The avifauna of Saipan, Northern Marianas Islands, includes a variety of endemic and range-restricted species of conservation concern. Monitoring population dynamics, trends, and vital rates of these species can help inform their conservation. Here we apply reverse symmetry models to 11 years (2008–2018) of capture–recapture data from 6 mist-netting stations on Saipan to estimate adult apparent survival probabilities, recruitment rates, population growth rate, and demographic contributions to population growth rate for five bird species: Mariana Kingfisher (Todiramphus albicilla albicilla), Rufous Fantail (Rhipidura rufifrons saipanensis), Bridled White-eye (Zosterops conspicillatus saypani), Golden White-eye (Cleptornis marchei), and Micronesian Myzomela (Myzomela rubratra saffordi). Population growth rate estimates suggested declines for all species except Golden White-eye. Survival was the largest contributor to annual population growth rate for all species except Micronesian Myzomela, for which population change was largely determined by recruitment (including 1-yo recruits and immigrating adults). Hierarchical models applied to the two species with the most captures and recaptures, Rufous Fantail and Golden White-eye, showed greater temporal than spatial variation in vital rates. Annual variation in vital rates confirmed the importance of survival in explaining population change, but also showed recruitment to be especially important in driving population growth in years of population increase. Our results provide new insights into drivers of population change in these species and highlight information gaps, such as a need for understanding seasonal habitat use and the scale and timing of movements.

Mesoscale eddies are ubiquitous oceanic structures that play pivotal roles in planktonic ecosystems. In this paper, we present observational evidence of the impact of a mesoscale cyclonic eddy on the phytoplankton biomass, measured by chlorophyll-a concentration, in the Bay of La Paz, Gulf of California, using information gathered during a multidisciplinary research cruise in the summer (August) of 2017. A CTD rosette system was used to record high-resolution hydrographic readings and to take water samples for nutrients and spectrophotometric determination of chlorophyll-a concentrations, throughout a grid of stations covering the whole area. The results showed that a mesoscale cyclonic eddy, with a diameter of ∼20 km and a maximum velocity of 0.95 m s^–1 at its periphery, had established from the surface to a depth of 100 m, inducing differences in the hydrographic properties of the water column. The phytoplankton biomass distribution was closely related to the circulation pattern, with the highest chlorophyll-a concentration (>3 mg m^–3) observed in the center of the eddy, in a layer between 20 and 30 m depth, with absolute maximum values located at 20 m depth as a consequence of nutrient pumping. The presence of mesoscale eddies in the Bay of La Paz has been described previously, but their impact on the phytoplankton biomass and its three-dimensional variability has not been quantified systematically. Therefore, further studies that document the effects of these eddies on phytoplankton biomass are needed to better understand highly productive marine areas, such as the Bay of La Paz, and to propose conservation and management strategies.

The study of island subspecies provides excellent “natural experiments” for examining the impacts of different selective regimes on animal taxa. We examined the morphological differences between the Hawaiian and continental North American subspecies of the Common Gallinule (Gallinula galeata sandvicensis and G. g. cachinnans, respectively), for which the existing literature is both scant and contradictory. More than 200 live gallinules and >100 museum specimens were measured, and a meta-analysis of literature values on North American Common Gallinules was conducted to quantitatively assess differences in wing chord, culmen and tarsus length, and body mass between these subspecies. Hawaiian Common Gallinules had smaller wing chords (–2.5 to –4.0%), larger culmen (+4.5 to +7.0%) and tarsi (+5.5 to +23.0%), and slightly larger body masses (∼+4.0%) than their mainland conspecifics. This is likely due to several factors including reduced predation pressure, shorter dispersal distances, nonmigratory behavior, and sedentary lifestyles associated with ecological differences between the Hawaiian Islands and the North American mainland. We also introduce the novel hypothesis that intra- and interspecific agonistic interactions due to habitat limitation are an additional selective force in driving these morphological changes.

Arbuscular-mycorrhizal (AM) fungi affect individual plants and the diversity of plant communities. AM interactions are sensitive to the physical properties and nutrient availability of soil. In contrast to the comprehensive knowledge of AM fungi's diversity in many mainland ecosystems, there is a considerable gap in the understanding of the communities of AM fungi on oceanic islands. We surveyed the community of AM fungi in the wet forests of Socorro Island (above an elevation of 600 m). Because of the influence of northerly winds, the island's windward side is presumably more humid than the leeward side, although, above 600 m elevation, fog is common on both sides of the island. Forty-six percent of AM fungi species occurred on only one side of the island. Also, four species common to both sides showed marked differences in abundance, and the abundances of the AM fungi correlated with the abundance of plant life-forms. Beta diversity was similar in the southern and northern forests. However, the contribution of nestedness to beta diversity was three-fold greater in the southern forests than in the northern forests. Root colonization by AM fungi was higher in the northern forests, where phosphorous content was also high. The prevalence of nestedness in beta diversity and the lower mycorrhizal colonization of roots in the southern forests could reflect known perturbations in the southern forests.

A sample of 128 individuals of the slender-toed geckos Nactus spp. from six islands of Papua New Guinea (Bougainville, Fergusson, Misima, New Britain, Rossel, Sudest) was examined for gastrointestinal helminths. Found were one species of Digenea, Mesocoelium brevicaecum; one species of Cestoda, Gekkotaenia novaeguineaensis; one species of Acanthocephala, Sauracanthorhynchus sphenomorphicola; and eight species of Nematoda, Aplectana zweifeli, Bakeria bakeri, Cosmocerca zugi, Meteterakis crombiei, Parapharyngodon maplestoni, Physalopteroides milnensis, Abbreviata sp. (larvae in cysts), Rictulariidae gen. sp. (larvae in cysts). A total of 1,256 helminths was found. Aplectana zweifeli (n = 447), Parapharyngodon maplestoni (n = 238), and Meteterakis crombiei (n = 221) were the most abundant helminths. Ten new host records are reported for Nactus spp. There was a mean of 7.3 ± 3.1 (3–11) helminth species per island. Bougainville Island had the fewest number of helminth species (3) and Misima Island (11) the highest. Nactus spp. are parasitized by generalist helminths that also infect other lizard species.

Ceratocystis lukuohia is one of two newly described pathogens of Metrosideros polymorpha (‘ōhi‘a) causing Rapid ‘Ōhi‘a Death, a phenomenon that is devastating sections of native forest across the state of Hawai‘i, USA. Ceratocystis lukuohia research has increased as the threat of the pathogen has become more apparent, resulting in a need for efficient production of fungal cultures to meet research demands. Therefore, the temperature and medium-dependent mycelium growth and spore production of three isolates, one from the outbreak area of Leilani Estates and two from beyond the area, were assessed in culture. Fungal growth, measured as mycelium diameter, did not differ for the three isolates after 7 days of incubation. Optimal growth temperatures were 25–30 °C on 10% V8 agar and 25 °C on malt yeast extract agar (MYEA). Spore production, as assessed in one isolate, was most abundant at 25 °C and on MYEA, followed by 10% V8, and MEA. Mycelium growth and spore production on 10% V8 were less variable compared to the other media and, while mean spore production was highest on MYEA, the test isolate produced at least 1 × 10⁶ spores/mL on 10% V8 agar, a commonly used spore concentration for inoculation experiments. Therefore, we recommend growing C. lukuohia at 25 °C on 10% V8 for inoculum production. These results contribute to the growing knowledge base of this newly discovered fungal pathogen and suggest a standardized methodology for propagating C. lukuohia for use in host-pathogen interaction studies.

This study reports parasitological records of eight species of marine rockfishes (Sebastes auriculatus, S. chlorostictus, S. umbrosus, S. miniatus, S. atrovirens, S. constellatus, S. serranoides, and Scorpaena guttata) collected from Todos Santos bay and San Quintin coast, Baja California, Mexico. The vermilion rockfish, S. miniatus, showed the highest parasite species richness (two species of monogeneans, two species of digeneans, three species of nematodes and one species of copepods), while the lowest richness was found in S. atrovirens and S. umbrosus (one species of copepod and one species of nematode, respectively). The species S. auriculatus, S. chlorostictus, S. constellatus, S. serranoides, and S. guttata showed a richness of up to four parasite species. Seven of the eight fish species (except S. atrovirens) presented larval stages of nematodes Anisakis sp., Pseudoterranova sp. and Hysterothylacium sp. (prevalences ranging from 8.3 to 100%), which were found in the fish mesentery (guts). The parasite species with the highest prevalence values (>80%) were found in S. miniatus (Anisakis sp.), S. guttata (Anisakis sp. and Hysterothylacium sp.), S. umbrosus (Anisakis sp.), S. auriculatus (Anisakis sp.), and S. constellatus (Anisakis sp.). The most abundant parasite species (>4 ind./host) were recorded in S. guttata (Anisakis sp. and Hysterothylacium sp.), S. umbrosus (Anisakis sp.), S. constellatus (Parabothriocephalus sagitticeps), and S. miniatus (Anisakis sp.). The parasite species with the highest intensity of infection values (>5 ind./host) were found in S. constellatus (P. sagitticeps), followed by S. guttata (Anisakis sp., Hysterothylacium sp.), S. umbrosus (Anisakis sp.), and S. serranoides (Microcotyle sebastis). The present study, in addition to listing the helminths and parasitic copepod species (and providing quantitative data on them) of eight commercially important scorpaenid fish species in the northwestern Mexico, can also serve as a baseline for future parasitological studies on these fish species.

The African tulip tree Spathodea campanulata is a major invasive species on the island of Tahiti (French Polynesia), where it has established from sea level up to montane cloud forest. This invader continues to spread across the island; however, little information is available about the seed rain and germination rate of Spathodea seeds. In this study, we quantified seed rain of Spathodea, estimated potential seed dispersal distances, and determined temperatures required for seed germination. Seed traps were positioned in a Spathodea-dominated forest and monitored over 86 days during the seed-fall period. The cumulative seed rain generated a density of 289 Spathodea seeds per square meter with a mean daily frequency of 3.3 seeds/m² in the plot. Based on seed production estimates from canopy pod counts, we inferred that many Spathodea seeds were dispersed away from the plot, rather than being deposited locally in the Spathodea invaded plot. A simple dispersal model indicated that seeds from a single tree perched on a steep precipice are capable of dispersing across the entire island of Tahiti during strong trade winds. Laboratory germination tests of freshly collected seeds showed that the maximum germination (100%) was obtained at 25 °C while 96% germination was observed at 20 °C; however, no germination was observed at 15 °C or 12 °C after 34 days. Thus, Spathodea invasion in Tahiti may currently be limited to elevations <1,500 m due to lack of germination at cooler temperatures. The large number of seeds per adult Spathodea as well as the seed dispersal ability and high rate of germination may provide an important establishment advantage to Spathodea in the tropical rainforests of Tahiti. We unexpectedly found that 61% of Spathodea seeds that fell in seed traps were depredated before falling in the traps. It is not known whether this predispersal seed predation has reduced Spathodea's rate of spread in Tahiti.

Kukui was an important element to indigenous Hawaiian agroforestry and retained some of its importance throughout Hawai‘i's history. We examine the historical ecology and trends of kukui, including a review of the ethnobotany. We use current and historical remote imagery to map kukui canopy on the five largest Hawaiian Islands. Kukui is still widespread through the state, being a significant component in many novel low-land forests. However, kukui is declining, having lost an average of ∼58% of total canopy cover over the last 70 years. Spatial trends suggest that kukui likely did not spread much following the large-scale shifts in Hawaiian socio-ecosystems that accompanied the arrival of colonial powers. We suggest that the footprint of kukui in Hawai‘i closely approximates the extent of indigenous agroforestry and forest alteration.