The species of Cryptophlebia occurring in Hawai‘i are reviewed, resulting in the discovery of a previously unrecognized native species, described here as C. alaula, sp. nov. The discovery of C. alaulaand its status as the putative sister species of C. illepida (Butler) supports the endemicity of C. illepida, a species whose status in Hawai‘i has historically been contested, and is often treated as an invasive pest of unknown origin. Cryptophlebia alaula is hypothesized to be a specialist on fruits and seeds of ‘a‘ali‘i (Dodonaea viscosa). This raises interesting questions regarding the evolution of monophagy and polyphagy in Cryptophlebia and patterns of speciation in Hawaiian Tortricidae more broadly. The conservation status of C. alaula is briefly discussed. All species occurring in Hawai‘i are described or redescribed, figured, with a key to species of both sexes provided.

Many insular plant taxa naturally consist of small populations, which are increasingly impacted today by herbivory, climate change, and competition with invasive plants. Are some insular species fated to extinction or do they still have potential to recover? To help explore this question, we studied Schiedea adamantis, a federally endangered shrub from the Hawaiian island of O‘ahu where it was originally known as a single population. This population underwent a population crash in the late 1990s, declining from >250 plants to a handful of plants before several more individuals were discovered nearby. Fortunately, plants grown from seed obtained before the bottleneck had been maintained ex situ in California. Using microsatellite markers, we confirmed that levels of genetic variation were lower in the bottlenecked population compared to the pre-bottleneck and offspring collections, but overall levels remained moderate in the wild population despite the severe reduction in size. The four remaining field individuals consisted of one plant that likely persisted through the bottleneck and its progeny. The ex situ offspring collection contained four unique alleles, indicating the value of these collections maintained offsite. Subsequently, new plants located downslope from the original population and a second genetically different population on the same island were also discovered, although numbers continue to decline. In addition to ongoing reintroduction efforts, levels of genetic variation and discovery of new individuals holds promise for in situ survival of this species, but only if its habitat can be protected from fire, increased drought, and competition from invasive species.

Examination of specimens from the Marquesas Islands, French Polynesia, disclosed the presence of an undescribed species of Jacquemontia Choisy from the uninhabited island of Mohotani: the new species Jacquemontia mohotaniensis is described here and its conservation status is proposed as critically endangered. To place this novelty in context, a review of the native and naturalized Indo-Pacific taxa of Jacquemontia is provided; 14 names are accounted for and some taxonomic problems are highlighted for future study. New combinations are made for two Australian species, J. distigma (Benth.) Halford and J. flexuosa (Spreng.) Halford; a second step typification is provided for the latter name to stabilize the nomenclature.

Before European contact, natural grasslands covered relatively little of Hawai‘i, with a grass flora composed of ∼48 species including 40 endemics. Following the proliferation of cattle ranches after the Great Mahele (land division) in the 1840s, it was quickly realized that the native grasses were not suitable for high intensity grazing. This sparked the importation of “improved” pasture grasses and set the path toward the contemporary dominance of foreign grasses across Hawai‘i. The importation of foreign grasses for forage accelerated dramatically in the early 1900s with the establishment of the Hawai‘i Agriculture Experiment Station (HAES) on O‘ahu by the United States government. The HAES imported seed, trialed grasses in introduction gardens, and distributed seed to ranchers across the islands. I performed a systematic review of literature produced by the HAES and similar organizations, newspapers, herbarium specimens, and floristic treatments to compile a record for the timeline of grass introductions, provide detailed historical context surrounding the introduction of these grasses, and reassess the status of species of controversial nativity. In total, 577 grasses were introduced post-1778, 158 of which were likely accidental introductions whereas 419 were deliberately imported. There are 232 species of grasses naturalized in Hawai‘i, including 102 deliberately introduced and 130 likely accidental. Deliberate introductions comprise the majority of invasive species which invade natural areas, whereas most accidental introductions are weeds associated with human disturbances. While deliberate introductions largely plateaued after 1970, new accidental introductions and some deliberate introductions with long lag periods continue to naturalize, with 30 newly naturalized grass species recorded between 2000 and 2023.

Introduced ungulates have a profound impact on Hawaiian ecosystems yet are also considered a valuable resource for recreational and subsistence hunting. These conflicting values have led to challenging issues for resource managers. Distribution assessments allow resource managers to simultaneously prioritize areas for targeted removal for conservation benefit while also maintaining or even promoting hunting opportunities in other areas. This study identified distribution trends for three introduced ungulate species, wild pigs (Sus scrofa), black-tailed deer (Odocoileus hemionus columbianus), and feral goats (Capra hircus) on the island of Kaua‘i in the Hawaiian Islands. Using species distribution modeling techniques, we aimed to identify patterns in ungulate distributions across ecosystems and time, and potential species interactions. Data were collected using motion activated cameras deployed across the entire island of Kaua‘i from July 2020 to July 2021. Wild pigs were the most frequently detected species, observed at 53 out of 59 locations, followed by black-tailed deer at 30 locations, and feral goats at 9 locations. Distribution models indicate some degree of competition between deer and pigs and show considerable overlap between black-tailed deer distribution and much of the last remaining critical habitat for threatened and endangered native species. Our results suggest that pigs prefer mid-elevation areas with moderate rainfall while goats preferred arid areas regardless of slope and elevation. Differences in the distribution and abundance of these species highlight the divergent impacts invasive ungulates have on native ecosystems throughout the Hawaiian Islands and may help identify high priority areas for their management.

The Indo-Pacific eel, Anguilla marmorata Quoy & Gaimard, has the widest geographic distribution of anguillid eels. At least four populations (North Pacific, Micronesia, Indian Ocean and South Pacific) of this species were estimated to exist by previous morphological and molecular genetic studies. Recent mitochondrial control region haplotype analysis of A. marmorata eels from the eastern Caroline Islands and Guam grouped them in two separated lineages with eels from the South Pacific and western Indian Ocean. To examine the composition and possible distribution of the Micronesia population of A. marmorata that may mostly be found in the Mariana (Guam) and Caroline (Palau, Yap, Chuuk, Pohnpei, Kosrae) islands in relation to other populations in the Indo-Pacific region, we statistically compared the total number of vertebrae (TV) of specimens collected from throughout most of the range of A. marmorata including 32 specimens from Kosrae and Pohnpei islands. The TV for 1298 specimens of A. marmorata in combined data from 15 localities ranged from 100 to 110. The mean TV (107.95, 108.03) and range (105–110) of eels from the Mariana and Caroline islands were clearly higher than other localities. The post hoc multiple pairwise comparisons of the 105 pairs of single localities showed that there were 57 significant TV differences between each locality. The most significant differences were between Mariana and Caroline eels and all the other 13 localities. The statistical differences of pooled regional TV data, various genetic studies, and general geography indicate that there are likely six spawning populations of A. marmorata. This study indicates that the Caroline Islands are included in the Micronesia population, but further research is needed to understand the spawning area and life history of the Micronesia population of A. marmorata that seems to live on a relatively small number of islands in Oceania.