Conservation of Hawaii's dry forest: An application of habitat suitability modeling, GIS, and field methods.

摘要

Tropical dry forests in Hawaii are among the most endangered forest types in the world with half of all plant species listed as federally threatened or endangered. Although there have been some efforts to protect remaining dry forest fragments, conservation of this ecosystem has proven difficult due to a poor understanding of the current distribution of native species, environmental factors influencing their distributions, potential sites for species reintroductions, and of how the dry forest has changed over the past 30 years. This dissertation addresses the question: How can field-based methods, habitat suitability modeling (HSM), geographic information systems (GIS), and remote sensing improve conservation and restoration efforts in Hawaii's dry forest? To answer this question, habitat suitability modeling is used to assess factors influencing species distributions and identify potential sites for endangered species restoration. Secondly, a field-based case study is conducted to evaluate the environmental variables affecting restoration success of an endangered plant. Finally, GIS and remote sensing are used to assess changes in dry forest dynamics over the past decade across the Hawaiian Islands. Results from habitat suitability modeling suggest that topography and soil variables may be a key driver in the distribution of endangered dry forest species and that current protected areas may not capture the best habitat for reintroductions. Furthermore, results from the restoration study suggest that sites with low soil moisture and high exposure to sunlight may be the most suitable reintroduction sites for endangered dry forest species like, Hibiscus brackenridgei. The methodology and findings from this dissertation will provide a framework for conservation management of endangered dry forest fragments in Hawaii as well as other oceanic islands.