Pacific Science, vol. 65, no. 4 (2011)

Pacific Science 65, no. 4, cover image

Spatial and Temporal Comparisons of Benthic Composition at Necker Island, Northwestern Hawaiian Islands
Stephanie A. Schopmeyer, Peter S. Vroom, and Jean C. Kenyon, 405-417

Necker Island, a remote island located in the Northwestern Hawaiian Islands, provides a unique opportunity to investigate species-level algal and benthic invertebrate assemblages and assess temporal variation of coral reef ecosystems exposed to minimal anthropogenic impacts. This study provides a robust baseline of common benthic species at Necker Island and their relative abundances before any known ecological response to changing oceanographic conditions. Rapid ecological assessment (REA) methods using photoquadrat imagery from long-term monitoring sites coupled with towed-diver surveys conducted between 2002 and 2006 were analyzed to determine percentage cover of benthic organisms around the island, and macroalgal species lists were compiled from voucher specimens. Benthic substrates were typically dominated by turf algae at all sites for all years, and macroalgal and coral covers were found to be low. A total of 25 macroalgal and 11 anthozoan species was identified. Of these, 13 macroalgal species and one coral species represent new records for Necker Island. Analyses of community similarity found spatial differences among sites in 2006, as well as temporal differences between 2005 and 2006, an outcome primarily driven by significant increases in percentage cover of macroalgae and coral at one site. However, benthic communities observed during extensive towed-diver surveys around Necker Island did not identify significant differences among geographical sectors or years, suggesting that benthic communities are relatively homogeneous. Necker Island contains macroalgal and coral populations similar to those of neighboring reef systems within the Northwestern Hawaiian Islands, and this study provides a baseline of benthic assemblages for ongoing temporal monitoring.

Oceanic Diet and Distribution of Haplotypes for the Green Turtle, Chelonia mydas, in the Central North Pacific
Denise M. Parker, Peter H. Dutton, and George H. Balazs, 419-431

A diet analysis was conducted on the gastrointestinal contents of 10 oceanic green turtles, Chelonia mydas, collected as bycatch mortalities in pelagic fisheries. Size distribution of the green turtles ranged from 30 to 70 cm curved carapace length (CCL). Prey items found indicated pelagic green turtles to be carnivorous with some omnivorous tendencies, foraging within the first 100 m of the water column. Most frequent identifiable prey items were Zooplankton, pelagic crustaceans, and mollusks (listed in order of frequency of occurrence, which ranged from 80% to 40% frequency): Pyrosoma spp., Lepas spp. (goose barnacles), amphipods, Carinaria spp. (sea snails), and Cavolinia spp. (sea butterflies). Other coelenterates such as salps, ctenophores, and cnidarians (jellyfish) were also identified. Plastics and anthropogenic debris were commonly found (70% frequency, mean = 4% of gastrointestinal content by volume). The turtles examined consisted of two distinct morphotypes corresponding to the central Pacific and the eastern Pacific green turtle populations. Genetic analysis confirmed turtles of the central Pacific morphotype to be of Hawaiian origin and at least one of the eastern Pacific morphotype turtles to have a mtDNA haplotype found in the population nesting in the Revillagigedo archipelago off Mexico. Other eastern Pacific morphotypical turtles had a different common Mexican haplotype found among the nesting populations throughout Mexico and the Galápagos. Turtles of the central Pacific morphotype were distributed north of the Hawaiian Islands, and turtles of the eastern Pacific morphotype were all encountered south of Hawai’i, suggesting a dichotomy in the oceanic distribution of these two populations. Our records of green turtles as large as 70 cm CCL in pelagic waters suggest that some green turtles, mainly those with eastern Pacific green turtle morphology and mtDNA haplotype, delay their recruitment to nearshore (neritic) habitats or move back and forth between neritic and open ocean waters as adults.

Tropical Eastern Pacific Records of the Prickly Shark, Echinorhinus cookei (Chondrichthyes: Echinorhinidae)
Douglas J. Long, John E. McCosker, Shmulik Blum, and Avi Klapfer, 433-440

Most records of the prickly shark, Echinorhinus cookei Pietschmann, 1928, are from temperate and subtropical areas of the Pacific rim, with few records from the tropics. This seemingly disjunct distribution led some authors to consider E. cookei to have an antitropical distribution. Unreported museum specimens and underwater observations of E. cookei from Cocos Island, Costa Rica; the Galápagos Islands; and northern Peru confirm its occurrence in the tropical eastern Pacific and, combined with other published records from the eastern Pacific, establish a continuous, panhemispheric eastern Pacific distribution.

Habitats Used by Juvenile Flagtails (Kuhlia spp.; Perciformes: Kuhliidae) on the Island of Hawai‘i
Mark G. McRae, Lori Benson McRae, and J. Michael Fitzsimons, 441-450

Patterns of juvenile habitat use by two species of kuhliid fishes (āholehole) on the island of Hawai’i were examined. Kuhlia sandvicensis was observed in marine habitat types only, but juvenile K. xenura were observed in freshwater streams, estuaries, on reef flats, along rocky shorelines, and in tide-pool habitats. Principal components analysis indentified nonrandom microhabitat selection by juvenile K. sandvicensis and K. xenura. Both species selected microhabitats that were higher in salinity and temperature and nearer to the open ocean than were areas randomly available to them. Although distributions of juvenile K. sandvicensis and K. xenura overlapped in marine habitats, characteristics of the marine microhabitats used by each species differed. Along rocky shorelines, K. sandvicensis used microhabitats that were characteristic of high-energy surge zones—deep areas close to the open ocean that had high salinities. The rocky shorelines most frequently inhabited by K. xenura, conversely, were shallower areas that were farther from the open ocean with lower salinity. A similar pattern was observed in tide-pool habitats, with K. sandvicensis using microhabitats typical of surge zones, and K. xenura utilizing protected tide pools with low salinities. Protection of a variety of inshore habitats is important for conservation of juvenile Hawaiian kuhliid fishes.

Fasciation in Invading Common Mullein, Verbascum thapsus (Scrophulariaceae): Testing the Roles of Genetic and Environmental Factors
Shahin Ansari and Curtis C. Daehler, 451-463

In Hawai‘i, Verbascum thapsus L. exhibits high rates of fasciation, which could have ecological and evolutionary consequences for spread of this noxious weed. Fasciated plants produce more seed capsules on average; however, the cause of fasciation in V. thapsus is not known. This study investigated whether fasciation in V. thapsus has a simple genetic basis, or whether it is caused by physical damage or pathogenic bacteria. Plants derived from self-pollinated fasciated and normal plants were grown in a field common garden and subjected to mechanical damage (simulated herbivory) and natural herbivory. Bacteria cultured from normal and fasciated plants were compared, and field plants were inoculated with a slurry of fasciated tissue. In the common garden, 31% of plants developed fasciation, but fasciation did not follow a simple monogenic pattern of inheritance. Artificial damage substantially reduced fasciation rates; damaged plants were between 1.3 and 32 times less likely to become fasciated, compared with undamaged plants. Bacterial isolates were similar between normal and fasciated plants and no inoculated plants developed fasciation, suggesting that bacteria do not cause fasciation. Fasciated and normal plants often grow less than 1 m apart, indicating that climatic factors are not inducers of fasciation. Localized combinations of environmental conditions in Hawai‘i may promote frequent and persistent fasciation.

Pittosporum halophilum Rock (Pittosporaceae: Apiales): Rediscovery, Taxonomic Assessment, and Conservation Status of a Critically Endangered Endemic Species from Moloka‘i, Hawaiian Islands
Kenneth R. Wood and Michael Kiehn, 465-476

Pittosporum halophilum Rock originally was known only from the type collections made in 1910 and 1911 along the windward sea cliffs of Moloka’i. In the most recent revision of Hawaiian Pittosporum it was treated as synonymous with the more common species P. confertiflorum A. Gray. Since 1994, several plants fitting the circumscription of P. halophilum have been discovered near the type locality. Careful studies of these individuals and of plants cultivated from their seeds clearly revealed that they are not only characterized by salt tolerance, but differ from P. confertiflorum also in several other characters (i.e., a small, shrubby habit; smaller leaves with cuneate bases and unique tan to golden yellow wooly dense tomentum on abaxial leaf surfaces; shorter petioles; subcuboid to ovoid capsules; and, in most individuals, functionally unisexual flowers). Based on these substantial differences we conclude that P. halophilum merits recognition on species level. In this paper we give a detailed description of P. halophilum including remarks on its conservation status.

Earthstars (Geastrum, Myriostoma) of the Hawaiian Islands Including Two New Species, Geastrum litchiforme and Geastrum reticulatum
D. E. Hemmes and D. E. Desjardin, 477-496

An updated, annotated list of earthstars found in the Hawaiian Islands is presented that includes 19 species of Geastrum and Myriostoma coliforme. Favored habitats for these gasteroid fungi include periodically wet windward coastal Casuarina groves, windward Leucaena thickets, and leeward coastal Prosopis groves. In contrast to these nonnative vegetation zones, earthstars such as Geastrum minimum, G. campestre, and G. corollinum are found also in largely native leeward montane Sophora/Myoporum forests, whereas Geastrum velutinum and G. reticulatum appear in montane native Acacia koa/Metrosideros forests. Eighty-two percent of the collections were made between September and February, although Geastrum triplex may be found earlier during the summer months. Two species, Geastrum litchiforme Desjardin & Hemmes and Geastrum reticulatum Desjardin & Hemmes, are described as new, accompanied by illustrations and comparisons with allied taxa. Geastrum xerophilum, originally published without Latin diagnosis, is formally validated. Specific collections are documented and island distribution and preferred habitats of the various species are listed. An artificial dichotomous key to aid in identification is provided.

Reptiles of the Hall Islands, Chuuk State, Federated States of Micronesia
Donald W. Buden, 497-505

Thirteen species of reptiles are recorded from the Hall Islands, all but two sea turtles for the first time. None of the 11 species of lizards (six geckos, five skinks) is endemic, and most are widely distributed throughout Micronesia and often well beyond. Emoia boettgeri has the most limited range, which extends from Chuuk State in the central Caroline Islands eastward to the Marshall Islands. Emoia caeruleocauda is the most common skink, and Lepidodactylus lugubris is the most common gecko. The apparent absence of other common Micronesian species, such as Nactus pelagicus, Emoia cyanura, E. impar, and Lipinia noctua is unexpected and possibly an artifact of limited sampling. A recent incident of turtle poisoning (chelonitoxism) attributed to the consumption of hawksbill turtle, Eretmochelys imbricata, resulted in the death of six Murilo Atoll islanders and sickened many others.

Thysanoptera of the Galápagos Islands
Mark S. Hoddle and Laurence A. Mound, 507-513

Thysanoptera from the Galápagos Islands were inventoried from 627 slide-mounted specimens that were made with material that had been stored at the Reference Collection of Terrestrial Invertebrates at the Charles Darwin Research Station, Galápagos, Ecuador. Museum material was complemented by field collections conducted over the period October–November 2009. This inventory was augmented from records in the published literature. Identification of museum and field-collected material added an additional 27 species to the already known fauna, an increase of 54%. A total of 77 species of thrips from 42 genera in four families is now known from 17 different islands in the Galapagos. At least nine species are serious pests, of which four, Frankliniella occidentalis, Gynaikothrips uzeli, Thrips palmi, and Thrips tabaci, are reported from the Galapagos Islands in the primary scientific literature for the first time.

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