Hawaii Cooperative Studies Unit (HCSU)

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2011 Kiwikiu (Maui Parrotbill) and Maui `alauahio abundance estimates and the effect of sampling effort on power to detect a trend.
(2016-01-25) Brinck, Kevin; Camp, Richard; Gorressen, P. Marcos; Leonard, David; Mounce, Hanna; Iknayan, Kelly; Paxton, Eben
The Kiwikiu (Pseudonestor xanthophrys), also called the Maui Parrotbill, is an endangered, forest bird found only in high elevation, wet forest of the eastern portion of Maui Island. Recent surveys, conducted at five year intervals, have revealed wide variation in abundance estimates (Camp et al. 2009). Effective management and conservation requires accurate estimates of abundance, which is difficult for rare species such as the Kiwikiu because low density leads to few observations, resulting in low sample size and high uncertainty in abundance estimates. In addition to being rare, they occur in remote, difficult to access terrain, which makes them difficult to detect and further reduces the accuracy of counts. The Maui `Alauahio (Paroreomyza montana), sometimes called the Maui Creeper, historically occupied the entire island of Maui (Gorresen et al. 2009). It has since been extirpated from much of its original habitat and now occurs in forested areas of East Maui where its habitat overlaps with that of the Kiwikiu. Though they share the same habitat, the `Alauahio is much more abundant—by more than two orders of magnitude—and occurs over a wider range than the Kiwikiu. Both species appear to have no statistically significant population trend from 1980–2001, but abundance estimates vary widely from survey to survey and have wide uncertainties (Camp et al. 2009). Ideally survey design should result in estimates precise enough to be able to detect significant declines in abundance that may trigger management intervention. We wished to improve the accuracy of Kiwikiu abundance estimates and the ability to detect significant trends in abundance. To that end, in 2011, repeated point count surveys were conducted across the Kiwikiu range, excluding Haleakalā National Park (Figure 1). The increased sampling effort increases sample size and improves the precision of estimates, and repeat samples also allowed us to partition within-year and between-year variation in surveys, increasing the statistical power to detect trends.
2015-2016 Palila abundance estimates
(2016-05-29) Camp, Richard J.; Brinck, Kevin W.; Banko, Paul C.
The palila (Loxioides bailleui) population was surveyed annually during 1998−2016 on Mauna Kea Volcano to determine abundance, population trend, and spatial distribution. In the latest surveys, the 2015 population was estimated at 852−1,406 birds (point estimate: 1,116) and the 2016 population was estimated at 1,494−2,385 (point estimate: 1,934). Similar numbers of palila were detected during the first and subsequent counts within each year during 2012−2016; the proportion of the total annual detections in each count ranged from 46% to 56%; and there was no difference in the detection probability due to count sequence. Furthermore, conducting repeat counts improved the abundance estimates by reducing the width of the confidence intervals between 9% and 32% annually. This suggests that multiple counts do not affect bird or observer behavior and can be continued in the future to improve the precision of abundance estimates. Five palila were detected on supplemental survey stations in the Ka‘ohe restoration area, outside the core survey area but still within Palila Critical Habitat (one in 2015 and four in 2016), suggesting that palila are present in habitat that is recovering from cattle grazing on the southwest slope. The average rate of decline during 1998−2016 was 150 birds per year. Over the 18-year monitoring period, the estimated rate of change equated to a 58% decline in the population.
2017-2018 Palila abundance estimates and trend
(2018-12-25) Genz, Ayesha S.; Brinck, Kevin W.; Camp, Richard J.; Banko, Paul C.
The palila (Loxioides bailleui) population was surveyed annually from 1998–2018 on Mauna Kea Volcano to determine abundance, population trend, and spatial distribution. In the latest surveys, the 2017 population was estimated at 1,177−1,813 birds (point estimate: 1,461) and the 2018 population was estimated at 778−1,420 (point estimate: 1,051). Only two palila were detected outside the core survey area during a mountain-wide survey in 2017, suggesting that most, if not all, palila inhabit the western slope during the annual survey period. Since 1998, the size of the area containing palila detections on the western slope did not show a significant change, suggesting that the range of the species has remained stable; although this area represents only about 5% of its historical extent. During 1998−2003, palila numbers fluctuated moderately (coefficient of variation [CV] = 0.20). After peaking in 2003, population estimates declined steadily through 2011; since 2010, estimates have continued to decline at a slower rate. The average rate of decline during 1998−2018 was 168 birds per year with very strong statistical support for an overall declining trend in abundance. Over the 21-year monitoring period, the estimated rate of change equated to a 76% decline in the population.
2018 Kaua'i forest bird population estimates and trends
(2020-11-11) Paxton, Eben H.; Brinck, Kevin W.; Crampton, Lisa H.; Hite, Justin; Costantini, Maria
Kaua‘i's native forest birds have experienced steep declines since the beginning of systematic surveys in 1981, and declines have accelerated in recent decades. This report details the analysis of the most recent surveys conducted in 2018. Incorporating the new survey results, long-term trends continue to show sharp declines for all native honeycreeper species with the exception of ‘apapane (Himatione sanguinea), which has stable numbers in core areas of its range. Kaua‘i ‘elepaio (Chasiempis sclateri) continued to decline in the outer portions of its range but increased in the core areas of its range. Abundance estimates of forest birds ranged from slightly higher to slightly lower in most species, indicating a relatively stable period from 2012–2018, and a pause from the rapid declines seen in earlier periods. Many native species now exist in very low numbers, and variation in estimates from survey to survey will increase.
2019–2021 Palila abundance estimates and trend
(2022-01-24) Genz, Ayesha S.; Brinck, Kevin W.; Asing, Chauncey K.; Berry, Lainie; Camp, Richard J.; Banko, Paul C.
The palila (Loxioides bailleui) population on Mauna Kea Volcano, Hawai‘i Island, was estimated from annual surveys in 2019−2021, and a trend analysis was performed on survey data from 1998−2021. The 2019 population was estimated at 1,030−1,899 birds (point estimate: 1,432), the 2020 population was estimated at 964−1,700 birds (point estimate: 1,312), and the 2021 population was estimated at 452−940 birds (point estimate: 678). Since 1998, a visual inspection of the size of the area containing palila detections on the western slope based on the minimum/maximum elevations has not shown a substantial change, indicating that the range of the species has remained stable; although this area represents only about 5% of its historical extent. During 1998−2005, palila numbers fluctuated between 4,000 and 6,000, followed by a steep decline. After 2010, palila estimates stabilized around an abundance of 2,000 with a much slower rate of decline. The decline during 1998−2021 was on average 229 birds per year with very strong statistical support for an overall downward trend in abundance. Over the 23-year monitoring period, the estimated rate of change equated to an 89% decline in the population.
2021 Tinian Island forest bird abundance estimates
(2022-05-26) Camp, Richard J.; Bak, Trevor; Genz, Ayesha S.
The U.S. Navy, through Micronesian Environmental Services, surveyed landbirds in the Military Lease Area on Tinian Island in May and June 2021 using point-transect distance sampling methods. There were 2,074 individuals of 14 species detected during 123 point counts. Six species were detected during >50% of the counts and were observed at relatively high abundances, while eight species occurred at <50% of the counts and were uncommon to rare. Densities of native landbirds in the Military Lease Area ranged from the uncommon Mariana kingfisher (Todiramphus albicilla) at 0.46 birds/ha (95% confidence interval [CI] = 0.33–0.63) to the very abundant bridled white-eye (Zosterops conspicillatus) at 102.63 birds/ha (95%CI = 86.70–122.91). Most distances recorded during the 2021 Military Lease Area survey were rounded to distance intervals of 0 and 5. Measuring exact distances of detected animals is preferable to collecting distances grouped into bins or rounding. Direct comparison with previously published estimates was not possible because of changes in the sampling frame; however, densities of six species were greater, two were smaller, and one was similar to the 2008 survey estimates for the Hagoi, Diablo, and Masalog regions. Our findings indicate that the landbird community in the Military Lease Area appears to be dynamic and resilient.
A baseline analysis of the distribution, host range, and severity of the rust Puccinia psidii in the Hawaiian Islands, 2005-2010.
(2016-01-25) Anderson, Robert
Puccinia psidii was first described by Winter (1884) on guava (Psidium guajava L.) in Brazil. The rust is still a major pest of native guava in Brazil and is often referred to as “guava rust” internationally. It is unusual among rust fungi because of its broad and ever-expanding host-range within the Myrtaceae plant family (Simpson et al. 2006). The pathogen is regarded as a major threat to Eucalyptus plantations and other Myrtaceae worldwide (Coutinho et al. 1998, Grgurinovic et al. 2006, Glen et al. 2007). Infections of leaves and meristems are particularly severe on susceptible seedlings, cuttings, young trees, and coppice, causing plants to be stunted and multi-branched, inhibiting normal growth and development, and sometimes causing death to young seedlings (Booth et al. 2000, Rayachhetry et al. 2001). The fungus has expanded its host-range in Brazil, affecting both native and introduced Myrtaceae (Coutinho et al. 1998). Since its discovery in 1884, P. psidii has continually been discovered to have an expanding host-range within the Myrtaceae, affecting hosts throughout much of South and Central America and the Caribbean. Spreading out originally from Brazil in 1884, the fungus has been reported on hosts in the following countries (first record in parentheses): Paraguay (1884), Uruguay (1889), Ecuador (1891), Colombia (1913), Puerto Rico (1913), Cuba (1926), Dominican Republic (1933), Venezuela (1934), Jamaica (1936), Argentina (1946), Dominica (1948), Trinidad and Tobago (1951), Guatemala (1968), United States (Florida; 1977), Mexico (1981), El Salvador (1987), and Costa Rica (1998) (Simpson et al. 2006). It is possible that P. psidii was present in El Salvador and Costa Rica prior to 1980, but was not reported until 1987 and 1998, respectively. Until recently, Puccinia psidii was restricted to the Neotropics, Mexico, and the state of Florida in the United States. While the rust has been present in Florida for over 30 years, only recently has it spread westward. Although possibly present earlier, P. psidii was found in California in November 2005 in a nursery in San Diego County on Myrtus communis and documented by a report in a nursery newsletter (Mellano 2006). Puccinia psidii was first found in Hawai`i on a young plant of `ōhi`a (Metrosideros polymorpha) in April 2005, in a nursery on the island of O`ahu (Killgore and Heu 2005; Uchida et al. 2006). The fungus subsequently spread to most islands of the Hawaiian chain, infecting `ōhi`a and other myrtaceous hosts (Hauff 2006, Anderson et al. 2007). P. psidii was first found in Japan in May 2007 on cultivated `ōhi`a (Kawanishi et al. 2009). Most recently, a rust identified as Uredo rangelii was discovered in April 2010 in New South Wales, Australia (Carnegie et al. 2010). This rust is closely related to Puccinia psidii and is part of the guava rust complex described by Simpson et al. (2006). Although treated as a separate species by Simpson et al. (2006), many authors now consider U. rangelii a synonym for U. psidii, which is the anamorph (asexual stage) of P. psidii, and therefore, the same species (Glen et al. 2007, Carnegie et al. 2010). Because of the large diversity of native Myrtaceae present in Australia, the number of Myrtaceae hosts attacked by species of the guava rust complex will likely grow now that U. rangelii has arrived and is spreading in the country. As of this writing (June 2011), 94 species of Myrtaceae have been identified as hosts of U. rangelii in the states of New South Wales and Queensland. Damage is severe on nearly one-third of the species affected, and 16 of these species are threatened or endangered native species (Secretary of Australia, May 2011). The presence of Puccinia psidii in Hawai`i is particularly alarming for at least two reasons: (1) M. polymorpha is the dominant overstory tree of the native forest, and (2) P. psidii is now established in the Pacific region, where numerous Myrtaceae species are native. Native ecosystems in Hawai`i and the Pacific could be seriously affected by the spread of P. psidii, as both native and introduced Myrtaceae are significant components of many different plant communities throughout the region (Glen et al. 2007). Because the guava rust complex (i.e., P. psidii and U. rangelii) now attacks well over 100 species of Myrtaceae worldwide, it is currently a priority for international quarantine and import restrictions in an effort to prevent further spread among Australasian and Pacific Myrtaceae. Several different studies have been done to determine what degree of genetic variation exists between isolates of Puccinia psidii from many different host plants and many different locations (Langrell et al. 2008, Kawanishi et al. 2009, Kadooka 2010, Graça et al. 2011). So far, all of these studies have shown that all of the Hawaiian samples tested so far have had the same genetic composition. Given that the P. psidii strain in Hawai`i has continually been shown for over five years to lack genetic variation at microsatellite marker sites (which are believed to undergo relatively rapid genetic change), a baseline evaluation of incidence and severity should be especially valuable to provide comparisons with future conditions. Worldwide, 23 Neotropical species in 11 genera and 59 Australasian and Pacific species in 13 genera had been recorded as hosts of Puccinia psidii before 2010 (Simpson et al. 2006, Anderson et al. 2007). Of those 82 species known to be hosts elsewhere, 42 are cultivated or naturalized in Hawai`i. Because of its wide host-range and aggressive pathogenicity, rust disease caused by P. psidii poses a considerable disease threat to many native and cultivated Myrtaceae throughout the world (Coutinho et al. 1998, Booth et al. 2000, Simpson et al. 2006). However, there are few reports comparing the severity of rust infection on native, introduced, and cultivated Myrtaceae (Rayachhetry et al. 2001, Perez et al. 2010). Since government agencies and the public are concerned about the extent of the rust movement within and to Hawai`i (Loope and La Rosa 2008, Loope 2010), there is a need to better understand the incidence, severity, and distribution of P. psidii in Hawai`i. To address that need, this research project was initiated to survey forests, surrounding plant communities, botanical gardens, and commercial nurseries to detect the presence and severity of P. psidii rust infections throughout Hawai`i on plants in the Myrtaceae family. This study provides a baseline on the host distribution and severity to compare current and future impacts of rust infections caused by P. psidii on native, naturalized, and cultivated Myrtaceae in Hawai`i.
A five-year study of Hawaiian hoary bat (Lasiurus cinereus semotus) occupancy on the island of Hawai`i
(2016-01-25) Gorressen, P. Marcos; Bonaccorso, Frank; Pinzari, Corinna; Todd, Christopher; Montoya-Aiona, Kristina; Brinck, Kevin
Using acoustic recordings of the vocalizations of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus) collected over a five-year period (2007–2011) from 25 survey areas across the island of Hawai`i, we modeled the relationship between habitat attributes and bat occurrence. Our data support the conclusion that hoary bats concentrate in the coastal lowlands of Hawai`i during the breeding season, May through October, and migrate to interior highlands during the winter non-breeding season. Highest occupancy peaked on the Julian date 15 September across the five-year average and during the season of fledging by the young of the year. Although the Hawaiian hoary bat is a habitat generalist species and occurs from sea level to the highest volcanic peaks on Hawai`i, there was a significant association between occupancy and the prevalence of mature forest cover. Trends in occupancy were stable to slightly increasing during the breeding season over the five years of our surveys.
A landscape-based assessment of climate change vulnerability for all native plants.
(2016-01-25) Fortini, Lucas; Price, Jonathan; Jacobi, James; Vorsino, Adam; Burgett, Jeff; Brinck, Kevin; Amidon, Fred; Miller, Steve; Gon III, Sam; Koob, Gregory; Paxton, Eben
In Hawaiʽi and elsewhere, research efforts have focused on two main approaches to determine the potential impacts of climate change on individual species: estimating species vulnerabilities and projecting responses of species to expected changes. We integrated these approaches by defining vulnerability as the inability of species to exhibit any of the responses necessary for persistence under climate change (i.e., tolerate projected changes, endure in microrefugia, or migrate to new climate-compatible areas, but excluding evolutionary adaptation). To operationalize this response-based definition of species vulnerability within a landscape-based analysis, we used current and future climate envelopes for each species to define zones across the landscape: the toleration zone; the microrefugia zone; and the migration zone. Using these response zones we calculated a diverse set of factors related to habitat area, quality, and distribution for each species, including the amount of habitat protection and fragmentation and areas projected to be lost to sea-level rise. We then calculated the probabilities of each species exhibiting these responses using a Bayesian network model and determined the overall climate change vulnerability of each species by using a vulnerability index. As a first iteration of a response-based species vulnerability assessment (VA), our landscape-based analysis effectively integrates species-distribution models into a Bayesian network-based VA that can be updated with improved models and data for more refined analyses in the future. Our results show that the species most vulnerable to climate change also tend to be species of conservation concern due to non-climatic threats (e.g., competition and predation from invasive species, land-use change). Also, many of Hawaiʽi’s taxa that are most vulnerable to climate change share characteristics with species that in the past were found to be at risk of extinction due to non-climatic threats (e.g., archipelago endemism, single-island endemism). Of particular concern are the numerous species that have no compatible-climate areas remaining by the year 2100. Species primarily associated with dry forests have higher vulnerability scores than species from any other habitat type. When examined at taxonomic levels above species, low vulnerabilities are concentrated in families and genera of generalists (e.g., ferns or sedges) and typically associated with mid-elevation wet habitats. Our results replicate findings from other regions that link higher species vulnerability with decreasing range size. This species VA is possibly the largest in scope ever conducted in the United States with over 1000 species considered, 319 of which are listed as endangered or threatened under the U.S. Endangered Species Act, filling a critical knowledge gap for resource managers in the region. The information in this assessment can help prioritize species for special conservation actions, guide the management of conservation areas, inform the selection of research and monitoring priorities, and support adaptive management planning and implementation.
A rapid diagnostics test and mobile "Lab-in-a-suitcase" platform for detecting Ceratocystis spp. responsible for rapid `Ōhi`a death
(2017-04-23) Atkinson, Carter T.; Watcher-Weatherwax, William; Roy, Kylle; Heller, Wade P.; Keith, Lisa M.
We describe a field compatible molecular diagnostic test for two new species of Ceratocystis that infect `ōhi`a (Metrosideros polymorpha) and cause the disease commonly known as Rapid `Ōhi`a Death. The diagnostic is based on amplification of a DNA locus within the internal transcribed spacer region that separates fungal 5.8S ribosomal genes. The assay uses forward and reverse primers, recombinase polymerase, and a fluorescent probe that allows isothermal (40oC) amplification and simultaneous quantification of a 115 base pair product with a battery operated fluorometer. DNA extractions are field compatible and can be done by heating wood drill shavings to 100oC in Instagene® solution containing Chelex® resin to bind potential amplification inhibitors. The initial heat treatment is followed by a short bead beating step with steel ball bearings and zirconium beads to release DNA. DNA is subsequently purified with a magnetic bead based extraction method that does not require silica columns or centrifugation. The assay is designed around a portable “lab-in-a-suitcase” platform that includes a portable fluorometer, miniature centrifuge, and heat block that operate off either 120V AC power sources or a 12 volt battery with a portable inverter, a magnetic rack designed for 1.5 ml tubes and magnetic bead DNA purification, pipettes and consumable reagents and tubes. The entire assay from DNA extraction to results can be performed in less than 90 minutes on up to six independent samples plus a positive and negative control. Sensitivity based on suspensions of Ceratocystis endoconidia (spores) that were added to wood shavings and processed under field conditions by Instagene® magnetic bead DNA extraction was up to 163 spores/mg wood for Species A and 55 spores/mg wood for Species B in 95% of replicates as determined by probit analysis. Sensitivity increased 5–10 fold to 19 spores/mg wood for Species A and 9 spores/mg wood for Species B when extractions were performed with a commercial, silica column based DNA purification kit. The test did not cross react with other common fungi that have been isolated from `ōhi`a.
A Test of Sex Specific Genetic Markers in the Hawaiian Hoary Bat and Relevance to Population Studies
(2018-10-14) Pinzari, Corinna A.; Bonaccorso, Frank J.
We tested the utility of a protocol using genetic markers that previously proved successful to identify the sex of Vespertilionid bats on tissues collected from live bats and carcasses of varying age from the Hawaiian hoary bat (Lasiurus cinereus semotus). This molecular method is based on genes unique to X and Y chromosomes in mammals and previously was used successfully on North American hoary bats (L. c. cinereus). We amplified two markers within intron regions of the zinc-finger-X (Zfx) and zinc-finger-Y (Zfy) genes using a multiplexed polymerase chain reaction technique and obtained product bands that were easily visualized using gel electrophoresis. Genotyping determined the sex of 36 individual Hawaiian hoary bat carcasses previously assigned sex only by external genitalia and identified sex for 29 “unknown” bat carcasses that could not be classified by external genitalia. Employing this method for sexing Hawaiian hoary bats will permit more reliable evaluation of the ratio of males to females in subpopulations affected by fatalities from emerging threats. This is critical to the conservation and management of this endangered bat.
Abundance and distribution of feral pigs at Hakalau Forest NWR, 2010-2013
(2016-01-25) Hess, Steven; Leopold, Christina; Kendall, Steve
The Hakalau Forest Unit of the Big Island National Wildlife Refuge Complex has intensively managed feral pigs (Sus scrofa) and monitored feral pig presence with surveys of all managed areas since 1988. Results of all available data regarding pig management activities through 2004 were compiled and analyzed, but no further analyses had been conducted since then. The objective of this report was to analyze recent feral ungulate surveys at the Hakalau Forest Unit to determine current pig abundance and distribution. Activity indices for feral pigs, consisting of the presence of fresh or intermediate sign at 422 stations, each with approximately 20 sample plots, were compiled for years 2010–2013. A calibrated model based on the number of pigs removed from one management unit and concurrent activity surveys was applied to estimate pig abundance in other management units. Although point estimates appeared to decrease from 489.1 (±105.6) in 2010 to 407.6 (±88.0) in 2013, 95% confidence intervals overlapped, indicating no significant change in pig abundance within all management units. Nonetheless, there were significant declines in pig abundance over the four-year period within management units 1, 6, and 7. Areas where pig abundance remained high include the southern portion of Unit 2. Results of these surveys will be useful for directing management actions towards specific management units.
Abundance, distribution, and population trend of the Hawaiian Hawk; 1998-2007.
(2008-04) Gorresen, P. Marcos; Camp, Richard J.; Klavitter, John L.; Pratt, Thane K.
The current population size and distribution of the endemic Hawaiian Hawk (or`Io in Hawaiian, Buteo solitarius) on Hawai`i Island was determined as part of a reevaluation of the species’ endangered status. Locations originally sampled in 1998 were resurveyed in 2007 with variable circular plot (VCP) count methods to produce habitat-specific estimates of density and assess trends in abundance. In addition, we developed a method for correcting density estimates for the unobserved movement of hawks attracted to call playbacks. We estimated that the 5,755 km2 breeding range harbored 3,239 hawks (95% CI = 2,610 to 3,868) in 1998 and 3,085 hawks (95% CI = 2,496 to 3,680) in 2007. No significant difference in densities was found among years at either regional or island-wide scales. However, pooled 1998 and 2007 densities did show significant differences among habitats and regions. Our 1998 and 2007 population estimates are as much as twice that of previous estimates, and we discuss reasons for this including differences among studies in the accuracy of distance estimation, accounting for unobserved hawk movement, and the extent of area used for the extrapolation of mean densities. The Hawaiian Hawk appears to persist as a viable population well-distributed throughout forest and adjacent habitats on Hawai`i Island. However, with a population comprised of about 3,000 individuals confined to a single island, the species is vulnerable to the effects of human-caused change to its habitat base.
Abundance, distribution, and removals of feral pigs at Big Island National Wildlife Refuge Complex 2010-2015.
(2016-03) Leopold, Christina R.; Hess, Steven C.; Kendall, Steve J.; Judge, Seth W.
The Hakalau Forest Unit (HFU) of Big Island National Wildlife Refuge Complex (BINWRC) has intensively monitored non-native ungulate presence and distribution during surveys of all managed areas since 1988. In this report we: 1) provide results from recent ungulate surveys and the number of removals at HFU to determine the distribution, abundance, and efficacy of removals of feral pigs, the dominant ungulate, from 2010 to 2015; 2) present results of surveys of the presence and distribution of several ungulate species at the Kona Forest Unit (KFU) of BINWRC from November of 2012 to April of 2015; 3) present results of surveys of weed presence and cover at both refuge units; and 4) present comparative analyses of forest canopy cover at KFU from visual estimates and geospatial imagery. Removals of feral pigs at HFU appear to have significantly decreased pig abundance over the study period from 2010–2015. A grand total of 1,660 feral pigs were removed from managed areas of HFU from 2010 until September of 2015. Management units 2 and 4 contained the majority of pigs at HFU. Recent surveys recorded high densities of pigs in the unenclosed, unmanaged area of Lower Maulua, reaching 14.9 ± (3.2) pigs/km2 in March of 2015. The total amount of ungulate sign ranged from 22.2 to 54.3 percent of plots surveyed at KFU from November of 2012 to April of 2015. The ability to differentiate sign of ungulate species remains problematic at KFU; although there appears to have been a significant decline in feral cattle sign at KFU, this result is likely to be unreliable because cattle and pig sign were not differentiated consistently during later surveys. Spatial distributions in weed cover are distinctive; however, some weed species may not be reliably represented due to observers’ inconsistencies in recording data and abilities to recognize less common weeds.
Acoustic surveys of Hawaiian hoary bats in Kahikinui Forest Reserve and Nakula Natural Area Reserve on the island of Maui
(2016-07-08) Todd, Christopher M.; Pinzari, Corinna A.; Bonaccorso, Frank J.
The Kahikinui Forest Reserve and the adjoining Nakula Natural Area Reserve (KFR-NNAR) was established in 2011 as a conservation area on the leeward slope of Haleakalā Volcano on the island of Maui to protect unique natural features and endangered species including the Hawaiian hoary bat, Lasiurus cinereus semotus. We recorded bat vocalizations from July 2012 to November 2014 using automated echolocation detectors at 14 point locations in the KFR-NNAR. Our study area included remnants of recovering mesic montane forest with interspersed grasses (1,250‒1,850 m elevation, hereafter called “forest”) and xeric subalpine shrubland plant communities (1,860‒2,800 m, hereafter called “shrubland”). Monthly detections of Hawaiian hoary bats, Lasiurus cinereus semotus, within the KFR-NNAR identified areas of high and low detection probability as well as foraging activity. Sixty per cent of all detector-nights had confirmed bat vocalizations and included detections in every month of the study. Monthly detection probability values were highest from July to November 2012; these values were significantly greater than values measured in any month thereafter. Pooled values of detection probabilities, mean pulses/night, percentage of nights with feeding activity, and acoustic detections all were greater in the recovering forest zone than corresponding values from the shrublands. Our data provide baseline levels of hoary bat echolocation activity that may be compared with future studies in the KFR-NNAR relative to success criteria for Hawaiian hoary bat habitat restoration.
Aging and sexing guide to the forest birds of Hawai`i Island
(2016-12-12) Paxton, Eben H.; McLaughlin, Rachelle; Levins, Stephanie; Vanderwerf, Eric; Lancaster, Nolan
We banded birds in Hakalau Forest National Wildlife Refuge from 2012 to 2016, collecting photographs of birds and making detailed observations on coloration, morphology, and molting patterns. While we believe the criteria in this guide are applicable to forest birds across Hawai’i Island, as well as on other Hawaiian islands for ‘Apapane, ‘I‘iwi, and Hawai‘i ‘Amakihi, certain characteristics such as morphometrics may vary across populations, and users should verify the guide’s criteria with other available field data.
An assessment of arthropod prey resources at Nakula Natural Area Reserve, a potential site of reintroduction for kiwikiu (Pseudonestor xanthophrys) and Maui alauahio (Paroreomyza montana)
(2016-01-21) Peck, Robert; Banko, Paul; Cappadonna, Justin; Steele, Claire; Leonard, David; Mounce, Hanna; Becker, C. Dusti; Swinnerton, Kirsty
Hawaiian forest birds have declined dramatically since humans arrived in the archipelago. Birds from all foraging guilds have been affected but insectivorous species are currently at greatest risk of extinction. On the island of Maui, populations and ranges of the insectivorous kiwikiu (Maui parrotbill; Pseudonestor xanthophrys) and Maui ‘alauahio (Maui creeper; Paroreomyza montana) have declined significantly from historic levels primarily due to habitat loss, predation, disease, and food web disruption, leading to federal listings of endangered species and species of concern, respectively. Recovery plans for these birds include reestablishment of populations in parts of their former range. Nakula Natural Area Reserve on the leeward side of Haleakalā Volcano has been targeted for release of wild-caught or captive-bred individuals. The mesic, montane koa-‘ōhi‘a (Acacia koa-Metrosideros polymorpha) forest at Nakula has been heavily impacted through grazing by feral ungulates, but recent management actions to exclude these animals are promoting forest recovery. The objective of this study was to assess the arthropod prey base at Nakula in preparation for reintroductions of kiwikiu and Maui ‘alauahio. To accomplish that goal, we compared arthropod abundances at Nakula to those at Hanawi Natural Area Reserve and Waikamoi Preserve, areas where kiwikiu and Maui ‘alauahio are currently found. We also identified diets of kiwikiu and Maui ‘alauahio from fecal samples to better understand and evaluate the prey base at Nakula. Assessment methods included clipping branch tips to sample arthropods within the foliage of koa and ‘ōhi‘a, using traps to quantify arthropods on koa and ‘ōhi‘a bark surfaces, counting exit holes to quantify abundances of beetles (Coleoptera) within dead branches of koa, and measuring the density of arthropods within the stems of ‘ākala (Rubus hawaiiensis). The diet of kiwikiu was dominated by caterpillars (Lepidoptera larvae), which comprised 90% of all prey items for 50 adult birds and 98% of all prey for two nestlings. Caterpillars were also the most important prey for Maui ‘alauahio (43% for 104 adult birds) although spiders (Araneae, 16%), beetles (12%) and true bugs, planthoppers and psyllids (Hemiptera; 12%) were also important. Caterpillars were generally the most abundant type of arthropod in the foliage of koa and ‘ōhi‘a, although spiders, beetles and hemipterans were also common. Total arthropod biomass and caterpillar biomass at Nakula was as great, or greater, than that observed at Hanawi and Waikamoi per unit of foliage of both koa and ‘ōhi‘a. Spiders generally dominated the bark fauna on both koa and ‘ōhi‘a at all sites although isopods (Isopoda), millipedes (Myriapoda: Millipeda) and lacewings (Neuroptera) were also abundant at Waikamoi and Hanawi. Total arthropod biomass on bark, as well as the biomass of several individual taxa, was significantly lower at Nakula than the other sites. Our measurement of the density of beetle exit holes in dead koa branches found no difference between Nakula and Waikamoi. Finally, no difference existed in the abundance of arthropods (primarily caterpillars and moth pupae) within ‘ākala stems among sites. With the exception of bark surfaces, our results suggest that the arthropod prey base for birds on primary foraging substrates at Nakula is similar to that found at two sites within the current range of kiwikiu and Maui ‘alauahio. However, our results should be viewed with caution because they are limited to the scale of individual branch, tree, or ‘ākala stem. To complete the assessment, our results should be scaled up to the landscape level by determining the density of each substrate within each site. Key arthropod prey of kiwikiu and Maui ‘alauahio are available at Nakula and, as habitat restoration continues, food abundance should increase to the point at which populations of these birds can be supported.
Ants of the National Park of American Samoa.
(2016-01-06) Peck, Robert; Banko, Paul
American Samoa makes up the eastern end of the Samoan Archipelago. On the islands of Tutuila, Taʽū and Ofu, the National Park of American Samoa (NPSA) protects about 4,000 ha of coastal, mid-slope and ridge-top forest. While the ant fauna of the Samoan Archipelago is considered relatively well documented, much of NPSA has never been surveyed for ants, leaving the fauna and its distribution poorly known. To address this shortfall, we systematically surveyed ants within the Tutuila and Taʽū units of NPSA using standard methods (hand collecting, litter sifting, and baits) at 39 sites within six vegetation types ranging from 8 to 945 m elevation. Forty-four ant species were identified, 19 of which are exotic to the Samoan Archipelago. Two notoriously aggressive species, Anoplolepis gracilipes and Pheidole megacephala were detected at two and seven sites, respectively. Both of these species largely excluded all other ants from bait, although their impact on ant community composition is unclear. A suite of habitat variables measured at each site was assessed to explain park-wide ant distributions. Of eight variables evaluated, only elevation was associated with ant community structure, as the ratio of native to exotic ant species increased significantly with elevation on Tutuila. Our survey documented two species not previously reported from American Samoa. Strumigenys eggersi, detected at 12 sites, appears to be a new immigrant to the Pacific Basin. A species of Pheidole was collected that likely represents an undescribed species. Solenopsis geminata, an aggressive species first reported on Tutuila in 2002, was not detected during our survey.
Arial-broadcast application of diphacinone bait for rodent control in Hawai`i: efficacy and non-target species risk assessment
(2015-11) Spurr, Eric B.; Foote, David; Lindsey, Gerald D.; Perry, Charlotte F.
Introduced rats (Rattus rattus, R. exulans, and R. norvegicus) have been implicated in the decline or extinction of numerous species of plants and animals in Hawai‘i. This study investigated the efficacy of aerial-broadcast application of Ramik® Green baits containing 50 ppm (0.005%) diphacinone in reducing rat and mouse populations and the risk to non-target species. The study was undertaken in paired 45.56-ha treatment and non-treatment plots in Hawai‘i Volcanoes National Park. All 21 radio-collared rats in the treatment plot died within nine days of bait application, whereas none of the 18 radio-collared rats in the non-treatment plot died. There was a 99% drop in both the rat capture rate and percentage of non-toxic census bait blocks gnawed by rats in the treatment plot relative to the non-treatment plot three weeks after bait application. The only rat captured in the treatment plot three weeks after bait application was not ear-tagged (i.e., it was not a recapture), whereas 44% of the 52 rats captured in the non-treatment plot were ear-tagged. Most of the bait had disappeared from the forest floor within about one month of application. No birds likely to have eaten bait were found dead, although residues of diphacinone were found in the livers of three species of introduced seed-eating/omnivorous birds captured alive after bait application. No predatory birds were found dead one month or three months after bait application. The remains of a Hawaiian hawk (Buteo solitarius) were found six months after bait application, but it was not possible to determine the cause of death. This study demonstrated the efficacy of aerially broadcast diphacinone bait for control of rats and mice in Hawaiian montane forests, and was part of the dataset submitted to the U.S. Environmental Protection Agency for the national registration of a diphacinone bait for the control of rat populations in conservation areas.
Arthropod community structure on bark of koa (Acacia koa) and `ohi`a (Metrosideros polymorpha)
(2016-01-25) Peck, Robert; Banko, Paul; Stelmach, Matt
The arthropod community associated with tree bark contains a wide variety of taxa but is poorly described, particularly in Hawaiʽi. Our overall goals were to evaluate the abundance of arthropods available to foraging birds and how variation in bark substrates may contribute to arthropod distributions in native forests. Our study aimed to identify this fauna on the dominant canopy-forming trees koa (Acacia koa) and ʽōhiʽa (Metrosideros polymorpha) within wet montane forest at Hakalau Forest National Wildlife Refuge, Hawaiʽi Island. At two sites roughly similar in elevation and habitat structure, we deployed three trap types designed to intercept arthropods moving along bark within tree canopies: a bole trap based on a pre-existing design and two traps specially designed for this study. Bole traps were placed on koa and ʽōhiʽa while branch traps were established on large and small branches of ʽōhiʽa. In total, 15 arthropod orders were identified, with Collembola most abundant (number/trap-day) generally followed by Isopoda and Araneae. Differences in abundance were found in some instances, but overall, few differences were detected between tree species or sites. Relative abundances of arthropod groups were also generally similar between trees and sites and among different parts of ʽōhiʽa. These results indicate that bark-dwelling arthropod communities are similar on koa and ʽōhiʽa, and birds should not develop strong preferences for gleaning arthropods from the bark of either species of tree based on prey availability.

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