Hawaiian tree snails in subfamily Achatinellinae have experienced drastic population declines and range reductions as a result of habitat destruction, overcollection, and introduced predators. In 1991, 11 individuals from one of the last remaining populations of Achatinella fuscobasis, a federally listed species, were brought to the University of Hawai‘i's tree-snail captive-rearing facility. After increasing in population size to 441 snails in 2005, the population subsequently declined to only 120 snails by 2014, a 73% reduction. In this study, we assessed demographic and genetic changes that occurred in the captive-bred population of A. fuscobasis. Demographic data were compared to genetic data collected from 11 microsatellite markers for the F₁ to F₃ generations to investigate the role bottleneck effects such as loss of genetic diversity and inbreeding may have had on the population decline. Demographic measures such as juvenile survival and survival to maturity remained constant for the F₁ and F₂ generations, and significantly decreased in the F₃ generation. There was no difference in genetic diversity measures such as allelic richness, gene diversity, and observed heterozygosity among generations, but all generations were characterized by low genetic diversity and high inbreeding. The drastic population decline appears to have been due to stochastic demographic dynamics characteristic of small populations, with bottleneck effects that occurred before the founding of the ex situ population acting in synergy with factors such as disease.

We explore the future of the population of the Island of Hawai‘i and its welfare up to the year 2100 by adapting the World3-03 model that couples nonrenewable resources, population, human activity, and environment, taking into account interactions between this island and the rest of the world. The island is very poor in nonrenewable resources, but it can acquire technology and some food through tourism revenues and outside investment. Under this model, the size and well-being of the island's permanent population track closely that of the rest of the world, but even if the global population stabilizes, the island will still experience moderate social decline. Short-term (earthquakes, tsunamis, etc.) and long-term (rising ocean levels, geologic subsidence, etc.) effects are not contemplated in our scenarios.

Palmyra Atoll, USA, in the Central Pacific, has remained mostly uninhabited since construction and abandonment of a U.S. naval base during World War II. However, the effects of Navy modifications have persisted, affecting physical conditions and benthic habitat quality of Palmyra's lagoon sand flats. Sand flats provide important nonbreeding habitat for Bristle-thighed Curlews (Numenius tahitiensis), a migratory shorebird listed as “vulnerable” by the International Union for Conservation of Nature and Natural Resources. We used camera trapping, observations of focal individuals, and quantification of prey availability and sediment characteristics to assess curlew habitat use across different levels of historical anthropogenic impact. Habitat preferences were not determined by the degree of land reclamation impact on lagoon flat habitat, although the two most preferred sites were both highly impacted. Curlew abundance was most strongly correlated with availability of prey items, such as spionid polychaetes (Malacoceros sp.). Our findings provide new ecological information on a shorebird species that is rarely studied and provides useful information for habitat management at Palmyra Atoll and other curlew wintering grounds.

We surveyed coral reefs communities before (September 2007–March 2009) and during (September 2009) the 2009–2010 El Niño event on the coast of Oaxaca, southern Mexican Pacific to evaluate community changes associated with the warming event. From May 2009 to December 2010, we recorded positive deviations from the historical in situ sea surface temperature values. There were differences among the coral species Pocillopora damicornis, Pavona gigantea, and Porites panamensis with significant reductions in chlorophyll a and Symbiodinium density during El Niño, resulting in bleaching (>13%) and increase in algal coverage (mainly geniculate coralline algae). Concurrently, echinoderm and fish assemblages also experienced significant modifications; abundances of the sea urchins Eucidaris thouarsii and Centrostephanus coronatus increased during the warming event, whereas Diadema mexicanum declined; meanwhile, fish species such as Thalassoma lucasanum declined in favor of Stegastes acapulcoensis and Haemulon maculicauda during the warming event. During the El Niño event, changes in composition and abundance of echinoderms and fish may have been due to horizontal and/or vertical redistribution of species rather than species mortality or recruitment. The observed changes in coral physiology and consequent modifications in coral, echinoderm, and fish communities highlight that the 2009–2010 El Niño event impacted several levels of biological organization in the coral reefs of southern Mexico, beyond the actual corals themselves. The observed changes add to local stressors associated with coastal development and ultimately threaten the health of the once considered best-developed reef system in the Eastern Pacific.

Most decapod crustaceans are nocturnal. However, because cleaner shrimp at cleaning stations act in concert with their hosts, they clean debris and parasites off the body surfaces of diurnal hosts during daytime. It is not known how cleaner shrimp physiologically accommodate diurnal environments and perform cleaning behaviors. We examined the effect of light cues on the daily rhythmicity of the banded coral shrimp Stenopus hispidus (Decapoda, Stenopodidae), a cleaner shrimp in coral reefs. Shrimp were individually kept in aquaria under conditions of 12-hr light and 12-hr darkness (LD) and constant darkness (DD). Double-plotted actogram analyses revealed that shrimp under LD were active during scotophase and inactive during photophase. Locomotor rhythms were observed in most shrimp under DD. Periodogram analyses showed a weak circadian rhythm in shrimp under DD. Our results show that this species is nocturnal and that its locomotor activity is controlled primarily by the LD cycle. Day-night differences in locomotor activity were reduced in shrimp under LD with weak irradiance, and they remained active during photophase. Shrimp under LD using blue or green light-emitting diode light, but not red light-emitting diode light, showed a day-inactive and night-active rhythmicity. These results indicate that this species can be active under environments with low green and blue spectra—for example, during twilight hours, at depth, or on cloudy days—even during daytime, and this weakness of the circadian clock may be advantageous in their role as cleaner shrimp. It is concluded that in addition to the presence of visiting hosts, light conditions at cleaning stations are likely to influence cleaning activity.

Species assemblages on islands are products of colonization and extinction events, with traditional models of island biogeography emphasizing build-up of biodiversity on small islands via colonizations from continents or other large landmasses. However, recent phylogenetic studies suggest that islands can also act as sources of biodiversity, but few such “upstream” colonizations have been directly observed. I report four putative examples of recent range expansions among the avifauna of Makira and its satellite islands in the Solomon Islands, a region that has recently been subject to extensive anthropogenic habitat disturbance. They include three separate examples of inter island dispersal, involving Geoffroyus heteroclitus, Cinnyris jugularis, and Rhipidura rufifrons, which together represent three distinct possible patterns of colonization, and one example of probable downslope altitudinal range expansion in Petroica multicolor. Because each of these species is easily detected when present, and because associated localities were visited by several previous expeditions, these records likely represent recent dispersal events rather than previously overlooked rare taxa. These observations demonstrate that both large landmasses and small islands can act as sources of island biodiversity, while providing insights into the potential for habitat alteration to facilitate colonizations and range expansions in island systems.

Riparian leaf litter is a major source of allochthonous organic material to temperate and tropical streams, promoting primary and secondary productivity in lotic and nearshore habitats. In tropical island streams, where native leaf-shredding macroinvertebrates are absent, physical fragmentation from stream flow is an important factor affecting leaf litter breakdown and, thus, organic matter dynamics. Additionally, the invasion of exotic plants into riparian areas is expected to affect litter composition and, consequently, its degradation. We compared the interactions of stream flow and inputs of leaf litter from native and exotic plants on leaf litter breakdown in two streams of varying flows on Hawai‘i Island. Decay rates were greater in the high flow stream than in the low flow one for exotic Spathodea campanulata (0.037 vs. 0.023 day^-1), but not significantly different for exotic Psidium cattleianum (0.003 vs. 0.003 day^-1), and native Metrosideros polymorpha (0.005 vs. 0.002 days^-1). In contrast, the exotic Falcataria moluccana (a nitrogen fixer) decomposed more rapidly in the low flow stream (0.017 day^-1) than in the high flow stream (0.010 day^-1). Breakdown rates also varied among species, with S. campanulata > F. moluccana > M. polymorpha > P. cattleianum. Breakdown rates were generally positively correlated to leaf nitrogen content and negatively correlated with leaf structure characteristics (toughness, organic carbon content, percentage lignin). Our findings indicate that stream flow regimes altered by climate change are likely to influence leaf litter decomposition, and S. campanulata and F. moluccana will likely impact organic matter dynamics in Hawaiian and other Pacific Island streams. However, predicted changes depend on the species composition of riparian leaf litter.

Selenops galapagoensis was recently synonymized with Selenops mexicanus because the types of the former did not differ from the latter in any visible way. Additionally, a large molecular analysis of the genus from North and Central America and the Caribbean that included both nuclear and mitochondrial genes showed no differences indicating two separate species. However, no specimens from the Galápagos Islands, the only place where no distributional overlap occurs between the putative species, were previously available for molecular analysis. Recently, specimens suitable for molecular data collection became available from the Galápagos, allowing us to test whether genetic differences existed between mainland and island specimens and whether molecular data supported their synonymization. We performed phylogenetic analyses of mitochondrial and nuclear DNA of newly obtained Galápagos specimens, confirmed S. mexicanus specimens, and appropriate outgroups. We found that almost all of the Galápagos specimens share identical haplotypes despite being collected from different islands in different years, and that these haplotypes are also shared with, or differ by only a few nucleotides from, mainland specimens. The genetic variation between the island and mainland specimens is much less than the genetic variation observed among other Selenops species and within S. mexicanus across its distribution. The results from the molecular data indicate that S. mexicanus was likely transported to the Galápagos Islands via humans within the past 500 years, and these data also support the synonymization of S. galapagoensis with S. mexicanus.

We used morphological and molecular data to infer the identity and origin of frogs in the genus Fejervarya that have been introduced to the island of Guam. Mensural and meristic data were collected from 96 specimens from throughout their range on the island and a principal component analysis was used to investigate the distribution of these data in morphological space. We also amplified a fragment of the 16S ribosomal ribonucleic acid mitochondrial gene from 27 of these specimens and compared it to 63 published sequences of Fejervarya and the morphologically similar Zakerana. All examined Fejervarya from Guam are morphologically indistinguishable and share an identical haplotype. The molecular data identify them as Fejervarya cancrivora with a haplotype identical to F. cancrivora from Taiwan.

This study documents temporal changes in abundance and prevalence of larval anisakid nematodes in two commercially important fish; the vermilion rockfish Sebastes miniatus, and the ocean whitefish Caulolatilus princeps, collected in coastal waters of San Quintin, Baja California, Mexico. Anisakis sp., Hysterothylacium aduncum, and Pseudoterranova decipiens (Anisakidae) were found in S. miniatus, while H. aduncum and P. decipiens were present in C. princeps. The vermilion rockfish constitutes a new host for H. aduncum; C. princeps is a new host for Anisakis sp. and H. aduncum. San Quintin constitutes a new geographic locality for Anisakis sp. and H. aduncum. Hysterothylacium aduncum was the most abundant parasite (S. miniatus = 37; C. princeps = 15.5), and Anisakis sp. was the most prevalent species (S. miniatus = 91.8%; C. princeps = 95%). The nematode abundance increased in summer in both S. miniatus and C. princeps. Both species were highly infected with nematode larval stages of Anisakis sp., P. decipiens, and H. aduncum (S. miniatus: 10,323 specimens, C. princeps: 2,575 specimens). These fish constitute one of the most important ground fish resources for recreational and commercial fisheries in Baja California (Mexico) and California (USA) and make up a substantial part of the regional seafood cuisine. Except for Anisakis sp. 1, the other anisakid species appear to show less organ specificity because they were found in almost all internal organs; their importance as a potential of human infection cannot be excluded due to possible migration to muscle, and fish should be gutted soon after capture to avoid worm migration into flesh.