The Hawaiian Archipelago is one of the world’s most isolated island groupings and supports a multitude of ecosystems that vary in complexity, content, and structure. The diversity of native plant life can be attributed to millions of years of isolation from other land masses, a remarkable diversity of microclimates occurring within short distances of one another, and a scant number of original plant founders. These factors gave rise to some of the most unique examples of insular evolution in the world.
Today, it is estimated that 1,400 vascular plant taxa (including species, subspecies, and varieties) are native to the Hawaiian Islands, with nearly 90 percent of these found nowhere else in the world. Hawai‘i has the dubious distinction of being the “Endangered Species Capital of the World,” with 365 plant taxa (of which 7 are thought to be extinct) listed as Endangered or Threatened by the U.S. Fish and Wildlife Service and the Hawai‘i Department of Land and Natural Resources. There are currently 46 additional taxa that are Proposed as Endangered, and another 18 species are Candidates for listing. A further 248 taxa are unofficially tracked as “Species of Concern” and may eventually merit listing as Endangered or Threatened.
Taken together this means that nearly 700 vascular plant taxa are declining or considered to be of conservation concern, roughly half of the native flora. Situated in 193.5 acres of tropical rainforest, the Harold L. Lyon Arboretum-University of Hawai‘i at Manoa is a permanent ex situ repository for more than 5,000 living plant taxa, primarily from Hawai‘i, and sub-tropical and tropical areas of the world. The plant collections are diverse, and include living specimens that are common to extremely rare in their native habitat, as well as tropical ornamentals and economically important crop plants. The preservation of plant genetic resources is vital to the economic well-being of any state, and no where else is it more evident than in Hawai‘i where the number one industry is tourism.
With over 7.6 million visitors and $12.8 billion of tourism generated income annually, it is imperative that the Hawaiian landscape remain aesthetic, appealing, and as natural as possible. Aside from beaches, the flora and fauna are the most visible elements of Hawai‘i’s ecosystems and provide the back drop for the multi-million dollar eco-tourism industry. Preservation of native plants, especially of wild populations, through plant re-introductions, may also have far reaching effects by protecting the balance and integrity of ecosystems. Plant conservation programs, such as those of the Lyon Arboretum, can mitigate the effects of soil erosion, flooding, and loss of wildlife habitat. Currently, the Hawaiian Islands are being subjected to a number of environmental pressures (e.g. alien pest species, pathogens, climatic changes, urban encroachment, and pollution) that are leading to rapid ecosystem degradation.
Common native species are becoming increasingly rare, leading to an urgent need for in situ management, field collections, and ex situ storage before local populations disappear or become so depauperate that they are unsustainable. Within the past decade, the Lyon Arboretum has become a major contributor to the development of plant conservation initiatives, especially in the fields of conservation biology, ethnobotany, and horticulture. The Lyon Arboretum Hawaiian Rare Plant Program, for example, aids in fulfilling the Arboretum’s conservation mission through the development of a viable and comprehensive germplasm “bank,” consisting of critically at risk native Hawaiian plants and culturally significant crop plants, and by serving as a national model which provides information to its peers, researchers, and the conservation community.