Mapping Lāna‘i’s Vegetation: Lucas Fortini’s Kuahiwi a Kai Project
Map showcasing the fine-scale land cover of Lāna‘i based on 2020 satellite imagery. Legend for the land cover map of Lāna‘i, listing types and corresponding colors. Click here to view an interactive map.
In 2019, the Kuahiwi a Kai: Lāna‘i Watershed Conservation Program began its mission to preserve and enhance Lāna‘i’s unique natural and cultural resources. This effort aimed to address the severe impacts of overgrazing and mismanagement of introduced ungulates, which have caused unnatural erosion patterns, burying historic cultural sites and smothering coral reefs and beaches with sediment.
Among the 11 grants awarded at the time, one project was led by Lucas Fortini, a research ecologist with the U.S. Geological Survey. Fortini’s project focused on mapping native and non-native vegetation communities on Lāna‘i using advanced technologies like LiDAR and high-resolution satellite imagery.
Fortini described the project’s goal as “trying to get a better idea of what the landscape across the island looks like today and understanding changes over the last few decades.” The integration of LiDAR data and satellite imagery allowed for the creation of a detailed map of the landscape, identifying various vegetation types and tracking their changes over time.
“We used LiDAR data, combined with high-resolution satellite imagery, to get a very accurate estimate of the island’s layout,” said Fortini. This data helped in identifying different vegetation types and understanding their distribution.
LiDAR, which stands for Light Detection and Ranging, is a technology that uses laser light to measure distances. It works by emitting laser pulses from an aircraft, which bounce back after hitting the ground. The time it takes for the pulses to return is measured, creating a highly accurate 3D map of the terrain. This technology was crucial for the project as it provided detailed elevation data that is essential for mapping vegetation.
However, ground verification was also a critical component. Fortini said, “You need somebody that knows the landscape to provide those examples. So, that’s why we partnered with folks from Pūlama Lāna‘i to provide hundreds of examples of these different types of vegetation classes.” On the ground expertise ensured that the models accurately reflected the real-world conditions on Lāna‘i.
The project’s map includes a variety of vegetation types found on Lāna‘i, which are color-coded on the map:
A‘ali‘i native shrubland
Albizia
Bare earth
Brazilian pepper
Cook pine
Eucalyptus
Formosan koa
Ironwood
Kiawe, Klu, and Koa haole
Kukui
Mixed non-native grass and shrubs
Non-native grassland
Strawberry guava
Talus
Uluhe and ‘Ohi‘a
Mesic native forest
Mesic mixed forest
Dry invasive forest
Dry native shrubland
Unvegetated
Dry invasive grassland
The map created from this project provides crucial data for future conservation efforts. “Having a clear snapshot of the island’s current state allows us to plan effectively for the future,” said Fortini. This data enables better monitoring and adjustment of conservation strategies as needed.
Fortini has created a web map to showcase the fine-scale land cover maps for Lāna‘i based on 2020 satellite imagery. This map provides detailed information about the island’s vegetation and land cover, helping to guide future conservation and management efforts, including responses to invasive species, climate change and land management practices such as erosion and sediment control planning.
For more detailed information on the vegetation types and their distribution across the island, the community can access the interactive web map at https://rconnect.usgs.gov/Lanai_land_cover_ viewer/.
This project was made possible through a grant from the National Fish and Wildlife Foundation with support from Pūlama Lāna‘i.