods of generating knowledge of life history and species-habitat associations are too slow for many rare or rapidly declining species. Hawaiian honeycreepers are experiencing catastrophic population collapse, largely due to mosquito-borne avian malaria, and ecological knowledge gaps limit the effectiveness of conservation tools. To fill these gaps, we compared species detections with Light Detection and Ranging (LiDAR) and Phased Array L-band Synthetic Aperture Radar (PALSAR) data and built Maximum Entropy models for each of five vulnerable Hawaiian honeycreepers on Kauaʻi: ʻakikiki ( Oreomystis bairdi ), ʻakekeʻe ( Loxops caeruleirostris ), ʻanianiau ( Magumma parva ), ʻiʻiwi ( Drepanis coccinea ), and Kauaʻi ʻamakihi ( Chlorodrepanis stejnegeri ). We characterized topography and forest structure of selected habitat, built maps of habitat suitability, and estimated species ranges. All species selected high elevations, where mosquitoes and malaria are restricted by colder temperatures. We observed selection for tall, dense canopy with short understory, typical of mature native forests. Our maps identified overlapping habitat cores shared among species in the eastern Alakaʻi Plateau, providing targets for mosquito control and other conservation actions. In line with recent work, we documented range contractions of up to 65% since 2017. Our results demonstrate that PALSAR data enables efficient habitat assessments to inform avian conservation actions in Hawaiʻi and worldwide. In the face of rapid extinctions, these results provide much needed insights into the habitat requirements of our target species, informing necessary conservation actions and establishing methods for species outside of Hawaiʻi. • Kauaʻi's honeycreepers selected high elevation forests with complex canopy. • Vulnerable honeycreepers share common core habitat in the eastern Alakaʻi Plateau. • Maps of habitat suitability identified priority areas for conservation action. • Updated range maps document drastic contractions of up to 65% since 2017.