April 2015 issue of Pacific Science now available on BioOne
Biology and Impacts of Pacific Island Invasive Species. 11. Cinchona pubescens (Red Quinine Tree) (Rubiaceae)
Heinke Jäger, 133
Abstract: Cinchona pubescens Vahl (red quinine) is an evergreen tree ranging in height from 10 to 25 m with broad leaves and white or pink fragrant flowers arranged in clusters. Growing at altitudes between 130 and 3,300 m, it is one of 23 species in the genus Cinchona and has a natural distribution from Costa Rica to Bolivia. Cinchona pubescens has been cultivated in tropical regions (e.g., in South America, Africa, China, India, and Indonesia) for its quinine-containing bark and has become invasive in some regions. This is especially the case in the Pacific region, where C. pubescens has invaded humid highland areas of Galápagos, Hawai‘i, and Tahiti. It shades out and reduces cover of native plant species and adversely affects endemic birds. In addition, it changes microclimate and nutrient cycling in the soil, especially phosphorus, in Galápagos. Characteristics that make it such a successful invader include production of numerous, windborne seeds and vigorous vegetative reproduction by resprouting from underground stems and fallen trees. In Galápagos, C. pubescens is currently being manually controlled by uprooting the trees and by applying herbicides to cuts in the bark. However, this method requires continuous hand pulling of seedlings to be successful. Disturbance by control actions appears to facilitate establishment and invasion by other nonnative plant species, especially blackberry (Rubus niveus). Quinine and other alkaloids extracted from Cinchona bark are still being used for medicinal purposes today and the wood is increasingly used as construction material in Galápagos. Ironically, C. pubescens is now considered rare and endangered in its native range in Ecuador.
Underwater Sound Measurements of a High-Speed Jet-Propelled Marine Craft: Implications for Large Whales
Alexis B. Rudd, Michael F. Richlen, Alison K. Stimpert, and Whitlow W. L. Au, 155
Abstract: Radiated noise from a high-speed jet-propelled watercraft (the M/V Alakai, 1,646 tons, length 117 m) was measured at hydrophone depths of 3, 6, and 10 m while the ship passed by at speeds of 6.17333 m/sec (12 knots), 12.3467 m/sec (24 knots), and 19.0344 m/sec (37 knots). Noise spectra were similar for all speeds and hydrophone depths. Spectra peaked below 100 Hz and dropped off continuously at higher frequencies. Calculated source level noise was 10 to 20 dB lower than noise from propeller-driven ships and much lower than for ships of similar speed. Although exposure to noise radiating from the M/V Alakai over short time periods is unlikely to cause hearing damage to whales, the combination of low radiated noise levels and high transit speeds leads to a shorter closing time (defined as time between when source level of the ship at a stationary receiver is greater than ambient noise and time that a ship traveling directly toward the receiver arrives at its location) between ship and whale. Compared with other types of ships traveling at similar speeds, closing time for the Alakai ranges from 20 sec shorter (at 6.17333 m/sec [12 knots]) to 22 min shorter (at 19.0344 m/sec [37 knots]). Shortest closing time for the Alakai is 89.1 sec at a speed of 6.17333 m/sec (12 knots). Shortened closing time might reduce successful detection and avoidance of high-speed jet-propelled ships by whales, and increased speed shortens the time during which whales have the opportunity to respond to this detection.
Limnological Characterization of the Largest Freshwater Lake in Remote Oceania (Lake Letas, Gaua Island, Vanuatu)
Ursula Sichrowsky, Robert Schabetsberger, Karin Pall, Bettina Sonntag, Maya Stoyneva, Donna Kalfatak, Finn Økland, Alexander Scheck and Meelis Tambets, 165
Abstract: With a total area of 19.7 km2, Lake Letas (119 m maximum depth, 399 m above sea level [a.s.l.]) on Gaua Island, Vanuatu, is one of the largest caldera lakes in Oceania. The crescent-shaped lake encircles the active volcano Mount Garet (754 m a.s.l.) whose last major eruption occurred in 2009. In 2012 and 2013, we investigated the lake and its effluent river Mbe Solomul. Physicochemical depth profiles revealed a thermocline between 10 and 15 m depth. Oxygen dropped gradually from 7.67 mg liter-1 at the surface to 0.28 mg liter-1 at 95 m depth, indicating occasional holomixis. Inflow of ion-rich water from volcanic springs (913 µS cm-1) led to relatively high concentrations of SO 2-/4 (100 mg liter-1) and Cl- (60 mg liter-1) throughout the water column. Conductivity was highest at the surface (610 µS cm-1), decreased to a minimum of 571 µS cm-1 at 60 m depth, and increased slightly to 576 µS cm-1 above the sediment, probably due to solution of ions out of volcanic ashes. Surface pH at 7.8 was remarkably lower than measured in 2004 (8.9), possibly as a result of the increased volcanic activity. A Secchi depth of 1.3 m indicated meso- to eutrophic conditions. In contrast, total phosphorus concentration at the surface was relatively low at 11.8 µg liter-1. In total 47 phytoplankton taxa were identified, of which most occurred in the littoral area. Open water was dominated by the filamentous green alga Planctonema lauterbornii and the coccoid desmid Staurastrum depressiceps var. gracilis. Total phytoplankton biomass of 1.06 mg liter-1 in the epilimnion reflected the mesotrophic character of the lake. The ciliate assemblage included euplanktonic taxa (Halteria, Mesodinium, Coleps, and Stentor) that are commonly detected in temperate and tropical lakes. The zooplankton community was dominated by the copepod Thermocyclops crassus macrolasius, which reached a maximum abundance of 138 ind. liter-1 at 5 m depth. The littoral was characterized by a dense macrophyte belt consisting predominantly of Chara australis and Ceratophyllum demersum. The vegetation limit was found at 4.8 m mean depth. Two freshwater eel species, Anguilla megastoma and A. marmorata, were the only fishes found in the lake, feeding exclusively on macrozoobenthos. In the effluent river the largest Anguilla obscura hitherto reported in literature was caught (129 cm), showing that these ecosystems are a habitat of primary importance to Pacific eels.
Food Webs and Feeding Habits on the Revillagigedo Islands, Mexico
Bayard H. Brattstrom, 181
Abstract: Food webs on oceanic islands are often markedly different from continental food webs due to low species diversity and absence of key components of mainland ecosystems. Food webs and feeding habits are described from observations and scat, pellet, and gut analysis on the four islands of the Revillagigedo Islands, Mexico, when in their near-original state. Changes in food habits after introduction of exotics are described. Food webs increase in complexity with increase in island size, largely as a function of increase in habitat diversity seen with an increase in island size. Seabirds are the major components of food webs on the two smaller islands, and reptiles, passerine birds, hawks, owls, parrots, and doves are more important on the two larger islands. Some island vertebrates have food habits similar to those of their mainland counterparts, but others have become food specialists (e.g., the Socorro Red-tailed Hawk, in the absence of small mammals, eats mostly lizards and land crabs). Other birds have seasonally or permanently switched food (ravens and owls on Clarión eat cactus, towhees eat insects, red-tailed hawks eat plants). Some of this food switching may be due to presence of a harsh dry season and/or to the unique fauna and flora of the islands. Insectivorous birds on Socorro apparently reduce competition by utilizing different foraging heights, habitats, and feeding methods. Sheep introduced onto Socorro in 1869, whose numbers fluctuated over the years, destroyed some vegetation, but they have now been eradicated. Exotics introduced in connection with military garrisons and an airfield may have major effects on the ecosystem of these islands in the future.
Segregation in Diet between Black Noddy (Anous minutus) and Brown Noddy (A. stolidus) from the Southern Lagoon of New Caledonia
Pascal Villard, Vincent Bretagnolle, and Philippe Borsa, 197
Abstract: The Black Noddy (Anous minutus) and the Brown Noddy (A. stolidus) occur sympatrically in the Southern Lagoon of New Caledonia, breeding on islets located at the edge of a wide, productive coral-reef lagoon next to oceanic waters enriched by a seasonal upwelling. The diets of the two species were determined from regurgitations from birds nesting at Kouaré Islet during two consecutive breeding seasons (2002/2003 and 2003/2004) and compared. The average prey load in the Brown Noddy was heavier than that in the Black Noddy, as expected from its larger body size and from a predicted longer foraging distance. Fish prey dominated the diet of both species (100% and 81.8% biomass in Black and Brown Noddies, respectively); the remainder consisted of squid. Black Noddy ate small pelagic fishes inhabiting the reef and the lagoon, mainly round herrings (Spratelloides spp.), and Brown Noddy mainly preyed on offshore species including buccaneer anchovy (Encrasicholina punctifer) and larger pelagic fishes (Exocoetidae) and squids. The segregation in diet between Black and Brown Noddies in New Caledonia thus indicated spatial segregation in foraging zones (i.e., inshore versus offshore, respectively), which was more pronounced than previously reported for other sites where the two species co-occur.
Avifauna from the Teouma Lapita Site, Efate Island, Vanuatu, including a New Genus and Species of Megapode
Trevor H. Worthy, Stuart Hawkins, Stuart Bedford and Matthew Spriggs, 205
Abstract: The avifauna of the Teouma archaeological site on Efate in Vanuatu is described. It derives from the Lapita levels (3,000–2,800 ybp) and immediately overlying middens extending to ∼2,500 ybp. A total of 30 bird species is represented in the 1,714 identified specimens. Twelve species are new records for the island, which, added to previous records, indicates that minimally 39 land birds exclusive of passerines were in the original avifauna. Three-fourths of the 12 newly recorded species appear to have become extinct by the end of Lapita times, 2,800 ybp. The avifauna is dominated by eight species of columbids (47.5% Minimum Number Individuals [MNI]) including a large extinct tooth-billed pigeon, Didunculus placopedetes from Tonga, and a giant Ducula sp. cf. D. goliath from New Caledonia. Seabirds are rare despite the coastal location of the site. Fowl are important contributors to the Teouma avifauna, with the human-introduced Red Junglefowl Gallus gallus accounting for 15% MNI and present in all sampled layers. There are two species of megapodes (∼10% of MNI), with the extant Vanuatu Megapode Megapodius layardi most abundant and represented at all levels in the deposits. A substantially larger extinct megapode, Mwalau walterlinii, n. gen., n. sp., is present only in the Lapita midden area, where it is relatively rare. This extinct species was larger than all extant megapodes but smaller than the extinct Progura gallinacea from Australia, with proportions most similar to those of Alectura, and was a volant bird. The remaining significant faunal component is rails, with four species present, of which Porphyrio melanotus was the most abundant. Rare but notable records include an undescribed large rail; a parrot, Eclectus sp. cf. E. infectus; a hornbill, Rhyticeros sp. cf. R. plicatus; and a coucal, Centropus sp. indet., all conservatively considered likely to be conspecific with known taxa elsewhere in Melanesia.
Can Ornithophilous Hawaiian Lobeliads Produce Seeds in the Absence of Pollinators? A Test Using Clermontia kakeana and Cyanea angustifolia (Campanulaceae)
Coleen Cory, Richard Pender, and C. Eugene Jones, 255
Abstract: The native Hawaiian bird-pollinated flora is primarily composed of five ornithophilous lobeliad genera, collectively containing approximately 140 species. Historically, these genera were believed to have been pollinated by at least some of the 10 specialist nectarivorous bird species endemic to Hawai‘i. However, since human colonization, both bird and ornithophilous native plant species have undergone wide-scale declines and extinctions, resulting in the potential loss of pollination for this component of the native flora. In an attempt to assess if lobeliad species can produce viable seeds in the absence of pollinators, two pollination treatments (open control and pollinator exclusion) were applied to two Hawaiian lobeliad species [Clermontia kakeana Meyen and Cyanea angustifolia (Cham.) Hillebr.] in single populations of each species on O’ahu. In each lobeliad species, mean seed counts were not significantly different in fruits resulting from open-pollinated and pollinator-excluded flowers. This suggests that both species are capable of autogamy and can produce seeds in the absence of pollinators.
Seasonal Changes in Species Composition of Glass Eels of the Genus Anguilla (Teleostei: Anguillidae) Recruiting to the Cagayan River, Luzon Island, the Philippines
Jun Aoyama, Tatsuki Yoshinaga, Akira Shinoda, Fumiaki Shirotori, Apolinario V. Yambot, and Yu-San Han, 263
Abstract: Tropical species of anguillid glass eels have recently been exploited to be a substitute for the commercially important Anguilla japonica or A. anguilla, so information about their life histories is needed to facilitate conservation. To understand ecological aspects of glass eel recruitment patterns of tropical eels, Anguilla spp., monthly monitoring of species compositions at the mouth of the Cagayan River in northern Luzon in the Philippines was carried out at different time periods from May 2008 to September 2009 and from November 2011 to December 2012. Species identifications were made for 32,178 glass eels using morphology and/or genetics, and a total of five anguillid species, Anguilla bicolor pacifica, A. celebesensis, A. japonica, A. luzonensis, and A. marmorata, were found. In both time periods A. marmorata was dominant followed by A. luzonensis and A. bicolor pacifica, but the proportion of A. marmorata decreased from 55.1% in 2008–2009 to 41.2% in 2011–2012, with A. bicolor pacifica increasing from 3.9% to 26.3% and A. luzonensis staying relatively stable (41.0%, 32.5%). Two other species, A. japonica and A. celebesensis, that were reported in previous studies from the Cagayan River were extremely rare. This study indicated that selective glass eel catch of a commercially preferred tropical species in this area is not feasible, because the harvest will include a high proportion of bycatch of economically less-important species, potentially having considerable impacts on their populations.
Reptiles of Uman District Islands (Southeastern Chuuk Lagoon and Kuop Atoll), Federated States of Micronesia
Donald W. Buden, 271
Abstract: Thirteen species of reptiles are recorded from among 23 islands in the southeastern sector of Chuuk Lagoon and on adjacent Kuop Atoll (= Uman District islands), Federated States of Micronesia (FSM). They include two sea turtles, five geckos, five skinks, and one monitor lizard. None is endemic to Chuuk, and most are found widely throughout the western Pacific. Perochirus ateles was the most frequently encountered species, followed closely by Emoia boettgeri. Sea turtles are scarce due in large measure to indiscriminant harvesting of adults and eggs. The common house gecko, Hemidactyus frenatus, probably was introduced to Chuuk during post-World War II human-assisted transport to many Pacific islands, and Chuuk Islanders claim the Pacific monitor, Varanus indicus, was brought to Chuuk during the Japanese administration. The monitor lizard has apparently since been extirpated on the two Uman District islands where it was previously recorded. To what extent the other species colonized Chuuk islands by natural dispersal or human-assisted dispersal or a combination of the two is uncertain.
Cryptapseudes leroyi, a New Species of Apseudomorphan Tanaidacean (Crustacea: Peracarida: Metapseudidae) from the Hawaiian Archipelago
Shanna E. David and Richard W. Heard, 281
Abstract: Previously nine species belonging to the crustacean order Tanaidacea have been described from Hawaiian waters. Specimens of a new metapseudid tanaidacean, Cryptapseudes leroyi David & Heard, n. sp., from the western Main Hawaiian Islands were discovered in collections of the Bernice P. Bishop Museum. The new species, which represents the fourth member of the genus Cryptapseudes Băcescu, is distinguished from the other three members of the genus by a combination of characters including an antennule with the outer flagellum having three or four articles (no more than two reported for other known species) and article-3 of the mandibular palp with seven to eight finely pectinate setae. An artificial key is presented to distinguish the four species. Discovery of C. leroyi in Hawaiian waters extends the range for the genus from the western Indian Ocean over 14,000 km northeast to the tropical waters of the midnorthern Pacific Ocean.
Assocation Affairs, 295