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Tropical drylands are among the most threatened ecosystems worldwide, and fewer than 10% of tropical dry forests in Hawai'i remain intact. Terrestrial arthropods comprise most of the endemic fauna on many islands, including Hawai'i, where they provide ecosystem services such as pollination, decomposition, and a reliable prey base for predators. The objective of our study was to measure understory arthropod diversity and relative abundances in two common habitat types within dryland Hawai'i--a non-native grassland, dominated by Cenchrus setaceus (fountain grass) with few native shrubs, and a native woodland, dominated by Metrosideros polymorpha ('ohi'a). We used generalized additive models to examine patterns of understory arthropod dynamics measured monthly or bimonthly in relation to the two habitat types and local climatic variables. We found that temperature and habitat type were significant predictors of the abundance of certain arthropod families and orders. A greater abundance of spiders was in the woodland than grassland habitat, and more beetles and ants (particularlythe Argentine ant, Linepithema humile) were in the grassland than woodland habitat. Temperature significantly predicted overall family-level richness and diversity of arthropods as well as Araneae, Heteroptera, Hymenoptera, and Lepidoptera abundance. Precipitation significantly predicted Heteroptera abundance. Significant positive associations were found among some arthropod groups, including several arachnid groups and families of Hemiptera. Documentation of insect and other arthropod community dynamics improves our understanding of ecological community function, supporting management of island communities comprised of both native and non-native species. Keywords: Pohakuloa Training Area, Hawai'i, arthropod, diversity, understory, invasive species, native species, tropical dry forest, ARTHROPOD DIVERSITY and distributions are poorly known for Hawaiian dry forests, despite these areas being highly threatened and historically botanically diverse (Rock 1913, Hatheway 1952, Carlquist 1970, Cabin et al. [...]

Because of its extreme isolation and lack of historical connection to a mainland, the Hawaiian Archipelago is thought to have no native nonvolant terrestrial reptiles. Several squamate species have been introduced to the archipelago, likely starting with early Polynesian contact, and increasing as human traffic in the Pacific has amplified. Of the earlier introductions, one species of skink, Cryptoblepharus poecilopleurus, belongs to a genus known for its ability to naturally disperse long distances, even across oceans. The earliest herpetofaunal surveys from Hawai'i describe the skink as widespread and abundant across the archipelago. A recent phylogenetic analysis reveals substantial haplotype divergence between Hawaiian individuals and other known populations in the Pacific, raising the possibility that this species was an early and natural arrival to the archipelago before human contact. Recent surveys suggest that the species has undergone a dramatic reduction in range across the archipelago, possibly due to the invasion of highly competitive species. Given this information, we aim to further assess the origin of C. poecilopleurus in Hawai'i, determine its current range, and suggest specific needs for future work. Here, we review the earliest European voyages in the Pacific that are known to have sampled C. poecilopleurus, review literature and museum specimens to develop an understanding of this species' history in the islands, survey the island of O'ahu to characterize its current range, and provide preliminary genetic analyses to show the relationship of the Hawai'i populations to the rest of the Pacific. Keywords: Hawai'i, historical review, herpetofauna, Pacific, phylogenetics, THE HAWAIIAN ISLANDS are an isolated volcanic archipelago that supports high levels of endemism, particularly in birds, some invertebrate species groups, and plants (Stemmermann 1983, Baldwin 1997, Cowie and Holland [...]

The study of nocturnally active bats is difficult even for those species that seasonally congregate. This challenge is particularly acute for 'ope'ape'a (Hawaiian hoary bat; Lasiurus semotus) because of its solitary foliage-roosting behavior. Yet surveys are essential for conservation and management of this endangered species and only land mammal endemic to the Hawaiian Islands. We surveyed for 'ope'ape'a at 23 sites and a range of elevations (33-2,341 m) on Hawai'i Island from May 2018 to August 2021. We captured 138 unique bats (37 female, 101 male) over 224 mist-netting events. We averaged 16 net-hours per bat capture, with peak captures 30-90 min after sunset. We marked all captured individuals in this study with identifying forearm bands and recaptures represented 7% of total captures (10 of 148). We developed generalized linear mixed models to examine the relationship of nightly bat captures by sex to elevation and time-of-year while accounting for variable sampling effort and repeated sampling in this study. Both males and females were captured at low and high elevations with peak capture rates occurring at approximately 930 m. The capture rate for females was highest during the reproductive season (May to September), whereas it was highest for males during the non-reproductive season (October to April). This study informs future fieldwork with a description of 'ope'ape'a capture on Hawai'i Island by sex, elevation, time-of-year and time-of-night, radio transmitter retention, and recapture frequency. Keywords: Hawaiian hoary bat, 'ope'ape'a, Lasiurus semotus, Hawai'i, mist-net capture, VESPER BATS (FAMILY VESPERTILIONIDAE) are relatively small and primarily nocturnal, making it difficult to evaluate distribution, abundance, and population trends (Carter et al. 2003). One approach common to bat studies [...]

Rose-ringed parakeets (Psittacula krameri; parakeets) are among the most invasive bird species worldwide. In their introduced range, populations of this species have caused negative effects on native species, natural environments, economies, and human safety. Lethal population management has been complicated by the intelligence of the birds, as they quickly alter behavior to avoid risks. Further, lethal control programs have been halted due to public opposition, as parakeets are considered to be charismatic by animal welfare advocates. The contraceptive DiazaCon has been demonstrated to effectively reduce fertility in captive parakeets. In field applications, any chemical control agents (e.g., toxicants or contraceptives) must be delivered in a manner that prohibits access by non-target species. Parakeets are known to feed from bird feeders throughout their native and introduced range, suggesting contraceptive-treated bait may be a useful management strategy. However, our 24-week trials with free-ranging parakeets using platform, hopper, and tube feeders on the island of Kaua'i did not result in any parakeet visitation and thus precluded further testing of using feeders to selectively deliver fertility control products. Nonetheless, multiple citizen science reports and other documentation indicate parakeets using feeders on the island of O'ahu over a period of >10 years, and recently on the island of Maui. Our findings suggest the chemical control of nonnative parakeet populations is a promising technique, but implementation success will likely vary by target population acceptance, location, local faunal diversity, and availability of alternative forage. Keywords: citizen science, fertility control, Hawai'i, invasive species, Psittacula krameri, rose-ringed parakeet, toxicant delivery, INVASIVE BIRD POPULATIONS have become problematic throughout the world but can be particularly detrimental to agriculture and native biota on islands (Brochier et al. 2010). An estimated 15% of the [...]

Sida fallax Walp. ('ilima) (Malveae, Malvoideae, Malvaceae) is native to the Pacific area and is broadly distributed throughout this region. Sida fallax is the most widespread and variable taxon of Malvaceae in the Hawaiian Islands and it occurs with diverse morphological forms and in different habitats from Hawai'i Island to Midway Atoll. The low elevation and mountain ecotypes are two extreme ecological forms of S. fallax with many intermediate morphological types existing between these extreme ecotypes in the Hawaiian Islands. The range of morphological and ecological diversity in Sida fallax suggests that this species requires further biosystematics investigation. The purpose of this study was two-fold. First, explore the genetic diversity among S. fallax populations throughout its native range in the Pacific region to assess if it is a single species or potentially multiple cryptic species; second, investigate the biogeographic origin of S. fallax. To do this, Sida fallax was sampled throughout the Hawaiian Islands and in different parts of the Pacific region. Bayesian phylogenetic analyses based on nuclear (ITS and ETS) and chloroplast regions (psbA-trnH) were carried out. Results indicate that there is very little sequence-level variation in this species throughout its distribution and phylogenetic analysis clearly demonstrated that Sida fallax is a single species throughout the Pacific region and the different forms of Hawaiian S. fallax are not genetically distinct at the sequence level. Although the pattern of dispersal of S. fallax is not clear, an American origin is most likely. Keywords: Hawai'i, Malveae, Malvaceae, Pacific Islands, phylogeny, Sida fallax, OCEANIC ARCHIPELAGOS have been long considered as natural laboratories for studying evolution (Darwin 1859, Lack 1947, Carlquist 1974, Schluter 2000). The isolation, topographic complexity, and habitat heterogeneity of many archipelagos [...]

While the influence of elevation and seasonal variation on isotopic composition has been studied on Maui, Hawai'i Island, and O'ahu (Scholl et al. 1996, Scholl et al. 2002, Scholl et al. 2007, Dores et al. 2020, Fackrell et al. 2020, Tachera et al. 2021), this work is the first to investigate event-based precipitation in detail on the island of O'ahu. The stable isotopic composition of water has been used to track the movement of water within the hydrosphere, to investigate the type and origin of a rainfall event, and elevation of collection, among other characteristics. Here, we present a high-resolution study of the stable isotopes [[delta].sup.2]H and [[delta].sup.18]O of precipitation along a compact land-to-sea transect in Waikikl,a southwest facing region on O'ahu. The study provides a unique, in-depth investigation into the nature of individual storm events, and how they contribute to a larger seasonal climatic pattern. Monthly precipitation samples were collected at three sites along the transect from December 2017 to March 2019 and event-based samples were collected at the Makai site from October 2018 to February 2019. Storm direction, temperature, and relative humidity were recorded for each event-based sample. Results suggest that evaporative conditions at different elevations influence the isotopic composition of precipitation, either through net addition as moisture recycling, or net loss of evaporated water. The spatial distribution of these patterns from site to site illustrates the extreme heterogeneity of Hawaiian watersheds. Keywords: stable istopes, precipitation, deuterium excess, tropical climate, hydrology, FOR TROPICAL ISLANDS, where precipitation becomes the groundwater resource used for drinking water, investigating the origin of recharge as precipitation is important for understanding the relationship between groundwater and its [...]

Riparian litter fall is an important source of organic matter to rivers and accounts for a large fraction of their dissolved organic carbon (DOC) load. DOC is metabolically important in rivers, and therefore changes in riparian vegetation species composition should affect riverine DOC bioavailability. Worldwide, invasive vegetation composes a large percentage of riparian vegetation. In Hawai'i, riparian vegetation changes from native to invasive species with decreasing elevation. To assess how changes in riparian vegetation affect riverine DOC dynamics, we compared DOC bioavailability from native (Acacia koa and Metrosideros polymorpha) and invasive (Falcataria moluccana and Psidium cattleianum) riparian trees to freshwater and estuarine bacteria from the Wailuku River on Hawai'i Island through dark bioassays. DOC bioavailabilities in riverine and estuarine waters were similar among all riparian vegetation types. In contrast, vegetation-derived DOC was more bioavailable (52%±4%) than the riverine and estuarine DOC (14%±3%). Combining DOC bioavailability and leaf litter input data from our native and invaded riparian sites suggests that a shift in leaf litter inputs from native to invasive species may increase the amount of bio-available DOC entering Hawaiian rivers and streams. This DOC input has the potential to impact the metabolism and food webs of downstream ecosystems., Leaf litter inputs from the riparian zone play a fundamental role in rivers by supplying an allochthonous source of carbon (C) and nutrients to their food webs (Wallace et al. [...]

Hawaiian lowland dry forests have been reduced by >90% since first human contact. Restoration has focused on protection from fire and ungulates, and removal of invasive grasses as ways to stimulate native forest regeneration. Despite these efforts, natural regeneration of native plants has been infrequent. To assess effects of previous restoration treatments on natural regeneration, we monitored seed rain and dynamics of seedlings and juveniles for a period of 3 yr (2004-2007) within three restoration units within a remnant forest on the island of Hawai'i. All units had been protected from fire for many decades but differed in time since ungulate exclusion and grass removal. The units were as follows: (1) long-term restoration (fenced 1956, grass removal initiated 1995), (2) short-term restoration (fenced and grass removal initiated 1997), and (3) unmanaged (fenced 1997, no grass removal). Overall juvenile plant abundance was highest in the short-term unit, but native abundance was highest in the long-term unit. Native woody seedlings established in all units, but recruitment into larger size classes was restricted to units with grass removal, primarily the long-term unit. Native seed rain explained much of the variation in native seedling abundance between units with grass removal. Nonnative grass seed rain was extensive but was reduced by an order of magnitude with grass removal. This study suggests that natural regeneration may enhance restoration actions in sites with native canopy, but this is likely only when restoration activities have been maintained for several years to coincide with favorable rainfall conditions that are highly unpredictable over time., Tropical dry forests are one of the most endangered ecosystems in the world. Almost all of the remaining tropical dry forests (~97%) are at risk from multiple threats such as [...]

Falcataria moluccana (albizia) is an exotic nitrogen (N)-fixing tree currently invading riparian forests in Hawai'i, U.S.A. This study examined how this invasion is impacting stream ecosystems by using naturally occurring stable isotopes of carbon (C) and N to compare food web structure between a non-invaded and an albizia-invaded stream reach on the island of Hawai'i. Isotopic signatures of particulate organic matter (POM), macroalgae, invertebrates, and fishes were collected and compared between the two stream reaches. Stable C isotopic signatures of organic matter sources (POM and macroalgae) and consumers (amphipods, caddisflies, crayfish, and fishes) from the invaded site were depleted in [sup.13]C compared with the noninvaded site. In contrast, all samples from the invaded site were enriched in [sup.15]N compared with the noninvaded site. Results from IsoSource and two-source mixing models suggested that albizia was a major contributor to diets of lower-level consumers within the invaded site, displacing POM and macroalgae as their major food sources. Albizia was also an indirect C and N source for higher-level consumers within the invaded site because albizia was the major dietary constituent of their prey. In addition, [sup.15]N enrichment of the macroalgae at the invaded site suggests that albizia may be an important N source to benthic primary producers and could be further altering the food web from bottom up. Our study provides some of the first evidence that invasive riparian N-fixing trees can potentially alter the structure of stream food webs., The presence of nitrogen (N)-fixing plants in forests can greatly impact nutrient cycling and affect the export of N from watersheds through shedding and decomposition of their N-rich leaves on [...]

Technical and analytical improvements in aircraft-based remote sensing allow synoptic measurements of structural and chemical properties of vegetation across whole landscapes. We used the Carnegie Airborne Observatory, which includes waveform light detection and ranging (LiDAR) and high-fidelity imaging spectroscopy, to evaluate the landscapes surrounding four well-studied sites on a substrate age gradient across the Hawaiian Islands. The airborne measurements yielded variations in ground topography, canopy height, and canopy nitrogen (N) concentration more accurately than they could have been obtained by any reasonable intensity of ground-based sampling. We detected spatial variation in ecosystem properties associated with the properties of different species, including differences in canopy N concentrations associated with the native species Metrosideros polymorpha and Acacia koa, and differences brought about by invasions of the biological N fixer Morella faya. Structural and chemical differences associated with exotic tree plantations and with dominance of forest patches by the native mat-forming fern Dicranopteris linearis also could be analyzed straightforwardly. This approach provides a powerful tool for ecologists seeking to expand from plot-based measurements to landscape-level analyses., Substantial effort has gone into determining and analyzing ecosystem properties and processes on a long substrate age gradient (LSAG) across the Hawaiian Archipelago (Crews et al. 1995, Kitayama and Mueller-Dombois [...]

Body and feather mass data are important in avian studies and are required for determining things such as body condition and energetic carrying capacity. There are 12 subspecies of Common Moorhens (Gallinula chloropus), six continental and six island subspecies, of which two are endangered. Body mass data for multiple individuals are available for only three subspecies, and feather mass data have been reported for only one individual. Body mass (n = 82) and feather mass (n = 2) for adults and body mass for three subadult age classes (n = 27) are provided for the Hawaiian subspecies of Common Moorhen (G. c. sandvicensis). Other body size measurements, including tarsus length, shield-bill length, shield width, and wing cord length also are presented. Adult Hawaiian Moorhen body mass averaged 350.7 g (± 50.0 SD; range, 232-522; 95% CI, 339.8-361.6), and young birds appear to develop like young of G. c. chloropus and other Rallidae. Based on published data, G. c. sandvicensis is heavier than G. c. guami, female G. c. chloropus, and G. c. meridionalis; lighter than G. c. Garmani and males of G. c. cachinnans; and similar in mass to G. c. cachinnans females, males of G. c. chloropus, and G. c. orientalis. There do not appear to be systematic differences in body mass between mainland (data for four subspecies) and island subspecies (data for three subspecies). Total mass of all feathers for two males was 16.2 and 12.1 g, which made up 3.1% and 3.8%, respectively, of their total body mass., Body mass is a central piece of data required for many avian studies in which re searchers are interested in evaluating body condition or calculating energetic carrying capacity (e.g., Guthery [...]

The presence of fire in Hawai'i has increased with introduction of nonnative grasses. Fire danger estimation using the National Fire Danger Rating System (NFDRS) typically requires 5 to 10 yr of data to determine percentile weather values and fire activity. The U.S. Army Pohakuloa Training Area in Hawai'i is located in the interface zone between windward and leeward weather conditions and needed to develop fire danger values but did not have sufficient weather or fire occurrence data. Use of simulation to estimate fire danger (expressed as fire risk) for areas with limited weather data was investigated. Influence of spatial resolution of weather information on fire risk was examined by comparing fire risk calculated using one or three weather stations and gridded weather predictions from the Mesoscale Spectral Model. Predicted gridded temperature was positively correlated with observed temperature; predicted and observed relative humidity were not significantly correlated. Simulated fire risk differed between weather data percentiles and between weather data resolutions. Predicted risk estimated from gridded weather data agreed more closely with observed risk estimated from weather data observed at all three remote automated weather stations. Correlation between simulated fire risk and the NFDRS Ignition Component was statistically significant for the single weather station simulations. Correlations between risk and the Ignition Component were not statistically significant for the three station and gridded weather data scenarios, which illustrates the difference between fire danger determined at broad spatial scales and fire risk resolved at finer spatial scales. Fire spread simulation modeling to estimate fire risk in areas with limited historical weather and fire occurrence data can provide finer-scale information than the NFDRS, which is better suited to larger, homogeneous areas with more complete fire and weather data. Values for the NFDRS Burning Index were determined and incorporated into the wildland fire management plan for Pohakuloa Training Area., Wildland fire is an integral component of many terrestrial ecosystems within and surrounding the Pacific Ocean. In Hawai'i, the role that fire has played in the evolution of the island [...]

This study examined the endemic species of kleptoparasitic spiders in the genus Argyrodes from the Hawaiian Islands, a lineage previously known in the archipelago from only a single described species, Argyrodes hawaiiensis Simon. Here, two additional endemic species are described, A. ilipoepoe Rivera and Gillespie, n. sp., and A. laha Rivera and Gillespie, n. sp., with their biogeographical patterns, and the allotype female and paratypes of A. hawaiiensis are designated. As with A. hawaiiensis, both new species are commonly found as kleptoparasites on the sheet webs of large nocturnal spiders in the genus Orsonwelles (Linyphiidae). Hawaiian Argyrodes are characterized by small and rounded abdomens, unpronounced clypeal projections, and variably long fangs. Argyrodes hawaiiensis; A. ilipoepoe, n. sp.; and A. laha, n. sp., include all the known endemic representatives of the group in the Hawaiian Islands, which mostly occur in wet and mesic forests., The Hawaiian archipelago is well known for being host to many diverse terrestrial arthropod assemblages, yet many of these lineages, including those of the endemic spider fauna (Gillespie et al. [...]

Natural tropical wetlands constitute an important but still poorly studied source of atmospheric methane, a powerful greenhouse gas. We measured net methane emission, soil profiles of methane generation and oxidation, and related environmental parameters in a tropical wetland occupying the Ka'au extinct volcanic crater on the Hawaiian island of O'ahu. The wetland has a fluctuating water table with dynamics that can be reproduced using precipitation data and a simple model. Median net methane flux was 117 mg [m.sup.-2] [day.sup.-1] and is consistent with measurements at other tropical sites. Net methane flux in the Commelina diffusa--dominated vegetation pattern (honohono) was significantly higher than that of the invasive Psidium cattleianum--dominated pattern (strawberry guava). Net methane emission in the honohono vegetation pattern was also significantly higher during the 'wet' season compared with the 'dry' season, although we did not find a clear correlation between net methane emission, water table level, or precipitation. We show that the measured fluxes are consistent with the integrated potential methane generation over the uppermost 30 cm of soil and consumption of @50% of that methane in the soil. Absence of a correlation between net methane emission and water table level may be due to suppression of the activity of strictly anaerobic methanogens by dynamic redox conditions in the upper layers of soil and varying rates of methane oxidation by facultive methanotrophs. doi: 10.2984/64.1.057, Atmospheric methane ([CH.sub.4]) is a powerful greenhouse gas responsible for 20% of the anthropogenic change in direct radiative forcing (Intergovernmental Panel on Climate Change 2001). Its concentration has more than [...]

Abstract: Hawaiian fringing reefs display sand bodies on their surfaces that are potentially important components of littoral sediment budgets. This work provides a regional survey of modern reef-top sediment storage [...]

Abstract: Sea-surface temperatures off southern California from Scripps Pier and from Koko Head, Hawai'i, were examined to determine what impact regime shifts that occurred in 1976-1977 and 1988-1989 had on [...]

Abstract: The leeward Kohala Field System on the island of Hawaii was one of the most intensive pre-European contact dryland agricultural systems. Archaeological and soil analysis has documented changes in [...]

Abstract: The labrid fish Cymolutes praetextatus, previously known from East Africa to the Society Islands but not east of the Marshall Islands in the North Pacific, is reported from the [...]

Abstract: Coral reefs at Kaua'i, O'ahu, Moloka'i, Maui, and Hawai'i were surveyed using a rapid assessment method for marine nonindigenous and cryptogenic species commonly found in Hawaiian harbors and embayments [...]

Abstract: A 3-year study of Wainiha River on Kaua'i, Hawai'i, was carried out to determine the impact that water removal had on key stream ecosystem parameters and functions. The study [...]

Abstract: Twenty-three stream segments (seven on O'ahu, eight on Kaua'i, and eight on Hawai'i) were sampled for macroalgae in the Hawaiian Islands. Stream segments ranged greatly in size from 1.2 [...]

Abstract: The Indo-Pacific labrid fishes of the genus Xyrichtys Cuvier, popularly referred to as razorfishes, are reclassified in Iniistius Gill. The razorfishes of the Atlantic and eastern Pacific currently placed [...]

Abstract: Samples of roots and root-zone soil from the threatened species Argyroxiphium sandwicense subsp. macrocephalum and the endemic species Dubautia menziesii, both members of the Asteraceae, were collected in a [...]

Abstract: Trechus obtusus Erichson (tribe Trechini), native to Europe and North Africa and introduced to the Pacific coast of North America, is recorded for the first time from East Maui [...]

Abstract The soleid fish Aseraggodes holcomi, the third Hawaiian species of the genus, is described from six specimens collected off O'ahu, from sand in 0.6-27 m. It is distinct in [...]

John E. Randall (2) Stuart G. Poss (3) Abstract: The wide-ranging Indo-Pacific scorpionfish Scorpaenodes fowleri (Pietschmann), long placed in the genus Scorpaenopsis (largely because it lacks palatine teeth), is reclassified [...]

Amy Lacks [9] It has been estimated that there are over 800 species of stony corals in the world's oceans. Many of these are difficult to distinguish because of high [...]

JAMES A. ALLEN [2,3] KEN W. KRAUSS [2] NORMAN C. DUKE [4] DERRAL R. HERBST [5] OLLE BJORKMAN [6] CONNIE SHIH [6] ABSTRACT: At least two mangrove tree species in [...]

BRADLEY M. WETHERBEE [2] STEPHEN M. KAJIURA [3] ABSTRACT: The first occurrence of the rare viper shark, Trigonognathus kabeyai, from the central Pacific Ocean is reported. Morphometrics are compared between [...]

PAUL D. KRUSHELNYCKY [2] ABSTRACT: The annual, endemic, coastal herb Centaurium sebaeoides is the only native Hawaiian species in the gentian family. The U.S. Fish and Wildlife Service listed it [...]

SHERWIN CARLQUIST [2] EDWARD L. SCHNEIDER [2] CHARLES H. LAMOUREUX [3] ABSTRACT: Tracheary elements of three species (Mecodium recurvum, Vandenboschia devallioides, and Callistopteris baldwinii) (two epiphytic, one terrestrial) representing three [...]

Prey size selection and clearance rates of Oikopleura fusiformis were investigated at two sites along the northern and western shores of O'ahu, Hawai'i, during summer of 2001. Experiments were conducted [...]

Community structure on Hawai'i's rocky intertidal shores has received relatively little attention when compared with reef, pelagic, forest, and grassland communities. In fact, there is a common misconception that there [...]

In response to the need to better understand climate change and to address related impacts in the Pacific, PSA is involved in efforts to establish the Pacific Islands Climate Change [...]

Predator (top-down) and resource (bottom-up) influences in food webs are strong and pervasive, but few studies have investigated their interactive effects in real terrestrial ecosystems. This study focused on arthropods [...]