Limahuli Preserve covers nearly a thousand acres and includes habitats ranging from lowland mesic forest to montane rain forest. Most of the restoration ecology projects are undertaken in the Preserve, where the ecological health of the habitats ranges from pristine to highly degraded. The Preserve is not open to the public. Within the Preserve there are 12 species that are Federally listed as Threatened and Endangered (T&E) and 9 “Candidate” species (proposed for T&E status). The NTBG Conservation efforts place special emphasis through its Prevention of Extinction Program (PEP) on species that have fewer than 50 individuals existing in the wild; there are 5 such species in Limahuli Preserve, some of which are only found in Limahuli Valley."*
Limahuli Preserve is divided into two major zones: Lower Limahuli Preserve (approximately 600 acres) and Upper Limahuli Preserve (approximately 400 acres). The two areas are separated by an 800-foot waterfall and are ecologically distinct. The Upper Preserve can only be accessed by helicopter. Restoration strategies differ for each area.
The Lower Preserve includes lowland mesic forest and lowland wet forest. After almost 100 years of damage from grazing by feral cattle followed by two intense hurricanes a decade apart (1982 and 1992), the Lower Preserve contains large areas of highly degraded forest as well as patches of remnant forest.
Within the Lower Preserve we have three restoration sites that comprise approximately 20 acres: a mesic lowland forest, a wet forest, and a riparian zone. In our mesic forest restoration site (our oldest site) we have successfully re-established a native canopy and we are noticing regeneration. Our focus is now to restore the native understory.
An important team in this restoration work is the volunteers who come from the local community as well as from across the country. Project Stewardship, a program in which we partner with local high schools, provides hands-on experience for local students to learn about restoration ecology. All of the restoration work that we do at Limahuli is grounded in traditional Hawaiian ahupua‘a resource management techniques that focus on protecting the interrelationship between all aspects of the terrestrial, aquatic, and marine environments. These cultural traditions are supported by relationships with local cultural practitioners who help us maintain the restoration site in exchange for being able to collect forest resources in a place that is conducive to following cultural protocols.
The Upper Limahuli Preserve contains some of the most pristine montane wet forest left in all of Hawai‘i. In this area our focus primarily is eliminating incipient invasive species and augmenting the populations of the T&E species that exist there. The lowest 50 acres of the Upper Preserve were once a pristine native ecosystem until the Valley was ravaged by the aforementioned hurricanes. These severe storms not only damaged the vegetation, but also spread aerial-borne alien seeds. Recent work trips via helicopter to this remote area have aided in controlling exotic invasives and allowed out-planting of extremely rare species, such as the native mint Phyllostegia renovans and a handsome palm only found in Limahuli Valley (Pritchardia limahuliensis).
* Data as of August 2006