PHYTOSOCIOLOGY AND ECOLOGY OF THE NATURAL DRY-GRASS COMMUNITIES ON OAHU, HAWAII

Using the Braun-Blanquet and ordination techniques, nine dry-grass community types were recognized on Oahu,seven of which were dominated by exotic grasses and two by native grasses, Hctcrnpogna eontortus and Erarjrostis variabilis.These community types occured in summer-drought, summer-dry and humid climates.The distribution of certain community types could be correlated directly with rainfall and soil pH. In the summer-drought climate the occurrence of the community types was related to topography,wind exposure, rockiness of the land surface and stoniness of the soil.The nine community types were not related to the established soil series, organic matter content and watsr retaining' capacity of the surface soils.Three distinct soil-water regimes were recognized in five community types: drought, dry and wet types.Seasonal variations in soil-water content were correlated closely with the rainfall pattern.The introduction and spread of exotic species resulted in a gradual disappearance of the native grass communities in the summer-drought zone. In the summer-dry zone, Grevillea robiista. trees and Meliiiis minutiflora grass mats were invading the Rhynchelytrum repens community. Artdropogon virginiciis, introduced in 1932, formed a wide spread herbaceous community in the humid zone. In some places, this community was invaded by Dicranopteris linearis fern mats and trees of Acacia, koa or Metrosideros collina. Fire in both the summer-dry and humid zones maintained and extended the grass communities

The PABITRA Project: Island landscapes under global change

The Pacific-Asia Biodiversity Transect (PABITRA) is a network of the Ecosystem Division in the Pacific Science Association's Task Force on Biodiversity. The PABITRA project seeks to develop a network of ocean-to mountain transects on islands across the Pacific to test hypotheses about biodiversity and promote sustainable use of island ecosystems under the influence of global change. A specific objective of PABITRA was to establish an ocean to-mountain transect in Fiji with major involvement of the resident islanders. Along this transect, a number of biodiversity study sites were to be selected for further research. The transect was established during two consecutive field workshops, from 18 November to 3 December 2002. Involved were 25 University of the South Pacific (USP) students, eight local faculty including Fiji Government and nongovernmental organization officials, and seven overseas collaborators. The outcome was documented in a 69-page illustrated report issued by the USP Institute of Applied Sciences as well as at a special symposium presented during the 20th Pacific Science Congress in Bangkok (17-21 March 2003) titled "Island Landscapes under Global Change: the PABITRA Project." Seven papers presented by members of the Fijian PABITRA group are published here, following this introductory paper. In addition, five papers introducing PABITRA activities outside Fiji are included in this special issue. The PABITRA project is ongoing and it is hoped that these papers will stimulate broad interest and participation in PABITRA's key objectives of promoting integrative resource management in Pacific Island environments

Ohia rain forest study: ecological investigations of the ohia dieback problem in Hawaii

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.This final report summarizes the more important results of a two year study of the ohia (Metrosideros collina subsp. polymorpha) rain forest, extending from within Hawaii Volcanoes National Park north across the east flank of Mauna Kea, Island Hawaii. The study focus was on the ohia dieback which occurs in many areas of this terrain. A 1:48,000 vegetation map was produced, which is included in selected copies of this report. In addition, an independent habitat classification was developed from physical soil and moisture regime differences occurring in the area. Over 35 ohia forest stands were sampled in detail for their ohia population structures and 39 releves were analyzed for their floristic content. Five different forms of dieback were recognized. Two of these, called the Dryland and Wetland Diebacks appear to be the more rapid and dramatic forms. Their causes are not from disease or insect attack, but are presumed to be from climatic triggers, acting through the soil. These diebacks are clearly associated with ohia-stand rejuvenation. A third form of dieback, here called Bog-formation Dieback, appears to be a slower form of stand dieback related to permanent site changes. An Ohia-displacement Dieback occurs in the Olaa Tract area, where tree ferns seem to gradually take over the habitats. Here the dieback cause appears to be overmaturity. Individual tree dieback, the fifth form of dieback, is found as an isolated, but common phenomenon in many non-dieback stands examined. All diebacks appear to have natural causes, which are suggested in detail. A new theory is presented, which proposes that there are a number of dynamic phases, including the dieback, which provide for the perpetuation of the shade-intolerant, dominant tree species (ohia) in this rainforest ecosystem.National Park Service Contract No. CX 8000 6 000

ガラパゴスのスカレシア林の個体群構造、一斉枯死、再生について

The original publication is available at www.springerlink.co

'Ohi'a Dieback in Hawaii: 1984 Synthesis and Evaluation

Attention is first drawn to the state of knowledge in 1981 of the Hawaiian Metrosideros polymorpha ('ohi'a) stand dieback. New findings that have largely been developed or published since then are described; these encompass vegetation, soils, hydrology, climatology, and experimental, historical and evolutionary research. A brief comparison of canopy dieback in Hawaii with that in other forest systems is made. New facts on the Hawaiian dieback are summarized within the context of climatic instability, soil, and stand factors . These facts are then related to ideas of environmental disturbance, disease , and cohort senescence. There are strong indications that the primary factor causing 'ohi'a dieback develop s in the dieback population itself due to synchronized aging of cohort stands. External abiotic (environmental) and biotic stress factors (insects and fungal pathogens) appear to play secondary and/or subsidiary roles , respectively. Based on this new knowledge, policy and management considerations are discussed with regard to the role of dieback and its impact on preserve design, forest hydrology, and soil fertility . Finally, a number of recommendations are made for new management-related research and for further research into the etiology of canopy dieback

The ohia dieback problem in Hawaii: a proposal for integrated research

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The current status of ohia (Metrosideros collina subsp. polymorpha) forest dieback research in Hawaii is reviewed, and a proposal is made for a relatively small integrated complementary program. This is suggested to consist of five subprojects to be carried out primarily by graduate student dissertation research. The five subprojects are: (1) to determine the percent cover of defoliated crowns in the ohia rainforest by remote sensing techniques and to develop a monitoring program, (2) to develop a large scale vegetation map on the basis of structural criteria, (3) to carry out a detailed floristic sampling by many small sample plots and to study by structural analyses techniques the dynamic trends of the woody species populations in a few, large sample plots, (4) to map and study the substrate variations in terms of soil nutrient and soil water regimes to develop a habitat classification for watershed purposes and (5) to study by experimental procedures in the field and in a glass house the response of ohia trees and seedlings to irrigation treatments with natural seepage water from dieback areas. The experimental subproject will be designed further for testing the performance of different Metrosideros ecotypes under different moisture and nutrient regimes. The program is developed to verify or discard the alternate hypothesis that the ohia dieback is a natural phenomenon of primary succession rather than a pathological disease problem as is pursued by the current ohia dieback research of other institutions.National Park Service Science Cente

The biological resource value of native forest in Hawaii with special reference to the tropical lowland rainforest at Kalapana

"A report prepared on request of Bio Power Corporation President Mr. Warren Ramey."A public controversy has arisen over the recent logging and wood chipping operation in native forest at Kalapana. I got involved at a point where the argument of dispute was whether the forest at Kalapana was unique or not. The question of uniqueness is important with regard to future land management of this area, but uniqueness is not the only aspect worth considering. This I will explain later in my conclusions. A sizeable segment of the interested public considers the forest unique, while the landowner (Campbell Estate Corporation) and the logging company (Bio Power Corporation) are not convinced of the uniqueness of this native forest. Therefore, more information was requested specifically by Mr. Warren Ramsey, the President of Bio Power Corporation, who agreed to mitigate his operation orentirely pull out of the area if more creditable evidence could begiven.Mr. Ramsey's request for such information came to me inform of a letter dated December 27, 1984. His letter was a response to a December 18 letter of mine, which summarized some of the points I had presente