Pacific Science, Volume 46, Numbers 1-4, 1992

46: Index - Pacific Science

Wed, 01 Jan 1992 00:00:00 GMT

Diversity in Intertidal Habitats: An Assessment of the Marine Algae of Select High Islands in the Hawaiian Archipelago

Smith, Celia M — Thu, 01 Oct 1992 00:00:00 GMT

Quantitative and qualitative sampling of intertidal algal assemblages on a limestone bench (O'ahu) and basalt benches (O'ahu and Hawai'i) resulted in enumeration of more than 100 species of macrophytic and turf species on O'ahu and over 60 species of primarily turf algae on Hawai'i. These assemblages are diverse and of a mosaic type and represent subcosmopolitan species, pantropical species, West Pacific species, and apparent endemic species. The algal community on Hawai'i shares 40 to 75% similarity with O'ahu populations that in one case shared only 66% similarity with adjacent sites for the same substrate type. It is suggested that the differences in species distributions are associated with age-related substrate effects and possibly settlement shadow effects.

Mycorrhizal Status of Gunnera petaloidea in Hawai'i

Koske, RE; Gemma, JN; Doyle, MF — Thu, 01 Oct 1992 00:00:00 GMT

Eight collections of the endemic Hawaiian angiosperm Gunnera petaloidea ssp. kauaiensis were examined for mycorrhizae. Soil-inhabiting roots of all specimens possessed extensive vesicular-arbuscular mycorrhizae 01AM). Aerial roots lacked mycorrhizae. Soil from the root zones of the plants contained propagules of VAM fungi, and spores of two species of VAM fungi were found in the soil. The discovery of mycorrhizae in Gunnera adds another symbiont to the Gunnera-Nostoc symbiosis.

New Taxa of Ceramieae (Rhodophyta) from Hawai'i

Norris, Richard E; Abbott, Isabella A — Thu, 01 Oct 1992 00:00:00 GMT

A new genus and five new species belonging in the Ceramieae have been found in recent analyses of the Hawaiian Ceramiaceae. Ardreanema, the new genus, is a microscopic plant having a simple moniliform structure with light cortication where cells meet (nodes) in the filament. Several gonimolobes composed of uniseriate rows of carposporangia are formed on female plants, and tetrasporangia, one per segment, are borne in a series near distal ends of branches. A single species, A. farifructa, n. sp., is assigned to the genus. The other new species are Ceramium dumosertum, Ceramium womersleyi, Ceramium hanaense, and Ceramium ptilocladioides.

Observations on Egg Hatching in the Estuarine Crab Sesarma haematocheir

Saigusa, Masayuki — Thu, 01 Oct 1992 00:00:00 GMT

A female of the terrestrial crab Sesarma haematoeheir incubates 30,000-50,000 eggs on her abdomen. After 1 month of embryonic development, zoeae larvae are released into estuarine waters within 3-5 sec by means of vigorous fanning motions of the abdomen. Hatching (breakage of the outer egg membrane) occurs on land just before larval release. The release behavior itself does not cause rupture of the egg case, nor has the presence of a "hatching enzyme" been obviously demonstrated. Hatching seems to be induced by mechanical rupture of the egg case. The pressure responsible for hatching may be produced either by the larva itself, or by osmotic swelling of thin inner membranes encasing the larva, although neither of these hypotheses is sufficient at present to explain the complete hatching mechanism. If hatching is explained by such mechanisms, then there remains the question of how hatching is synchronized among the large number of embryos attached to the female. Hatching of detached embryos is synchronized to some extent, but the degree of synchronization is less than that occurring in the larvae carried by the female. This observation suggests that stimuli from the female are important in establishing highly synchronized hatching. The ecological significance of the hatching system is also discussed.

William T Brigham's Hawaiian Birds and a Possible Historical Record of Ciridops anna (Aves: Drepanidini) from Molokai

Olson, Storrs L — Thu, 01 Oct 1992 00:00:00 GMT

Two of the five known specimens of the extinct Hawaiian bird Ciridops anna (Dole, 1878) came to the Museum of Comparative Zoology with a small collection of Hawaiian birds of unknown origin. Historical evidence is marshaled to show that this material was almost certainly collected by William T. Brigham in 1864-1865. Circumstantial evidence suggests that the specimens of Ciridops anna may have come from the island of Molokai, where the species was previously unknown during the historic period.

Marine Phytogeography of the Juan Fernandez Archipelago: A New Assessment

Santelices, B — Thu, 01 Oct 1992 00:00:00 GMT

A new assessment of the geographic affinities of the marine algae of the Juan Fernandez Archipelago indicates a flora with a small number of species and very high endemism (about 30%) as compared to other oceanic islands of similar age, size, origin, and abiotic conditions. The flora also contains many widely distributed species (45%) and a small group of species with circumpolar-subantarctic affinities (about 13.5% of the flora). The potential algal species sources for this flora seem to be distant localities in the southern Pacific, including the southern tip of South America, southern Australia, New Zealand, and several subantarctic islands. Considering effective dispersal distances of marine benthic algae, the Juan Fernandez Archipelago appears as more isolated than Easter Island, which previously was supposed to be the most isolated point in the Pacific basin. An analysis of the endemic components suggests that there has been speciation but no radiation in these islands. Some species originating in the archipelago might have migrated across the Pacific to continental South America, perhaps via El Nino/Southern Oscillation (ENSO).

Geographic Patterns of Diversity in Benthic Marine Algae

Silva, Paul C — Thu, 01 Oct 1992 00:00:00 GMT

Study of the geography of benthic marine algae has traditionally taken the form of descriptions of floras, analyses of floras in terms of floristic components, comparison of the flora and vegetation of one area with that of another area, and delineation of floristic provinces. The concept of genetic diversity transcends floristic analysis and leads to the recognition of geographic diversity patterns related to, but not coincidental with, floristic patterns. Unlike vascular plants, in which the ratio of tropical to nontropical species is 2 : 1, benthic marine algae reach their peak of species diversity on transitional warm-cool temperate coasts. Lowest species diversity, as would be expected, is exhibited by the arctic and antarctic floras. The Mediterranean flora is highly diverse. In the Atlantic, the cold-water flora is richest in the east, while the warm-water flora is richest in the west. In the vastly broader Pacific, the cold-water flora is equally rich on both sides, but again the warm-water flora is richest in the west. Moreover, many warm-water species extend into the Indian Ocean. The Pacific is complicated by the presence of a myriad of islands of various sizes, shapes, structure, ages, and degree of isolation. In the Indian Ocean, the high species diversity of the floras of Natal and southwestern Australia is matched by that of India, while intervening equatorial areas are significantly less rich. Taxonomic diversity is an assessment of the evenness of distribution of the species of a local flora compared to the regional taxonomic spectrum. The highest degree of intrageneric morphological diversity is exhibited by Codium and Caulerpa.

Symposium on Marine Diversity and Biogeography in the Tropics. Pacific Science Congress, May-June 1991, Honolulu

Abbott, Isabella A — Thu, 01 Oct 1992 00:00:00 GMT

Seven persons were asked to discuss the diversity and biogeography of various groups of marine organisms from as wide a geographic span as possible in the warm Pacific. The organisms covered were marine algae, marine mollusks, and fishes; unfortunately, J. E. N. Veron of Australia, who was expected to speak on corals, was unable to attend. We present here three abstracts and three full-length papers. No symposium on marine diversity has ever been presented to the Congress, although each member country in the Congress is impacted by one or more oceans or seas. Of the major groups of marine organisms, probably the least studied (and least understood) are the marine algae. The three papers are on algae and show different perspectives although the subject matter is systematics and ecology. In "Geographic patterns of diversity in benthic marine algae," Paul Silva defines diversity and shows that although land plant diversity is greater in the tropics, marine algae show more diversity in the warm-temperate boundaries. In "Marine phytogeography of the Juan Fernandez Archipelago: A new assessment," Bernabe Santelices shows that the relatively high diversity with 32% endemism found in the Juan Fernandez Islands is largely due to the physical barrier of the cold northward-flowing Peru or Humboldt Current. Celia Smith in "Diversity in intertidal habitats: An assessment of the marine algae of select high islands in the Hawaiian Archipelago" revealed many data that furnished the bases for far-reaching comparisons: age-related basalt substrates and limestone benches on an island about 35,000 yr old yielded a flora with greater diversity than similar transects on a younger basalt island, contributing to the conclusion that similar diversity patterns appear to depend on substrate similarity as well as current patterns around islands. The three abstracts cover algae from French Polynesia, fishes, and marine mollusks. The papers that stem from these abstracts have been or are being published elsewhere.

Environmental Control of Holocene Changes to the World's Most Northern Hermatypic Coral Outcrop

Veron, JEN — Thu, 01 Oct 1992 00:00:00 GMT

Tateyama, near Tokyo (35° N lat.), is the site of the world's most northern occurrence of living hermatypic corals and is also the site (in the Numa beds) of a substantial outcrop of Holocene fossil corals with a radiocarbon date of 5000-6000 yr B.P. This extraordinary co-occurrence provides the opportunity for a detailed reconstruction of environmental change during the Holocene, especially change in sea-surface temperature. The present study, combined with a series of previous studies, reveals 72 coral species in the Numa beds, of which 53 have been identified with reasonable certainty; and 34 species of extant corals at Tateyama, of which 25 have been located and identified. These data are compared with recently completed studies of the distribution of extant corals of Japan, and sea-surface temperatures of the principal regions of extant corals. Nearly one-half of all species from the Numa beds have remained extant at Tateyama until recent times, 85% are extant as far north as Kushimoto on the Kii Peninsula (33.5° N lat.), and all except two have been recorded extant somewhere in mainland Japan. There has been a major change in species dominance at Tateyama. The identified species from the Numa beds and those of the Izu Peninsula and Tateyama show a high degree of dissimilarity compared with other coral communities of mainland Japan. The closest extant fauna to the corals from the Numa beds appears to be that of Kushimoto. Based on six ways of measuring the temperature regimes of coral communities of modern mainland Japan, over the past 40 yr, this geographic comparison corresponds to a mean sea-surface temperature increase of 1.7°C. Although there are several assumptions in arriving at this number, the increase is clearly less than 2.1 °C, which is the temperature difference corresponding to the substantially richer coral communities of Tanegashima at the southern tip of mainland Japan. This study shows that an increase in sea-surface temperature of < 2°C, such as is widely predicted in response to the "greenhouse effect," should result in a greatly increased diversity of corals in high-latitude locations. It also shows that this temperature increase is sufficient to create a "high latitude subtropical" community in a region that appears almost devoid of corals in a fossil sequence.

46:4 Table of Contents - Pacific Science

Thu, 01 Oct 1992 00:00:00 GMT

Abstracts of Papers: Sixteenth Annual Albert L. Tester Memorial Symposium, 10-12 April 1991

Wed, 01 Jan 1992 00:00:00 GMT

The Albert L. Tester Memorial Symposium is held in honor of Professor Albert L. Tester, who, at the time of his death in 1974, was senior professor of zoology at the University of Hawaii. The faculty and students of the Department of Zoology proposed an annual symposium of student research papers as a means of honoring, in a continuing and active way, Dr. Tester's lively encouragement of student research in a broad range offields in marine biology. Papers reporting original research on any aspect of biology are solicited from students at the university, and these papers are presented at the symposium, which takes place during the spring semester. Income from contributions to the Albert L. Tester Memorial Fund of the University of Hawaii Foundation is used to provide two prizes for the best papers by graduate students. Papers are judged on quality, originality, and importance of research reported, as well as on the quality of the public presentation. Judges include several members of the faculty of the Department of Zoology as well as winners of the symposium from the preceding year, when possible. In addition, a distinguished scholar from another university is invited to participate in the symposium as a judge and to present the major symposium address. This year John Maynard Smith of the University of Sussex participated in the symposium.

Caledoniscincus austrocaledonicus (Reptilia: Scincidae) from Ile Surprise, D'Entrecasteaux Reefs, New Caledonia

Bauer, Aaron M; Renevier, Alain; Sadlier, Ross A — Wed, 01 Jan 1992 00:00:00 GMT

The common, endemic New Caledonian skink Caledoniscincus austrocaledonicus is reported for the first time from the far north of the territory, specifically from lie Surprise in the D'Entrecasteaux Reefs. The herpetofauna of lie Surprise is characteristic of littoral habitats in mainland New Caledonia. The overwater transport of C. austrocaledonicus, like that of C. atropunctatus, which occurs in Vanuatu as well as New Caledonia, has probably been relatively recent.

Status of Tree Snails (Gastropoda: Partulidae) on Guam, with a Resurvey of Sites Studied by H. E. Campton in 1920

Hopper, David R; Smith, Barry D — Wed, 01 Jan 1992 00:00:00 GMT

Tree snails of the family Partulidae have declined on Guam since World War II. One species, indigenous to the western Pacific, Partula radiolata, is still locally common along stream courses in southern areas of the island. The Mariana Island endemic Samoana fragilis is present but not found in abundance anywhere on Guam. Partula gibba, another Mariana endemic, is currently known only from one isolated coastal valley along the northwestern coast, and appears to be in a state of decline. The Guam endemic Partula salifana was not found in areas where it had been previously collected by earlier researchers, and is thus believed to be extinct. The decline and extinction of these snails are related to human activities. The single most important factor is likely predation by snails that were introduced as biological control agents for the giant African snail, Achatina fulica. The current, most serious threat is probably the introduced flatworm Platydemus manokwari. This flatworm is also the likely cause of extinctions of other native and introduced gastropods on Guam and may be the most important threat to the Mariana Partulidae.

Species of Fabriciola Friedrich, 1939 (Polychaeta: Sabellidae: Fabriciinae), from the California Coast

Fitzhugh, Kirk — Wed, 01 Jan 1992 00:00:00 GMT

Fabriciola berkeleyi Banse is the only species of Fabriciola reported from the California coast. It was described by Hartman as Fabricia berkeleyi in her Atlas of Sedentariate Polychaetous Annelids from California.. Hartman's specimens are redescribed and compared to the type specimens from British Columbia. California specimens differ from type specimens in that the former have abdominal neuropodial pin-head setae and the extent of body pigmentation is more restricted. Because the type series is in poor condition,· the California specimens are referred to F. cf. berkeleyi until better comparative material from the type locality can be examined. A new species from southern California, Fabriciola brevibranchiata, is described. Current cladistic relationships among Fabriciola species are discussed.

A New Moray Eel (Muraenidae: Gymnothorax) from Oceanic Islands of the South Pacific

Lavenberg, Robert J — Wed, 01 Jan 1992 00:00:00 GMT

A new moray of the genus Gymnothorax is illustrated and described from 69 individuals taken from oceanic islands and atolls in the subtropical South Pacific Ocean. It differs from all other Gymnothorax except the Atlantic G. bacalladoi in having a single branchial pore. The new species of Gymnothorax may be distinguished from G. bacalladoi by having fewer preanal vertebrae (48-53 rather than 54-56), more total vertebrae (138-146 rather than 130-131), a single rather than a double row of vomerine teeth, and fewer teeth in the inner maxillary tooth row. The new species appears to be allied to G. bacalladoi and G. panamensis based on coloration and dentition.

Origin and Population Growth of the Brown Tree Snake, Boiga irregularis, on Guam

Rodda, Gordon H; Fritts, Thomas H; Conry, Paul J — Wed, 01 Jan 1992 00:00:00 GMT

After the accidental introduction of the Brown Tree Snake, Boiga irregularis, to the island of Guam after World War II, the snake became exceedingly numerous, and most of Guam's native vertebrates either became endangered or disappeared from the island. In this paper we summarize what is known about populations of this snake on Guam and the likely origin of the Guam population. Scale counts and transportation records suggest that the Guam population originated in the Admiralty Islands, about 1500 km south of Guam. It was probably transported to Guam in ships that transported salvaged war materiel after World War II. For ca. 35 yr after its introduction, the presence of the snake on Guam was documented only by popular accounts, occasional photographs, and a few museum specimens, indicating that the snake's distribution was fairly limited initially, but ultimately a period of sharp population growth and wide dispersal occurred, with the snake reaching all parts of the island by the late 1960s. Peak population levels were attained about a decade or more after each area was colonized. Mark-recapture and removal data indicate that the capture of 50 snakes per ha at one site in northern Guam during 1985 probably represented a population density of around 100 snakes per ha, but by 1988 this population had declined to around 30% of the 1985 density. However, this reduction may not be permanent. In central Guam, where the snake irrupted decades ago, the snake's numbers have continued to fluctuate, and in some cases it has attained densities in excess of 50 per hectare.

Soils of the Laloanea Farm, Northwestern Upolu, Western Samoa

Morrison, RJ; Asghar, M — Wed, 01 Jan 1992 00:00:00 GMT

Soils of the Laloanea Farm (40 ha), in the uplands of northwestern Upolu, Western Samoa, were studied by an examination of nine pedons composing two toposequences, one running S-N and the other W-E across extensive portions of the farm. Over short distances considerable variability in the soils has led to their classification into two soil orders of Soil Taxonomy (Entisols and Inceptisols), two suborders, three great groups (Troporthents, Humitropepts, and Dystropepts), four subgroups, and seven families. Major factors contributing to the variability were depth to basaltic boulders or flow rock, presence or absence of a cambic horizon, amount of organic carbon in the profile, particle size distribution in the control section, and occurrence in some pedons of andic properties. Soils all had an oxidic mineralogy class and an isohyperthennic soil temperature regime. Relationship of the factors affecting variability to topographic position is discussed, together with an overview of the physical, chemical, and mineralogical properties of the soils. Similar variability might be expected in other humid tropical situations on young basaltic landscapes with steep, rolling, and benched terrain.

Rock Varnish on Hualalai and Mauna Kea Volcanoes, Hawai'i

Wed, 01 Jan 1992 00:00:00 GMT

Tropical rock varnishes found on Hualalai and Mauna Kea Volcanoes, Hawai'i, vary systematically with time and environment. Radiocarbon dating of encapsulated organic matter, (K+ + Ca2+)/Ti4+ ratios, and Zn, Cu, and Ni trace element concentrations in rock varnish are consistent with lava flowages established by K-Ar and 14C dating, where samples are collected from arid microsites well away from the soil surface. However, inaccurate ages are obtained from rock varnish in subsurface locations and from sites with abundant lichens, cyanobacteria, and fungi that chemically erode varnish. In contrast with continental deserts, Hawaiian varnishes commonly interfinger with and are less common than rock coatings of amorphous silica. Laboratory experiments on Hawaiian rock varnishes indicate that K and Ca are preferentially leached relative to Ti over time and at higher temperatures. The location of in situ leaching has been identified in Hawaiian varnishes as porous textures without abundant detrital grains.

Puu Mahana Near South Point in Hawaii Is a Primary Surtseyan Ash Ring, Not a Sandhills-type Littoral Cone

Walker, George PL — Wed, 01 Jan 1992 00:00:00 GMT

Puu Mahana has previously been interpreted to be a littoral cone, formed at a secondary rootless vent where lava flowed from land into the ocean, but a number of lines of evidence point to it being a remnant of a Surtseyan tuff ring built on a primary vent. The differences between it and littoral cones are highlighted by a comparison of Puu Mahana with the undoubted littoral cone of the Sandhills that was observed to form in the 1840 flank eruption of Kilauea Volcano. Puu Mahana contains abundant lithic debris and accretionary lapilli, absent in the Sandhills deposit. Compared with the Sandhills, the Puu Mahana pyroclastic deposit is finer grained and more poorly sorted, and its juvenile component is less dense and more highly vesiculated. Puu Mahana lies 3 to 4 km offMauna Loa's southwest rift zone. Identification of it as a primary vent implies that the lower rift zones of Hawaiian volcanoes can be much wider and more diffuse or more mobile than is currently acknowledged. The olivine grains that compose the well-known green-sand beach at Puu Mahana are likely derived from the ash, strongly concentrated and somewhat abraded by wave action.