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Two Hawaiian endemic yeast species, Metschnikowia hawaiiensis and Metschnikowia hamakuensis, were examined by means of multilocus characterization. In spite of their narrow range of distribution, restricted to the island of Hawai‘i, both species were found to be polymorphic at several loci. Alleles of different loci were distributed independently within local populations, confirming that sexual reproduction prevails among these facultatively asexual organisms. No alleles were shared across species, confirming their reproductive isolation. Although the sample size for the northern species, M. hamakuensis, is much less (N = 7) than that for its southern relative, M. hawaiiensis (N = 161), their genetic diversity is comparable. Genetic differentiation was detected in M. hawaiiensis populations at both regional (ca. 30–40 km) and local (ca. 1 km) scales. A single isolate recovered in a separate locality exhibited considerable allelic divergence from others, indicating that genetic isolation can occur over relatively short distances and suggesting a first step towards cessation of gene flow, which is required for speciation.
Little is known regarding pollination webs involving island coastal plants and pollinators, and roles that nonnative flower visitors may play in these interaction networks. Plant-pollinator observations made in March 2008 and 2009 were used to describe the pollination network for Ka‘ena Point, one of Hawai‘i's best-conserved coastal communities. The network includes 15 native plant species, two native bee species, and 26 nonnative insect taxa, forming 119 interactions. Network connectance is 29.4% and weighted nestedness is 17.9, which are similar to values of other dry-habitat, island networks. The network's structure has a core of generalized pollinators plus several more-specialized pollinators. Nearly all plant species interact with two or more generalist pollinators and a variable number of specialists. Small, nonnative bees (Lasioglossum, Ceratina), wasps (Proconura), and flies (mostly Tachinidae) were responsible for 72.7% of flower visits, and they visit five plant species not visited by native bees. The two native visitors were the bees Hylaeus anthracinus and H. longiceps (both proposed as endangered). Hylaeus spp. (especially females) provided 19.8% of flower visits, foraging at high visitation rates and on many species, including the endangered Scaevola coriacea and Sesbania tomentosa. In Hawai‘i's coastal habitat, nonnative insects form novel interactions with native species and may maintain an ecosystem's function following loss of most of the original native pollinators. However, their high visitation rates suggest that the two remaining native Hylaeus species are potentially important pollinators for many of the native plants on which they rely for nectar and pollen resources.
Typhoons can add to chronic threats such as incremental habitat loss and pressure from feral predators to jeopardize the unique biodiversity of Pacific Ocean islands. Typhoon Sudall severely damaged Yap, Federated States of Micronesia, in April 2004. To establish an initial assessment of consequences of the typhoon for the avian community on this poorly studied island, we surveyed birds along line transects in mangroves, savannah, and forest on Yap during the last week of August 2004. We found all expected 22 resident species in abundances whose rank order was very similar to results from surveys in the early 1980s. Most-common species were White Tern, Plain White-eye, Micronesian Starling, Micronesian Myzomela, and Yap Monarch. All five species were common in all three major habitats, mangroves, upland forest, and savannah, although terns nested primarily in forests. Least commonly encountered resident species were Common Cicadabird, Micronesian Pigeon, and White-throated Ground-Dove. We found one to six individuals of each of those species. We also encountered 27 species of migratory birds, including the first record for Yap of Greater Scaup. Populations of birds appeared to be about 50% lower across all resident species than estimates from 1983 – 1984, suggesting the possibility that Typhoon Sudall caused widespread mortality. However, other possible explanations for reduced abundances exist, which we review briefly. A long-term monitoring plan is needed to track population dynamics of birds on Yap.
The Bokikokiko or Christmas Island Warbler (Acrocephalus aequinoctialis) is found only on Kiritimati (Christmas) and Teraina (Washington) Islands in the Republic of Kiribati. The population on Kiritimati Island is threatened by habitat degradation, sea level rise, and predation from feral cats (Felis catus), Pacific rats (Rattus exulans), and recently arrived black rats (Rattus rattus). There is scant information about distribution and abundance of the Bokikokiko. From 2007 to 2012, we conducted surveys with song playbacks at 83 points on 12 transects in the northern half of Kiritimati Island to measure abundance of the Bokikokiko and begin monitoring for possible declines associated with the spread of rats, and we collected habitat data to investigate factors that influenced Bokikokiko abundance. Song playbacks resulted in a 263% increase in detection rate over passive listening. We detected an average (±1 SE) of 0.63 ± 0.11 birds per point using playbacks. Average population density was 0.36 ± 0.06 birds per hectare, but abundance varied among regions, and no birds were detected in some areas with apparently suitable habitat. Range of the Bokikokiko encompassed an area of 14,180 ha but was fragmented by many lagoons and bare ground, and only about half that area was actually occupied. Estimated population size was 2,550 ± 425 birds. Bokikokiko were more abundant in areas with taller Heliotropium trees and taller Scaevola shrubs, and less abundant in areas with more Suriana shrubs, bare ground, and grass. Conservation actions needed for the Bokikokiko include ongoing removal of rats from islets within the lagoons of Kiritimati Island, protection of preferred habitat from development and fires, and translocations to create additional populations on rat-free atolls.
In this study we investigated temporal patterns in activity of adult macro-moths in Colo-i-Suva mixed lowland tropical forest on Fiji's largest island, Viti Levu. Moths were collected for 2 or 3 nights per month over a 12-month period using a mercury-vapor light as an attractant and collecting moths that had settled onto a white sheet for 4 hr after dusk. In total 1,397 specimens were captured, belonging to 116 species in 10 families. There were no significant relationships between total abundance and species richness with any of the climatic factors measured: average minimum and maximum daily temperature, average daily rainfall, and relative humidity. There were no obvious trends in total abundance and species richness over the 12-month monitoring period, although multivariate analysis suggested that moth assemblages in the wet and dry seasons were distinct in terms of their composition. These differences appear to be caused by some of the more-common species exhibiting clear peaks in abundance at certain times of the year, whereas other less-common species were restricted to only dry-season or only wet-season samples. We believe that this study is the first to obtain detailed information on flight periods of adult macro-moths in Fiji. Further research is required to ascertain whether patterns we have observed at this location repeat themselves in subsequent years, and to compare seasonal patterns of moths in other forests, other habitats, and other Fijian islands.
Populations of amphidromous neritid gastropods are prone to habitat degradation by anthropogenic disturbances. To accumulate information on the life history of these neritids, seasonal growth patterns of four neritid species, Neritina turrita, N. plumbea, N. auriculata, and Clithon brevispina, were examined in an upper mangrove estuary on Ishigaki Island. Individual neritids in a fixed sampling area were captured and mark-released bimonthly over a 1-yr period. Growth rates of the four species were estimated from linear regression models and Ford-Walford graphs using data from recaptured individuals. A model-selection procedure identified the common Lmax model as the best model for describing seasonal growth fluctuations of the four species. Growth of the four species was generally higher in the warm season (April–October) and lower in the cool season (October–April). In addition, N. plumbea stopped growing in midsummer (June–August). Temporal changes in the size-frequency histograms showed several recruitment events of the four species. Estimated growth curves, in some cases, did not fit well to temporal changes of the size cohorts derived from the size-frequency histograms, indicating that size-dependent migration or mortality may occur in the sampling area.
The Veronicellidae include some of the most widespread and agriculturally damaging invasive slugs. However, they are difficult to distinguish and identify accurately based on external morphology because of their great intraspecific variability, especially in body color and pigmentation pattern. Based on the published accounts, museum collections, and recent surveys, four species had been recorded previously from the Hawaiian Islands: Diplosolenodes occidentalis, Laevicaulis alte, Sarasinula plebeia, and Veronicella cubensis; and the latter three plus an additional species, Semperula wallacei, were known from the Samoan Islands. We reexamined these identifications using external morphology, internal anatomy, and/or DNA sequences. Both L. alte and V. cubensis are present on all six of the largest Hawaiian Islands. Sarasinula plebeia, although recorded previously, was not present in the museum collections and was found in only one of our recent survey samples, on O‘ahu. It may in fact never have been present in the Islands previously, the earlier records being misidentifications; or it may have been present but highly localized and was not collected and deposited in the Bishop Museum (Honolulu). Unfortunately, the single Diplosolenodes occidentalis specimen was not found in the usnm collections. Molecular analyses of specimens from American Samoa, previously identified as L. alte and S. plebeia, showed them to be primarily V. cubensis, with a few Semperula wallacei and Laevicaulis sp., and a single L. alte and S. plebeia, and all specimens sequenced from independent Samoa were S. wallacei.
A new species of Eleotris, a freshwater eleotrid, is described from streams of the Solomon Islands using both genetic analysis based on the mitochondrial COI gene and morpho-meristic study. The new species is separated from E. acanthopoma, E. melanosoma, and E. fusca with a mean pairwise divergence of 14%, 11%, and 9.9%, respectively. It shares with E. fusca, its sister species, the same combination of cephalic free neuromast patterns (i.e., second, fourth, and sixth suborbital free neuromast rows on cheek extending ventrally past horizontal row d (2.4.6 pattern) and row os connecting with row oi at ventroposterior margin of opercle, but it differs by a combination of characters including scales in lateral series 42–46 versus 53–67, transverse back series 11–13 versus 13–21, and zigzag series 9–11 versus 12–17.
The bryozoan Amathia (= Zoobotryon) verticillata was found near the northern entrance to the Port of Kaohsiung in November 2015 and is the first record from Taiwan. This bryozoan can form extensive colonies and is considered to be one of the more invasive nonindigenous species, occurring worldwide from Mediterranean to tropical environments within the Atlantic and Indo-Pacific Oceans. Colonies extending to approximately 80 cm in length were on immersed ropes attached to quay walls. It is likely that the species is established in the Port of Kaohsiung. Its distribution within the Pacific is reviewed.