Feral pigs (Sus scrofa L.) are perhaps the most abundant, widespread, and economically significant large introduced vertebrate across the Pacific island region. Unlike many other nonnative invasive species, feral pigs have both cultural and recreational importance in the region, complicating their management. Today, Pacific island feral pigs are a mixture of several strains of domestic swine, Asiatic wild boar, and European wild boar. Due to their generalist diet and rooting behavior, feral pigs alter soils and watersheds and negatively impact native and nonnative flora and fauna. As a result, feral pigs have played a role in the extinction of several species of plants and animals on Pacific islands and have negative effects on both ecotourism and agricultural industries in the region. Despite numerous published studies on feral pigs in the Pacific island region, of which the majority include systematic analyses of original empirical data, some fundamental aspects of feral pig ecology remain poorly characterized, at least partly due to the remote and inaccessible environments that they often inhabit. To address these knowledge gaps, effort should be made to integrate research conducted outside the Pacific island region into local management strategies. This review summarizes the origins, history, ecology, environmental effects, and current management of feral pigs in the Pacific island region; integrates regional scientific findings with those of other insular and continental systems; and identifies current knowledge gaps requiring further research to inform the ecology and management of this impactful invasive species.

Invertebrates constitute the most diverse Pacific island animal lineages and have correspondingly suffered the most devastating extinction rates. Losses of native invertebrate lineages have been driven largely by ecosystem changes brought about by loss of habitat and direct predation by introduced species. Although Hawai‘i notably lacks native terrestrial reptiles and amphibians, both intentional and unintentional anthropogenic releases of herpetofauna have resulted in establishment of more than two dozen species of frogs, toads, turtles, lizards, and a snake. Despite well-known presence of nonnative predatory species in Hawai‘i, ecological impacts remain unstudied for a majority of these species. In this study, we evaluated diet of the Japanese wrinkled frog, Glandirana rugosa, an intentional biocontrol release in the Hawaiian Islands in the late nineteenth century. We collected live frogs on O‘ahu and used museum collections from both O‘ahu and Maui to determine exploited diet composition. These data were then compared with a published dietary analysis from the native range in Japan. We compiled and summarized field and museum distribution data from O‘ahu, Maui, and Kaua‘i to document current range of this species. Gut content analyses suggest that diet composition in the Hawaiian Islands is significantly different from that in its native Japan. In the native range, dominant taxonomic groups by volume were Coleoptera (beetles), Lepidoptera (moths, butterflies), and Formicidae (ants). Invasive frogs in Hawai‘i exploited mostly Dermaptera (earwigs), Amphipoda (landhoppers), and Hemiptera (true bugs). In Hawai‘i this species also exploited endemic insects (∼4% total volume, 7 genera) and snails (14 snails in three endemic genera). Our results suggest the need for more indepth assessment of ecological impacts of G. rugosa and other established herpetofauna in Hawai‘i to improve our ability to prevent and manage ecological damage and ultimately restore diverse island ecosystems.

Kokia (Malvaceae) is a tree genus consisting only of three endangered and one extinct species endemic to the Hawaiian Islands. Morphological and molecular population analyses suggested conflicting hypotheses as to colonization and dispersal among the Islands. To resolve this, 12 nuclear and four chloroplast gene regions were sequenced and compared to establish phylogenetic hypotheses and to make biogeographic inferences. Seven gene regions yielded phylogenies consistent with the progression rule hypothesis suggesting dispersal from older to younger islands, seven other gene regions were equivocal, and two weakly supported an alternative phylogeny. Combined analyses of all genes strongly supported the progression rule hypothesis, with initial colonization to Kaua‘i, or possibly an older and now submerged island, with subsequent dispersal to O‘ahu, Moloka‘i, and Hawai‘i Islands. Morphological characters plotted onto the molecular phylogeny suggested that many morphological traits are plastic or nonhomologous. Our study illustrates the perils of evaluating relationships among widely divergent taxa using morphological characters.

Geomorphological features of atolls in the Tuamotu archipelago (French Polynesia) created during glaciation periods of the Pleistocene enable unique studies of evolution. Atolls not far from one another may be classic open atolls with water exchange between the ocean and the lagoon, or they may have an enclosed lagoon, without a direct ocean connection since at least the last glaciation (20,000 yr ago). Niau's atoll has an enclosed lagoon that hosts a milkfish (Chanos chanos) population whose origin is enigmatic. The milkfish's co-occurrence with a tilapia species suggests a human introduction. However, there is no such record, and the people of Niau consider the milkfish population origin to be natural. The fish is used as staple food, and it also plays a major role in several of their cultural traditions. We compared genetic diversity and population history of the Niau milkfish to those of the milkfish of a nearby open atoll, Kauehi, using a mitochondrial marker. Niau's milkfish population exhibits a lower genetic diversity compared to that of the Kauehi population, suggesting that the population experienced a genetic bottleneck. However, the two populations are not differentiated, consistent with the hypothesis that Niau's milkfish population origin is human derived from the surrounding ocean population. Its smaller effective size suggests that this population has been self-sustaining for many generations. Ancient Polynesians were known for their transport of many species throughout the Pacific; this study is the first case suggesting transplantation of a marine fish. In addition, our results suggest that Niau's milkfish population is large enough to limit inbreeding depression and seems to have been effectively managed over multiple generations by the local Polynesian communities.

Coral abundance is declining on many coral reef ecosystems worldwide, which in some locations has resulted in regime shifts where coral has been replaced by other benthic organisms. Although transitions to sponge-dominated states have been reported from a number of locations across the world after coral declines, they are typically dominated by only one or few species. However, there is increasing evidence that high-diversity sponge-dominated reefs may persist in the future as reefs experience ocean warming and acidification, because sponges appear generally more resilient than corals. Here we quantify spatial variation in a highly unusual shallow-water (<5 m and deeper) coral reef system at Jaco Island in Timor-Leste (East Timor) that is dominated by diverse sponge assemblages and has little coral. We found a total of 33 sponge species (based on Operational Taxonomic Units) in a total sampling area of 15 m². We found that sponges were the dominant biological group at this site and covered approximately 29% of the benthos, with live coral, algae, and dead substrate cover at 7%, 7%, and 54%, respectively. Multivariate analysis identified that sponge assemblages varied significantly over a small spatial scale (100 m). Our findings differ from those from the generally low-diversity sponge reefs that have been reported elsewhere as coral has declined and may be more typical of future sponge-dominated reefs. Therefore, future studies to understand how this reef functions may provide insights into how future high-diversity sponge reefs might function.

Stylasterid corals from the North Pacific Ocean have been well studied and revised only in the Northeastern Temperate Region and in the tropical area around the Hawai‘i archipelago. However, few studies concerning stylasterids have been conducted in the Japanese region, and the number of species (including subspecies) known for the area is 26. Here we describe a new species of genus Lepidopora, L. iwasakii Pica & Puce, n. sp., from the deep sea off the Ryukyu Islands (Japan). The new species is characterized by having gastropores and dactylopores randomly arranged, reticulate-granular to linear-imbricate texture, presence of ring palisade, and short dactylopore spines without dactylostyles. Moreover, in the Northern Hemisphere in the Pacific Ocean the genus Lepidopora is not listed among the 11 genera recorded so far. Therefore, L. iwasakii represents the first record of this genus from Japan and the entire North Pacific Ocean.

The coral crab Fungicola fagei (Decapoda: Brachyura: Cryptochiridae) is recorded for the first time from the Hawaiian Islands, where it was discovered in a previously unknown association with the solitary, free-living mushroom coral Lobactis scutaria (Anthozoa: Scleractinia: Fungiidae). The associated crab species was discovered off Hilo on the island of Hawai‘i, where it appeared to be relatively common. It could have been previously overlooked because of its small size (max. ca. 1 cm long) and its hidden life style inside the host coral. Species identification is based on the morphology of the carapace and use of the cytochrome oxidase subunit I (COI) barcode gene as molecular marker. Fungicola fagei is known from other localities in the Indo-West Pacific region, where it is only hosted by mushroom coral species of the genera Podabacia and Sandalolitha. The record of F. fagei from the Hawaiian Islands represents a northeastward extension of its known geographical distribution range, 6,000 km away from its nearest locality in Vanuatu, despite the availability of host species as eastward as the Cook Islands and French Polynesia. Because these other host species do not occur in the Hawaiian Islands, F. fagei's occurrence here is only possible because of its association with L. scutaria, uniquely recorded from Hawai‘i.

We performed the first survey of terrestrial gastropods on Dåno′ (Cocos Island). Dåno′ is a 0.33 km2 uninhabited atoll island located 2.5 km southwest of Guam, the largest island in the Mariana archipelago, western Micronesia. In 4 days of examining vegetation, soil, and leaf litter, we found 14 species of mollusks arrayed in 12 genera and 11 taxonomic families. The fauna is a subset of that found on Guam. Five species are native to the Mariana Islands, two of which are endemic to the archipelago, and the remaining seven are likely introduced there, perhaps prehistorically. Ground-inhabiting species found only as abundant worn shells in soil suggest relatively recent turnover of these forms, perhaps from seawater inundation of the low-lying island during typhoons. There was no evidence of Mariana endemic snails in the family Partulidae, recently afforded legal protection under the U.S. Endangered Species Act. However, neither did we encounter the invasive flatworm Platydemus manokwari De Beauchamp, currently decimating partulids elsewhere in the Marianas. Hence, we suggest that if further surveys confirm the predator's absence, Dåno′ might serve as a novel sanctuary for transplanted populations of Guam's most endangered snails.

New insights into distribution and habitat preferences of the large scincid lizard Lacertoides pardalis at a local scale were made during the course of a translocation study undertaken on the Kwé Range, in the region of the Plaine des Lacs of southern New Caledonia. Information gathered showed it to be distributed widely in elevation across the range where suitable habitat of outcropping rock was present, with a preference for rock habitat located within moderately low but dense maquis shrubland with a ground cover of tall sedges. Association with this particular stunted vegetative structure in part likely reflects the extent to which plant matter, primarily fruits of shrubs, constitutes a substantial component of the species' diet, as confirmed by scat analysis of captured individuals during the study. Lacertoides pardalis is currently recognized as “Vulnerable” under IUCN criteria, a designation assigned by virtue of its extremely limited area of extent and specialized biology. However, we here report a major extension in range, indicating that the species could be more widespread in suitable habitat across the whole of the southern ultramafic region of the island.