Pacific Science 64, no. 1
Potential Economic Damage from Introduction of Brown Tree Snakes, Boiga irregularis (Reptilia: Colubridae), to the Islands of Hawai‘i
Stephanie A. Shwiff, Karen Gebhardt, Katy N. Kirkpatrick, and Steven S. Shwiff, 1-10
The Brown Tree Snake (Boiga irregularis) has caused ecological and economic damage to Guam, and the snake has the potential to colonize other islands in the Pacific Ocean. This study quantifies the potential economic damage if the snake were translocated, established in the state of Hawai‘i, and causing damage at levels similar to those on Guam. Damages modeled included costs of medical treatments due to snakebites, snake-caused power outages, and decreased tourism resulting from effects of the snake. Damage caused by presence of the Brown Tree Snake on Guam was used as a guide to estimate potential economic damage to Hawai‘i from both medical- and power outage–related damage. To predict tourism impact, a survey was administered to Hawaiian tourists that identified tourist responses to potential effects of the Brown Tree Snake. These results were then used in an input-output model to predict damage to the state economy. Summing these damages resulted in an estimated total potential annual damage to Hawai‘i of between $593 million and $2.14 billion. This economic analysis provides a range of potential damages that policy makers can use in evaluation of future prevention and control programs.
Potential Distribution of the Alien Invasive Brown Tree Snake, Boiga irregularis (Reptilia: Colubridae)
Dennis Rödder and Stefan Lötters, 11-22
The Brown Tree Snake (Boiga irregularis) is native to Southeast Asia and Australia and has been introduced to Guam. There it causes major ecological and socioeconomic problems and is considered to belong to the 100 worst alien invasive species worldwide. We used a maximum entropy-based Climate Envelope Model to identify worldwide areas outside the species’ known range that are potentially suitable under current climatic conditions. Projections revealed that this invasive alien species potentially occurs in tropical and some subtropical regions. In the closer vicinity of the snake’s known distribution, highest suitability was found for the Northern Mariana Islands, Hawaiian Islands, Madagascar, New Caledonia, and Fiji Islands. If predictions are interpreted as depicting invasiveness potential of B. irregularis, strategies to prevent invasion should focus on these regions. An analysis of potential distributions under different future anthropogenic climate-change scenarios showed that the Fiji Islands, Hawaiian Islands, and Northern Mariana Islands will remain overall most suitable habitat for the Brown Tree Snake. In addition, we noted an increase of suitability in New Zealand.
Rapid Invasion Despite Lack of Genetic Variation in the Erythrina Gall Wasp (Quadrastichus erythrinae Kim)
Daniel Rubinoff, Brenden S. Holland, Alexandra Shibata, Russell H. Messing, and Mark G. Wright, 23-31
The erythrina gall wasp, Quadrastichus erythrinae Kim, has recently and rapidly invaded a broad swath of the tropical and subtropical Pacific Basin, causing severe damage to most species of coral trees (Erythrina spp.). This small (length ~1.5 mm) wasp attacks the photosynthetic tissue (leaves, buds, stems, flowers) of ornamental and native Erythrina, often killing the trees. This invasion poses an immediate extinction threat to native Erythrina spp. throughout Asia, Australia, and a number of Pacific archipelagos, including Hawai‘i, where populations of the endemic E. sandwicensis have been devastated. Although this pest is known to occur naturally in East Africa, the precise geographic origin of the invasions remains unknown. In this study, 1,623 base pairs of mitochondrial (cytochrome c oxidase subunit I) and nuclear DNA (elongation factor alpha) were used to confirm systematic identity and to examine genetic divergence among invasive populations from Hawai‘i, Guam, American Samoa, Japan, Singapore, Taiwan, and China. Samples from all invasive populations included in our study showed a complete lack of genetic diversity. Molecular findings confirm that a single species, Q. erythrinae, is involved in this dramatic, recent range expansion and that introductions may have been associated with population bottlenecks that have reduced genetic diversity in populations sampled. Although reductions in genetic diversity are generally considered detrimental to fitness, this study provides an example of invasion success despite a lack of detectable genetic variation. The monomorphic genetic pattern observed also suggests that Q. erythrinae initially may have been introduced to one location, and this invasive population may have subsequently served as a source for additional secondary invasions by unknown introduction vectors.
A Native Besieged: Effects of Nonnative Frugivores and Ground Vegetation on Seed Removal in a Highly Endangered Hawaiian Shrub, Delissea rhytidosperma (Campanulaceae)
Tracy L. Erwin and Truman P. Young, 33-43
Nonnative species can have serious negative effects on regeneration and restoration of rare plant taxa, particularly in insular ecosystems. An endangered Hawaiian shrub, Delissea rhytidosperma (Campanulaceae), produces fruits and viable seeds, but no regeneration has been observed in the wild. We used cages and vegetation removal to explore direct and indirect effects of three groups of nonnative species on suspected seed predation of this endangered plant: a mat-forming grass (Oplismenus hirtellus), rats (Rattus spp.), and invertebrates. Substantial seed removal occurred in all treatments. Both rat exclusion and clearing of nonnative vegetation had strong significant negative effects on seed removal. Highest removal rates occurred with rats not excluded and vegetation present, and lowest removal occurred when rats were excluded and vegetation cleared. Without rat exclosures, 100% of seeds were removed within 15 days. Even when protected from rats, most seeds were removed by smaller herbivores, unless ground vegetation was cleared. Vegetation appears to harbor invertebrates that eat seeds, including nonnative slugs. These results revealed that different nonnative species combine to greatly increase rates of seed removal in endangered D. rhytidosperma.
Reproductive and Pollination Biology of the Endemic Hawaiian Cotton, Gossypium tomentosum (Malvaceae)
John M. Pleasants and Jonathan F. Wendel, 45-55
Gossypium tomentosum is a cotton species endemic to the Hawaiian Islands. We studied several aspects of its reproductive biology, including potential pollinators, floral biology, and diurnal and seasonal flowering phenology. Flower visitors were observed in G. tomentosum populations on O‘ahu, Kaho‘olawe, and Maui. Primary visitors were introduced species, honeybees and carpenter bees, both of which were pollinating the flowers. No native bee species were seen visiting flowers. In examining floral biology we found that in some cases 10% of flowers had styles that were as short as the anthers or were recurved toward the anthers. In the greenhouse, in the absence of pollinators, these flowers were the only ones that set fruit. Flowering of G. tomentosum commences in January and February, following the rainy season, peaks in May, and may continue into August and September. In one year, after higher than average precipitation during the rainy season, there was a greater abundance of flowering, and flowering persisted later into the year. Transgenic varieties of commercial cotton, G. hirsutum, are grown in Hawai‘i and are interfertile with G. tomentosum. Honeybees and carpenter bees are also known pollinators of commercial cotton. Because these pollinators are long-distance foragers, we estimate that transgenic cotton fields would have to be greater than 10 km from a G. tomentosum population to prevent gene flow.
Methane Emission from a Tropical Wetland in Ka‘au Crater, O‘ahu, Hawai‘i
Maxime Grand and Eric Gaidos, 57-72
Natural tropical wetlands constitute an important but still poorly studied source of atmospheric methane, a powerful greenhouse gas. We measured net methane emission, soil profiles of methane generation and oxidation, and related environmental parameters in a tropical wetland occupying the Ka‘au extinct volcanic crater on the Hawaiian island of O‘ahu. The wetland has a fluctuating water table with dynamics that can be reproduced using precipitation data and a simple model. Median net methane flux was 117 mg m-2 day-1 and is consistent with measurements at other tropical sites. Net methane flux in the Commelina diffusa–dominated vegetation pattern (honohono) was significantly higher than that of the invasive Psidium cattleianum–dominated pattern (strawberry guava). Net methane emission in the honohono vegetation pattern was also significantly higher during the “wet” season compared with the “dry” season, although we did not find a clear correlation between net methane emission, water table level, or precipitation. We show that the measured fluxes are consistent with the integrated potential methane generation over the uppermost 30 cm of soil and consumption of ~50% of that methane in the soil. Absence of a correlation between net methane emission and water table level may be due to suppression of the activity of strictly anaerobic methanogens by dynamic redox conditions in the upper layers of soil and varying rates of methane oxidation by facultive methanotrophs.
Climate and Vegetation Changes at Coringa-Herald National Nature Reserve, Coral Sea Islands, Australia
George N. Batianoff, Gillian C. Naylor, John A. Olds, Nigel A. Fechner, and V. John Neldner, 73-92
Climatic changes at Coringa-Herald National Nature Reserve (CHNNR) in the last 82 yr include a 0.7ºC rise in mean minimum winter temperatures and increases in drought duration and frequency. Between 1991 and 2002, a plague of the scale insects Pulvinaria urbicola (Cockerell), together with attendant ants destroyed Pisonia grandis R.Br. rain forest at South-West Coringa Islet. Scale insect damage of P. grandis has also been recorded at North-East Herald Cay. This study explored the reasons for vegetation dieback during current climate. Woody species such as Argusia argentea (L.) Heine, Cordia subcordata Lam., and the grasses Lepturus repens (G. Forst.) R.Br. and Stenotaphrum micranthum (Desv.) C. E. Hubb. have also declined at CHNNR. Ximenia americana L. and Digitaria ctenantha (F. Muell.) Hughes were found to be locally extinct. Dieback of forests results in reduction of canopy-breeding seabirds and burrowing shearwaters (Puffinus pacificus [Gmelin)]. Dieback species were replaced by the shrub Abutilon albescens Miq. and/or fleshy herbaceous plants such as Achyranthes aspera L., Boerhavia albiflora Fosberg, Ipomoea micrantha Roem. & Schult, Portulaca oleracea L., and Tribulus cistoides L. Increasing duration of droughts and increased temperatures, together with damage caused by exotic insect pests, appear to be the key drivers of the current vegetation changes.
Twig Cutting by the Black Rat, Rattus rattus (Rodentia: Muridae), on the Ogasawara (Bonin) Islands
T. Yabe, T. Hashimoto, M. Takiguchi, M. Aoki, and M. Fujita, 93-97
Introduced black rats (Rattus rattus) have been reported to damage endemic plants of the Ogasawara Islands by gnawing. This study used seasonal field observations of plants together with analysis of rat stomach contents and age structure to help understand the cause or mechanism of black rat twig-cutting activities. Twigs of Ochrosia nakaiana and Hibiscus glaber were found to be cut by black rats on the islands of Nishijima, Anijima, and Mukojima in March and April 2006 and 2007. Fragments of twig tissues in rat feces proved that the rats ate twigs, rather than only gnawing or cutting them. Age compositions of trapped black rats showed that the season of plant damage corresponded with that of low breeding activities of the rats and scarcity of preferred foods (January–March). We assume a link between low breeding activities of the black rats and food shortage, which motivated the rats to consume twig tissues.
Temporal Changes in Reef Community Structure at Bintan Island (Indonesia) Suggest Need for Integrated Management
Loke Ming Chou, Danwei Huang, Karenne P. P. Tun, Jeffrey T. B. Kwik, Ywee Chieh Tay, and Angie L. Seow, 99-111
Reefs in Southeast Asia, such as those in Indonesia’s Riau archipelago, are among the most diverse habitats in the sea, but limited baseline data pose a severe challenge for their conservation. Here, we surveyed five reef sites along the northern coast of Bintan Island to determine the most recent condition of the benthic and fish communities. Fourteen years of resort development on the island have elapsed since the last survey in 1993. Using several diversity measures to compare the reefs then and in 2007, we found that abundances of hard corals and fish remained high (average of >50% coral cover and >0.7 fish/m3), but taxonomic richness was compromised. The most common taxa now account for greater proportions of fish counts at all sites and of coral cover at three of four comparable sites. These shifts in coral and fish assemblages may be explained by freshwater influences and development along the north coast of Bintan Island. Because the local community and tourism industry still rely heavily on the reefs, we advocate implementing a comprehensive, integrated coastal management plan that mitigates further reef declines and promotes sustainable use.
Water-Quality Variables across Sekisei Reef, A Large Reef Complex in Southwestern Japan
Naoko Morimoto, Yasuo Furushima, Masayuki Nagao, Takahiro Irie, Akira Iguchi, Atsushi Suzuki, and Kazuhiko Sakai 113-123
At Sekisei Reef in southwestern Japan (24º N), coral cover dramatically decreased in the mid-1980s, probably due to a population outbreak of the coral predator Acanthaster planci. Coral communities subsequently recovered well outside the semiclosed lagoon, but recovery has been poor inside it. Hence, water-quality degradation including eutrophication has been a concern inside the lagoon. In addition, temporal variation in eutrophication parameters is common among high-latitude coral reefs, resulting in difficulties in evaluating them. Therefore, to address these issues, we monitored temperature, salinity, turbidity, chlorophyll-a, NOx-N (NO3-N+NO2-N), and NH4-N concentrations year-round across the lagoon at Sekisei Reef. Turbidity and NOx-N concentration increased with increasing wind velocity, suggesting that variation in turbidity and NOx-N concentrations was attributed to resuspension of bottom sediments, and NOx-N release through regeneration processes of microorganisms from the sediments and reef frameworks, respectively. In contrast, variation in chlorophyll-a and NH4-N concentrations appears to be mainly controlled by the seasonality of temperature and irradiance. Long retention time of seawater inside the lagoon seems to have enhanced NH4-N assimilation and increase of phytoplankton during summer. Inside the lagoon, turbidity, NOx-N, and summer chlorophyll-a concentrations were higher, and variation in temperature was larger than outside it. Although water quality appears not to be seriously degraded, multiple effects of these water-quality variables might have negatively affected recovery of coral communities inside the lagoon. Recent expansion of land use on nearby islands might have contributed to water-quality degradation inside the lagoon.
Immature East Pacific Green Turtles (Chelonia mydas) Use Multiple Foraging Areas off the Pacific Coast of Baja California Sur, Mexico: First Evidence from Mark-Recapture Data
Jesse Senko, Melania C. López-Castro, Volker Koch, and Wallace J. Nichols, 125-130
Since 2001, Grupo Tortuguero has been conducting monthly in-water monitoring of East Pacific green turtles (Chelonia mydas), also known as black turtles, at four neritic foraging areas (Bahía Magdalena, Laguna San Ignacio, Punta Abreojos, Laguna Ojo de Liebre) along the Pacific coast of Baja California Sur, Mexico. Extensive tagging (883 turtles tagged of 1,183 turtles captured) and recaptures (154 tagged turtles recaptured at least once) at these four areas suggest that immature East Pacific green turtles show strong site fidelity to their neritic foraging grounds. However, in 2007, we recaptured two immature turtles, one in Laguna San Ignacio and the other in Bahía Magdalena, that were both originally captured in Punta Abreojos. To our knowledge, this represents the first direct evidence of immature East Pacific green turtles using multiple foraging areas along the Baja California Peninsula. This report highlights the importance of long-term monitoring efforts that encompass several habitats on a relatively large spatial scale (~80 km between Punta Abreojos and Laguna San Ignacio and ~300 km between Punta Abreojos and Bahía Magdalena) to better understand the movements and habitat use of immature East Pacific green turtles on their neritic foraging areas.
Helminths of Ten Species of Geckos (Squamata: Gekkonidae) from Papua New Guinea, with Comparisons between Immigrant and Endemic Geckos
Stephen R. Goldberg, Charles R. Bursey, and Fred Kraus, 131-139
Two hundred three individuals representing 10 species of gekkonid lizards from Papua New Guinea collected from 2002 to 2005 were examined for helminths: Cyrtodactylus epiroticus (n = 2), C. klugei (n = 2), C. loriae (n = 7), C. novaeguineae (n = 3), C. sermowaiensis (n = 30), Gehyra mutilata (n = 22), G. oceanica (n = 27), Gekko vittatus (n = 41), Hemidactylus frenatus (n = 29), and Lepidodactylus lugubris (n = 40). One species of Digenea, one species of Cestoda, 18 species of Nematoda, as well as three taxa of nematode larvae (in cysts) were found. Thirty-one new host records and six new locality (= country) records are reported. Prevalence in endemic geckos was significantly higher than in nonendemic geckos.
Observations of the dragonfly Pantala flavescens (Fabricius) on Ngulu Island during early August 2008 constitute the first report of Odonata on Ngulu Atoll, Yap State, Federated States of Micronesia; no other odonate is documented on the atoll, but descriptions by local residents of a larger, rarely encountered, blue dragonfly may pertain to Anax guttatus (Burmeister). The sudden appearance of P. flavescens on Ngulu after its apparent absence during the previous two and a half weeks of this study, together with the absence of exuviae at potential breeding sites and remarks by local residents alluding to its appearance each year around August and September, suggests that it occurs regularly in migration and that there is no permanent resident population. Its appearance often coincides with winds from a westerly direction.
Association Affairs, 145
Pacific Science 64, no. 2
Biogeographic Breaks in Vanuatu, a Nascent Oceanic Archipelago
Alison M. Hamilton, Elaine R. Klein, and Christopher C. Austin, 149-159
The study of distinct biogeographic demarcations has played a pivotal role in our understanding processes responsible for patterns of species distributions and, importantly, the role of geologic processes in promoting biotic diversification. Biogeographic barriers such as Wallace’s line have been shown to be the result of old geologic processes shaping ancient faunal or floral diversification events. Based on distributions of birds, bats, reptiles, plants, and invertebrates we identify a distinct biogeographic disjunction in Vanuatu, a geologically nascent oceanic archipelago. We discuss mechanisms contributing to this concordant pattern across these disparate taxonomic groups in light of geologic history, ocean currents, vegetation, soil, and bioclimatic data, and propose the name Cheesman’s line to indicate the faunal and floral discontinuity between the northern and southern islands of Vanuatu.
Diel and Seasonal Occurrence Patterns of Drifting Fish Larvae in the Teima Stream, Okinawa Island
Ken Maeda and Katsunori Tachihara, 161-176
Drifting fish larvae were collected with a plankton net in the lower reaches of a freshwater area of the Teima Stream, Okinawa Island, Japan, during 24 hr periods each month from June 1998 to October 1999 (except July 1998). Newly hatched larvae of several gobioid and two pipefish species were collected, and their morphology was described. The larval occurrences suggested that most species spawn mainly from spring to fall, with some Rhinogobius species spawning in winter. Larvae of all fishes occurred predominantly during hours after dusk throughout the year. It is suggested that larvae of amphidromous fishes spawned in freshwater streams on Okinawa Island begin to drift soon after hatching at dusk and complete their exit from freshwater areas into the estuary and sea by midnight.
Distribution of Virus-Infected Bacteria in the Western Equatorial Pacific
Chung Yeon Hwang and Byung Cheol Cho, 177-186
Viruses are generally considered an important agent of bacterial loss in diverse marine environments. However, the impact of viruses on bacteria is unknown in the western equatorial Pacific, where surface waters are warm and phytoplankton biomass is low (i.e., oligotrophic). Further, little is known about their importance in the mesopelagial, where bacteria and heterotrophic nanoflagellates are known to be metabolically active. To elucidate the ecological characteristics of viruses in the western equatorial Pacific, abundances of bacteria and viruses were measured, along with frequencies of visibly infected cells (FVIC) and frequencies of dividing cells (FDC) in epipelagic and mesopelagic samples at three stations near the equator from August to September 2002. Measurements of Secchi depth (20 m) and chlorophyll a concentrations (0.07–0.4 μg chl a liter-¹) indicated that the study area was oligotrophic during the investigation. FVIC ranged from 0.4% to 1.8% and 0.5% to 1.8% in the epipelagic and mesopelagic zones, respectively. Virally induced bacterial mortality was inferred to range from 4.5% to 20.8% in the epipelagic zone, suggesting that viruses contribute substantially to bacterial mortality in oligotrophic seawaters. In addition, these values were similar to those estimated for the mesopelagic zone (5.0%–21.2%). Overall, viruses appear to be an important factor in the loss of bacterial production in both oligotrophic epipelagic and mesopelagic zones in the study area.
Distribution and Performance of the Nonnative Sea Grass Zostera japonica across a Tidal Height Gradient on Shaw Island, Washington
Kevin H. Britton-Simmons, Sandy Wyllie-Echeverria, Elizabeth K. Day, Katherine P. Booth, Kelsey Cartwright, Susana Flores, Cheyenne C. Garcia, Tessa L. Higgins, Cynthia Montanez, Arielle Rames, Kasey M. Welch, and Victoria Wyllie-Echeverria, 187-198
In the Northeast Pacific the nonnative seagrass Zostera japonica frequently exists at the same sites as the native seagrass Zostera marina. Although at some sites their vertical distributions overlap, at most sites in the Pacific Northwest there is a distinctive unvegetated zone between them. The objective of this study was to better understand why a gap between the lower limit of Z. japonica and the upper limit of Z. marina exists. To address this issue we carried out transplant experiments, conducted in situ monitoring of existing Z. japonica patches, and collected sediment samples at South Beach on Shaw Island, Washington, during the spring and summer of 2006. Transplant and in situ monitoring data indicate that survival and performance of Z. japonica are reduced lower in the intertidal zone. In addition, Z. japonica patches tended to be smaller and more spaced out at lower tidal heights. Although we found no Z. japonica seeds within or outside extant Z. japonica patches, high transplant mortality indicates that Z. japonica dispersal limitation is an unlikely cause of the unvegetated gap zone. Our field observations further suggest that herbivory, bioturbation, and epiphytes are unlikely causes of the gap pattern at our study site. Instead, we hypothesize that light limitation prevents Z. japonica from occurring lower in the intertidal. A review of published vertical distribution data for both Zostera species indicates that the lower limit of Z. japonica is relatively invariant among sites. In contrast, the upper limit of Z. marina is highly variable, ranging by more than 4 m within some subregions in Washington State. Consequently we hypothesize that intersite variability in the vertical distribution of Z. marina is the primary driver of spatial variability in the presence of the unvegetated gap.
Estimation of Fire Danger in Hawai‘i Using Limited Weather Data and Simulation
David R. Weise, Scott L. Stephens, Francis M. Fujioka, Tadashi J. Moody, and John Benoit, 199-220
The presence of fire in Hawai‘i has increased with introduction of nonnative grasses. Fire danger estimation using the National Fire Danger Rating System (NFDRS) typically requires 5 to 10 yr of data to determine percentile weather values and fire activity. The U.S. Army Pōhakuloa Training Area in Hawai‘i is located in the interface zone between windward and leeward weather conditions and needed to develop fire danger values but did not have sufficient weather or fire occurrence data. Use of simulation to estimate fire danger (expressed as fire risk) for areas with limited weather data was investigated. Influence of spatial resolution of weather information on fire risk was examined by comparing fire risk calculated using one or three weather stations and gridded weather predictions from the Mesoscale Spectral Model. Predicted gridded temperature was positively correlated with observed temperature; predicted and observed relative humidity were not significantly correlated. Simulated fire risk differed between weather data percentiles and between weather data resolutions. Predicted risk estimated from gridded weather data agreed more closely with observed risk estimated from weather data observed at all three remote automated weather stations. Correlation between simulated fire risk and the NFDRS Ignition Component was statistically significant for the single weather station simulations. Correlations between risk and the Ignition Component were not statistically significant for the three station and gridded weather data scenarios, which illustrates the difference between fire danger determined at broad spatial scales and fire risk resolved at finer spatial scales. Fire spread simulation modeling to estimate fire risk in areas with limited historical weather and fire occurrence data can provide finer-scale information than the NFDRS, which is better suited to larger, homogeneous areas with more complete fire and weather data. Values for the NFDRS Burning Index were determined and incorporated into the wildland fire management plan for Pōhakuloa Training Area.
New Species of Endemic Kleptoparasitic Spiders of the Genus Argyrodes (Araneae: Theridiidae) in the Hawaiian Islands
Malia Rivera and Rosemary G. Gillespie, 221-231
This study examined the endemic species of kleptoparasitic spiders in the genus Argyrodes from the Hawaiian Islands, a lineage previously known in the archipelago from only a single described species, Argyrodes hawaiiensis Simon. Here, two additional endemic species are described, A. ilipoepoe Rivera and Gillespie, n. sp., and A. laha Rivera and Gillespie, n. sp., with their biogeographical patterns, and the allotype female and paratypes of A. hawaiiensis are designated. As with A. hawaiiensis, both new species are commonly found as kleptoparasites on the sheet webs of large nocturnal spiders in the genus Orsonwelles (Linyphiidae). Hawaiian Argyrodes are characterized by small and rounded abdomens, unpronounced clypeal projections, and variably long fangs. Argyrodes hawaiiensis; A. ilipoepoe, n. sp.; and A. laha, n. sp., include all the known endemic representatives of the group in the Hawaiian Islands, which mostly occur in wet and mesic forests.
Ostracoda (Myodocopina) of the Hawaiian Islands
Louis S. Kornicker, Elizabeth Harrison-Nelson, and S. L. Coles, 233-283
Ostracoda (Myodocopina) from four of the Hawaiian Islands (Kaua‘i, Moloka‘i, Maui, and Hawai‘i) are identified, and a new species, Pterocypridina colesi Kornicker & Harrison-Nelson, that was present on all the Islands is described and illustrated, including all five instars and the adult male and female. The genus was not previously known from the area, and its ontogeny had not been described. The number of species collected on the Islands varied from two on Moloka‘i to six on Kaua‘i.
On Some Octocorallia (Alcyonacea) from Hong Kong, with Description of a New Species, Paraminabea rubeusa
Y. Benayahu and K. Fabricius, 285-296
Octocorals from Hong Kong were studied at 18 sites down to a depth of 25 m in 1999. The collection of ~90 specimens yielded nine species distributed in seven genera of the families Alcyoniidae, Nephtheidae, and Xeniidae (all are new zoogeographical records for Hong Kong), plus ca. 70 samples of azooxanthellate octocorals of the genera Dendronephthya (family Nephtheidae), Chironephthya, and Nephthyigorgia (family Nidaliidae), which were not identified to species level. The collection included Paraminabea rubeusa Benayahu & Fabricius, n. sp., which is described here. The impoverished nature of the zooxanthellate octocorals is reflected in the low number of species found in the families Alcyoniidae and Xeniidae (seven and one, respectively), families that typically contribute a high proportion of species in the Indo-Pacific region. It is crucial to implement effective conservation policies in Hong Kong to preserve its remaining zooxanthellate octocoral species and thereby prevent the local extinction of these species, including the newly described Sarcophyton tumulosum Benayahu & Ofwegen, 2009, and Lobophytum mortoni Benayahu & Ofwegen, 2009, which may be endemic to the region.
Breeding Avifauna of the Chesterfield Islands, Coral Sea: Current Population Sizes, Trends, and Threats
Philippe Borsa, Mireille Pandolfi, Serge Andréfouët, and Vincent Bretagnolle, 297-314
This paper reports on post-1991 census data and on the breeding phenology of seabirds of the Chesterfield-Bampton and Bellona groups of coral islets in the Coral Sea. In total, 13 resident bird species were observed [Wedge-tailed Shearwater (Puffinus pacificus), Masked Booby (S. dactylatra), Brown Booby (Sula leucogaster), Red-footed Booby (S. sula), Lesser Frigatebird (Fregata ariel), Great Frigatebird (F. minor), Black Noddy (Anous minutus), Brown Noddy (A. stolidus), Crested Tern (Sterna bergii), Sooty Tern (S. fuscata), Fairy Tern (S. nereis), Black-naped Tern (S. sumatrana), and Buff-banded Rail (Gallirallus philippensis)]. Segregation for nesting habitat was similar to that previously observed on other coral-reef islets of the Coral Sea. Breeding periods were either in the winter (Masked and Red-footed Boobies, Frigatebirds, Fairy Tern) or in the summer (Wedge-tailed Shearwater, Black and Brown Noddies, Crested and Black-naped Terns) or year-round (Brown Booby). Sooty Terns bred twice a year (summer and spring), but this was not consistent across years. Estimates of breeding population sizes for the whole Chesterfield-Bampton and Bellona groups are proposed for Wedge-tailed Shearwater (90,000 to 106,000 breeding pairs), Masked Booby (280–500 pairs), Brown Booby (3,800–5,800 pairs), Red-footed Booby (7,200–7,300 pairs), Lesser Frigatebird (1,600 pairs), Great Frigatebird (350–480 pairs), Black Noddy (29,000–45,000 pairs), Brown Noddy (15,000–23,000 pairs), Crested Tern (80–100 pairs), Sooty Tern (11,000–46,000 pairs), and Black-naped Tern (70–90 pairs). Interannual fluctuation in breeding population size was apparent in Wedge-tailed Shearwater. Over the last 30 yr, an increase in Brown Booby abundance was noted, whereas declines are suspected for the Fairy Tern and Buff-banded Rail. Among the threats to nesting seabirds are stress and other disturbances caused by human frequentation, including poaching of seabird chicks and introduced mice.
Prehistoric Birds from Rurutu, Austral Islands, East Polynesia
David W. Steadman and Robert Bollt, 315-325
We identify 70 bird bones from the Peva dune site, Rurutu, Austral Islands. These bones represent 10 species, dominated by the extant White-tailed Tropicbird, Phaethon lepturus; the nonnative chicken, Gallus gallus; and an undescribed species of extinct rail, Gallirallus sp. Two other species are extinct (the ground-doves Gallicolumba undescribed spp. 1 and 2). No species of Gallirallus or Gallicolumba has been recorded previously from the Austral Islands. All but three of the 70 bird bones are from the lowest cultural strata at Peva, which date from the thirteenth to early fifteenth century A.D. (the Archaic or Early East Polynesian cultural phase). The small set of bird bones from the Peva dune site increases the number of indigenous species of land birds known from Rurutu from three to six.
Body Size, Growth, and Feather Mass of the Endangered Hawaiian Moorhen (Gallinula chloropus sandvicensis)
David W. DesRochers, Michael D. Silbernagle, Aaron Nadig, and J. Michael Reed, 327-323
Body and feather mass data are important in avian studies and are required for determining things such as body condition and energetic carrying capacity. There are 12 subspecies of Common Moorhens (Gallinula chloropus), six continental and six island subspecies, of which two are endangered. Body mass data for multiple individuals are available for only three subspecies, and feather mass data have been reported for only one individual. Body mass (n = 82) and feather mass (n = 2) for adults and body mass for three subadult age classes (n = 27) are provided for the Hawaiian subspecies of Common Moorhen (G. c. sandvicensis). Other body size measurements, including tarsus length, shield-bill length, shield width, and wing cord length also are presented. Adult Hawaiian Moorhen body mass averaged 350.7 g (±50.0 SD; range, 232–522; 95% CI, 339.8–361.6), and young birds appear to develop like young of G. c. chloropus and other Rallidae. Based on published data, G. c. sandvicensis is heavier than G. c. guami, female G. c. chloropus, and G. c. meridionalis; lighter than G. c. garmani and males of G. c. cachinnans; and similar in mass to G. c. cachinnans females, males of G. c. chloropus, and G. c. orientalis. There do not appear to be systematic differences in body mass between mainland (data for four subspecies) and island subspecies (data for three subspecies). Total mass of all feathers for two males was 16.2 and 12.1 g, which made up 3.1% and 3.8%, respectively, of their total body mass.
Characteristics of Coral Cay Soils at Coringa-Herald Coral Sea Islands, Australia
George N. Batianoff, Gillian C. Naylor, Rod J. Fensham, and V. John Neldner, 335-347
Coral cay soil chemical and physical properties were described from Coringa-Herald National Nature Reserve, Australia. Soil A horizons under littoral herblands and Argusia argentea shrubs were shallow and coarse textured. Interior soil A horizons, particularly under Pisonia grandis closed forest, were deeper (1.2 m) with finer textures. Average surface soil pH values ranged from pH 8.76 at the seashores to pH 8.09 in the interior. Average surface soil organic carbon ranged from 2.4% to 4.8%; and phosphorus (Colwell-P) concentrations ranged from 467 mg/kg to 882 mg/kg within the interior areas. Chemical fertility of all A horizons increased from the seashore to the island interior. The higher fertility levels are attributed to high organic matter contributed by vegetation, combined with activities of seabirds, particularly the burrowing wedge-tailed shearwater, Puffinis pacificus. Leaching of nutrients from surface soils is reflected in the rapid decline in soil fertility with depth. Deeper interior A horizons are interrupted by formation of an abrupt white C profile. It is speculated that the formation of this layer is the product of periodic “washing” by a seasonally high fresh/brackish water table.
An Observation of Mating in Free-Ranging Blacktip Reef Sharks, Carcharhinus melanopterus
Douglas J. McCauley, Yannis P. Papastamatiou, and Hillary S. Young, 349-352
We describe the mating behavior of free-ranging Blacktip Reef Sharks, Carcharhinus melanopterus, at Palmyra Atoll. This is the first primary report of mating in C. melanopterus and the first direct observation of mating for an obligate swimming shark species. Similar to that in other nonobligate swimming shark species, mating in C. melanopterus was characterized by multiple males following a single female, a male grabbing the female near the pectoral fin and positioning her head down on the bottom, and the insertion of a single clasper. Copulation lasted 68 sec, which is shorter than the durations recorded for most other shark species.
Pacific Science 64, no. 3
Top-Down Analysis of Forest Structure and Biogeochemistry across Hawaiian Landscapes
Peter M. Vitousek, Michael A. Tweiten, James Kellner, Sara C. Hotchkiss, Oliver A. Chadwick, and Gregory P. Asner, 359-366
Technical and analytical improvements in aircraft-based remote sensing allow synoptic measurements of structural and chemical properties of vegetation across whole landscapes. We used the Carnegie Airborne Observatory, which includes waveform light detection and ranging (LiDAR) and high-fidelity imaging spectroscopy, to evaluate the landscapes surrounding four well-studied sites on a substrate age gradient across the Hawaiian Islands. The airborne measurements yielded variations in ground topography, canopy height, and canopy nitrogen (N) concentration more accurately than they could have been obtained by any reasonable intensity of ground-based sampling. We detected spatial variation in ecosystem properties associated with the properties of different species, including differences in canopy N concentrations associated with the native species Metrosideros polymorpha and Acacia koa, and differences brought about by invasions of the biological N fixer Morella faya. Structural and chemical differences associated with exotic tree plantations and with dominance of forest patches by the native mat-forming fern Dicranopteris linearis also could be analyzed straightforwardly. This approach provides a powerful tool for ecologists seeking to expand from plot-based measurements to landscape-level analyses.
Potential Effects of an Invasive Nitrogen-Fixing Tree on a Hawaiian Stream Food Web
Trisha B. Atwood, Tracy N. Wiegner, Jason P. Turner, and Richard A. MacKenzie, 367-379
Falcataria moluccana (albizia) is an exotic nitrogen (N)-fixing tree currently invading riparian forests in Hawai‘i, U.S.A. This study examined how this invasion is impacting stream ecosystems by using naturally occurring stable isotopes of carbon (C) and N to compare food web structure between a noninvaded and an albizia-invaded stream reach on the island of Hawai‘i. Isotopic signatures of particulate organic matter (POM), macroalgae, invertebrates, and fishes were collected and compared between the two stream reaches. Stable C isotopic signatures of organic matter sources (POM and macroalgae) and consumers (amphipods, caddisflies, crayfish, and fishes) from the invaded site were depleted in ¹³C compared with the noninvaded site. In contrast, all samples from the invaded site were enriched in ¹⁵N compared with the noninvaded site. Results from IsoSource and two-source mixing models suggested that albizia was a major contributor to diets of lower-level consumers within the invaded site, displacing POM and macroalgae as their major food sources. Albizia was also an indirect C and N source for higher-level consumers within the invaded site because albizia was the major dietary constituent of their prey. In addition, ¹⁵N enrichment of the macroalgae at the invaded site suggests that albizia may be an important N source to benthic primary producers and could be further altering the food web from bottom up. Our study provides some of the first evidence that invasive riparian N-fixing trees can potentially alter the structure of stream food webs.
Survival of Feral Cats, Felis catus (Carnivora: Felidae), on Mauna Kea, Hawai‘i, Based on Tooth Cementum Lines
Raymond M. Danner, Chris Farmer, Steven C. Hess, Robert M. Stephens, and Paul C. Banko, 381-389
Feral cats (Felis catus) have spread throughout anthropogenic and insular environments of the world. They now threaten many species of native wildlife with chronic depredation. Knowledge of feral cat population dynamics is necessary to understand their ecological effects and to develop effective control strategies. However, there are few studies worldwide regarding annual or lifetime survival rates in remote systems, and none on Pacific islands. We constructed the age distribution and estimated survival of feral cats in a remote area of Hawai‘i Island using cementum lines present in lower canine teeth. Our data suggest annual cementum line formation. A log-linear model estimated annual survival ≥1 yr of age to be 0.647. Relatively high survival coupled with high reproductive output allows individual cats to affect native wildlife for many years and cat populations to rebound quickly after control efforts.
Changes in Benthic Macrofauna Associated with a Shallow-Water Hydrothermal Vent Gradient in Papua New Guinea
David J. Karlen, Roy E. Price, Thomas Pichler, and James R. Garey, 391-404
Infaunal macroinvertebrates were characterized along an environmental gradient from a shallow-water hydrothermal vent located at Tutum Bay, Ambitle Island, Papua New Guinea. Samples were collected at three sites located at 7.5, 60, and 150 m from the vent and from a nonhydrothermal reference site located to the north. Temperature and arsenic concentration were found to decrease and pH increased with distance away from the vent. At each site, five replicate core samples were taken randomly from a 1 m² sampling grid. All infaunal invertebrates >500 μm were sorted, identified to the lowest practical taxonomic level and counted. Results from the macrofauna data show a strong trend of increasing abundance, species richness and diversity relative to distance away from the vent, but even at 150 m the benthic macrofauna appeared to be depressed relative to the reference site. Mollusks were completely absent 7.5 m from the vent, rare at 60 m, and abundant at 150 m, suggesting that the low pH values associated with the hydrothermal activity play an important role in the benthic community structure.
Reproductive Synchrony in Acropora Assemblages on Reefs of New Caledonia
Andrew H. Baird, Marie C. Kospartov, and Steven Purcell, 405-412
Despite a recent expansion in the geographical focus of studies on coral reproduction, there remain many regions in the Indo-Pacific, such as Melanesia, where research is limited. For example, although New Caledonia in southern Melanesia is home to the world’s second largest barrier reef, which has recently been given UNESCO World Heritage listing, almost nothing is known of the reproductive biology of the coral fauna there, in particular the timing of spawning. In this study we sampled Acropora assemblages in November 2004 to test for reproductive synchrony at eight sites in New Caledonia separated by up to 200 km. In total, 80% of 1,055 Acropora colonies sampled contained mature oocytes, and 34 (92%) of 37 species sampled had at least one mature colony. These data demonstrate that reproduction in Acropora is highly synchronous over a large scale in New Caledonia and suggest a multispecies spawning event following the full moon in November coincident with the mass spawning period on the Great Barrier Reef, Australia. The high synchrony of reproductive effort implies that even a brief halt of activities that threaten fertilization and early development of coral propagules, such as discharge of liquid waste from ore processing, could have a major mitigating effect on the potential damage to these globally valued reefs.
Ten species of Hawaiian primnoids are described and/or discussed, completing the review of the 28 primnoids known from the Hawaiian Islands. This family constitutes 29% of the Hawaiian octocoral fauna. Callogorgia americana is synonymized with C. gilberti, resulting in a disjunct distribution in the Pacific and Northwest Atlantic. Two new species are described (Plumarella circumoperculum Cairns and Parastenella bayeri Cairns), and two (Callogorgia gilberti and C. robusta) are reported for the first time since their original descriptions over a century ago. Keys are provided for the Hawaiian primnoid genera and all species of the genus Parastenella; comparative tables are provided for the Hawaiian Callogorgia and Fanellia. A distinctive nematocyst pad is described for the genus Parastenella. Highly modified polyps caused by copepod parasites are described for two species: Callogorgia gilberti and Thouarella hilgendorfi.
Microhabitat Distribution of the Hermit Crabs Calcinus haigae and Calcinus hazletti (Decapoda: Anomura: Diogenidae)
Brian A. Hazlett and Catherine E. Bach, 441-447
Two sympatric species of hermit crabs, Calcinus haigae and Calcinus hazletti, appear to have different microhabitat distributions in the subtidal. Several biotic factors may be influencing this microhabitat difference. We documented the field distributions of these two species as a function of coral species and investigated whether aggregation behavior, avoidance behavior, and/or shell exchanges are influencing the distribution patterns. Individuals of C. hazletti occurred predominantly on the cauliflower coral Pocillipora meandrina. In addition, individuals of C. hazletti aggregated toward conspecifics in the laboratory. Individuals of C. haigae avoided individuals of C. hazletti in the field unless the C. haigae were in damaged shells. Individuals of C. haigae did not initiate interspecific shell exchange attempts in the laboratory, but individuals of C. hazletti did initiate interspecific shell exchanges. Thus, both intraspecific and interspecific interactions affect the distributions of these crabs.
Rare Sightings of a Bryde’s Whale (Balaenoptera edeni) and Sei Whales (B. borealis) (Cetacea: Balaenopteridae) Northeast of O‘ahu, Hawai‘i
Mari A. Smultea, Thomas A. Jefferson, and Ann M. Zoidis, 449-457
In the Hawaiian Islands small numbers of Bryde’s whales (Balaenoptera edeni) have been documented only in the Northwestern (leeward) Hawaiian Islands, and sei whales (B. borealis) have only recently been confirmed near the islands of Maui and Hawai‘i. In November 2007, one Bryde’s whale and two sei whale groups (including three subadults) were documented during a 7-day, systematic vessel-transect survey conducted east and northeast of O‘ahu. The Bryde’s whale sighting is the first in nearshore (<70 km) waters of the main Hawaiian Islands, and the two sei whale sightings are the first near O‘ahu, including the first documented subadult sei whales there. The latter information suggests that Hawai‘i may be a reproductive area for the endangered sei whale, whose breeding and calving ground locations remain unknown in the Pacific Ocean. Other than rare incidence, the lack of historical sightings of these two species despite many years of previous shipboard and aerial surveys off Hawai‘i may be due to misidentification and/or poor sea conditions prevalent in deep, offshore windward waters of the Hawaiian Islands. We recommend conducting more offshore vessel surveys for, and biopsy sampling of, these species to clarify habitat use and current stock boundaries and numbers, information important for management of Pacific populations.
Occurrence of the Phoronid Phoronopsis albomaculata in Cocos Island, Costa Rica
Harlan K. Dean, Jeffrey A. Sibaja-Cordero, and Jorge Cortés, 459-462
The phoronid Phoronopsis albomaculata was collected in subtidal (28-35 m) sandy sediments in Bahía Chatham during a benthic survey designed to describe the biota of Cocos Island (Isla del Coco), Costa Rica, a national park and Human Heritage Site. Occurrence of this widespread species in Cocos Island is the first report of a phoronid for Costa Rican waters and is the second locality recorded for the eastern Pacific. Taxonomically significant characters (presence of an epidermal collar, extent of coiling of lophophore and nephridia) are discussed. Comparisons are made between depth and abundance of this species from Cocos Island and results of previous studies.
Protodrilidae (Annelida: Polychaeta) from the Hawaiian Islands and Comparison with Specimens from French Polynesia
Julie H. Bailey-Brock, Claude Jouin-Toulmond, and Richard E. Brock, 463-472
Three species of Protodrilidae were collected from the islands of O‘ahu and Ni‘ihau in the Hawaiian chain, including specimens closely resembling Parenterodrilus taenioides (Jouin, 1979), described from Mo‘orea (French Polynesia). Others are probably an undescribed species of Parenterodrilus that was found in fine sand substrate collected off Wai‘anae, O‘ahu. A third species, Protodrilus albicans Jouin, 1970, described from Banyuls-sur-Mer (Mediterranean Sea) and recorded from Mo‘orea and Tahiti as well, was also collected from O‘ahu. Depths and habitat characteristics are given for these new records to the Hawaiian fauna. It is suggested that the wide geographical distribution of the different “cosmopolitan species” of Protodrilidae is related both to the dispersal by free-swimming larvae and to the ancient origin of this interstitial fauna.
Reptiles of Ngulu Atoll, Yap State, Federated States of Micronesia
Donald W. Buden, 473-480
Fourteen species of reptiles (two sea turtles, six geckos, six skinks) are recorded from Ngulu Atoll, Yap, Micronesia, all but the turtles for the first time. None is endemic and most occur widely in Oceania; the phylogenetic status of an undescribed species of Lepidodactylus is undetermined, and a phenotypically male Nactus cf. pelagicus is recorded from Micronesia for the first time. Lepidodactylus moestus is the most common gecko on Ngulu Island, and Emoia caeruleocauda, E. impar, and E. jakati are the most abundant skinks. The islands are an important nesting site for green turtles, Chelonia mydas. Isolation, a small resident human population, and traditional conservation practices contribute to sustaining turtle populations, although occasional poaching by outside visitors persists. The report of a small snake on Ylangchel Island, possibly a species of Ramphotyphlops, requires confirmation.
Association Affairs, 481-487
Pacific Science 64, no. 4
Biology and Impacts of Pacific Island Invasive Species. 6. Prosopis pallida and Prosopis juliflora (Algarroba, Mesquite, Kiawe) (Fabaceae)
Timothy Gallaher and Mark Merlin, 489-526
Prosopis pallida and P. juliflora (commonly referred to as algarroba, mesquite, or kiawe) were introduced from South America to areas in Oceania, Asia, and Africa during the early nineteenth century. In many cases, they naturalized and became widespread. In some places, alien Prosopis species are highly valued for the products and services that they can provide such as shade, cattle fodder, wood for fuel and fence posts, and nectar for honey production. In Australia, four Prosopis species including P. pallida, P. juliflora, P. glandulosa, P. velutina, and their hybrids are considered invasive and are subject to control efforts. After its introduction to Hawai‘i in 1828, P. pallida became a dominant tree in arid areas of the main Hawaiian Islands, replacing the native lowland dry forest species that had been decimated by human activity, particularly by the introductions of goats and cattle. Prosopis pallida also has become an important economic species in Hawai‘i. Prosopis juliflora, a more recent introduction to Hawai‘i, is now spreading and is considered to be a noxious weed. Competition between Prosopis and native species as well as negative impacts of Prosopis on soil and local hydrology have been reported; however in some cases Prosopis species are characterized as midsuccessional species that rehabilitate degraded soils, eventually facilitating later-successional woodland. This provides a potential opportunity to use these species in reforestation efforts. Management decisions regarding these species should include a consideration of both their positive and negative ecological roles. If control or eradication is desired, a number of methods have been employed with various degrees of success.
Can Ptilinopus greyii (Columbidae) Disperse Seeds in New Caledonia’s Dry Forests?
Jacques Tassin, Mélanie Boissenin, and Nicolas Barre, 527-532
Conservation of endangered habitats of South Pacific islands is partially dependent on activity of seed dispersers. In consuming fruits, animals can spread seeds from parent plants to distant sites, thus contributing to plant regeneration and colonization of new sites. In the dry forests of New Caledonia, the red-bellied fruit-dove, Ptilinopus greyii, is a potential disperser of many fleshy-fruited species. Trials with a captive bird showed that gut passage enhanced seed germination for Diospyros fasciculosa and Mimusops elengi but not for Vitex cf. collina, compared with whole fruits. Gut passage did not shorten duration of seed dormancy, which is consistent with evidence of a simple deinhibition effect for D. fasciculosa and M. elengi. Minimum Retention Time (MRT) of seeds in the gut differed significantly between the three tree species, from a mean of 17.4 min for D. fasciculosa to a mean of 52.4 min for M. elengi. These times are longer than observed foraging times in fruiting trees, potentially making this fruit-dove an effective seed disperser.
Native Species Regeneration Following Ungulate Exclusion and Nonnative Grass Removal in a Remnant Hawaiian Dry Forest
Jarrod M. Thaxton, T. Colleen Cole, Susan Cordell, Robert J. Cabin, Darren R. Sandquist, and Creighton M. Litton, 533-544
Hawaiian lowland dry forests have been reduced by >90% since first human contact. Restoration has focused on protection from fire and ungulates, and removal of invasive grasses as ways to stimulate native forest regeneration. Despite these efforts, natural regeneration of native plants has been infrequent. To assess effects of previous restoration treatments on natural regeneration, we monitored seed rain and dynamics of seedlings and juveniles for a period of 3 yr (2004–2007) within three restoration units within a remnant forest on the island of Hawai‘i. All units had been protected from fire for many decades but differed in time since ungulate exclusion and grass removal. The units were as follows: (1) long-term restoration (fenced 1956, grass removal initiated 1995), (2) short-term restoration (fenced and grass removal initiated 1997), and (3) unmanaged (fenced 1997, no grass removal). Overall juvenile plant abundance was highest in the short-term unit, but native abundance was highest in the long-term unit. Native woody seedlings established in all units, but recruitment into larger size classes was restricted to units with grass removal, primarily the long-term unit. Native seed rain explained much of the variation in native seedling abundance between units with grass removal. Nonnative grass seed rain was extensive but was reduced by an order of magnitude with grass removal. This study suggests that natural regeneration may enhance restoration actions in sites with native canopy, but this is likely only when restoration activities have been maintained for several years to coincide with favorable rainfall conditions that are highly unpredictable over time.
Comparison of Dissolved Organic Carbon Bioavailability from Native and Invasive Vegetation along a Hawaiian River
Tracy N. Wiegner and Randee L. Tubal, 545-555
Riparian litter fall is an important source of organic matter to rivers and accounts for a large fraction of their dissolved organic carbon (DOC) load. DOC is metabolically important in rivers, and therefore changes in riparian vegetation species composition should affect riverine DOC bioavailability. Worldwide, invasive vegetation composes a large percentage of riparian vegetation. In Hawai‘i, riparian vegetation changes from native to invasive species with decreasing elevation. To assess how changes in riparian vegetation affect riverine DOC dynamics, we compared DOC bioavailability from native (Acacia koa and Metrosideros polymorpha) and invasive (Falcataria moluccana and Psidium cattleianum) riparian trees to freshwater and estuarine bacteria from the Wailuku River on Hawai‘i Island through dark bioassays. DOC bioavailabilities in riverine and estuarine waters were similar among all riparian vegetation types. In contrast, vegetation-derived DOC was more bioavailable (52%±4%) than the riverine and estuarine DOC (14%±3%). Combining DOC bioavailability and leaf litter input data from our native and invaded riparian sites suggests that a shift in leaf litter inputs from native to invasive species may increase the amount of bioavailable DOC entering Hawaiian rivers and streams. This DOC input has the potential to impact the metabolism and food webs of downstream ecosystems.
Impacts of Recreational Divers on Palauan Coral Reefs and Options for Management
Chris Poonian, Patricia Z. R. Davis, and Colby Kearns McNaughton, 557-565
Recent growth in the popularity of recreational scuba diving has generated concerns about resulting impacts to coral reefs, particularly in locations such as the Republic of Palau, a world-renowned dive destination with rapidly increasing numbers of visitors. Divers were observed in-water at three of the most visited dive sites in the Rock Islands–Southern Lagoon Area: German Channel, Ngerchong, and Big Drop-off. Dive guides were interviewed about diver impacts at German Channel and Ngerchong. Divers’ contact rates with hard coral ranged from 0.87±0.27 to 2.98±0.59 contacts diverˉ¹ 10 minˉ¹ (mean±SEM). Three instances of obvious physical damage were observed. Holding and fin contacts were the most common potentially damaging behaviors of divers, particularly those with cameras or gloves. Guides identified natural impacts (63% of respondents) and divers (34% of respondents) as the primary causes of damage to coral. Proactive management is essential to mitigate any negative impacts of recreational diving on coral reefs and to ensure resilience against other increasing threats. Long-term monitoring of dive sites, controls on the use of gloves and underwater photography, and training of guides are suggested to minimize damage caused by divers to coral reefs in Palau and elsewhere.
Records of Great White Sharks (Carcharodon carcharias) in New Caledonian Waters
Philippe Tirard, Michael J. Manning, Isabelle Jollit, Clinton Duffy, and Philippe Borsa, 567-576
The occurrence of great white sharks (Carcharodon carcharias) in New Caledonia is documented from 30 observation events (sightings or captures or forensic examination of wounds) made between 1943 and 2009, involving 34 individual sharks. Nine of the observation events concerned animals caught on lines set for deep-sea fishes, five were encounters with scuba divers or snorkelers, and one was a fatal attack on a surfer; two other observations included great white sharks feeding on whale carcasses; two were from pop-up archival transmitting tag records that monitored individuals tagged in the Chatham Islands, New Zealand; one was a forensic identification from wounds sustained by another large shark; and seven were fortuitous sightings from boats. Nearly all observations were of solitary sharks. Observation events were concentrated in the southern lagoon of New Caledonia or along its barrier reef. They occurred from July to March, with most records in September and November, coinciding with a peak of occurrence of large cetaceans.
Review of Crocodile (Reptilia: Crocodilia) and Dugong (Mammalia: Sirenia) Sightings in the Federated States of Micronesia
Donald W. Buden and John Haglelgam, 577-583
Three confirmed occurrences of crocodiles, one identified as Crocodylus porosus (two others presumed C. porosus), and four occurrences of the dugong, Dugong dugon, are recorded for the Federated States of Micronesia. The records of a crocodile and a dugong on Eauripik Atoll and a dugong on Kosrae are reported in the literature for the first time. On geographic grounds, the crocodiles and dugongs recorded from Yap State, in the western part of the FSM, probably pertain to vagrants from Palau, approximately 450 km to the southwest, whereas those recorded from the eastern islands (Pohnpei and Kosrae) are more likely to have originated from populations in the Bismarck Archipelago and Solomon Islands area, approximately 1,500 km to the southwest, rather than from Palau, which is a much greater distance to the west.
Marine Benthic Algae of Johnston Atoll: New Species Records, Spatial Distribution, and Taxonomic Affinities with Neighboring Islands
Roy T. Tsuda, Isabella A. Abbott, Peter S. Vroom, and Jack R. Fisher, 585-605
Forty-five of the 107 species of marine benthic algae collected during 2004 and 2006 NOAA cruises to isolated Johnston Atoll and two additional species from earlier collections represent new species records. Total number of algae is now increased to 189 species: 26 species of cyanobacteria (blue-green algae), 105 species of red algae, 15 species of brown algae, and 43 species of green algae. The macroalga Caulerpa serrulata and the epiphyte Lomentaria hakodatensis were the most widely distributed species at Johnston Atoll based on frequency of occurrence at 10 of 12 stations and 8 of 12 stations, respectively, during the 2004 NOAA cruise. Despite the atoll’s isolation, the parasitic red alga Neotenophycus ichthyosteus and the cyanobacterium Borzia elongata are the only endemic algal species on Johnston Atoll. Nonmetric multidimensional scaling analyses indicate that taxonomic affinities of Johnston Atoll lie between French Frigate Shoals and Wake Atoll. In terms of atolls, biodiversity of the marine flora of Johnston Atoll (i.e., 189 species) is surpassed only by the 256 algal species of the much-larger and better-studied Enewetak Atoll in the Marshall Islands.
Origins and Nature of Vessels in Monocotyledons. 12. Pit Membrane Microstructure Diversity in Tracheary Elements of Astelia
Sherwin Carlquist and Edward L. Schneider, 607-618
Xylem of stems and roots of three species of Astelia, a monocot with relatively unspecialized xylem, was examined with scanning electron microscopy (SEM) to better understand structural conditions intermediate between tracheids and vessel elements. Both macerations and hand-sectioned material were studied. Tracheary elements of roots of Asteliaceae can be characterized as tracheids, with some degrees of transition to vessel elements. Pit membrane remnants, which take the form of pores, reticula, or threads, are present commonly in end walls of tracheary elements of roots of Astelia. Stems of Astelia have tracheids with less-conspicuous porosities in the pit membranes of end walls than those of roots. Sectioned materials show that the porose (reticulate) cellulosic layers of the primary wall, which is embedded in a matrix of amorphous material, can be exposed to various degrees by the sectioning process; the cellulosic network faces the lumen, and the amorphous material is the compound middle lamella. Astelia shows stages of transition between vessel elements and tracheids. These character expressions relate to occupancy of moist habitats (Astelia) with steady availability of moisture during the year. There appears to be little difference between a terrestrial species (A. chathamica) and the scandent/epiphytic species A. argyrocoma and A. menziesiana in terms of tracheary element microstructure, suggesting that habitat is more important than habit as a determinant of tracheary element microstructure and the degree to which lysis of pit membranes occurs. Freehand sectioning of ethanol-fixed materials, as in earlier studies in this series, provides a reliable way of observing pit membrane/perforation structure when viewed with SEM. Astelia is one of several monocots that demonstrate the difficulty of discriminating between tracheids and vessel elements.
Index to Volume 64