Authors: Thomas Gillespie*, UCLA
Topics: Biogeography, Environmental Science, Applied Geography
Keywords: Biogeography, Species Distribution Models, Endangered Species, Hawaii
Session Type: Paper
Start / End Time: 8:00 AM / 9:40 AM
Room: Poydras, Sheraton, 3rd Floor
Presentation File: No File Uploaded
Tropical dry forests of Hawaiʻi are one of the most endangered forest types worldwide with 45% of all native tree and shrub species listed as federally threatened or endangered. Supplementation and reintroduction of endangered dry forest species are necessary to maintain viable population sizes. The goal of this research was to reintroduce Hibiscus brackenridgei mokuleianus, the state flower of Hawaiʻi and a federally endangered species, into its historical range on Oʻahu. We determined the environmental variables contributing to plant survival and growth, assessed the effectiveness of a reintroduction program with minimal management, and evaluated the potential for habitat suitability models to assist in selection of optimal sites for reintroduction. Forty-five individuals were grown from cuttings and transplanted in two regions: Kaʻena Point (2 sites, 10 individuals each site) and along Kealia Trail (5 sites, 5 individuals each site). Survival and height measurements were taken four times over the course of two years. After two years, there was 58% survival and significant average plant growth of 107.84 cm (± 11.6 cm). Kaʻena Point had significantly lower survival and growth rates than Kealia Trail. Overall, plants survived at sites with steep slopes and high soil moisture and grew the most in sites with steeper slopes, higher soil moisture, and lower soil bulk density. The 10 m habitat suitability model was marginally correlated with survivorship. These findings provide insight into environmental variables which should be considered prior to planting as well as the intensity of site management which should occur post reintroduction.