Biology and Impacts of Pacific Island Invasive Species. 2. Boiga irregularis, the Brown Tree Snake (Reptilia: Colubridae)
Gordon H. Rodda and Julie A. Savidge, 307
The Brown Tree Snake, Boiga irregularis (Merrem, 1802), was accidentally transported to the island of Guam shortly after World War II. Over the following two decades it spread throughout the island with little public or professional recognition of its extent or impacts. This secretive nocturnal arboreal snake occurs in all habitats on Guam, from grasslands to forests. Under the right conditions, it is capable of high rates of reproduction and population growth. The Brown Tree Snake caused the extirpation of 13 of Guam’s 22 native breeding birds and contributed to the extirpation of several species of native bats and lizards. Guam’s 12 forest birds were especially impacted, with 10 species eliminated and the other two severely reduced. In addition, the snake continues to substantially impact domestic poultry, pets, the island’s electrical power infrastructure, and human health. To protect other vulnerable Pacific islands, the U.S. government annually spends several million dollars inspecting cargo outbound from Guam to exclude Brown Tree Snakes. Cargo destinations most at risk are in Micronesia, especially the Northern Mariana Islands, but Guam also has direct air transportation links to Hawai‘i that will soon be supplemented with direct ship traffic. Ultimately, all Pacific islands are at risk but especially those obtaining cargo through Guam.
Human Impacts on the Nearshore Environment: An Archaeological Case Study from Kaua‘i, Hawaiian Islands
Alex E. Morrison and Terry L. Hunt, 325
Archaeology provides a long-term framework to document prehistoric resource use and habitat modification. Excavation at Nu‘alolo Kai, Kaua‘i, yielded a large, well-preserved shellfish assemblage. Analysis determined the susceptibility of mollusk communities to human foraging pressures in the past. Some coral reef and intertidal species, such as Turbo sandwicensis and Strombus maculatus, declined in abundance as a result of heavy exploitation. In contrast, shoreline mollusk communities remained fairly stable through time. Archaeological research provides baselines for modern conservation efforts and fisheries management.
Soil Phosphorus and Agricultural Development in the Leeward Kohala Field System, Island of Hawai‘i
Molly Meyer, Thegn N. Ladefoged, and P. M. Vitousek, 347
The leeward Kohala Field System on the island of Hawai‘i was one of the most intensive pre–European contact dryland agricultural systems. Archaeological and soil analysis has documented changes in soil nutrients over time. Soils were collected under agricultural field walls of different relative ages within the Kohala Field System. These field walls preserved soil from the time of their construction (between ca. A.D. 1400 and 1800), so soil samples from underneath older field walls have been exposed to a shorter period of cultivation than the soils under more recent field walls. Total P and P : Nb ratios of these buried soils were greater under walls than in once-cultivated surface soils, and greater under older walls than under younger walls. These results suggest that precontact cultivation decreased soil P reserves in this intensive agricultural landscape.
Coral (Anthozoa: Scleractinia) Recruitment at Bahías de Huatulco, Western México: Implications for Coral Community Structure and Dynamics
R. A. López-Pérez, M. G. Mora-Pérez, and G. E. Leyte-Morales, 355
Over the past decades there has been an increasing awareness of community structure and dynamics in eastern Pacific coral reef systems, yet the processes producing these patterns are poorly known. We conducted a quantitative analysis of patterns of sexual and asexual recruitment through fragmentation at six localities in Huatulco, México. Between January 2001 and January 2002, sexual recruitment was evaluated by using terracotta tiles. Fragmentation was addressed twice using quadrats. Two hundred ninety-two corals (291 Porites panamensis Verrill, 1 Pocillopora sp.) were recruited to the settlement tiles. Changes in abundance of recruits among sites were determined by coral cover of P. panamensis at each area. Fragmentation was restricted to Pocillopora spp., and processes producing fragments had no connection with those promoting their reattachment and survival. Sexual and asexual recruitment patterns and potential survival asymmetries displayed by P. panamensis and Pocillopora spp. in the area are of capital importance in the occurrence of local communities and potentially of those of the entire eastern Pacific region. Sexual and asexual recruitment patterns suggest that recovery of frame-building corals following disturbance is highly species-specific. Recovery of P. panamensis following coral removal can be relatively fast, but greatly prolonged for Pocillopora; however, in communities with low to moderate disturbance where patches of Pocillopora were preserved reef recovery can proceed at a moderate to relatively fast pace following disturbance. Coordinated multidisciplinary and interinstitutional efforts, including genetic, histological, and ecological approaches, are necessary to determine unequivocally the processes controlling community structure and dynamics in the area.
Linckia multifora (Echinodermata: Asteroidea) in Rarotonga, Cook Islands: Reproductive Mechanisms and Ecophenotypes
Terry J. Crawford and Bruce J. Crawford, 371
In Rarotonga, Linckia multifora (Lamarck) exists in two forms: a blue gray type that is found on the reef intertidally and a red form that is found subtidally. Both types reproduce asexually by regeneration of autotomized arms, as well as sexually, but the relative potential for sexual reproduction varies greatly between these different sites. In the laboratory, reciprocal crosses of the blue gray intertidal form and the red subtidal form developed as successfully as the controls and were indistinguishable in morphology. In addition, both the blue gray intertidal form and the red subtidal form contain two different classes of haplotypes of the mitochondrial gene cytochrome oxidase subunit I (COI), which exhibit 12 fixed differences. These results suggest that L. multifora of Rarotonga has a dual origin and that the two different forms seen in the two environments belong to a single interbreeding population and may represent ecophenotypes.
Estimating Abundance of Reef-Dwelling Sharks: A Case Study of the Epaulette Shark, Hemiscyllium ocellatum (Elasmobranchii: Hemiscyllidae)
M. R. Heupel and M. B. Bennett, 383
Benthic reef sharks play an important role in reef ecosystems, but little is known about their abundance or population dynamics. Abundance of the epaulette shark, Hemiscyllium ocellatum (Bonnaterre), on Heron Island Reef, Great Barrier Reef, Australia, was examined via a mark-recapture study. A total of 496 sharks was tagged between July 1994 and August 1997 in a 0.25-km² area of reef flat, with 80 tagged sharks recaptured for a total of 102 recapture events. Captured individuals ranged in size from juveniles to adults (285–750 mm total length). Recaptured sharks were collected after 1–725 days at liberty and at distances of 0–329 m from their original capture point. The overall recapture rate was 20.6% with an estimated 17.5% tag loss. Population size was estimated using both closed and open population models. Closed population models produced various abundance estimates, with the Chao M(th) ranked best in model performance with an estimate of 2,224 sharks and 95% confidence intervals ranging from 1,730 to 2,916. Open population models produced lower estimates, with the Jolly D model producing an estimate of 559 individuals within the study site and confidence intervals ranging from 26 to 1,092. All models produced density estimations of 0.3 to 1.2 sharks per 100 m². Based on thorough examination of model assumptions and results, open population models appear to provide the best population estimate within the study area.
A Visual Sighting and Acoustic Detections of Minke Whales, Balaenoptera acutorostrata (Cetacea: Balaenopteridae), in Nearshore Hawaiian Waters
Shannon Rankin, Tom F. Norris, Mari A. Smultea, Cornelia Oedekoven, Ann M. Zoidis, Ethan Silva, and Julie Rivers, 395
Minke whales, Balaenoptera acutorostrata (Lacépède), have been considered a rare species in Hawaiian waters due to limited sightings during visual and aerial surveys. However, our research suggests that they are more common than previously considered. In spring 2005, a combined visual-acoustic survey of cetaceans in Hawaiian waters resulted in the sighting of a minke whale within 22 km of Kaua‘i. Minke whale vocalizations were also detected at several other locations near Kaua‘i and O‘ahu. These 2005 reports are the first from nearshore (<50 km) Hawaiian waters despite years of previous shipboard and aerial surveys. The lack of historical sightings is likely due to misidentification or the inability to detect these animals during poor sighting conditions. We recommend that future cetacean surveys in Hawaiian waters include a passive acoustic component to increase the likelihood of detecting minke whales.
Neosabellaria vitiensis, n. sp. (Annelida: Polychaeta: Sabellariidae), from Shallow Water of Suva Harbor, Fiji
Julie H. Bailey-Brock, D. W. Kirtley, Eijiroh Nishi, and Susanne M. J. Pohler, 399
A new species of the genus Neosabellaria Kirtley, 1994, is described from shallow-water locations of Suva Harbor, Fiji. Neosabellaria vitiensis Bailey-Brock, Kirtley, Nishi, & Pohler, n. sp., is a gregarious sabellariid; its tubes are constructed of sand and shell debris and form small “reefs” exposed during low tides. The new species is distinguished by the structure of opercular paleae in the middle row, which are shoe-shaped with circular tips, and paleae in the outer row, which have distal lateral teeth and denticulate median plume. Detailed morphological features of the new species are described and compared with other Pacific sabellariid species, particularly with most closely related N. clandestina (Menon & Sareen, 1966). Neosabellaria vitiensis is endemic to the Fiji Islands.
A new species in the Group II complex of the gekkonid lizard genus Lepidodactylus Fitzinger is described based on recently collected material from Namoluk Atoll, Mortlock Islands, Chuuk State, Federated States of Micronesia. Lepidodactylus oligoporus Buden, n. sp., is distinguished from other members of Group II by differences in the numbers of midbody scale rows (130–134), fourth-toe scansors (15–19), interorbital scales (34–35), and precloacal/femoral pore-bearing scales (12–15) and by the lack of cloacal spurs and the presence of a moderate amount of webbing between the toes. In body size and scutellation, it most resembles L. novaeguineae Brown & Parker from New Guinea and L. pulcher Boulenger from the Admiralty Islands.
Twenty species of reptiles are recorded from the Mortlock Islands, Chuuk, Federated States of Micronesia. The eight geckos and eight skinks together comprise 80% of the herpetofauna; amphibians are absent. Most of the species are widespread in the west-central Pacific, but the recently described gecko Lepidodactylus oligoporus is known only from the type locality on Namoluk Atoll. Hemidactylus frenatus appears to be displacing Gehyra mutilata, which is common only on Namoluk Atoll, where H. frenatus is unrecorded. Five species of skinks of the genus Emoia are sympatric on Satawan Atoll. Partial habitat segregation was observed in three morphologically very similar species of Emoia, with E. cyanura being more frequently encountered in beach strand and other open, sun-exposed areas; E. caeruleocauda in shady forest; and E. impar in sun-dappled forest patches.
First Report of Gastrointestinal Helminths from the Wokan Cannibal Frog, Lechirodus melanopyga (Amphibia: Limnodynastidae) from Papua New Guinea
Stephen R. Goldberg, Charles R. Bursey, and Fred Kraus, 429
The initial gastrointestinal helminth list is established for Lechriodus melanopyga (Doria) from Papua New Guinea. Examination of the digestive tracts of 16 L. melanopyga from April–May (n = 14) and October (n = 2) revealed six helminth species: Digenea: Mesocoelium monas; Nematoda: Aplectana macintoshii, Cosmocerca novaeguineae, Oswaldocruzia bakeri, Abbreviata sp. (larvae in cysts); Acanthocephala: Acanthocephalus bufonis. Cosmocerca novaeguineae was present in the greatest numbers (171) and shared the highest prevalence (88%) with Acanthocephalus bufonis. Lechriodus melanopyga represents a new host record for each of these helminths. New Guinea is a new locality record for Mesocoelium monas and Acanthocephalus bufonis.