Prior to the arrival of the first Polynesian canoes nearly 1,500 years ago, Hawaii's natural wetlands provided habitat for resident and migratory waterbirds. Among the natural wetlands were forested bogs, streams, estuaries, lakes, and coastal marshes. Wetland mapping indicates that Hawaii (Region 32*) contains approximately 44,860 ha of wetlands and deep-water habitats, of which 81% are classified as palustrine scrub-shrub and forested habitats. These wetlands are located at mid- to high elevations as bogs and rainforest ecosystems. The USFWS estimates 9,100 ha of wetlands within coastal plains of Hawaii circa 1780. In 1990, the USFWS estimates 6,265 ha remaining, a decrease of 31%.
A total of 106 endemic species and subspecies of birds have been described from the Hawaiian Islands (Pyle 1988, Olson and James 1991). Of these, 35 became extinct before the arrival of Captain Cook in 1778, and an additional 23 since then, leaving 48 extant endemic taxa. The Hawaiian Islands historically supported a diverse array of waterbirds in wetland and forest habitats. During the past 2,000 years of human presence, all of Hawaii's endemic rails, flightless geese, and an ibis have become extinct (Olson and James 1982). This massive extinction is attributed to the impacts of humans and the plants and animals they introduced to Hawaii. Polynesian settlers and Europeans have both played significant roles in the alteration of Hawaiian ecosystems and the resulting extinction of species (Olson and James 1991).
The six extant species of endemic waterbirds are koloa maoli or Hawaiian duck, Laysan duck, 'alae 'keo'keo or Hawaiian coot, 'aeo or Hawaiian stilt, 'alae 'ula or Hawaiian moorhen, and nene or Hawaiian goose. All of these species are federally listed as endangered, have populations fewer than 3,000 birds, and require wetlands for survival (Engilis and Pratt 1993). Nearly 30 species of migratory ducks and geese and more than 30 species of migratory shorebirds have been recorded in the Hawaiian Islands (Pyle 1977). Among the most common species of migrant waterfowl are northern pintail, northern shoveler, lesser scaup, American wigeon, and Eurasian wigeon. These species use the island habitat for wintering, with the exception of resident mallard and fulvous whistling duck that have become established. Migratory waterbirds have shown a marked decline from tens of thousands in the 1950s to only a few thousand in the 1990s.
In the two centuries since the first European ships reached the islands, most of the wetlands have been degraded. As early as the 1850s, significant losses in wetland habitat began with conversion of wetlands to taro and then crops such as rice and sugarcane. More recently, urbanization of lowland, coastal areas, particularly on Oahu, has accelerated the conversion or alteration of wetlands. The coastal wetlands of Waikiki were drained in the 1920s and have been totally lost to development. Most degraded wetland systems have been filled or hydrological modified and are now occupied by hotels, houses, golf courses, shopping centers, landfills, military installations, highways, agricultural fields, and industrial sites (Griffin et al. 1989).
Introduction of exotic species has negatively impacted waterbird species. Exotic plants, such as California grass, Indian fleabane, pickleweed, and red mangrove present serious threats in many wetlands by out-competing more desirable native species and eliminating the interspersion of open water and vegetated areas. A major threat to the Hawaiian duck is hybridization with increasing numbers of resident feral mallards. The threat of hybridization is exacerbated on Oahu with severe reduction in wetland habitat and increasing numbers of mallard in lake and golf course areas. Introduction of the mongoose to control rats has resulted in a very serious threat to ground nesting birds. Only Kauai, Lanai, and Niihau are free of mongoose.
Protection and restoration of Hawaii's wetlands are essential to the recovery of the endemic waterbirds, as well as the migrant waterfowl and shorebirds. There are 476 ha of secured wetland habitat on Kauai, principally at Hanalei NWR (371 ha) and Huleia NWR (96 ha). Oahu has 708 ha of secured wetlands, principally at Kawainui Marsh (304 ha), Heeia Marsh (162 ha), and Kahuku Wetlands (57.5 ha), although all of these systems have been hydrologically altered. Maui/Molokai have 287 ha of secure wetlands, principally Kealia Pond NWR (202 ha) and Kanaha Pond (58 ha). The Big Island has some 30 ha secured, principally at Aimakapa, Kaloko, and Parker Ranch.
*Region 32 - Hawaii does not have a NABCI Bird Conservation Region Number
Since 1990, DU and its partners have completed six restoration and four planning projects, protecting and restoring 143 ha and committing $157,828. Strategic partnerships have established conservation projects on six of the main Hawaiian Islands, thus providing program anchors from which to build "Wetlands Hawaii". Principal partnerships to date have included USFWS, Hawaii Division of Forestry and Wildlife, Natural Resource Conservation Service, Department of Defense (DOD), Bernice P. Bishop Museum, Harold K. L. Castle Foundation, Campbell Estate, Parker Ranch, Chalon International, Umikoa Ranch, and Cyanotech.
DU's partnerships have been with the USFWS and National Audubon Society, with principal effort in developing managed wetlands on Hanalei NWR. Completed in 1993, the initial effort restored 8.1 ha of wetlands on the refuge. In 1997, DU began working with refuge staff in designing a fish screen to exclude tilapia from refuge wetlands. This non-native fish reproduces rapidly, can quickly populate small wetlands managed for waterbirds, and directly impact vegetation and insect-life. In addition, DU is assisting the expansion of new refuge lands, restoration of existing lands, and support of taro field development on private lands where it is compatible with waterbird habitat needs.
The partnerships on Oahu have been coordinated with the State Division of Forestry and Wildlife, USFWS, the DOD, NRCS, the City and County of Honolulu, and several private landowners. DU has developed two project anchors, one on windward Oahu, and the other in Pearl Harbor. The windward Oahu program is centered on the development of a wetlands information system using the restoration of Kawai nui Marsh as a model. This effort is underwritten by the Harold K. L. Castle Foundation, Kailua, Oahu. To date, DU has completed one project in the area, the protection of Hamakua Marsh. This was accomplished through a partnership involving a land donation to DU from Kaneohe Ranch. DU then took the value of this land and leveraged initial restoration funds from the USFWS. After restoration was completed, DU donated the wetland to the State of Hawaii.
The other project anchor is the Pouhala Marsh (Pearl Harbor) project that brings together a diverse partnership with DU coordinating project design and restoration planning. DU raised funds from internal programs and Mainland foundations to match USFWS and State grants to undertake the restoration design for this 28 ha tidal wetland. In addition, DU assisted Campbell Estate to continue its economic development by participating in a unique mitigation opportunity that allows the Estate to offset wetland losses at Barber's Point by partially funding DU's restoration at Pouhala Marsh. DU is also providing technical advice to Chevron Hawaii on Pouhala Marsh as a mitigation site to offset the effects of the 1985 oil spill at Pearl Harbor. Long-term goals are to restore and manage Pouhala Marsh and then address wetlands efforts in Pearl Harbor by expanding our partnership to lands owned and managed by the U.S. Navy and the USFWS.
One of the newest and most important wetland refuges in Hawaii, Kealia Pond NWR is the focus of restoration work on Maui. DU will provide wetlands planning, design for restoration and enhancement, and long-term management plans for the refuge. This site is a coastal playa with muted hydrology. Surveys are complete for the Ulupalakua Ranch, in partnership with the NRCS. Wetland restoration in concert with native forest rehabilitation are planned to benefit nene and koloa.
The program anchor on Molokai is in the south coastal wetlands, west of Kaunakaki. DU has restored the Ohiapilo Marsh, a 10 ha mitigation project. DU is also working with Molokai Ranch and private landowners in enhancing wetlands in this important seasonal wetland complex, which can hold over 90% of the island's endangered stilt population.
The program anchor on Hawaii has been to develop partnerships with private landowners to provide wetlands that support native waterbirds. Our program has focused on our partnership with the NRCS and private ranches on the Big Island. WRP and NAWCA grants will support restoration efforts on three ranches: Parker Ranch, Chalon International, Inc., and Umikoa Ranch. Wetlands restored on these areas will directly support the endangered Hawaiian duck, nene, and Hawaiian hawk. In an unrelated private lands project, DU and NRCS are working with the Bishop Estate to develop a restoration plan for Opaeula Pond. Lastly, DU has designed and assisted in development of a modified algae pond with Cyanotech that can support Hawaiian Stilt on their property. These algae processing ponds have attracted numerous stilts, but specific management plans need to be developed.
- Clearly define each major wetland area on the islands that can contribute to restoration of waterbird populations.
- Secure protected status, either in private or public ownership, for all major wetland areas within the next 10 years.
- Restore and enhance important wetland areas that are degraded.
- Increase all endangered waterbird populations above 2,000 individuals, with the exception of the Laysan duck where a goal of tripling the current population is feasible.
- Increasing wetland area and quality will increase waterbird populations.
- Major limiting factors for waterbirds are quality wetland habitat, introduced predators, and urban expansion.
- Wetlands in Hawaii can be individually recognized and analyzed for priorities in restoration and enhancement.
- Concentrate initial restoration efforts at Hanalei floodplain, Kealia playa, Pouhala Marsh, and Big Island ranches.
- Develop prioritization model to assure restoration and protection is completed in order of highest need.
- Assist in population viability analyses for each of the endangered waterbird species (after Reed et al. 1994).
- Secure habitat usage information by koloa, both in montane breeding areas and coastal lowland wintering areas to better guide protection and restoration efforts.
- Develop a better understanding of migrant pathways for wintering birds beyond the Pacific Ocean.
- Develop better understanding of natural hydrologic patterns to improve design of restoration efforts (e.g., Hanalei River floodplain).
- Establish adaptive resource management within the islands through cooperatively developed management plans and annual workshops for managers.