Use of high resolution lidar data to inform inter island translocation of endangered avian species in Hawaii

Two Hawaiian honeycreepers endemic to Kauai, Akikiki (Oreomystis bairdi) and Akekee (Loxops caeruleirostris), are experiencing drastic population declines due to the spread of invasive disease exacerbated by climate change. We use habitat suitability modelling and high resolution lidar data to assess the potential management strategy of translocation to a novel environment. We transferred improved Maxent models based on topographic and forest structure metrics of the Alakai Plateau to native forest bird habitat on East Maui. Climate models previously developed for Akikiki and Akekee on Maui were used to restrict the lidar-based Maxent results. Additional models were produced for three endemic and native Maui species; Akohekohe (Palmeria dolei), Maui Alauahio (Paroreomyza montana) and Kiwikiu (Pseudonestor xanthophrys). Structurally suitable and climatically suitable habitat lined up well for both Kauai species on East Maui. Canopy density was consistently the most important variable in the Kauai species models. Given the denser canopy and shorter vegetation structure metrics, East Maui favors Akikiki nesting habitat and Akekee general use habitat. We estimated an increase in Akikiki nesting habitat from the current Kauai range (13.09 km2) to the range under future climate conditions on East Maui (23.43 km2). The opposite is true for Akekee with a nesting range of 38.48 km2 on Kauai and 26.29 km2 on East Maui. To inform selection of potential release sites, we produced predictive nest and occurrence maps at the 100 m scale for Akikiki and Akekee on East Maui. Results from the Maui species models allowed for the assessment of potential niche competition between translocated individuals and species endemic to East Maui. Weighted overlap areas between the species from both islands were moderate (<12 km2) and correlations between Maui and Kauai bird habitat were generally low. Results suggest that translocation to East Maui could be a viable option for Akikiki but would be more uncertain for Akekee