Pacific Science 60, no. 1
Effects of Water Removal on a Hawaiian Stream Ecosystem
Robert A. Kinzie III, Charles Chong, Julia Devrell, Dan Lindstrom, and Reuben Wolff, pp. 1–47
Abstract: A 3-year study of Wainiha River on Kaua‘i, Hawai‘i, was carried out to determine the impact that water removal had on key stream ecosystem parameters and functions. The study area included a diversion dam for a hydroelectric plant that removes water at an elevation of 213 m and returns it to the stream about 6 km downstream at an elevation of 30 m. There were two highelevation sites, one with undiverted flow and one with reduced flow, and two low-elevation sites, one with reduced flow and one with full flow restored. Monthly samples were taken of instream and riparian invertebrates and plants. When samples from similar elevations were compared, dewatered sites had lower concentrations of benthic photosynthetic pigments than full-flow sites, and benthic ash-free dry mass (AFDM) was higher at the two low-elevation sites regardless of flow. Benthic chlorophyll a (chl a) and AFDM were higher in summer months than in the winter. Benthic invertebrate abundance was highest at the full-flow, low-elevation site and benthic invertebrate biomass was highest at the full-flow, high-elevation site. Season had only marginal effects on abundance and biomass of benthic invertebrates. Diversity of benthic invertebrates was higher at the more-downstream sites. Abundance of drifting invertebrates was highest at the site above the diversion dam and generally higher in winter than in summer months. Biomass of drifting invertebrates was also highest at the above-dam site but there was little seasonal difference. Almost all parameters measured were lowest at the site just downstream of the diversion dam. The biotic parameters responded only weakly to flows that had occurred up to 1 month before the measurements were made. Flow, elevation, and season interact in complex ways that impact ecosystem parameters and functions, but water diversion can override all these environmental factors.
Baseline Climatology of Viti Levu (Fiji) and Current Climatic Trends
Melchior Mataki, Kanayathu C. Koshy, and Murari Lal, pp. 49–68
Abstract: In this paper we characterize the climate at Nadi and Suva in Fiji from 1961 to the present, providing a picture of ongoing climate trends. The focus is on surface observations of air temperature and rainfall, although some information on South Pacific Ocean climate is also discussed, given its relevance for Fiji. Our findings suggest that surface air temperatures have registered increasing trends at both Suva and Nadi (the two observatory sites in Fiji identified as Weather Observing Stations under the global network of the World Meteorological Organization) during the period 1961–2003. There has been a steady increase in the number of days per year with warmer nighttime temperatures in recent decades. The rise in annual mean surface air temperature over Suva was ~1.2 °C over the 43-yr period considered here (at a significantly increasing rate of 0.25 °C per decade, which is 1.5 times higher than the trends in global average temperature increase during the past century). The rate of increase in annual mean surface air temperature at Nadi was 0.07 °C per decade. No trend in annual mean rainfall has been observed, however, at either of the locations. Significant interannual variability in annual as well as summer rainfall observed at both sites (including extreme rainfall events during the 43-yr period) can largely be attributed to El Niño–Southern Oscillation (ENSO) events and intraseasonal oscillations in the mean position of the South Pacific Convergence Zone.
Vertebrates of Tetepare Island, Solomon Islands
John L. Read and Katherine Moseby, pp. 69–79
Abstract: Tetepare is the largest unlogged and uninhabited lowland rain-forest island in the South Pacific and is being managed primarily for conservation. An inventory was conducted, and 25 reptile, 4 frog, 76 bird, and 13 mammal species were recorded from Tetepare, including several birds and turtles of international conservation significance. Their relative abundance and local names were collected to assist landowners in attracting researchers and ecotourists and also to develop a conservation management plan for Tetepare.
Marine Algae of French Frigate Shoals, Northwestern Hawaiian Islands: Species List and Biogeographic Comparisons
Peter S. Vroom, Kimberly N. Page, Kimberly A. Peyton, and J. Kanekoa Kukea-Shultz, pp. 81–95
Abstract: French Frigate Shoals represents a relatively unpolluted tropical Pacific atoll system with algal assemblages minimally impacted by anthropogenic activities. This study qualitatively assessed algal assemblages at 57 sites, thereby increasing the number of algal species known from French Frigate Shoals by over 380% with 132 new records reported, four being species new to the Hawaiian Archipelago, Bryopsis indica, Gracilaria millardetii, Halimeda distorta, and an unidentified species of Laurencia. Cheney ratios reveal a truly tropical flora, despite the subtropical latitudes spanned by the atoll system. Multidimensional scaling showed that the flora of French Frigate Shoals exhibits strong similarities to that of the main Hawaiian Islands and has less commonality with that of most other Pacific island groups.
A Vermetid Gastropod with Complex Intracapsular Cannibalism of Nurse Eggs and Sibling Larvae and a High Potential for Invasion
Megumi F. Strathmann and Richard R. Strathmann, pp. 97–108
Abstract: A vermetid gastropod, previously unreported from the Pacific Ocean, was found at O‘ahu, Hawai‘i, in aquariums at the Kewalo Marine Laboratory, in fouling communities on docks, and on intertidal and shallow subtidal coral rubble. It also occurs on coral rubble in Florida. Eggs, or nurse eggs, and early embryos are about 100 µm in diameter. Young are brooded in 1–13 stalked capsules attached inside the tubular shell. Intracapsular development involves an unusual complex adelphophagy (sibling cannibalism). Most eggs are nondeveloping nurse eggs. Ten to 20 eggs develop into apparently normal small veligers. Of these most arrest as small veligers, but a few grow to hatch as large pediveligers or juveniles. The species has a high potential for invasion and establishment following maritime transport or natural rafting. Protected intracapsular development ends with the release of crawling hatchlings that also produce mucous threads on which they can drift. Juveniles settle readily on hard substrata. An apparent rarity or absence of males suggests long-term sperm storage, hermaphroditism, or parthenogenesis, any of which could aid colonization. Adults and juveniles occur in fouling communities and can survive extended periods in still seawater and at low food levels. The species’ global distribution and history of invasions are unknown. We predict widespread distribution and invasions in warm waters.
Anguilla marmorata (Giant Mottled Eel) Discovered in a New Location: Natural Range Expansion or Recent Human Introduction
Alex Handler and Shelley A. James, pp. 109–115
Abstract: Freshwater eels in the family Anguillidae spend a majority of their adult life in freshwater but migrate to the ocean to spawn and die. Because freshwater eels are believed to have a long larval period in the open ocean, it is unclear how the present global distribution of species arose. A stock of freshwater eels of the family Anguillidae was found on Palmyra Atoll in the central Pacific Ocean, in June 2003. In October 2003, a single eel specimen was caught using a hand net from this small group of eels on Palmyra Atoll. Morphological and molecular characters (12S and 16S mitochondrial rRNA and cytochrome b mtDNA sequences) were used to identify the species as Anguilla marmorata Quoy & Gaimard. The discovery of these eels on Palmyra supports the hypothesis of natural range expansion from the Indo-Pacific eastward to the Galápagos through the Line Islands, but further analysis of oceanic currents and more variable genes are required to assess whether humans are involved in the recent spread of Anguilla marmorata to these new locations.
Bryoliths (Bryoza) in the Gulf of California
D. W. James, M. S. Foster, and J. O’Sullivan, pp. 117–124
Abstract: Populations of Diaperoforma californica (d’Orbigny) bryoliths were discovered in rhodolith beds, a sand habitat, and on a cobble bottom in the Gulf of California, Mexico, the first known observation of a modern free-living cyclostome bryozoan in the Northern Hemisphere. Densities ranged from a mean of 9.2 to 22.6 individuals/0.06 m2. Bryoliths from the deepest site were irregularly shaped and had the highest variation in shape; those from shallow sites were spheroidal. Water motion and bioturbation move the bryoliths and may determine their morphology. Schizomavella robertsonae (Soule, Soule & Chaney) bryoliths also occurred occasionally in one rhodolith bed sampled. Fossilized bryolith specimens of the cyclostome Diaperoforma californica (d’Orbigny) were found in a Pleistocene deposit near modern habitats.
A New Genus and Species of Diplodactylid Gecko (Reptilia: Squamata: Diplodactylidae) from Northwestern New Caledonia
Aaron M. Bauer, Todd Jackman, Ross A. Sadlier, and Anthony H. Whitaker, pp. 125–135
Abstract: A new genus and species of diplodactylid gecko, Oedodera marmorata Bauer, Jackman, Sadlier & Whitaker, is described from low-elevation maquis habitat near Paagoumène in the northwest of the Province Nord, New Caledonia. The new gecko is a robust form that is superficially similar to members of the genus Bavayia Roux but differs in several digital characteristics, the presence of a patch (versus 1–2 rows) of precloacal pores, and a uniquely swollen neck. In addition, molecular data indicate that the new form is the basal member of the entire radiation of New Caledonian diplodactylids. The new species is at risk due to wildfires, introduced predators and perhaps competitors, and planned mine development into part of its range.
A New Species of Extinct Parrot (Psittacidae: Eclectus) from Tonga and Vanuatu, South Pacific
David W. Steadman, pp. 137–145
Abstract: A new extinct species of parrot, Eclectus infectus Steadman, is described from 21 bones from archaeological (late Holocene) and paleontological (late Pleistocene) sites on three islands in the Kingdom of Tonga, with limited referred material (ulna, tibiotarsus) from a late Holocene archaeological site on Malakula, Vanuatu. Probably, therefore, the range of E. infectus also included at least the intervening island group of Fiji. The extinction of E. infectus occurred since the arrival of people in this region ca. 3,000 yr ago and presumably was due to human impact. A single, very fragmentary parrot tibiotarsus from Rota (Mariana Islands) may pertain to an indeterminate species of Eclectus. The only extant species of Eclectus is E. roratus, which occurs from the Solomon Islands westward to the Moluccas. Eclectus infectus provides the first evidence of the genus east of the Solomon Islands, although its biogeographic implications are not unique. Within Oceania (outside New Zealand and the Hawaiian Islands), human activities have eliminated the easternmost species in at least 17 other genera of land birds.
Pacific Science Association, pp. 147–151
Pacific Science 60, no. 2
Community Structure of Hermatypic Corals at French Frigate Shoals, Northwestern Hawaiian Islands: Capacity for Resistance and Resilience to Selective Stressors
Jean C. Kenyon, Peter S. Vroom, Kimberly N. Page, Matthew J. Dunlap, Casey B. Wilkinson, and Greta S. Aeby, pp. 153–175
Abstract: Georeferenced towed-diver surveys covering more than 100,000 m2 of benthic habitat and site-specific surveys at 30 sites during 2000–2002 determined distribution and abundance of scleractinian corals at French Frigate Shoals (FFS), Northwestern Hawaiian Islands. Percentage cover of corals was quantified by genus or species in forereef, backreef, and lagoon habitats and at La Perouse Pinnacles using three complementary methods: towed-diver surveys, video transects, and photoquadrats. Habitat-specific colony density and size-class distributions from measurements made within belt transects at fixed sites indicated that three coral genera, Porites, Pocillopora, and Acropora, accounted for more than 93% of total coral cover throughout the atoll, and their relative percentage cover, densities, and size distributions varied according to habitat and geographic location within the atoll. These descriptive data, which provide the most comprehensive overview yet of the scleractinian coral community at FFS, were used to assess the coral reefs’ potential for resistance and resilience to selective stressors including bleaching, disease, and Acanthaster outbreaks. They also serve as a baseline for an ecosystem-based, long-term monitoring program with an objective of linking coral community change to other biological and physical factors.
Coral Reef Benthic Video Surveys Facilitate Long-Term Monitoring in the Commonwealth of the Northern Mariana Islands: Toward an Optimal Sampling Strategy
Peter Houk and Robert Van Woesik, pp. 177–189
Abstract: This study describes a step-by-step process used to design an effective benthic video survey component of the Commonwealth of the Northern Mariana Islands long-term monitoring program. Documenting abundance of major benthic groups at relatively large spatial scales, at the appropriate localities, can empower monitoring programs with the capacity to detect changes over time and assess whether management practices are working. Most pertinent to any long-term monitoring program is the overriding question: do we have enough information, or statistical power, to detect changes if changes occur? To assess the power of our benthic video surveys to detect change in coral cover and diversity we varied (1) transect lengths, (2) number of transects, (3) number of frames per transect, and (4) number of data points per frame. Five replicated 50-m transects yielded the most consistent estimates with the highest statistical power, compared with more numerous replicates of shorter (35-m and 15-m) transects. Increasing the number of frames analyzed per 50-m transect yielded greater power than increasing the number of data points per frame, but increasing the number of data points was more effective at estimating species richness. The greatest power of detecting a change in the benthos at each site, within a feasible sampling period, was evident using 5 by 50 m random transects, extracting 60 frames per transect, and analyzing five data points on each frame. This optimal sampling strategy was tested at 23 other long-term monitoring sites and yielded 90% power to detect a 20–30% relative change in dominant benthos abundance estimates (benthos >20% coverage). Our study addresses the sampling unit, accuracy, and ways to improve estimates, but this does not remove the onus of concisely stated questions for monitoring programs pertaining to management.
Stream Macroalgae of the Hawaiian Islands: A Floristic Survey
Alison R. Sherwood, pp. 191–205
Abstract: Between January 2001 and May 2003, 167 stream segments on the islands of Kaua‘i, O‘ahu, Maui, and Hawai‘i were sampled for stream macroalgae and measured for a series of physical and chemical conditions. Conditions ranged more widely than previously reported, which is likely due to the greater diversity of habitats accessed and the year-round sampling representation in this study. Water temperature ranged from 12.5 to 27.5 °C (mean = 21.4 °C ± 2.4), pH from 5.5 to 8.9 (mean = 7.8 ± 0.5), and specific conductance from 20 to 490 µS·cm–1 (mean = 102 µS·cm–1 ± 75.9). A total of 160 specific and subspecific taxa was identified, of which 27 are new records for the Hawaiian Archipelago. The Chlorophyta compose the majority of the taxa, followed by the Cyanobacteria, Rhodophyta, Bacillariophyta, and Tribophyta. The mean number of taxa per stream segment was 5.0 ± 2.7, which is the highest such value reported. Grouping of taxa by morphological form demonstrates that the majority of taxa were free filaments (58%), followed by mats (17%), tufts (13%), and gelatinous colonies (9%). A principal coordinates analysis of the stream sites indicated that a high degree of overlap in floristic composition is evident for most of the Islands, and only sites on the island of Hawai‘i exhibit a localized positioning to one side of the principal coordinates bi-plot. The flora of Hawai‘i Island appears to be unique only in the sense that it contains fewer broadly distributed taxa than the remaining islands, which may be a function of island age. Cluster analysis of the islands based on two types of comparisons suggests stronger similarities between the islands of Maui and Kaua‘i, and O‘ahu and Hawai‘i than previously reported. The Hawaiian stream macroalgal flora contains a number of cosmopolitan taxa, although it is recognized that concepts of some of these taxa may change with additional data.
Habitat Preferences and Site Fidelity of the Ornate Wobbegong Shark (Orectolobus ornatus) on Rocky Reefs of New South Wales
Robert Carraro and William Gladstone, pp. 207–223
Abstract: Habitat and microhabitat preferences and site fidelity of Orectolobus ornatus were assessed between September 2002 and August 2003 to assess potential suitability of marine reserves for its conservation. Of six rocky reef habitats available in the study area (sponge gardens, artificial structures, barren boulders, sand, sea grass, macroalgae), O. ornatus exhibited a significant preference for sponge gardens, artificial structures, and barren boulders habitats. Habitat preferences of males and females, and individuals <1 m and >1 m, did not differ. Orectolobus ornatus selected daytime resting positions with a high topographic complexity and crevice volume and did not select on the basis of prey availability. Habitat and microhabitat preferences may be related to the need for predator avoidance. Regular monitoring of 40 individually identified O. ornatus revealed that none was a permanent resident of the study area. Seven individuals exhibited short-term temporary fidelity to the study area; they were resighted frequently for part of an intensive 100-day survey. Remaining individuals were temporary visitors; they were resighted at most once after initial identification or returning after extended absences. Monthly population surveys confirmed the turnover of O. ornatus in the study area. The lack of long-term site fidelity suggests that small marine reserves will be ineffective as a conservation strategy for O. ornatus.
Life History Characteristics of a Small Cardinalfish, Ostorhinchus rubrimacula (Percoidei: Apogonidae), from Koro, Fiji
Ken Longenecker and Ross Langston, pp. 225–233
Abstract: We describe aspects of the life history of the small cardinalfish Ostorhinchus rubrimacula from a single, large collection taken at Koro, Fiji. We determined size at maturity and batch fecundity, examined otolith microstructure to construct a vonBertalanffy growth curve, described a length-weight relationship, and performed a dietary analysis. Ostorhinchus rubrimacula is a gonochore that matures at 35 mm standard length (SL). Batch fecundity is related to body size by the equation: eggs spawned = 0.0013(SL)3.8685. Assuming each otolith ring corresponds to 1 day in age, the oldest individual in our collection lived 274 days. Growth is described by the equation: SL = 40.84[l – e–0.014(age in days – 22.45)]. Total body mass (mg) = 4.806 · 10–6(SL)3.5163. Ostorhinchus rubrimacula feeds primarily on harpacticoid copepods, but isopods (mostly gnathidean) and polychaetes were also important dietary components.
Unusual Mortality of Krill (Crustacea: Euphausiacea) in Bahía de La Paz, Gulf of California
David J. López-Cortés, José J. Bustillos-Guzmán, and Ismael Gárate-Lizárraga, pp. 235–242
Abstract: Surface aggregations and beach strandings of a species of krill, Nematoscelis difficilis Hansen, were observed in June 2003 at locations along the shore of Bahía de La Paz in the Gulf of California. For 10 days before the krill die-off, a steady wind blew from the south at speeds between 4 and 5 m/sec. For that period, satellite images showed water temperatures between 18 and 22 °C along this coast, which is low compared with typical seasonal water temperatures of 26 to 28 °C for June. Phytoplankton biomass, determined by pigment concentration and cell counts, was the highest in the area in June. The diatom Chaetoceros debilis represented more than 96% of the phytoplankton community. Nutrients were in relatively higher concentrations. These data suggest that upwelling conditions occurred and the diatom bloom was in its final phase. Based on this limited data set, we present a hypothetical scenario describing the sea-surface aggregations and beach strandings of N. difficilis.
Ostracoda (Myodocopina) of Tutuila, American Samoa
Louis S. Kornicker and Elizabeth Harrison-Nelson, pp. 243–259
Abstract: Three species (two new) of myodocopid Ostracoda are reported from Tutuila, American Samoa: Paravargula trifax Kornicker, 1991; Cypridina mellentini Kornicker & Harrison-Nelson, n. sp.; and Asteropterygion samoa Kornicker & Harrison-Nelson, n. sp. Only C. mellentini was abundant. The genus Asteropterygion is reported for the first time from a southwestern central Pacific island. Paravargula trifax had been reported previously from Enewetak.
Analysis of Plant Microfossils in Archaeological Deposits from Two Remote Archipelagos: The Marshall Islands, Eastern Micronesia, and the Pitcairn Group, Southeast Polynesia
Mark Horrocks and Marshall I. Weisler, pp. 261–280
Abstract: Pollen and starch residue analyses were conducted on 24 sediment samples from archaeological sites on Maloelap and Ebon Atolls in the Marshall Islands, eastern Micronesia, and Henderson and Pitcairn Islands in the Pitcairn Group, Southeast Polynesia. The sampled islands, two of which are “mystery islands” (Henderson and Pitcairn), previously occupied and abandoned before European contact, comprise three types of Pacific islands: low coral atolls, raised atolls, and volcanic islands. Pollen, starch grains, calcium oxylate crystals, and xylem cells of introduced non-Colocasia Araceae (aroids) were identified in the Marshalls and Henderson (ca. 1,900 yr B.P. and 1,200 yr B.P. at the earliest, respectively). The data provide direct evidence of prehistoric horticulture in those islands and initial fossil pollen sequences from Pitcairn Island. Combined with previous studies, the data also indicate a horticultural system on Henderson comprising both field and tree crops, with seven different cultigens, including at least two species of the Araceae. Starch grains and xylem cells of Ipomoea sp., possibly introduced I. batatas, were identified in Pitcairn Island deposits dated to the last few centuries before European contact in 1790.
New Species of Rails (Aves: Rallidae) from an Archaeological Site on Huahine, Society Islands
Jeremy J. Kirchman and David W. Steadman, pp. 281–297
Abstract: We examined 50 bones previously assigned to “Gallirallus new sp.” from the prehistoric (1,250–750 yr B.P.) Fa‘ahia archaeological site on Huahine, Society Islands. Most of these specimens (n = 47), representing nearly all major cranial and postcranial skeletal elements, belong to a medium-sized flightless rail that we name Gallirallus storrsolsoni. Three femora represent a second species of extinct rail that we name Porphyrio mcnabi. With the description of these two species of rails, the total number of extinct species of land birds from the Fa‘ahia site stands at seven, consisting of two rails, two doves, two parrots, and a starling. Fa‘ahia also has yielded bones of six other species of land birds that no longer exist on Huahine but survive elsewhere in Oceania.
Recovery of Native Species following Rat Eradication on Mokoli‘i Island, O‘ahu, Hawai‘i
David G. Smith, Ethan K. Shiinoki, and Eric A. VanderWerf, pp. 299–303
Abstract: Rats were eradicated from Mokoli‘i, a 1.6-ha island off the east shore of O‘ahu, using snap traps, cage traps, and diphacinone bait stations. A total of 18 black rats (Rattus rattus) were caught, and 354 bait blocks were used. There was no sign of rats on the island after 27 May 2002. Wedge-tailed Shearwaters (Puffinus pacificus) nest on Mokoli‘i, but only a single chick survived during 1999–2001; the number of surviving chicks increased to 126 in 2002 and 185 in 2003. The number of intertidal invertebrates and native plants, including the endangered Carter’s panic grass (Panicum fauriei var. carteri ), also appeared to increase after rat eradication. Rats had a devastating impact on the flora and fauna of Mokoli‘i, and their eradication has allowed a dramatic recovery of native species. The majority of the labor for the eradication effort was provided by the local community, demonstrating what can be achieved with dedicated volunteers and community support.
Pacific Science Association, pp. 315–317
Pacific Science 60, no. 3
Conservation Value of Remnant Forest Patches: Tree Composition, Spatial Patterns, and Recruitment in the Ottoville Lowland Forest, American Samoa
Joshua O. Seamon, Sheri S. Mann, Orlo C. Steele, and Ruth C. B. Utzurrum, pp. 319–332
Abstract: Native forests increasingly have been reduced to remnant fragments on many Pacific islands. Island and continental ecosystems differ in a number of ways that may increase conservation value of such forest fragments on islands. However, few studies have examined performance of tree populations in Polynesian forest fragments. We tested potential conservation value of the largest contiguous patch of lowland lava flow forest on Tutuila, American Samoa, by determining uniqueness, potential vulnerability, and possible viability of the tree community therein. We recorded 1,186 trees ≥ 10 cm dbh (diameter at breast height) from 37 species in 12 transects (each 10 m wide) running from edge to edge across the forest, as well as 1,332 seedlings and 991 saplings within 62 miniplots (each 25 m2). Locations within the forest of all 462 trees ≥ 30 cm dbh, of the 10 most dominant species, were then plotted. The most dominant tree species was Pometia pinnata. Similarity indices between the study site and other protected forests on Tutuila were very low. Spatial distributions and abundances of adult trees, as well as the dispersed distribution of seedlings and saplings, suggested low vulnerability to spatially discrete disturbances. We found evidence of potential edge effects in seedling distributions of two species. Abundances of seedlings and saplings indicated a high potential for continued recruitment of characteristic tree species. Species composition of these recruits is largely composed of characteristic primary forest species rather than secondary forest or invasive species. These results show that even very small forest fragments may have substantial value for conservation, because they can combine high within-island uniqueness with a relatively high likelihood of persistence if left undisturbed.
Composition and Structure of Lowland Rain-Forest Tree Communities on Ta‘u, American Samoa
Edward L. Webb, Martin van de Bult, Wanlop Chutipong, and Md. Enamul Kabir, pp. 333–354
Abstract: This study examined the composition and structure of tropical rain forest in four permanent plots on the island of Ta‘u, American Samoa. Two 1-ha plots were established in coastal forest, one in an abandoned coastal cultivation site (a “plantation” ca. 17 yr post-abandonment) and another in a Dysoxylum samoense–dominated coastal forest. Two 2-ha plots were established in lowland forest at 200–250 m elevation, one in an abandoned plantation (ca. 13 yr post-abandonment) and the other in less-disturbed mid- to late-secondary mixed lowland forest. In the total 6 ha, we encountered 54 tree species, with Dysoxylum samoense the most dominant species overall and abundant in all four plots. The upper forest plot was the most diverse plot and exhibited low similarity with any of the other three plots. This plot exhibited a rarefaction curve similar to those of four lowland hill forest plots on Tutuila but was most similar in composition to regenerating disturbed forest on Tutuila rather than mature, less-disturbed forest. Low similarity was found between the two Dysoxylum-dominated coastal forests and the Dysoxylum-Pometia–dominated Ottoville lava flow forest on Tutuila. By examining the populations of D. samoense across the four plots we found an impact of agriculture and cyclones on height structure of the forest. Examination of species’ diameter class distributions allowed us to propose several hypotheses related to the life histories of several tree species. We documented the natural establishment of the introduced species Flueggea flexuosa into both abandoned plantations and natural forest. Monitoring these plots over time will allow us to better understand successional processes in natural and human-impacted forest including changes in composition, structure, relative abundance of nonnative species, as well as the impact of cyclones on different forest types.
Colonization of Nishino-shima Island by Plants and Arthropods 31 Years after Eruption
Tetsuto Abe, pp. 355–365
Abstract: Although many researchers have studied colonization, the process has rarely been observed on newly emerged oceanic islands. To describe the colonization process of a remote oceanic island, I investigated the flora, vegetation, and pollinators of Nishino-shima Island 31 yr after a major eruption in 1973. Nishino-shima Island, which is 22 ha in size, is located 1,000 km south of mainland Japan. Vegetation cover had increased, especially on new lowland area, since a preliminary survey done 10 yr after the eruption, but plant species richness remained poor (only six species). Thus, the plant colonization rate (0.10 species/yr) was far slower than that of other volcanic islands such as Krakatau. Most plants (four species) had ocean-dispersed seeds, but two species were likely dispersed via attachment to seabirds. Despite colonization by only a few plant species, there were abundant flower visitors including ants, bugs, a butterfly, and a fly ( but no bee species), and the average visitation rate per flower was 5.5 visits/12 hr in total observations. Most of the insects used multiple food sources, concurrently acting as scavengers or herbivores.
Influence of Propagule Flotation Longevity and Light Availability on Establishment of Introduced Mangrove Species in Hawai‘i
James A. Allen and Ken W. Krauss, pp. 367–376
Abstract: Although no mangrove species are native to the Hawaiian Archipelago, both Rhizophora mangle and Bruguiera sexangula were introduced and have become naturalized. Rhizophora mangle has spread to almost every major Hawaiian island, but B. sexangula has established only on O‘ahu, where it was intentionally introduced. To examine the possibility that differences in propagule characteristics maintain these patterns of distribution, we first reviewed the literature on surface currents around the Hawaiian Islands, which suggest that propagules ought to disperse frequently from one island to another within 60 days. We then tested the ability of propagules of the two species to float for periods of up to 63 days and to establish under two light intensities. On average, R. mangle propagules floated for longer periods than those of B. sexangula, but at least some propagules of both species floated for a full 60 days and then rooted and grew for 4 months under relatively dense shade. A large percentage (~83%) of R. mangle propagules would be expected to float beyond 60 days, and approximately 10% of B. sexangula propagules also would have remained afloat. Therefore, it seems likely that factors other than flotation ability are responsible for the failure of B. sexangula to become established on other Hawaiian islands.
Current Extent and Historical Expansion of Introduced Mangroves on O‘ahu, Hawai‘i
Rodney A. Chimner, Brian Fry, Mahealani Y. Kaneshiro, and Nicole Cormier, pp. 377–383
Abstract: In Hawai‘i, mangrove trees are introduced species that can rapidly colonize many nearshore environments. Mangroves have been introduced on O‘ahu, and Rhizophora mangle in particular has created numerous problems that have led to several mangrove removals and increased interest in long-term management of mangroves. The objective of this project was to quantify current locations of mangroves and their historical rate of expansion on O‘ahu. We used the Geographic Information System (GIS) to map mangroves from digitized air photographs from six time periods: 1951–1953, 1963–1965, 1978, 1982, 1991, and 2001. We found that mangroves are still expanding at a rapid rate on O‘ahu 80 yr after their introduction. Mangroves have colonized many different landforms, including tidal flats, riverbanks, fishponds, canals, protected reefs, embayments, lagoons, and other protected areas. Currently, mangroves are widely distributed and occur on all coasts except the dry leeward coast and occupy a total of 147 ha. Roughly 70% (102 ha) of all mangroves occur in Pearl Harbor.
Population Dynamics of Marsilea villosa (Marsileaceae) on O‘ahu, Hawai‘i
Lyndon Wester, John Delay, Lam Hoang, Byron Iida, Nicholas Kalodimos, and Tamara Wong, pp. 385–402
Abstract: Marsilea villosa Kaulfuss is an endemic Hawaiian fern with a very small, fragmented natural range and an ephemeral habit that makes it difficult to assess population health. Its sporocarps are presumed to remain viable for many years, allowing it to survive periods of drought and then sexually reproduce when there is sufficient precipitation to cause them to be submerged in standing water. Surveys of plant cover at ‘Ihi‘ihilauākea Crater, where the largest and best-protected stand was located, have shown that vigorous growth of the species occurs after the crater floor is flooded. This study documents dramatic decline over the last 8 yr, during which growth has been largely vegetative. Analyses of rainfall records suggest that events producing long-duration floods occur on average every 6.5 yr, yet 13 yr have elapsed since the last one. Although this may in part explain the poor condition of the population, other ecological changes have occurred including decline of the dominant trees and invasion of alien grasses that may influence flooding frequency. Marsilea villosa may be able to avoid extinction because flooding caused by rare climatic events will kill off the competitors that have encroached on its former ecological space. However, it is predicted to be a less-conspicuous part of the ecosystem most of the time unless management can effectively suppress invaders.
A New Eastern Limit of the Pacific Flying Fox, Pteropus tonganus (Chiroptera: Pteropodidae), in Prehistoric Polynesia: A Case of Possible Human Transport and Extirpation
Marshall I. Weisler, Robert Bollt, and Amy Findlater, pp. 403–411
Abstract: Five bones, representing one adult of the Pacific Flying Fox, Pteropus tonganus, were recovered from an archaeological site on Rurutu (151° 21′ W, 22° 27′ S), Austral Islands, French Polynesia, making this the most eastern extension of the species. For the first time, flying fox bones from cultural deposits were directly dated by accelerator mass spectrometry, yielding an age of death between A.D. 1064 and 1155. Their stratigraphic position in an Archaic period archaeological site and the absence of bones in the late prehistoric to historic layers point to extirpation of the species. No flying fox bones were found in prehuman deposits and human transport of the species cannot be ruled out.
Ants (Hymenoptera: Formicidae) of Niue, Polynesia
James K. Wetterer, pp. 413–416
Abstract: Niue is a single isolated island in Polynesia. Based on reexamination of specimens from an earlier study and unpublished specimen data, I removed three erroneous records from the list of known ants from Niue (Paratrechina flavipes, Pheidole mus, and Tetramorium bicarinatum), corrected one name (Monomorium liliuokalanii instead of Monomorium monomorium), and added one new species record (Vollenhovia samoensis). Of the 33 ant species I report from Niue, 18 are Indo-Pacific natives and 15 are exotics. The ant fauna of Niue is almost entirely a subset of the fauna of neighboring Tonga and Samoa. Of the ant species native to the Indo-Pacific region found in Niue, only one was not also known from both Tonga and Samoa. Most or all of the other 17 species seem likely to be native to Niue (i.e., predating human arrival). This is particularly apparent for a local endemic species, V. samoensis, which was once considered to be a Samoan endemic but is now also known from Tonga and Niue.
First Record of Brachiopods from the Marquesas Islands, French Polynesia, South Central Pacific
Maria Aleksandra Bitner, pp. 417–424
Abstract: Two species of Recent brachiopods, Eucalathis cf. murrayi and Frenulina sanguinolenta, have been identified in the collection from the Musorstom 9 Expedition to the Marquesas Islands in 1997. They represent the first record of brachiopods from the Marquesas Islands. Both species previously have been reported from the western Pacific, and F. sanguinolenta is also known from Hawai‘i in the North Central Pacific. Presence of these species in the Marquesas extends the eastern boundary of their biogeographic range. The brachiopods from the Marquesas show very low diversity when compared with the fauna from the western Pacific, as well as with that from the Hawaiian Islands. This decrease in number of species in the Pacific from west to east is also observed in other benthic invertebrate groups.
Pacific Science Association, pp. 425–428
Pacific Science 60, no. 4
Invasion of French Polynesia by the Glassy-Winged Sharpshooter, Homalodisca coagulata (Hemiptera: Cicadellidae): A New Threat to the South Pacific
Julie Grandgirard, Mark S. Hoddle, George K. Roderick, Jérôme N. Petit, Diana Percy, Rudolph Putoa, Charles Garnier, and Neil Davies, pp. 429–438
Abstract: The glassy-winged sharpshooter, Homalodisca coagulata (Say), is a major pest of agricultural, ornamental, and native plants. It is native to the southeastern United States and northeastern Mexico. Homalodisca coagulata was first recorded in Tahiti (French Polynesia) in 1999. It reproduced and spread rapidly in French Polynesia and is currently found in almost all islands in the Society Islands group (Tahiti, Moorea, Raiatea, Huahine, Bora Bora, Tahaa, Maupiti), in Nuku Hiva in the Marquesas, and in Tubuai and Rurutu in the Australs. Tahiti and Moorea are the most heavily infested islands, where H. coagulata populations have reached densities far exceeding those observed in California (this pest invaded California in the late 1980s) or in its native range. Major factors responsible for high population densities of H. coagulata in French Polynesia are permissive environmental conditions (mild climate and abundant year-round feeding and oviposition substrates), absence of host-specific natural enemies, intoxication of generalist predators that attack nymphal and adult stages, and limited competition for resources. Homalodisca coagulata causes several problems in French Polynesia: dripping excreta from high densities of feeding adults and nymphs affect outdoor recreation under trees and create a social nuisance, attraction of large numbers of flying adults to lights at night and collisions with people are severe annoyances, and large numbers of H. coagulata feeding on plants can cause impaired growth. The major concern for French Polynesia is the possibility of this pest acquiring and vectoring the lethal plant bacterium Xylella fastidiosa, which could have a disastrous impact on ornamental, agricultural, and native plants. Surveys are currently under way to detect X. fastidiosa in French Polynesia. Presence of large populations of H. coagulata in French Polynesia presents a major threat to agriculture and the biodiversity of South Pacific countries because this insect has clearly demonstrated a high invasion potential.
Historical Review of Control Programs for Levuana iridescens (Lepidoptera: Zygaenidae) in Fiji and Examination of Possible Extinction of This Moth by Bessa remota (Diptera: Tachinidae)
Mark S. Hoddle, pp. 439–453
Abstract: Coconut production in Fiji was a mainstay of the economy and indigenous culture in the late 1800s to early 1900s. From around 1877 coconut production on Viti Levu was severely affected by Levuana iridescens Betheune-Baker, a small purple moth, whose larvae trenched the underside of coconut leaves. A variety of cultural and chemical control strategies over approximately a 16-yr period failed to bring this pest under effective control. A biological control program initiated in 1925 resulted in importation and release of a parasitic fly, Bessa remota (Aldrich), which provided immediate and effective control of L. iridescens. This well-documented classical biological control program has subsequently become highly controversial with regard to arguments over endemicism of L. iridescens to the Fijian archipelago and the possibility that B. remota has caused the extirpation of L. iridescens and the endemic Heteropan dolens Druce in Fiji. A synopsis is provided of the cultural, chemical, and biological control programs for L. iridescens in Fiji. In addition, evidence for extinction of L. iridescens and H. dolens is examined through an analysis of little-known literature and neglected museum records. It is suggested that the reason for lack of reports of L. iridescens after 1956 was due to the declining value of copra, which resulted in less research on coconuts; the recall from Fiji of entomologists that worked on the L. iridescens control program by the Imperial Bureau of Entomology; and the subsequent increased abundance of another leaf-trenching lepidopteran, Agonoxena argaula Meyrick, which would have made easy detection of low-density L. iridescens populations difficult. To verify the continued presence of L. iridescens and H. dolens in Fiji will require a comprehensive campaign employing visual searches of coconut palm fronds, the use of ground and aerial malaise traps, canopy fogging, and perhaps chemical analysis of unidentified lepidopteran pupal cocoons found on the thatch of coconut fronds for comparison with chemical profiles of known L. iridescens cocoons.
A 19-Year Study of the Dynamics of an Invasive Alien Tree, Bischofia javanica, on a Subtropical Oceanic Island
Kenji Hata, Jun-Ichirou Suzuki, Naoki Kachi, and Yasuo Yamamura, pp. 455–470
Abstract: A 19-yr study of the dynamics of an invasive alien species, Bischofia javanica Blume, in a secondary forest was conducted in the Bonin Islands, Japan. The study was begun in 1984 when another alien species, Pinus luchuensis Mayer, had begun to die because of infection by a pine nematode as well as typhoon damage in 1983. Diameters at breast height (DBHs) of all trees in a 20 by 20 m plot and heights of all saplings (<1.3 m, ≥0.3 m in height) were measured almost every 3 yr. The total basal area of P. luchuensis decreased over time, and all trees had fallen over by 1998. The total basal area of B. javanica increased more than 10-fold over 19 yr without changes in tree or sapling density. Up to 1990, growth rates of trees of B. javanica were higher than those of two native canopy trees (Pouteria obovata and Machilus kobu), but a third native canopy tree (Schima mertensiana) had growth rates comparable with those of B. javanica. After 1990, there were few differences between growth rates of B. javanica and native species. However, mortality and recruitment of B. javanica were lower than those of native species of canopy trees during the survey period. The higher growth rate, lower mortality, and lower recruitment led to a shift from a skewed size distribution of the individuals of B. javanica toward a more bellshaped size distribution. Our results suggest that regeneration and maintenance of B. javanica populations in the secondary forests depend on canopy gaps occasionally created by disturbances.
Arbuscular Mycorrhizae Effects on Growth of Two Hawaiian Species: Indigenous Osteomeles anthyllidifolia (Rosaceae) and Invasive Psidium cattleianum (Myrtaceae)
R. E. Koske and J. N. Gemma, pp. 471–482
Abstract: Two important plant species of Hawai‘i, the indigenous Osteomeles anthyllidifolia (Sm.) Lindl., a component of Hawai‘i’s most endangered habitat, and the highly invasive Psidium cattleianum Sabine were grown with or without arbuscular mycorrhizal fungi in a soilless mix at different soil-solution phosphorus (P) levels. At P levels similar to those in the field (0.007 mg P/liter), shoot biomass of inoculated plants of O. anthyllidifolia was 189% greater than that of controls, and that of P. cattleianum was 93% greater. Root weight of O. anthyllidifolia and leaf-tissue P of both species also were significantly higher in inoculated plants. At a higher concentration of soil-solution P (0.020 mg P/liter), inoculated plants of O. anthyllidifolia had 176% more biomass than controls, and those of P. cattleianum had 49% more. In a growth medium with soil-solution P equivalent to that of good agricultural soil (0.200 mg P/liter), inoculated plants of O. anthyllidifolia were 101% larger than controls. Results suggest that presence of arbuscular mycorrhizal fungi is of vital importance to establishment of O. anthyllidifolia in Hawaiian soils and that their absence may limit P. cattleianum invasion of sites that are highly deficient in available P.
Rapid Assessment of Nonindigenous Marine Species on Coral Reefs in the Main Hawaiian Islands
S. L. Coles, F. L. M. Kandel, P. A. Reath, K. Longenecker, and L. G. Eldredge, pp. 483–507
Abstract: Coral reefs at Kaua‘i, O‘ahu, Moloka‘i, Maui, and Hawai‘i were surveyed using a rapid assessment method for marine nonindigenous and cryptogenic species commonly found in Hawaiian harbors and embayments with restricted circulation. In 41 sites surveyed by rapid assessment 26 nonindigenous and cryptogenic species (three algae, 19 invertebrates, and four fishes) were recorded from a total of 486 total taxa identified, and 17 of the nonindigenous and cryptogenic species occurred at only one or two sites. No more than six nonindigenous and cryptogenic species were recorded at any one site, and 21 of the 41 sites had fewer than three. By comparison, laboratory identification of samples collected from seven of the sites closest to harbors found 6–23 nonindigenous and cryptogenic species per site. Values for nonindigenous and cryptogenic species from rapid assessment were compared with factors potentially influencing spread and proliferation of introduced marine species. These factors included distances from harbors, boat-launching ramps, stream mouths, and shorelines; degree of shoreline urbanization; quantity of artificial surfaces in the water; reef condition and isolation from the open ocean; and native species richness. A best subsets regression model explained over 65% of the variance in nonindigenous and cryptogenic species from two predictor variables and their interaction: isolation from the open ocean and number of native taxa, with most of the variance explained by a highly significant relationship of nonindigenous and cryptogenic species with isolation from open-ocean conditions.
Nearshore Distribution and an Abundance Estimate for Green Sea Turtles, Chelonia mydas, at Rota Island, Commonwealth of the Northern Mariana Islands
Steven P. Kolinski, Ronald K. Hoeke, Stephani R. Holzwarth, Larry I. Ilo, Evelyn F. Cox, Robert C. O’Conner, and Peter S. Vroom, pp. 509–522
Abstract: Seventy-three green turtles, Chelonia mydas (Linnaeus, 1758), were observed in 84 sightings along 28 transects covering 67% of Rota’s shoreline and outer reef perimeter in the Commonwealth of the Northern Mariana Islands. No other sea turtle species were encountered. Juvenile turtles of various sizes dominated in all surveyed environments, and observations of turtles with estimated straight carapace lengths ≤ 40 cm suggested recent and continuing recruitment at Rota. Distribution of turtles appeared temporally stable when compared with previously reported observations and data, with turtle concentrations highest along northeast, east, and southeast coasts of the island. Approximately 118 turtles were projected to inhabit nearshore habitats at Rota. Although this population may appear minor and indistinct compared with those at nearby Tinian and Saipan, continued monitoring would be useful for comparison of Mariana Islands trends. Thirty-five species of cyanophytes, algae, and a sea grass noted as green turtle forage in other world regions were identified at Rota in this and previous surveys.
Killer Whales in Hawaiian Waters: Information on Population Identity and Feeding Habits
Robin W. Baird, Daniel J. McSweeney, Christopher Bane, Jay Barlow, Dan R. Salden, La’Ren K. Antoine, Richard G. LeDuc, and Daniel L. Webster, pp. 523–530
Abstract: Killer whales (Orcinus orca) have only infrequently been reported from Hawaiian waters, and most of what is known about killer whales worldwide comes from studies in coastal temperate waters. Here we present 21 records of killer whales from within the Hawaiian Exclusive Economic Zone between 1994 and 2004. Killer whales were recorded nine months of the year, most around the main Hawaiian Islands. Although there were more records than expected during the period when humpback whales are abundant around the Islands, there is likely an increase in sighting effort during that period. Killer whales were documented feeding on both a humpback whale and cephalopods, and two species of small cetaceans were observed fleeing from killer whales. Although it is possible that there are both marine mammal-eating and cephalopod-eating populations within Hawaiian waters, it seems more likely that Hawaiian killer whales may not exhibit foraging specializations as documented for coastal temperate populations. Saddle patch pigmentation patterns were generally fainter and narrower than those seen in killer whales from the temperate coastal North Pacific. Analysis of skin samples from two animals indicated two mitochondrial haplotypes, one identical to the “Gulf of Alaska transient 2” haplotype (a mammal-eating form), and the other a new haplotype one base different from haplotypes found for mammal-eating killer whales in coastal Alaskan waters.
Impact of Post-typhoon Hunting on Mariana Fruit Bats (Pteropus mariannus)
Jacob A. Esselstyn, Arjun Amar, and Dustin Janeke, pp. 531–539
Abstract: We examined the abundance of Mariana fruit bats (Pteropus mariannus Desmarest) on the Pacific islands of Rota and Guam before and after a severe typhoon in December 2002. After the typhoon, bat abundance declined by 70% on Rota. On Guam, bat abundance initially increased by ca. 100 individuals (103%), perhaps due to immigration from Rota, but then declined an average of 32% from pretyphoon levels for the remainder of 2003. An increase in post-typhoon hunting pressure represents at least a partial cause for the decline observed on Rota. Interviews with 29 suspected poachers on the island revealed a 34% increase in bat harvest from 2002 to 2003. Hunting of bats is rare on Guam because access to their remaining habitat is restricted by the U.S. military. However, juvenile bats are preyed on by introduced brown tree snakes (Boiga irregularis Bechstein) on Guam to such an extent that little to no within-island recruitment occurs. We therefore suggest that the brief increase and subsequent decrease in bat abundance on Guam was due to interisland movements, a reduction in the source population (Rota), and/or changes in roosting patterns on Guam. Rota is vital to recovery prospects for P. mariannus in the southern Mariana Islands because it holds the only viable population in this part of the archipelago. If the species is not conserved, forest ecosystems may suffer because P. mariannus is almost certainly an important seed disperser and pollinator on these depauparate islands. We recommend that agencies responsible for managing hunted fruit bat populations make special efforts to prevent illegal hunting after severe typhoons.
Evidence for Sequential Hermaphroditism in Sabellastarte spectabilis (Polychaeta: Sabellidae) in Hawai‘i
David R. Bybee, Julie H. Bailey-Brock, and Clyde S. Tamaru, pp. 541–547
Abstract: Understanding the reproductive characteristics of Sabellastarte spectabilis (Grube, 1878), an economically important polychaete worm collected for the aquarium trade, is essential to the development of artificial propagation and conservation of coral reefs. The purpose of this study was to determine whether S. spectabilis is hermaphroditic. Using histological techniques, 180 individuals were examined for gametes. Gametes were present only in abdominal segments. Primary oocytes were 7–8 µm in diameter in histologically prepared sections. Sperm appeared as round black dots about 2 µm in diameter on histologically prepared slides. Most individuals sampled had only one type of gamete in the coelom, but both eggs and sperm were seen in the coelom of 15% of individuals, demonstrating the occurrence of hermaphroditism in Hawaiian populations of S. spectabilis. The sex ratio of males to females was skewed significantly toward males in both the small (6–8 mm diameter) and medium (9–10 mm diameter) sized worms. Among the largest worms (11–13 mm diameter), the sex ratio did not diverge significantly from 1: 1. There was a significantly higher proportion of hermaphrodites (30%) in the large size class. Worms of unknown gender, although present in all size classes examined, were most frequent (33%) in the medium size class. These patterns are consistent with sequential (protandrous) hermaphroditism.
First Record of the Labrid Fish Cymolutes praetextatus from the Hawaiian Islands
John E. Randall, Ross C. Langston, and Mike Severns, pp. 549–553
Abstract: The labrid fish Cymolutes praetextatus, previously known from East Africa to the Society Islands but not east of the Marshall Islands in the North Pacific, is reported from the Hawaiian Islands from two specimens collected in 18 m and an underwater photograph taken in 27 m. One of the color descriptions by Jordan and Evermann in 1905 in their species account of C. lecluse indicates that they had a specimen of praetextatus.
Pacific Science Association, pp. 555–558
Index to Volume 60