Pacific Science 65, no. 1
Hawai‘i’s forest ecosystems are changing rapidly due to a high level of species introductions, and it is an open question whether native species will be maintained. Several studies have explored the potential for native species to succeed in future communities dominated by introduced species in Hawai‘i, but the results have been conflicting and most of the studies have been limited to relatively young forest (<30 yr old). I surveyed a remote, 80-yr-old noncommercial plantation on Hawai‘i Island to determine whether any native tree species were able to succeed in the planted forest. I compared abundance and composition of native species in the plantation to that in a relict, native-dominated forest adjacent to the plantation and located on the same substrate type. After 80 yr, native species constituted just 4.5% of basal area and 12.1% of stem density in the plantation. However, I found that the relative success of native species varied strongly by species. Of nine native species encountered in the relict forest, six were rare or absent in the planted forest. A seventh (Metrosideros polymorpha) dominated the relict forest but was unable to recruit in the planted forest. However, two shade-tolerant understory tree species (Psychotria hawaiiensis and Psydrax odorata) were at least as common in the plantation as in the relict forest, and the latter was significantly more abundant in the plantation. Thus, although I found no evidence that native species will dominate with continued succession, I found that at least two native species may remain important components of plantation-derived Hawaiian forests in the future.
Role of Fire in the Germination Ecology of Fountain Grass (Pennisetum setaceum), an Invasive African Bunchgrass in Hawai‘i
Edith Nonner, Susan Cordell, and Donald R. Drake, 17
Field and laboratory studies were carried out to test factors expected to be relevant for the germination of fountain grass: (1) light; (2) emergence of fountain grass seedlings from depths of 0, 2.5, and 5 cm; (3) fire passing over exposed and buried seeds; (4) laboratory heat treatment mimicking exposure to grass fire. Both fire in the field and heat applied in the laboratory killed fountain grass seeds. In the laboratory, some seeds were killed after exposure to 75°C for 3 min, and all seeds were killed at 100°C. During the prescribed burns, temperatures at the soil surface reached at least 204°C, but temperatures at depths of 2.5 and 5 cm showed no measurable change. Light is not essential for germination of fountain grass seeds, and seedlings can emerge from depths of at least 5 cm. Both of these traits contribute to the invasive capacity of the species. Because fountain grass seeds are killed at temperatures in excess of 100°C, the species depends on its ability to resprout and quickly set seed after fire for population growth and spread. Seeds buried beneath the soil may escape exposure to fire, and substrate heterogeneity may provide refuge from temperature extremes experienced during fire. The morphology of fountain grass seeds likely inhibits burial in the soil for the most part, but there are several potential burial mechanisms. Prescribed burns could prove to be a useful tool for fountain grass control in large, degraded sites where fountain grass has invaded but only when coupled with additional control measures.
Pattern of Twig Cutting by Introduced Rats in Insular Cloud Forests
Tetsuto Abe and Hiromi Umeno, 27
We examined seasonal patterns of twig cutting by the introduced black rat, Rattus rattus, on Haha-jima Island, an island in the Ogasawara (Bonin) group of Japan. Censuses were conducted along seven routes to count the number of trees damaged by twig cutting in each month. Overall, 42.6% (23/54 species) of woody species were damaged. Twig cutting was greatest in spring (March-May). Probability of damage by twig cutting was not correlated with species frequency in the vegetation. This suggests that twig cutting is associated with particular characteristics of target species. Endemic plants experienced a significantly higher probability of twig cutting than alien plants. This may be due to an evolutionary loss of plant defense mechanisms in the absence of herbivorous mammals. Because the overall proportion of individuals damaged by twig cutting was not high, the behavior is unlikely to influence the population dynamics of trees and cause vegetation change. But intense twig cutting was also found on critically endangered plants, so twig cutting by black rats could be a threat to those species.
Excluding Nontarget Species from Brown Tree Snake, Boiga irregularis (Reptilia: Colubridae), Bait Stations: Experimental Tests of Station Design and Placement
Tom Mathies, Russell Scarpino, Brenna A. Levine, Craig Clark, and Julie A. Savidge, 41
Bait stations with toxic baits are an emerging technology for eradication of the invasive brown tree snake (Boiga irregularis) on Guam, yet potential interferences by nontarget species are largely unknown. We tested the efficacies of three bait station designs together with three commonly used station support structures to exclude nonnative rats (roof rat, Rattus rattus; Norway rat, Rattus norvegicus; Polynesian rat, Rattus exulans) and native coconut crabs (Birgus latro). When directly presented, all species readily consumed the dead neonatal mouse baits (nontoxic) including those replicating decomposing baits in the field. When bait stations were made easily accessible by placement near ground level, all rat species were able to enter all station types, but some individual roof rats and Norway rats exhibited apparent neophobia. When stations were placed up on support structures, simulating those in the field (~1 m above ground level), numbers of station accessions by roof rats and Norway rats remained essentially unchanged, but Polynesian rats then showed almost no inclination to enter stations. However, ability to access entrances of stations (but not interiors) when on support structures was extremely high for roof rats and appreciable for the other rat species, including Polynesians. The station type currently in widest use, when placed on chain-link cyclone fence, had the highest probability of accession. Crabs readily accessed station entrances but never interiors. The two downward-angled station designs, when placed in simulated vegetation, had the lowest probabilities of accession. In areas where nontarget species are a concern, we recommend use of either of the downward-angled station designs and suspension from vegetation wherever possible.
Survival of European Mouflon (Artiodactyla: Bovidae) in Hawai‘i Based on Tooth Cementum Lines
Steven C. Hess, Robert M. Stephens, Tommy L. Thompson, Raymond M. Danner, and Ben Kawakami Jr., 59
Reliable techniques for estimating age of ungulates are necessary to determine population parameters such as age structure and survival. Techniques that rely on dentition, horn, and facial patterns have limited utility for European mouflon sheep (Ovis gmelini musimon), but tooth cementum lines may offer a useful alternative. Cementum lines may not be reliable outside temperate regions, however, because lack of seasonality in diet may affect annulus formation. We evaluated the utility of tooth cementum lines for estimating age of mouflon in Hawai‘i in comparison to dentition. Cementum lines were present in mouflon from Mauna Loa, island of Hawai‘i, but were less distinct than in North American sheep. The two age-estimation methods provided similar estimates for individuals aged ≤3 yr by dentition (the maximum age estimable by dentition), with exact matches in 51% (18/35) of individuals, and an average difference of 0.8 yr (range 0–4). Estimates of age from cementum lines were higher than those from dentition in 40% (14/35) and lower in 9% (3/35) of individuals. Discrepancies in age estimates between techniques and between paired tooth samples estimated by cementum lines were related to certainty categories assigned by the clarity of cementum lines, reinforcing the importance of collecting a sufficient number of samples to compensate for samples of lower quality, which in our experience, comprised approximately 22% of teeth. Cementum lines appear to provide relatively accurate age estimates for mouflon in Hawai‘i, allow estimating age beyond 3 yr, and they offer more precise estimates than tooth eruption patterns. After constructing an age distribution, we estimated annual survival with a log-linear model to be 0.596 (95% CI 0.554–0.642) for this heavily controlled population.
Prehistoric Birds and Bats from the Atiahara Site, Tubuai, Austral Islands, East Polynesia
Trevor H. Worthy and Robert Bollt, 69
The Austral Islands in French Polynesia have a depauperate land bird fauna and until recently have been little investigated archaeologically or paleontologically to know whether this is natural. Here we report an avifaunal assemblage and bones of bats of the genus Pteropus from the Archaic period (ca. A.D. 1000–1450) cultural site Atiahara, on Tubuai. Fifteen taxa are reported from the island, and a new species of rail in the genus Gallirallus is described. The data indicate that several petrel species have been extirpated from the island and that former land bird inhabitants included at least two small pigeons and a flightless rail.
Pelagic Larval Duration and Settlement Size of Apogonidae, Labridae, Scaridae, and Tripterygiidae Species in a Coral Lagoon of Okinawa Island, Southern Japan
Taiki Ishihara and Katsunori Tachihara, 87
Pelagic larval duration and settlement sizes in species of Apogonidae, Labridae, Scaridae, and Tripterygiidae in a coral lagoon in southern Japan were examined. Sampling was conducted monthly from July 2004 to June 2005 in the coral lagoon and channel of the Oh-do Beach on Okinawa Island, Japan. Pelagic larval duration was estimated by the number of otolith increments. Mean standard length at settlement of apogonids ranged from 7.7 to 13.9 mm, and mean pelagic larval duration ranged from 14.0 to 30.6 days (14 species, 418 individuals). In labrids, mean standard length at settlement and pelagic larval duration varied greatly (mean standard length: 5.4–11.0 mm; pelagic larval duration: 18–57 days, four species, four individuals). Scarids showed consistent mean standard length at settlement and pelagic larval duration (mean standard length: 7.1–7.6 mm; pelagic larval duration: 29–42 days, five species, 25 individuals). In tripterygiids, pelagic larval duration was more consistent (range: 18–29 days, mean: 22.2±2.1 days), but mean standard length at settlement ranged from 7.8 to 10.3 mm (six species, 32 individuals). These results suggest that the pelagic larval duration of Apogonidae and Tripterygiidae (nonpelagic egg spawning) is shorter than that of Labridae and Scaridae (pelagic egg spawning), and the dispersal strategy of labrids and scarids may include wider dispersal than that of apogonids and tripterygiids.
Trace Metal Partitioning in a Nearshore Tropical Environment: Geochemistry of Carbonate Reef Flats Adjacent to Suva Harbor, Fiji Islands
John D. Collen, Jane E. Atkinson, and John E. Patterson, 95
Namuka Reef is a broad fringing reef flat situated immediately adjacent to the populous and heavily industrialized areas surrounding Suva Harbor, Fiji Islands. Reef flat sediments are mainly very poorly to moderately sorted carbonate gravels and sands with occasional boulders and very little silt, with terrigenous sediments limited to a narrow, nearshore strip. Bulk sediment geochemical analyses show that trace metal concentrations are generally very low across the reef flat and closely similar to pristine reef areas offshore rather than to the nearby contaminated areas within Suva Lagoon. Exceptions occur close to villages, however, where sediments are enriched in Pb, As, and other trace metals, and possibly near wreck sites on the reef where Fe increases locally. These data together with those for major and minor oxides show that there is little or no movement of sediments from the rivers and deeper lagoon onto the carbonate reef flat even though extreme events such as tsunamis or cyclones affect the area. This indicates that the geomorphic separation of reef flats from adjacent contaminated environments is sufficient to prevent the introduction of solid contaminants. Reef flats may thus retain healthy ecosystems and provide resources to the community even though close to heavily contaminated areas.
Type material of Bangia vieillardii Kütz. from New Caledonia has been studied and determined to belong to the green algal genus Chaetomorpha. The name Chaetomorpha vieillardii (Kütz.), n. comb., is effected, and this binomial is proposed to serve for what has previously been known in tropical seas as C. crassa. Genuine C. crassa (C. Agardh) Kütz., based on European type specimens, has been treated by others to be conspecific with C. linum (O. F. Müll.) Kütz.
New Records of Butterflies from Yap Outer Islands, Micronesia: Fais Island and Ngulu, Ulithi, and Woleai Atolls
Donald W. Buden and W. John Tennent, 117
Eight species of butterflies are recorded from among four different island groups in Yap Outer Islands, Federated States of Micronesia (FSM). Five species (63%) belong to the family Lycaenidae; the three others to Nymphalidae. Hypolimnas bolina is the most ubiquitous species, being the only one recorded on all the islands. Ngulu Atoll, which has the smallest land area, also has one of the most depauperate butterfly faunas, with only two species recorded, but it is located between Palau and Yap proper, which host the richest butterfly faunas in southwestern Micronesia. Ulithi Atoll, which is nearest to potential source populations on Yap, has the largest number of species. Small island size, limited habitat diversity, and lack of sufficient host plants combined with distance from potential source populations are likely to be the main factors contributing to the small number of species on these low-lying coralline islands.
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Pacific Science 65, no. 2
Floristic Composition and Natural History Characteristics of Dry Forests in the Pacific
Thomas W. Gillespie, Gunnar Keppel, Stephanie Pau, Jonathan P. Price, Tanguy Jaffré, Jean-Yves Meyer, and Kristin O’Neill, 127-141
We compare the floristic composition of tropical dry forests at the stand level using Gentry’s transect method (0.1 ha) in some of the largest and highest-quality remaining fragments in the Pacific (Hawai’i, 15 sites; Fiji, 9; the Marianas, 3; the Marquesas, 6; New Caledonia, 7) and compare results with neotropical dry forests. A total of 299 species or morphospecies ≥2.5 cm diameter at breast height were identified from all 40 sites in the Pacific. Rubiaceae (28 spp.), Euphorbiaceae (25 spp.), Fabaceae (23 spp.), Sapindaceae (18 spp.), and Myrtaceae (17 spp.) were the most speciose families in Pacific dry forest; however, no family dominated across regions in the Pacific. The most common species by frequency and density in each region were native with the exception of Hawai’i, which contains a high number of nonnative species. Observed and estimated (Chao 2) levels of native species richness show that New Caledonia and Fiji contain the highest species richness followed by Hawai’i, the Marianas, and the Marquesas. There is very little overlap at the native species level among regions, with Hawaiian dry forests the most dissimilar at the native species, genus, and family level and New Caledonia and Fiji the most similar. Unlike mainland neotropical dry forest, dry forests in the Pacific contain very few deciduous species and a low proportion of wind-dispersed species. There is a high proportion of dioecious species in Hawai’i, which is similar to the neotropics; however, other Pacific regions have fewer dioecious species.
Plant Dispersal, Introduced Species, and Vegetation Change in the South Pacific Kingdom of Tonga
Patricia L. Fall and Taly Dawn Drezner, 143-156
Dispersal guilds hold key ecological implications for the vegetation history of islands. This study considers dispersal vectors in conjunction with species origin and growth form to characterize vegetation dynamics on the islands of Tonga in the South Pacific. Data for over 700 species compiled from published literature on the plants of Tonga support a comparative study of dispersal mechanisms and growth forms for native flora, species brought by Polynesian settlers, and taxa introduced since European contact. The indigenous flora, predominantly trees, is characterized primarily by endozoochorous (internal) dispersal through birds and bats. European introductions, primarily herbs, disperse commonly through epizoochorous (external) animal dispersal. Bat dispersal is most important for overstory indigenous and Polynesian trees and vines. In addition, rodents commonly eat seeds of native rain forest trees. The understory, which is overwhelmingly introduced, consists of wind-dispersed and externally animal-dispersed species, which are often early successional. Rain forest thinning encourages establishment of wind-dispersed species and nonnatives. Thus, the prospect of sustained native flora in Tonga would be enhanced by the preservation of bats, a particularly important dispersal vector for indigenous and endemic species, and by the eradication of introduced rats.
Primary Succession along an Elevation Gradient 15 Years after the Eruption of Mount Pinatubo, Luzon, Philippines
Thomas E. Marler and Roger del Moral, 157-
We determined vegetation structure and environmental variables in the Pasig-Potrero and Sacobia River systems on the east flank of Mount Pina-tubo, Luzon, Philippines, to define growth form and taxonomic groups that have influenced primary succession during the 15 yr since the eruption. We selected eight sites within an east-west range of 11.5 km, a north-south range of 7 km, and an elevation gradient of ca. 500 m. The 58 plant taxa we encountered among 63 sampled plots belonged to 21 families. Cover was dominated by Parasponia rugosa (tree) and Saccharum spontaneum (large grass). Cover of these two species was inversely related at the plot level. Exotic species represented nearly 60% of this flora but only 32% of the vegetation cover. Family richness was high for Asteraceae, Fabaceae, and Poaceae. Elevation, distance to the caldera, and distance to human settlement exhibited the most control over the vegetation. The influence of elevation on cover, species composition, and structure differed in these adjacent canyons. Plot species richness, cover, and diversity indices were greatest at the highest elevation of the Pasig-Potrero River. On a small scale, current dominant species may control progression of species assemblages as mediated by geophysical, chemical, facilitative, and competitive changes. Our findings indicate that ongoing anthropogenic disturbances and the prevalence of exotic species may prevent the vegetation from returning to its preeruption state. The invasive Pennisetum setaceum and Chromolaena odorata were widespread in this landscape, and their negative influence on vegetation recovery is probable. Ours is the first detailed survey of vegetation on newly created volcanic surfaces in the region and provides a baseline for understanding the landscape-level processes determining continuing succession.
Runoff, Sediment Transport, and Effects of Feral Pig (Sus scrofa) Exclusion in a Forested Hawaiian Watershed
Dashiell O. Dunkell, Gregory L. Bruland, Carl I. Evensen, and Creighton M. Litton, 175-194
Browsing and trampling by nonnative feral pigs (Sus scrofa) negatively impact native flora and fauna in forested ecosystems and cause soil compaction. However, their impact on runoff and erosion is largely unknown. This study addressed this knowledge gap by investigating effects of feral pigs on runoff volume and total suspended solids (TSS) in runoff from the upper forested area of a Hawaiian watershed. Correlations between TSS, runoff, and other environmental variables were also examined. Runoff was collected monthly after 11 individual storm events from June 2008 to April 2009 at seven sites in the Mānoa watershed on the island of O’ahu. Each site consisted of paired runoff plots (5.04 m2) with one plot located inside a fenced pig exclosure (exclosures 1 yr old at study initiation) and the other located in an adjacent area open to feral pigs. Forest composition and structure (stem density, stand basal area, and seedling/ sapling counts) were quantified at each site. Soil moisture, throughfall, runoff volume, and TSS in runoff were sampled for each storm event. The seven sites varied considerably in terms of forest structure, with stem densities ranging from 1,500 to 9,000 stems ha-1 and basal areas ranging from 20 to 132 m2 ha-1. Vegetation at all sites was dominated by nonnative species. Runoff volumes from fenced and unfenced plots were highly variable, ranging from <1 to >128 liters. TSS levels in runoff ranged from <0.01 to 7.05 g liter-1. TSS levels were generally higher in wet-season months, but this pattern was not consistent across all sites. TSS in runoff was significantly correlated with throughfall, soil moisture, and coarse woody debris cover. Although pig exclusion did not reduce TSS, significant reductions in runoff volume from pig exclusion plots were observed at one site, and two other sites showed a similar trend. Longer-term studies may reveal stronger or more consistent impacts of feral pigs. Using paired fenced versus unfenced runoff plots to study erosion impacts of feral pigs is a novel approach, and results from this study will help forest managers better understand and manage runoff and erosion dynamics.
Stream Nutrient Concentrations on the Windward Coast of Hawai‘i Island and Their Relationship to Watershed Characteristics
Jene Michaud and Tracy Wiegner, 195-217
Dissolved inorganic and organic nutrients and physiochemical parameters were measured in 24 Hawai‘i Island streams. Particulate nutrients and instantaneous nutrient and sediment fluxes were measured in half of these streams. Stream waters were dilute and slightly alkaline and had low concentrations of ammonium, orthophosphate, dissolved organic phosphorus, and total suspended solids. Particulate matter comprised 45%, 73%, and 28% of nitrogen, phosphorus, and carbon pools, respectively. Dissolved nitrogen was comprised primarily of organic nitrogen (54%) and nitrate (34%). In some streams, nitrate and total nitrogen concentrations were slightly elevated relative to Hawai‘i Department of Health (HDOH) water quality standards. Instantaneous nitrate yields for the streams plus 26 HDOH stations were calculated, and the average from the combined data set was 7.1 (SD 11.1) moles N day-1 km-2. Nitrate concentrations and yields were 2.1 and 3.5 times higher, respectively, in Kohala watersheds than in Mauna Kea watersheds. Regression analysis was used to evaluate whether water quality parameters are predicted by watershed area, mean annual rainfall, population density, or percentage of agricultural land. Many water quality parameters were not predicted by these variables. In Mauna Kea streams, concentrations of dissolved organic nitrogen and dissolved organic carbon increased with increasing watershed area, nitrate concentrations increased with increasing population density, and both specific conductivity and nitrate yield increased with increasing percentage of agricultural lands. In Kohala streams, nitrate concentrations and yields were not predicted by watershed characteristics. Overall, watershed characteristics, as quantified in this study, were not strong predictors of water quality.
Chemical Ecology of Red Mangroves, Rhizophora mangle, in the Hawaiian Islands
Brian Fry and Nicole Cormier, 219-234
The coastal red mangrove, Rhizophora mangle L., was introduced to the Hawaiian Islands from Florida 100 yr ago and has spread to cover many shallow intertidal shorelines that once were unvegetated mudflats. We used a field survey approach to test whether mangroves at the land-ocean interface could indicate watershed inputs, especially whether measurements of leaf chemistry could identify coasts with high nutrient inputs and high mangrove productivities. During 2001–2002, we sampled mangroves on dry leeward coasts of southern Moloka’i and O’ahu for 14 leaf variables including stable carbon and nitrogen isotopes (δ13C, δ15N), macronutrients (C, N, P), trace elements (B, Mn, Fe, Cu, Zn), and cations (Na, Mg, K, Ca). A new modeling approach using leaf Na, N, P, and δ13C indicated two times higher productivity for mangroves in urban versus rural settings, with rural mangroves more limited by low N and P nutrients and high-nutrient urban mangroves more limited by freshwater inputs and salt stress. Leaf chemistry also helped identify other aspects of mangrove dynamics: especially leaf δ15N values helped identify groundwater N inputs, and a combination of strongly correlated variables (C, N, P, B, Cu, Mg, K, Ca) tracked the mangrove growth response to nutrient loading. Overall, the chemical marker approach is an efficient way to survey watershed forcing of mangrove forest dynamics.
Community Composition of Elasmobranch Fishes Utilizing Intertidal Sand Flats in Moreton Bay, Queensland, Australia
Simon J. Pierce, Tracey B. Scott-Holland, and Michael B. Bennett, 235-247
Thirteen elasmobranch species were collected during a 4-yr survey of the intertidal margins of Moreton Bay, a large subtropical embayment in southeastern Queensland, Australia. Stingrays were the most common large predators in the intertidal zone, with total catch dominated numerically by blue-spotted maskray, Neotrygon kuhlii (53.8%); estuary stingray, Dasyatis fluviorum (22.2%); and brown whipray, Himantura toshi (10.2%). There was a significant female bias within intertidal populations of N. kuhlii and D. fluviorum. Courtship behaviors were observed in July and September in D. fluviorum and in January for white-spotted eagle ray, Aetobatus narinari. Dasyatis fluviorum, a threatened Australian endemic stingray, remains locally abundant within the bay. Overall, the inshore elasmobranch fauna of Moreton Bay is relatively species rich compared with similar studies elsewhere in Australia, emphasizing the regional importance of this ecosystem.
New Records of Commercially Valuable Black Corals (Cnidaria: Antipatharia) from the Northwestern Hawaiian Islands at Mesophotic Depths
Daniel Wagner, Yannis P. Papastamatiou, Randall K. Kosaki, Kelly A. Gleason, Greg B. McFall, Raymond C. Boland, Richard L. Pyle, and Robert J. Toonen, 249-255
Mesophotic coral reef ecosystems are notoriously undersurveyed worldwide and particularly in remote locations like the Northwestern Hawaiian Islands (NWHI). A total of 37 mixed-gas technical dives were performed to depths of 80 m across the NWHI to survey for the presence of the invasive octocoral Carijoa sp., the invasive red alga Acanthophora spicifera, and conspicuous megabenthic fauna such as black corals. The two invasive species were not recorded from any of the surveys, but two commercially valuable black coral species, Antipathes griggi and Myriopathes ulex, were found, representing substantial range expansions for these species. Antipathes griggi was recorded from the islands of Necker and Laysan in 58–70 m, and Myriopathes ulex was recorded from Necker Island and Pearl and Hermes Atoll in 58–70 m. Despite over 30 yr of research in the NWHI, these black coral species had remained undetected. The new records of these conspicuous marine species highlight the utility of deepdiving technologies in surveying the largest part of the depth range of coral reef ecosystems (40–150 m), which remains largely unexplored.
Newly Collected Specimens of the Sleeper Eleotris acanthopoma (Teleostei: Eleotridae) from French Polynesia Indicate a Wide and Panmictic Distribution in the West and South Pacific
Ken Maeda, Takahiko Mukai, and Katsunori Tachihara, 257-264
The morphology of Eleotris acanthopoma collected from Moorea in French Polynesia is described. This is the first record of this species from French Polynesia, greatly expanding the known range, which was previously only considered to extend from southern Japan to New Caledonia. Nucleotide sequences of the mitochondrial ND5 gene of several Eleotris species and related genera indicate that E. acanthopoma from Moorea belongs to the same lineage as E. acanthopoma from Japan and the Philippines. Despite being separated by a distance of approximately 10,000 km, two of the specimens from Moorea and one from the Philippines had identical nucleotide sequences. Results of this study indicate that extensive dispersal occurs during the pelagic larval stage of this species.
Acanthurus nigros Günther, a Valid Species of Surgeonfish, Distinct from the Hawaiian A. nigroris Valenciennes
John E. Randall, Joseph D. DiBattista, and Christie Wilcox, 265-275
The Blueline Surgeonfish, Acanthurus nigroris Valenciennes, formerly considered as wide-ranging in the central and western Pacific, is restricted to the Hawaiian Islands. Acanthurus nigros Günther, type locality Vanuatu, is available for the sister species from the Pitcairn Islands west to the Great Barrier Reef and Caroline Islands. Although these two species are very similar in color, there are fin-ray and gill-raker differences, and the genetic difference (i.e., 4.12% mtDNA cytochrome b sequence divergence) alone warrants species recognition.
Reptiles of Fais Island, Yap State, Federated States of Micronesia
Donald W. Buden, 277-283
Eleven species of reptiles (six skinks, four geckos, one monitor lizard) are recorded from Fais Island, Micronesia, four of them (Gehyra mutilata, Lepidodactylus moestus, L. sp., and Eugongylus albofasciolatus) for the first time. The skinks Emoia caeruleocauda and E. jakati are the most common species; G. mutilata is the most common gecko in edificarian habitats, and L. moestus is the most common outside the areas of human habitation. Nearly all of the species are widespread in the western Pacific region, although Eutropis sp. is at the easternmost limits of its distribution in the Caroline Islands on Fais. The monitor lizard Varanus indicus was introduced during the Japanese administration. The other species may have arrived by natural dispersal, or by human assistance, or a combination of the two.
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Pacific Science 65, no. 3
Ant-Plant Mutualism in Hawai‘i? Invasive Ants Reduce Flower Parasitism but Also Exploit Floral Nectar of the Endemic Shrub Vaccinium reticulatum (Ericaceae)
Richard Bleil, Nico Blüthgen, and Robert R. Junker, 291
Ants had been absent from the Hawaiian Islands before their human introduction. Today they cause severe alterations of ecosystems and displace native biota. Due to their strong demand on carbohydrate-rich resources, they often exploit floral nectar of native Hawaiian plant species with largely unknown consequences for the plants’ reproduction. We examined effects of flower-visiting invasive ants on reproduction of the endemic shrub Vaccinium reticulatum (Ericaceae) in Hawai‘i Volcanoes National Park. Ant densities in flowers were high and floral nectar was excessively exploited, which may lead to a reduced visitation rate of pollinators. However, the ants’ presence on flowers strongly reduced flower parasitism by caterpillars of the introduced plume moth Stenoptilodes littoralis and thus decreased the loss of flowers and buds. This is, to our knowledge, the first documented mutualism between invasive ants and an endemic plant species in Hawai‘i. Developed fruits of this partly self-
incompatible plant, however, bore relatively low proportions of viable seeds, irrespective of the experimentally controlled visitor spectrum of the flowers. This may indicate that ants do not function as pollinators and that effective pollinators (probably Hylaeus bees) are scant or absent.
Diets of the Sympatric Pacific Sheath-Tailed Bat (Emballonura semicaudata rotensis) and Mariana Swiftlet (Aerodramus bartschi) on Aguiguan, Mariana Islands
Ernest W. Valdez, Gary J. Wiles, and Thomas J. O’Shea, 301
The Pacific sheath-tailed bat (Emballonura semicaudata rotensis) and Mariana swiftlet (Aerodramus bartschi) are two rare insectivorous taxa restricted to the southern Mariana Islands in western Micronesia. It is believed that populations of both have dwindled because of impacts to their food resources. However, there is little information on the food habits of A. bartschi and none exists for E. s. rotensis. In an effort to better understand the feeding habits of both, we investigated their diets using guano analysis. Guano was collected from two roosts in caves during a 2-week period in June and July at the onset of the rainy season. Important orders of insects consumed (percentage volume) by bats roosting at one cave included hymenopterans (64%), coleopterans (10%), lepidopterans (8%), isopterans (8%), and psocopterans (5%), whereas those at a second cave included lepidopterans (45%), hymenopterans (41%), coleopterans (10%), and isopterans (5%). Swiftlets, which roosted in only one of the caves, fed mostly on hymenopterans (88%) and hemipterans (6%). Significant differences existed between the two taxa in several insect orders eaten, with E. s. rotensis consuming more lepidopterans and coleopterans and A. bartschi taking more hymenopterans and hemipterans. Within Hymenoptera, bats fed more on ichneumoideans, whereas swiftlets ate more formicid alates and chalicidoideans. This new information on the feeding habits of E. s. rotensis and A. bartschi provides insight on the complexity of their diets during June and July, and serves as baseline information for future studies and management of their habitat.
Current Distribution and Abundance of O‘ahu ‘Elepaio (Chasiempis ibidis) in the Wai‘anae Mountains
Eric A. VanderWerf, Stephen M. Mosher, Matthew D. Burt, and Philip E. Taylor, 311
The O‘ahu ‘Elepaio (Chasiempis ibidis) is an endangered forest bird endemic to O‘ahu and has declined steadily during the past century. Current information on distribution and abundance is needed to help assess the species status and identify areas where recovery efforts can be focused. We used spotmapping methods to census O‘ahu ‘Elepaio in all suitable forest habitat in the Wai‘anae Mountains from 2006 to 2010 and compared results with previous surveys from the 1990s. We detected a total of 300 O‘ahu ‘Elepaio, including 108 breeding pairs and 84 single males. The sex ratio was strongly male biased due to nest predation on females. Their distribution was extremely fragmented, and the only concentrations were in ‘Ēkahanui (38 pairs), Schofield Barracks West Range (40 pairs), and Pālehua (15 pairs). We failed to detect ‘Elepaio in many areas where they were observed in the 1990s. ‘Elepaio have become more sparse in other areas, indicating that they are continuing to decline. Nest predation by alien black rats (Rattus rattus) and mosquito-borne diseases are the greatest threats. Rat control programs have helped reduce nest predation and stop declines in several areas, but only a fraction of remaining ‘Elepaio benefit from active management and further declines can be expected unless rats are controlled on a larger scale. Alternative methods of rat control should be explored, and restoration of native trees that are less attractive to rats might provide safer nest sites and reduce the need for rat control.
Distribution and Abundance Estimates for Cetaceans in the Waters off Guam and the Commonwealth of the Northern Mariana Islands
Gregory L. Fulling, Philip H. Thorson, and Julie Rivers, 321
Cetacean distribution and abundance are reported from the first systematic line-transect visual survey in the waters of Guam and the Commonwealth of the Northern Mariana Islands (CNMI). The survey was conducted during January–April 2007 following standard line-transect protocols. Trackline coverage (11,033 km) was dominated by high sea states (88.2%); however, 13 cetacean species were recorded. The sperm whale (Physeter macrocephalus) was the most frequently encountered whale, followed by Bryde’s and sei whales (Balaenoptera edeni and B. borealis, respectively). Occurrence of the sei whale is unique, because the species had not been confirmed to occur south of 20° N. The pantropical spotted dolphin (Stenella attenuata) was the most frequently sighted delphinid, followed by the striped dolphin (Stenella coeruleoalba) and false killer whale (Pseudorca crassidens). Humpback whales (Megaptera novaeangliae) were acoustically detected and later seen off Saipan. Numerous cetacean sightings were associated with steep bathymetric features including the West Mariana Ridge, the Mariana Ridge, and the Mariana Trench. Abundance estimates were based on 80 on-effort sightings for 12 species. Species were pooled into three separate groups for estimating detection probabilities: Balaenoptera spp., blackfish (medium-size odontocetes), and small dolphins. A separate detection function was generated for the sperm whale. Precision of abundance estimates are very low for all species due to low sighting rates and high sea states; however, these abundance estimates serve as the best scientific data available for the area and establish vital baseline information for future research efforts.
As a result of commencement of an incipient commercial fishery in the southern islands (SI) of the Commonwealth of the Northern Mariana Islands (CNMI), biological characteristics for the spotcheek emperor, Lethrinus rubrioperculatus, were estimated from the CNMI SI, including seasonality of spawning, sex ratios, length at sexual maturity (LM), length at transition (LT) to male phase, age, and growth. LM and LT estimates corresponded to ages of 1 and 3–4 yr, respectively, and are important in managing hermaphroditic species such as the spotcheek emperor by ensuring that fishery size selection does not significantly reduce effective stock reproduction. Age of the oldest fish was 8 yr, with South Southern Islands (SSI) fish mostly 0–2 yr old and North Southern Islands (NSI) fish 1–4 yr old. Average size of 0-age fish was 22.2 cm fork length (LF) from the SSI and 18.7 cm LF from the NSI, indicating an initial high growth rate not captured by specimen collection. Growth curves for the NSI and SSI were significantly different at the 5% level. Age and growth parameters were estimated using age- and length-based methods, which resulted in similar values for instantaneous growth coefficient (k) and asymptotic length (L∞). Results support further study into life history characteristics of the spotcheek emperor, in particular maximum age and lengths at maturity and transition, in other locations in the CNMI SI as well as in other Indo-Pacific jurisdictions.
First Documented Attack on a Live Human by a Cookiecutter Shark (Squaliformes, Dalatiidae: Isistius sp.)
Randy Honebrink, Robert Buch, Peter Galpin, and George H. Burgess, 365
An adult long-distance swimmer attempting to cross the ‘Alenuihāhā Channel between the Hawaiian islands of Hawai‘i and Maui was twice bitten by a cookiecutter shark (Squaliformes, Dalatiidae, Isistius sp.). One of these bites presented as an open, round, concave wound typically observed in cookiecutter shark bites inflicted by members of this genus on a broad spectrum of large biota such as marine mammals, elasmobranchs, and bony fishes. The open wound was debrided, subjected to negative pressure wound therapy, and a split thickness skin graft harvested from the left thigh. Postoperative recovery was complicated by delayed healing of the inferior portion of the graft, and cultures and biopsy were normal skin flora and normal tissue, respectively. At 6 months after the incident, the area appeared to be healing with a stable eschar, and by 9 months the wound was healed. Humans entering pelagic waters at twilight and nighttime hours in areas of Isistius sp. occurrence should do so knowing that cookiecutter sharks are a potential danger, particularly during periods of strong moonlight, in areas of man-made illumination, or in the presence of bioluminescent organisms.
Marine Sponges, Other Animal Food, and Nonfood Items Found in Digestive Tracts of the Herbivorous Marine Turtle Chelonia mydas
Dennis J. Russell, Stacy Hargrove, and George H. Balazs, 375
Although the usual diet of Chelonia mydas comes from algae and sea grasses (plant material), animal material has been found in samples taken over the past 35 yr. The small black-brown protein sponge Chondrosia chucalla resembles the alga Codium arabicum in size, color, and texture, and both grow next to each other on the reefs. We hypothesize that turtles are actively seeking and eating these sponges and not mistaking them for C. arabicum. Both protein and silica sponges occur in the diet of Chelonia, but only 6.8% of the time are eaten in addition to their usual plant diet. Thirty different kinds of other animals were found in the samples, including Cnidaria, Mollusca, Crustacea, Insecta, Echinodermata, squid, fish, tumor flesh, and other animals but in low frequency (5%). Most of the miscellaneous nonfood debris items were terrestrial leaves, plastic, paper, string, fibers, hair, and paint chips but also in low frequency (<7%). Among animal food items known to have nutritional value, the protein sponge C. chucalla could be contributing an important nutritive factor, but this needs further research.
Origin of the Helminth Community of an Exotic Invasive Lizard, the Brown Anole, Anolis sagrei (Squamata: Polychrotidae), in Southwestern Taiwan
Gerrut Norval, Charles R. Bursey, Stephen R. Goldberg, Jean-Jay Mao, and Kerry Slater, 383
Composition of the helminth community of the brown anole, Anolis sagrei, an exotic invasive species in Taiwan, was studied to identify the emigration point of this lizard. A total of 5,757 helminths was found, of which 5,734 (99.6%) were the nematode Cyrtosomum penneri. Also found were the digenean Mesocoelium monas (21, 0.4%) and one each of the nematodes Parapharyngodon sp. (female) and Acuariidae gen. sp. (larva). Cyrtosomum penneri has previously been reported in A. sagrei in Florida, supporting the contention that the Taiwan population of A. sagrei originated from Florida. This report provides a basis upon which future A. sagrei parasite studies in Taiwan can be based, and a helminth list for A. sagrei is included for future reference.
Additions to the Myxomycetes of Singapore
Wayne C. Rosing, David W. Mitchell, Gabriel Moreno, and Steven L. Stephenson, 391
Much of Southeast Asia remains understudied for myxomycetes (plasmodial slime molds or myxogastrids). This survey of myxomycetes was carried out at 12 study sites throughout Singapore during March 2009. Sporocarps that developed in moist-chamber cultures of bark, forest floor litter, and aerial litter were used to supplement field collections. In addition, a series of samples of various types of plant litter collected from one other study site during the summer of 2004 was processed for myxomycetes. Collectively, these efforts yielded 76 species of myxomycetes in 26 genera. Thirty-six species are new records for Singapore. The latter includes two previously unpublished records along with one collection of Didymium and one collection of Trichia that could not be assigned to any known species.
Association Affairs, 401
Pacific Science 65, no. 4
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.
Index to Volume 65