Pacific Science Volume 53, Number 4, 1999

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Pacific Science is a quarterly publication devoted to the biological and physical sciences of the Pacific Region.


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Now showing 1 - 5 of 12
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    53: Index - Pacific Science
    (University of Hawai'i Press, 1999-10)
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    Measuring Stem Growth Rates for Determining Age and Cohort Analysis of a Tropical Evergreen Tree
    (University of Hawai'i Press, 1999-10) Gerrish, Grant ; Mueller-Dombois, Dieter
    Metrosideros polymorpha (Myrtaceae) is the dominant canopy tree in many Hawaiian lowland and montane rain forests. It is a shade-intolerant species that persists throughout forest succession. Stands usually regenerate following synchronized dieback of the canopy cohort. Like most tropical evergreen trees, Metrosideros does not form growth rings, making determination of tree age and stand turnover rates difficult. This study measured the annual stem diameter growth rate for 3 yr in cohorts of six different stem size classes on young volcanic substrates at 1100 m above sea level on the island of Hawai'i. These side-by-side cohorts were assumed to represent a chronosequence of stand development in early primary succession. Growth rates were used to predict mean cohort tree age based on mean tree diameter, adjusting for variation in growth rate during the life cycle of the trees. Mean annual growth rate was about 2 mm yc1 for all the cohorts except the largest, which was significantly lower. This cohort was undergoing stand dieback, with regeneration of a new cohort and is assumed to represent the terminal stage of the cohort life cycle. The predicted age of this cohort was about 200 years; this appears to be a reasonable estimate of the turnover rate for cohorts in this environment. Individual growth rates within cohorts were highly variable. Other parameters, such as crown area and nearest neighbor distances, could not account for the variation. Analysis indicates that the growth rate of each individual tree probably fluctuates about the mean growth rate throughout its life. Year-to-year variation in mean cohort growth rates was significant only for the two largest cohorts. For these large trees, mean growth rate was negatively associated with rainfall. It is suggested that these trees may be light limited, because solar radiation itself is known to be negatively correlated with annual rainfall in the study area.
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    Hawaiian Plant DNA Library II: Endemic, Indigenous, and Introduced Species
    (University of Hawai'i Press, 1999-10) Randell, Rebecca A. ; Morden, Clifford W.
    The Hawaiian Plant DNA Library of endemic and indigenous plant species preserves genetic material from all Hawaiian Islands. DNA accession numbers are reported here for 155 native species representing 92 genera and 48 families. Federal status of endangered species is indicated where applicable. Accessions for 71 species in 52 genera and 10 families of introduced species are also reported. Pest and invasive species are also indicated.
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    Twenty Years of Disturbance and Change in Fagatele Bay National Marine Sanctuary, American Samoa
    (University of Hawai'i Press, 1999-10) Green, A.L. ; Birkeland, C.E. ; Randall, R.H.
    Fagatele Bay National Marine Sanctuary contains a moderately diverse coral reef community (150 coral species, 259 fish species) that is protected from most human activities. The coral community was devastated by a crown-of-thorns starfish invasion in 1979 and has recently been affected by two major hurricanes (1990 and 1991) and a period of unusually high water temperature (1994). Long-term monitoring of the sanctuary allows for description of the effects of these disturbances in the absence of anthropogenic processes. The crown-of-thorns damaged deeper portions of the coral communities most severely, whereas the hurricanes and warm water affected shallower portions to a greater degree. Soon after these disturbances, corals started recruiting abundantly and the reefs began to recover. This is in contrast to some other areas in American Samoa, where chronic anthropogenic effects seem to have inhibited coral recruitment and reef recovery. Fish communities were affected by the habitat degradation associated with the crown-of-thorns outbreak, but have remained relatively unchanged ever since.
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    New and Previous Records of Scleractinian Corals from Clipperton Atoll, Eastern Pacific
    (University of Hawai'i Press, 1999-10) Carricart-Ganivet, Juan P. ; Reyes-Bonilla, Hector
    Clipperton Atoll was visited from 23 to 25 November 1997. A total of 109 specimens of stony corals belonging to two orders, seven families, and 15 species was collected. Five taxa of Scleractinia represent new records for the atoll: Porites lutea, Porites australiensis, Psammocora superficialis, Astrangia sp., and Balanophylliasp. With these new records and species previously reported in the literature, the total number of scleractinians now known at Clipperton Atoll is 18 species. Observations on the fossil terraces on the island and on the dead coral fauna of the inner lagoon are presented.
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