Major Hawaiian Islands Research Articles

Persistence of widespread moderate Spinosad resistance among wild melon fly (Zeugodacus cucurbitae) and oriental fruit fly (Bactrocera dorsalis) populations on the major Hawaiian islands.

Insecticide resistance among invasive tephritid fruit flies poses a great risk to national food security and has the potential to disrupt quarantine and eradication programs, which rely on the efficacy of Spinosad to prevent widespread establishment in North America. During 2022 to 2023 we surveyed the extent of Spinosad resistance of two key species, oriental fruit fly Bactrocera dorsalis, and melon fly Zeugodacus cucurbitae, from 20 sites across five Hawaiian Islands including Kaua'i, O'ahu, Maui, Molokai and the "Big Island" (Hawai'i). We used topical thoracic applications of eight concentrations of Spinosad ranging from 0.028 to 3.6 mg/mL to evaluate the lethal concentration (LC50 and LC99) required to kill wild-caught males. Resistance ratios (RR) were calculated by comparing the LC50 of wild flies to laboratory susceptible lines maintained in colony. Our results identified at least two new sites of concern for melon fly resistance on the Big Island, and at least four sites of concern for oriental fruit fly, all of which were located on the Big Island. At these locations RRs were >5. On O'ahu, melon fly RRs were >10. The persistence of Spinosad resistance is concerning, yet it is a reduction compared to the values reported previously and before changes to Spinosad use recommendations by local extension agents beginning in 2017. For oriental fruit fly, these RR values are the highest levels that have been detected in wild Hawai'i populations. These data suggest that expanded Spinosad reduction and replacement programs are warranted given the ongoing issues with Spinosad resistance in Hawai'i and expansion in the number of species affected. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Aroplectrus dimerus (Hymenoptera: Eulophidae), Ectoparasitoid of the Nettle Caterpillar, Oxyplax pallivitta (Lepidoptera: Limacodidae): Evaluation in the Hawaiian Islands.

The stinging nettle caterpillar, Oxyplax (syn. Darna) pallivitta (Lepidoptera: Limacodidae), is a serious invasive pest of agricultural products and a health hazard on the Hawaiian Islands first discovered in 2001. Nursery workers and homeowners have been stung by the caterpillars while handling their plants, especially rhapis palms (Rhapis sp.). Throughout its invaded range, it causes widespread damage, including the many cultivated and native palm species that have grown in Hawaii. Larvae contain urticating hairs that secrete a toxin, causing painful skin swelling and irritation on contact. Horticulture and nursery products impacted by the limacodid pest are estimated at $84.3 million (2018 value). Suppression efforts with pesticides and lure traps were ineffective, and the moth population continued to spread to major Hawaiian Islands (Hawaii, Kauai, Maui, Oahu). The introduction of specific biological control agents from the native region was thought to be the long-term solution for this invasive pest. Initial exploration in Indonesia and Thailand resulted in the introduction of a pupal ectoparasitoid, Nesolynx sp. (Hymenoptera: Eulophidae: Tetrastichinae), that was not specific. The oriental wasp, Aroplectrus dimerus Lin (Hymenoptera: Eulophidae: Eulophinae), idiobiont gregarious ectoparasitoid of the stinging nettle caterpillar, was introduced from Taiwan in 2004 for host specificity studies and biocontrol in Hawaii. Host range testing showed the parasitoid attacked only limacodid species, and it was approved for field release in 2010. The parasitoid identity, host specificity under containment facility conditions, reproductive performance, and colonization on the major infested sites were assessed. A total of 13,379 parasitoids were colonized on 162 release sites on four Hawaiian Islands. Evaluations were conducted using field surveys of larvae, pupal counts, and male lure traps. Field parasitism was thoroughly investigated on Oahu Island, averaging 18.9 ± 5.6% of 3923 collected larvae during 2010-2023. The numbers of male moths caught/trap/month were significantly reduced on Oahu Island (p < 0.05). Recently, the hyperparasitoid, Pediobius imbreus Walker (Hymenoptera: Eulophidae: Entedoninae), was detected, reducing the efficiency of A. dimerus in the field. The mean hyperparasitism of A. dimerus pupae was 27.3 ± 7.6% on Oahu Island. There was no detailed biological assessment for A. dimerus or its field evaluation available in scientific literature. Results were discussed regarding the potential use of A. dimerus in biocontrol elsewhere if the stinging nettle caterpillar was invaded in the future.

Breeding and selection of taro (Colocasia esculenta) for improved disease‐resistance in Hawaiʻi

Societal Impact StatementTaro is a root crop with wide geographic range and high cultural significance to Indigenous peoples of Hawaiʻi and the Pacific. Taro Leaf Blight (TLB) is a worldwide disease of taro, and Hawaiian taro varieties exhibited little resistance to it. To improve TLB‐resistance, conventional breeding was conducted by hand‐pollination. Out of ~3500 taro seedlings, 18 varieties were selected and evaluated under non‐flooded conditions at four locations in Hawaiʻi over 5 years. Four varieties were identified as high yielding and disease‐resistant. Further, to prevent confusion of new taro varieties with traditional Hawaiian taro, we developed DNA fingerprints to differentiate them. Taken together, these results have provided information regarding new plant material and new tools for those interested in conservation and breeding across the Pacific.Summary Breeding and evaluation of taro (Colocasia esculenta (L.) Schott) was conducted in Hawaiʻi to increase resistance to Taro Leaf Blight (TLB), caused by oomycete pathogen Phytophthora colocasiae Racib., while maintaining high yields and desirable eating qualities. When breeding Indigenous crops such as taro, it is important to consider issues of Indigenous, intellectual property rights. In response to concerns by cultural practitioners about potential confusion of new taro genotypes with traditional landraces, we also sought to develop DNA fingerprints using single nucleotide polymorphisms (SNPs) to identify the new genotypes. Conventional breeding of taro was conducted by hand‐pollination of Hawaiian taro landraces with sources of TLB‐resistance from multiple countries. The most promising lines were multiplied and evaluated under upland (i.e., non‐flooded) conditions on four major Hawaiian Islands over 5 years. DNA was extracted from these new genotypes, analyses of SNPs conducted, and results compared to those of traditional Hawaiian landraces. Bayesian yield analysis of these multi‐year and multi‐location trials identified taro genotypes 1016‐003, 1016‐019, 1024‐215, and 1005‐084 as producing twice the fresh weight corm yield as control “Maui Lehua” and exhibiting disease‐resistance across years and environments. DNA fingerprints of new genotypes were able to differentiate them from traditional Hawaiian landraces that make up a portion of their parentage. Conventional breeding of taro in Hawaiʻi and multi‐year, multi‐location field trials have resulted in high yielding, disease‐resistant genotypes that maintain desirable qualities of some traditional Hawaiian landraces. DNA fingerprints of these new genotypes distinguish them from these traditional landraces, helping to preserve heritage germplasm.

Shifting magnitude and timing of streamflow extremes and the relationship with rainfall across the Hawaiian Islands

Flooding is a significant threat to life and property in Hawaiʻi. As climate warming continues to alter precipitation patterns and hydrological processes in the tropics, characterizing the shifting patterns in magnitude, seasonality, and location of floods would improve our understanding of the consequences and better prepare us for future flood events. In this study, 84 rain gauges and 111 crest gauges across five major Hawaiian Islands were analyzed from 1970 to 2005. We estimated trends in the annual maximum daily rainfall (RFmax) and the annual peak flow (PFmax) using the Mann-Kendall test and Senʻs slope. Subsequently, we examined the association between PFmax and rainfall. Then, we assessed temporal shifting by combining circular analysis with Senʻs slope. The main identified trends showed decreases in RFmax and PFmax(67% and 61% of all gauges, respectively). The physiography of the Hawaiian islands (i.e., windward vs. leeward) has little contribution to both trends. In addition, PFmax trend cannot be fully attributed to RFmaxtrend, and in many cases, RFmax andPFmax did not occur coincidently. We also found the timing of RFmax and PFmax occurred in early wet season during the El Niño years and shifted even earlier from 1970 to 2005, likely due to the change of El Niño. These findings have implications for assessing flood risk. Our finding will aid watershed management and flood mitigation, and can increase resilience of downstream communities and near-shore environments.

A new and likely extinct species of Antilissus Sharp, 1879 (Coleoptera: Zopheridae: Colydiinae) from Makauwahi Cave, Kauai, Hawaiian Islands.

This paper describes Antilissus makauwahi, sp. nov., from the subfossil record of Makauwahi Cave on the island of Kauai, Hawaii. This new species is the second species of Antilissus Sharp from Hawaii and second described species for the genus. The type species of Antilissus, A. aper Sharp, has been widely collected from under the bark of dead or dying trees, at higher elevations, on all major Hawaiian Islands. In contrast, A. makauwahi is so far known only from a small number of subfossil sclerites recovered from sediments dating to before human arrival in Hawaii (800 years before present). This potentially extinct species adds to the growing body of evidence suggesting the widespread extinction of Pacific island insects after human arrival.

Colonization as Continuum

The punctuation used in the word Hawai‘i (and many other Hawaiian words in the poem) looks like an apostrophe but is actually called an ‘okina. It is common in Pacific languages and indicates a glottal stop (like the sharp stop in the middle of the term “uh-oh”). The other notable punctuation mark is the horizontal line over a vowel, as in nēnē. It is called a kahakō and indicates that the vowel sound should be held slightly longer than usual. Hāpu‘u pulu (Cibotium splendens)—Hāpu‘u is a large tree fern that can grow to around twenty feet tall. Its fronds are covered with a silky golden-brown hair that was once used to stuff pillows. Before clearing and over-exploitation from harvesting, hāpu‘u was common on all the major Hawaiian Islands. Tree ferns are considered a threatened species (“Hāpu‘u (Hawaiian Tree Fern)”). Our front yard is a tree fern garden—hāpu‘u provide shade for anthuriums and orchids. We use the dead fronds as mulch in the garden and cover for weedy areas.

Repeated range expansion and niche shift in a volcanic hotspot archipelago: Radiation of C4 Hawaiian Euphorbia subgenus Chamaesyce (Euphorbiaceae).

Woody perennial plants on islands have repeatedly evolved from herbaceous mainland ancestors. Although the majority of species in Euphorbia subgenus Chamaesyce section Anisophyllum (Euphorbiaceae) are small and herbaceous, a clade of 16 woody species diversified on the Hawaiian Islands. They are found in a broad range of habitats, including the only known C4 plants adapted to wet forest understories. We investigate the history of island colonization and habitat shift in this group. We sampled 153 individuals in 15 of the 16 native species of Hawaiian Euphorbia on six major Hawaiian Islands, plus 11 New World close relatives, to elucidate the biogeographic movement of this lineage within the Hawaiian island chain. We used a concatenated chloroplast DNA data set of more than eight kilobases in aligned length and applied maximum likelihood and Bayesian inference for phylogenetic reconstruction. Age and phylogeographic patterns were co‐estimated using BEAST. In addition, we used nuclear ribosomal ITS and the low‐copy genes LEAFY and G3pdhC to investigate the reticulate relationships within this radiation. Hawaiian Euphorbia first arrived on Kaua`i or Ni`ihau ca. 5 million years ago and subsequently diverged into 16 named species with extensive reticulation. During this process Hawaiian Euphorbia dispersed from older to younger islands through open vegetation that is disturbance‐prone. Species that occur under closed vegetation evolved in situ from open vegetation of the same island and are only found on the two oldest islands of Kaua`i and O`ahu. The biogeographic history of Hawaiian Euphorbia supports a progression rule with within‐island shifts from open to closed vegetation.

Occurrence and removal of pharmaceutical compounds and steroids at four wastewater treatment plants in Hawai'i and their environmental fate

The occurrence of pharmaceutical and steroid compounds in groundwater due to wastewater reuse has been reported and is of concern in tropical islands which primarily rely on groundwater. The objective of this study was to investigate the occurrence and removal of 43 pharmaceutical and steroid compounds detected in wastewater at four different wastewater treatment plants (WWTPs) in Hawai‘i and to understand their environmental behavior through tropical soils as the treated effluents are used in landscapes for irrigation. Eight soil sampling locations, collected at three different depths, representing the most common soil types in Hawai‘i and four WWTPs located across the major Hawaiian Islands were used. Disturbed soil samples were used to conduct the soil sorption and degradation studies and to estimate the leaching risk associated to the identified compounds. Quantification of selected compounds was conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS).Among the investigated compounds, only ten were detected in the treated effluents at concentrations ranging from 0.004 to 0.900 μg L−1. Caffeine (64 μg L−1) and ibuprofen (96.5 μg L−1) showed the highest concentration in raw samples, while diphenhydramine (0.9 μg L−1) showed the highest concentration in treated effluent samples. Sulfamethoxazole showed the lowest removal (0–75%). Several pharmaceuticals showed consistently higher sorption capacity and longer persistency compared with steroids regardless of soil types and depths. Poamoho (Oxisol soil) and Waimānalo (Mollisol soil) showed the highest sorption capacity, while Waimea (Entisol soil) showed the lowest sorption capacity. Soil physico-chemical properties (i.e., clay content, level of organic carbon, and presence of metal oxide) and soil depth highly impacted the sorption behavior of the selected pharmaceutical compounds. In particular, the sorption capacity decreased with soil depth due to the higher level of organic carbon present in the first 30 cm compared with the deeper depths (60–90 cm).

A Tier-I leaching risk assessment of three anticoagulant compounds in the forested areas of Hawai'i

The anticoagulant rodenticides brodifacoum, chlorophacinone, and diphacinone have been proposed for broadcast application in some forested areas in Hawai'i to protect rare and endangered native bird species from introduced mice and rats. Groundwater resources in Hawai'i are prone to contamination due to the intrinsic aquifer vulnerability to leaching from the land surface. Because of the hydrogeologic complexity, Hawai'i uses a Tier-I leaching assessment tool, CLERS, to make registration decisions for new or existing chemicals. The CLERS tool uses soil and pesticide properties as well as water recharge through the soil profile in a GIS framework to estimate mass attenuation of the chemicals at a given depth and compares against this attenuation factor against those of a known leacher and a non-leacher. Disturbed soil samples were collected across the state of Hawai'i, including the islands of Hawai'i, Kaho'olawe, Kaua'i, Lana'i, Maui, Moloka'i, and O'ahu, with two sampling locations per island, except for Kaua'i which had three. As only limited information on chemical properties of these anticoagulants in soils is available, laboratory experiments were performed to determine the sorption capacity (Kd) and the degradation rate (T1/2) of brodifacoum, chlorophacinone, and diphacinone to construct a proper chemical database. Depending on the soil type, T1/2 values ranged between 37 and 248days for diphacinone, between 39 and 1000days for chlorophacinone, and between 72 and 462days for brodifacoum. These data were used in the CLERS tool to estimate leaching risks for these chemicals primarily in forested areas of the state where the chemicals are likely to be applied. The results from the CLERS tool indicate low risks of leaching of these three compounds into aquifers in five out of six major Hawaiian Islands. Diphacinone showed medium risk of leaching in a few remote areas in Maui.

Comparison of geostatistical approaches to spatially interpolate month‐year rainfall for the Hawaiian Islands

ABSTRACTThe Hawaiian Islands have one of the most spatially diverse rainfall patterns on earth. Knowledge of these patterns is critical for a variety of resource management issues and, until now, only long‐term mean monthly and annual rainfall maps have been available for Hawai‘i. In this study, month‐year rainfall maps from January 1920 to December 2012 were developed for the major Hawaiian Islands. The maps were produced using climatologically aided interpolation (CAI), where the station anomalies were interpolated first, and then combined with the mean maps. A geostatistical method comparison was performed to choose the best interpolation method. The comparison focuses on three kriging algorithms: ordinary kriging (OK), ordinary cokriging (OCK), and kriging with an external drift (KED). Two covariates, elevation and mean rainfall, were tested with OCK and KED. The combinations of methods and covariates were compared using cross‐validation statistics, where OK produced the lowest error statistics. Station anomalies for each month were interpolated using OK and combined with the mean monthly maps to produce the final month‐year rainfall maps.

Remembering Lili‘uokalani: Coverage of the Death of the Last Queen of Hawai‘i by Hawai‘i’s English-Language Establishment Press and American Newspapers

Remembering Lili‘uokalani:Coverage of the Death of the Last Queen of Hawai‘i by Hawai‘i’s English-Language Establishment Press and American Newspapers Douglas V. Askman (bio) Introduction: The Death of Liliu‘okalani On November 11, 1917, Lili‘uokalani, the last monarch of Hawai‘i, died at her residence, Washington Place, in Honolulu at the age of 79. The queen’s death and burial were covered extensively by the press in Hawai‘i, reflecting the enormous impact she had on the people of the territory. On the front page of the Pacific Commercial Advertiser on the day following her death was a declaration from the territorial governor, Lucius Pinkham. In his statement Governor Pinkham attested to Lili‘uokalani’s strong character, “I have found her tender and kind to her own race, thoughtful and helpful to others and a valued and appreciative friend.”1 Pinkham also ordered the flags of the United States and Hawai‘i to be lowered to half-staff in honor of the queen. [End Page 91] Government agencies demonstrated their respect for the queen in various ways, reflecting her great stature. Territorial courts were adjourned, ‘Iolani Palace was draped in black, and the House of Representatives chamber, formerly the palace’s throne room, hosted her funeral. The City and County of Honolulu closed its offices to mourn. Schools, both public and private, honored the queen by preparing special programs and flying their flags at half-staff. Public schools were given a half-day holiday in order for students to pay their respects to the queen, whose body rested in state at Kawaiaha‘o Church for several days prior to her funeral. Indeed, students from over half a dozen public schools marched in procession from Thomas Square to the church on November 16. From just one of those schools, St. Louis College in Honolulu, today St. Louis School, 900 students paid their respects to the former monarch. The Advertiser reported that in the course of just one day approximately 15,000 people passed through the church.2 The American military paid tribute to Lili‘uokalani as well. Soldiers from Schofield Barracks and Fort Shafter took part in the queen’s funeral as did other officials from the army, navy, and national guard companies from all of the major Hawaiian islands. The soldiers’ duties included not only marching in the funeral procession, but providing a twenty-one gun salute for the queen.3 Numerous local organizations also paid tribute to the former sovereign through official resolutions. These included the Honolulu Chamber of Commerce, the Japanese Chamber of Commerce, and the Honolulu Board of Supervisors. Indeed, members of the Japanese Chamber of Commerce, the Japanese Association of Hawai‘i, and the United Chinese Society marched in the funeral procession.4 The queen’s honorary pall bearers included the governor of Hawai‘i, chief justice of the territory, the president of the Hawai‘i senate, the speaker of the territorial house of representatives, officials of the American army and navy, a United States senator, and a member of the United States House of Representatives. Also in the funeral procession were other members of Congress, including senators and representatives from Montana, Utah, Kansas, Pennsylvania, New York, Massachusetts, Ohio, West Virginia, Minnesota, and Maine. Local representatives included members of the territorial legislature, the Hawai‘i Supreme Court, the mayor of Honolulu, and members of the Honolulu and Hawai‘i county boards of supervisors.5 [End Page 92] There was even an international component to the events surrounding the queen’s death. For example, on November 15, while the body of the queen rested in state at Kawaiaha‘o Church, Viscount Kikujiro Ishii, a special representative of the emperor of Japan who was traveling through Hawai‘i, visited the church and paid his official respects. Moreover, a contingent of several hundred Japanese sailors from the imperial navy participated in the queen’s funeral procession. In particular, a Japanese naval officer carried Lili‘uokalani’s Order of the Precious Crown of Japan, an award that was presented to the queen during her reign by the Japanese emperor. Also participating in the funeral were consuls representing Belgium, Denmark, Italy...

Trends in precipitation extremes and return levels in the Hawaiian Islands under a changing climate

Trends of annual maximum 1-day precipitation in three major Hawaiian Islands are investigated using a nonparametric Mann-Kendall method and Sen's test (MKS). The records are from 24 stations on Oahu, Maui, and Hawaii, and the period of analysis ranges from 1960 to 2009. To complement the MKS method, a non-stationary three- parameter generalized extreme value (GEV) distribution is also used to detect trends in precipitation extremes. Both methods demonstrate that negative trends prevail for Oahu and Maui but positive trends dominate the Island of Hawaii. The influence of the location and the scale parameter in the GEV model on different return levels (2-year, 20-year, and 100-year) are explicitly described. The return-level threshold values are found to change with time considerably. As a result, a rare storm with daily precipitation of 300 mm (20-year return period) in 1960 has become a rather common storm event (3-5-year return period) in 2009 on the Island of Hawaii. The opposite trend behavior in extreme events is observed on Oahu and Maui, where rainfall extremes have become less frequent in the last five decades. A positive relationship is found between the precipitation extremes and Southern Oscillation Index (SOI), implying greater extreme events during La Ni˜ na years and the opposite for El Niyears.

Feral Pig Control in Hawaii: Evolution of Control Methods

Author(s): Wittenmyer, Caleb; Quitazol, Francis | Abstract: The Nature Conservancy (TNC) of Hawaii manages preserves on all of the major Hawaiian Islands, effectively protecting over 36,000 acres. Through the development of partnerships, TNC has fostered and cared for over 200,000 acres of watershed lands throughout the state. Hawaii’s native forests evolved without the presence of large mammals. In Hawaii, there are only 2 native species of mammals: the Hawaiian hoary bat and the Hawaiian monk seal. The historical lack of large native mammals has left Hawaiian native forests vulnerable, unable to evolve defenses and recover from damage caused by feral pigs and other feral ungulates. Feral pig control in Hawaii is challenging because of the remoteness of the rainforest locations with diverse topography and constantly changing weather conditions. These challenges, among others, have forced managers to integrate and utilize many different methods of control in order to maintain zero-tolerance levels within TNC preserves and throughout the managed watershed areas.

Changes in Precipitation Extremes in the Hawaiian Islands in a Warming Climate

Abstract For the first time, trends of five climate change indices related to extreme precipitation events in the Hawaiian Islands are investigated using daily observational records from the 1950s to 2007. Four indices [simple daily intensity index (SDII), total number of day with precipitation ≥25.4 mm (R25), annual maximum consecutive 5-day precipitation amount (R5d), and the fraction of annual total precipitation from events exceeding the 1961–90 95th percentile (R95p)] describe the intensity (SDII), frequency (R25), and magnitude (R5d and R95p) of precipitation extremes, and the fifth index [consecutive dry days (CDD)] describes drought conditions. The annual probability density functions (PDFs) of precipitation indices for two epochs (i.e., 1950–79 and 1980–2007) are analyzed. Since the 1980s, there has been a change in the types of precipitation intensity, resulting in more frequent light precipitation and less frequent moderate and heavy precipitation intensity. The other three precipitation-related indices (R25, R5d, and R95p) demonstrate a shift toward the left of the distribution over time, suggesting shorter annual number of days with intense precipitation and smaller consecutive 5-day precipitation amounts and smaller fraction of annual precipitation due to events exceeding the 1961–90 95th percentile in the recent epoch relative to the first epoch. The changes of PDF distribution for SDII, R25, R5d, and CDD are significant at the 5% level according to a two-sample Kolmogorov–Smirnov test. A nonparametric trend analysis is then performed for four periods, with different starting years (e.g., the 1950s, the 1960s) but the same ending year (2007). Long-term downward trends are evident for four precipitation-related indices, and long-term upward trends are observed for CDD. Geographically, Kauai and Oahu are dominated by long-term decreasing trends for four precipitation-related indices, while increasing trends play the major role over the island of Hawaii. The upward trends of drought conditions in the long run are predominant on all the major Hawaiian Islands. To investigate whether the trends are stable throughout the time, the derivatives of trends for each of the 30-yr running series are calculated (e.g., 1950–79, 1951–80, … , 1978–2007) for four precipitation-related indices at each station. For Kauai and Oahu, positive derivatives prevail for all indices in the presence of long-term negative trends, suggestive of a phase change in precipitation extremes and such extremes showing an upswing recently. For the island of Hawaii, there is also an indication of phase reversal over the last 60 yr, with negative derivatives occurring in the presence of the background positive trends. A positive relationship is found between the precipitation indices and the Southern Oscillation index (SOI), implying more precipitation extremes during La Niña years and vice versa for El Niño years. Spatial patterns of standardized anomalies of indices are presented for the La Niña/−PDO minus El Niño/+PDO composites.

Assessment of wave energy resources in Hawaii

Hawaii is subject to direct approach of swells from distant storms as well as seas generated by trade winds passing through the islands. The archipelago creates a localized weather system that modifies the wave energy resources from the far field. We implement a nested computational grid along the major Hawaiian Islands in the global WaveWatch3 (WW3) model and utilize the Weather Research and Forecast (WRF) model to provide high-resolution mesoscale wind forcing over the Hawaii region. Two hindcast case studies representative of the year-round conditions provide a quantitative assessment of the regional wind and wave patterns as well as the wave energy resources along the Hawaiian Island chain. These events of approximately two weeks each have a range of wind speeds, ground swells, and wind waves for validation of the model system with satellite and buoy measurements. The results demonstrate the wave energy potential in Hawaii waters. While the episodic swell events have enormous power reaching 60 kW/m, the wind waves, augmented by the local weather, provide a consistent energy resource of 15–25 kW/m throughout the year.

Kahoolawe Island, Hawaii: The role of an ‘inaccessible’ shield volcano in the petrology of the Hawaiian islands and plume

Kahoolawe volcano (∼10×17 km) forms one of the eight major Hawaiian islands. Access for geologic sampling has long been restricted due to military and preservation policies. However, limited visits to Kahoolawe in the 1980s yielded >200 samples, many of which have since been used to study the volcano within the framework of Hawaiian shield and mantle source geochemistry, petrology, mineralogy, and igneous processes. Kahoolawe is a tholeiitic shield with tholeiitic caldera-filling lavas, and at least seven postshield vents that erupted tholeiitic and (sparse) alkalic lavas. On smaller scales are a gabbro intrusion and ultramafic and gabbroic xenoliths in some postshield lavas. There is no evidence for rejuvenated volcanism. In its structural setting, Kahoolawe lies along the “Loa” trend of Hawaiian shields. Major element compositions of shield and caldera-filling lavas are similar and cluster at ∼6–7 wt% MgO, range from ∼5.5 to 16 wt% MgO, and include ∼9 wt% MgO examples that can be modeled as parental to the evolved lavas. For example, least squares mass balancing demonstrates that from ∼15% to 30% crystallization of olivine (±orthopyroxene), clinopyroxene, and plagioclase accounts for the ∼5.5–6 wt% MgO range of tholeiitic lavas. Greater differentiation occurred in the gabbro (diabasic) intrusive body as a segregation vein with ∼2.9 wt% MgO, and extreme differentiation produced local, small-volume rhyolitic melts that segregated into lava vesicles. Postshield lavas are mainly tholeiitic, have ∼5–7 wt% MgO, and overlap shield compositions. Some are alkalic, as low as ∼3.9 wt% MgO (hawaiite), and can be modeled as liquids after a ∼9 wt% MgO alkalic magma crystallized ∼30% olivine, clinopyroxene, plagioclase, and magnetite. Important aspects of Sr, Nd, Hf, and Pb isotopic ratios in Kahoolawe shield and caldera-filling lavas are slightly higher 87Sr/ 86Sr than in Koolau shield lavas (Oahu island; Makapuu-stage; e.g., Koolau mantle ‘endmember’) when compared at a given 143Nd/ 144Nd (e.g., ∼0.7042 at 0.5128), 206Pb/ 204Pb largely at the low end of the range for Hawaiian shields (e.g., ∼18), and ε Hf generally comparable to the values of other Hawaiian shields and ocean islands (e.g., ε Hf 8 at ε Nd 4). The isotopic ratios overall suggest small-scale source heterogeneity, considering the island size, and that Kahoolawe shield and caldera lavas were derived from a Hawaiian plume source containing recycled oceanic crust of gabbro and sediments. Based on certain geochemical indicators, however, such as Ce/Sr and La/Nb vs. 87Sr/ 86Sr, the source contained slightly less gabbro component than other shield sources (e.g., Koolau). Isotopic data for Kahoolawe postshield lavas are scarce, but those available generally overlap the shield data. However, ratios among certain alteration-resistant incompatible trace elements (e.g., Zr/Nb) discriminate some postshield alkalic from shield lavas. But because the different ratios for those postshield lavas can be explained by smaller partial-melting percentages of the shield source and by differentiation, neither isotopes nor trace elements identify postshield magmas as originating in a source unlike that for the shield lavas.

First Report of Bamboo Rust Caused by Kweilingia divina on Bambusa domestica in Los Angeles County, California

Elongate, interveinal, hypophyllous lesions were observed on bamboo plants (Bambusa domestica) during an inspection of a plant shipment in November of 2006 in Los Angeles County, CA. Disease incidence was 100%. Minute uredinia were spaced at regular intervals within each lesion. Urediniospores were pale tan, echinulate, and 18 to 29 × 16 to 23 μm with 1- to 1.5-μm walls. The urediniospores were surrounded and partially covered by incurved pale-to-brownish yellow paraphyses 34 to 45 × 12 μm with walls that were primarily thickened apically and dorsally to 5 μm. Several telia were observed forming inside old uredinia. Telia were brownish black, forming a flabellar head of teliospores fused laterally and in chains of three to six cells. Teliospores were chestnut brown, cuboidal to oblong, and measured 10 to 12.5 × 12.5 to 25 μm. DNA sequence of the 28S large subunit nuclear ribosomal DNA was obtained using previously published methods (1). The sequence deposited in GenBank as Accession No. EF192212 matched sequence No. DQ354554 (1), Kweilingia divina from Costa Rica (1), with 100% identity. On the basis of morphological characteristics (2) and sequence information, the rust was identified as K. divina (Syd.) Buriticá (= Dasturella divina (Syd.) Mundk. & Khesw.), causal agent of bamboo rust. Bamboo rust is widespread in parts of Asia but has also been found in Africa, Colombia, Brazil, Central America (3), and Australia (4). The shipment was traced to a foliage plant producer in Hawaii where the disease was subsequently found in the environment on the four major Hawaiian Islands of Oahu, Hawaii, Kauai, and Maui. All 10 bamboo plants received by the nursery were located and destroyed. To the best of our knowledge, this is the first report of bamboo rust occurring in California.

Development and characterization of microsatellite markers for analysis of population differentiation in the tree legumeAcacia koa(Fabaceae: Mimosoideae) in the Hawaiian Islands

The aim of this research was to develop and use microsatellite markers to characterize the high-value timber tree Acacia koa (koa), which is endemic to the Hawaiian Islands. Genomic DNA fragments of 300-1000 bp were cloned and sequenced following enrichment for microsatellite motifs by PCR using 7 oligonucleotide repeat primers in separate reactions. Among 96 sequences analyzed, 63 contained unique microsatellite motifs flanked by variable sequences. A dual PCR method involving a primer walking step was used to develop 15 primer pairs. Another 16 primer pairs were developed directly from the variable sequences on both sides of the microsatellite motifs. These 31 primer pairs were tested on 172 koa plants representing 11 populations collected from 4 of the major Hawaiian Islands. Nine of the primers that identified polymorphic microsatellite loci and 3 that detected unique alleles exclusively in some populations were used for genetic diversity studies of koa. Cluster analysis and multidimensional scaling of the allelic phenotype data revealed that koa from Kauai formed a distinct group separate from koa of the neighboring islands of Oahu, Maui, and Hawaii. The oldest of the four islands, Kauai, also had the most diverse populations of koa.

A climatological study of the Keetch/Byram drought index and fire activity in the Hawaiian Islands

The Hawaiian Islands experience damaging wildfires on a yearly basis. Soil moisture or lack thereof, influences the amount and flammability of vegetation. The Keetch and Byram drought index (KBDI) estimates the amount of soil moisture by tracking daily maximum temperatures and rainfall. For the first time, the relationship between the KBDI and fire activity on the Hawaiian Islands is examined using a number of different techniques. The KBDI is calculated daily for a 20-year period and then tested on a monthly time-scale on four major Hawaiian Islands against total area burned (TAB). The use of monthly TAB data for an individual island is a necessity when considering the relatively low frequency of fire activity and the small spatial scale of the islands. The relationship between the KBDI with TAB is explored with a number of rigorous statistical methods. A strong relationship between the KBDI and fire activity for the islands of Oahu, Maui, and Hawaii is found. At present a network of stations is used to operationally monitor fire danger on a daily basis.

Hawaiian biogeography and the islands’ freshwater fish fauna

AbstractAim This paper describes known patterns in the distributions and relationships of Hawaiian freshwater fishes, and compares these patterns with those exhibited by Hawaii's terrestrial biota.Location The study is based in Hawaii, and seeks patterns across the tropical and subtropical Indo‐west Pacific.Methods The study is based primarily on literature analysis.Results The Hawaiian freshwater fish fauna comprises five species of goby in five different genera (Gobiidae). Four species are Hawaiian endemics, the fifth shared with islands in the western tropical Pacific Ocean. All genera are represented widely across the Indo‐west Pacific. All five species are present on all of the major Hawaiian islands. All five species are amphidromous – their larval and early juvenile life being spent in the sea. Although there has been some local phyletic evolution to produce Hawaiian endemics, there has been no local radiation to produce single‐island endemics across the archipelago. Nor is there evidence for genetic structuring among populations in the various islands.Main conclusions In this regard, the freshwater fish fauna of Hawaii differs from the well‐known patterns of local evolution and radiation in Hawaiian Island terrestrial taxa. Amphidromy probably explains the biogeographical idiosyncrasies of the fish fauna – dispersal through the sea initially brought the fish species to Hawaii, and gene flow among populations, across the archipelago, has hitherto inhibited the evolution of local island endemics, apparently even retarding genetic structuring on individual islands.