Authors: Matthew Lucas*, University of Hawaii at Manoa Dept. of Natural Resources and Environmental Management , Clay Trauernicht , University of Hawaii at Manoa Dept. of Natural Resources and Environmental Management , Kimberly Carlson, University of Hawaii at Manoa Dept. of Natural Resources and Environmental Management
Topics: Land Use and Land Cover Change, Remote Sensing, Pacific Islands
Keywords: Hawaii, Land Cover Change, Land Use, Agriculture Abandonment, Forest Transition, Spectral Unmixing, Google Earth Engine
Session Type: Paper
Start / End Time: 5:20 PM / 7:00 PM
Room: Iberville, Marriott, River Tower Elevators, 4th Floor
Presentation File: No File Uploaded
Over the past decades Hawaii has seen large scale land use change and land cover shifts, yet much these dynamics are only described anecdotally or studied at a single locale. With little information on the extent, rate, or outcome of change any effort to assess or prioritize consequences of past land use or management actions is stymied. As such, this project developed high-resolution, sub-pixel, percent cover maps of forest, grassland and bare earth annually from 1999 to 2016 using archived LANDSAT imagery and a custom remote-sensing algorithm developed in the Google Earth Engine platform. The aim of this work was to quantify total area of change, annual rates of change, and final cover outcomes for evaluating past and current land management history. Results indicated that nearly 10% of the state’s land surfaces have undergone landcover transitions during the study period. Statewide net change resulted in a gain in forest cover with largest areas of change occurring in un-managed, pastoral, commercial forestry and abandoned cultivated areas and highest rates of change being forest increases occurring in restoration and commercial forestry areas. This indicates that Hawaii is going through a forest transition, primarily driven by agricultural abandonment with likely influences from invasive species, and forestry production on former agricultural lands that show potential for native forest restoration. This study is first to quantify forest transition dynamics in Hawaii, and directly links land management history to land cover outcomes thus highlighting the need for similar assessments in post-agricultural landscapes on other oceanic islands.