Browsing by Author "Nash, Sarah"
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Item Avian monitoring entry form version 2.1 Hawai`i forest bird inter-agency database project(2016-01-25) Camp, Richard; Lam, Roger; Matsui, Victoriya; Cramer, Ashley; Pratt, Thane; Woodsworth, Bethany; Gorressen, P. Marcos; Nash, SarahFrom 1976–1981, the U.S. Fish and Wildlife Service conducted systematic surveys of forest birds and plant communities on the main Hawaiian Islands as part of the Hawaii Forest Bird Surveys (HFBS; Scott et al. 1986) Since the HFBS, more than 600 surveys of forest birds have been conducted in Hawai`i a variety of organizations, including the National Park Service, U.S. Fish and Wildlife Service, U.S. Forest Service, Hawai`i Department of Land and Natural Resources, Kamehameha Schools, University of Hawai`i, The Nature Conservancy, and private consultants. Prior to the initiation of the present project, these surveys were scattered among many different individuals and agencies, and most had never been entered into a computer, analyzed, or reported. These survey data represent a phenomenal informational resource that has not previously been widely available. The Hawai`i Forest Bird Interagency Database Project (HFBIDP) has as its goals to make these data usable and accessible by creating a centralized, standardized database of all forest bird surveys collected since the HFBS; develop current population size estimates, species-habitat models, and distribution maps for all native and exotic forest birds in Hawai`i; examine population trends in species of concern; and present these results in publications and on a webpage, making them available to cooperators throughout Hawai`i.Item Nihoa and Laysan Island passerines population abundances, trends, and habitat utilization(2024-06-18) Bak, Trevor; Camp, Richard; Farmer, Chris; Rounds, Rachel; Plentovich, Sheldon; Vetter, John; Banko, Paul; Nash, SarahNihoa and Laysan Island, part of the Northwestern Hawaiian Islands, are host to three endangered passerine species—Nihoa finch (Telespiza ultima), Nihoa millerbird (Acrocephalus familiaris kingi), and Laysan finch (Telespiza cantans). Using point-transect distance sampling survey records from 2010 to 2022 for Nihoa and 2013 to 2019 for Laysan Island, we estimated the density and abundance of all three species. We also compared densities between habitats for both islands, classifying Nihoa habitat as Eragrostis (grass) or mixed shrub and Laysan Island as open or dense habitat. The population of Nihoa finch remained stable with slight fluctuations among years, with a population size of 6,592 (4,954–8,655) birds for the most recent sampling year, 2022. Laysan finch also remained stable with a total population in both dense and open habitat of 17,657 (11,994–23,320) for the most recent sampling year, 2019. The Nihoa millerbird significantly increased on both Nihoa and Laysan Island with a global population of 1,907 (1,291–2,766) in 2019, the most recent year both islands were sampled. Overall, the populations of these three endangered species were stable or increasing. The increase of Nihoa millerbird on Laysan Island, after being translocated to the island in 2011 and 2012, represents the successful establishment of a second viable population, leading to a decrease in the species’ IUCN extinction risk status (from critically endangered to endangered). Continued population monitoring of these endangered species can help inform future management actions and ensure their preservation into the future.Item Peregrine Falcon predation of endangered Laysan Teal and Laysan Finches on remote Hawaiian atolls.(2015) Reynolds, Michelle; Nash, Sarah; Courtot, KarenWe report the first records of Peregrine falcon (Falco peregrinus) predation on endangered Laysan teal (or duck; Anas laysanensis) and predation on endangered Laysan finches (Telespiza cantans). At Midway Atoll, vagrant Peregrine falcons killed ≥4% of a newly translocated Laysan teal population in 2006 and ≥2% in 2008. On Laysan Island during 2008–2009, remains of >76 Laysan finches (<1% of the population) were found at peregrine perches. On Midway Atoll, all depredated Laysan teal and other seabirds were recovered at kill sites on tarmac (runways). If the frequency or duration of vagrant raptors visitation increases at small atolls, this could pose a mortality risk to consider, especially during proposed translocations of endangered species.Vegetation restoration of abandoned runways near wetlands at Midway Atoll would provide cover and may help reduce mortality of endangered species due to vagrant raptors.Item Photographic guide to the leaf litter arthropod community of the lowland wet forest ecosystem of the Island of Hawaiʻi(University of Hawai'i at Hilo, 2025-05-29) Hall, Trebor; Peck, Robert; Robins, Anuhea; Munstermann, Maya; Ostertag, Rebecca; Sebastián González, Esther; DiManno, Nicole; Cordell, Susan; Banko, Paul; Nash, SarahLeaf litter arthropods are important components of the food web in forests, and their presence and diversity can provide information on forest health. There has been very little documentation of the leaf litter arthropods in Hawaiian forest ecosystems. This technical report is a photographic guide to some common arthropods collected from forest leaf litter at the Liko Nā Pilina Hybrid Ecosystems Project study site, a lowland wet forest in Hilo, Island of Hawaiʻi, USA. Leaf litter samples were collected from plots of invaded and experimental restoration communities using two complementary methods (litterbags and quadrats), and arthropods were extracted using Berlese funnels. The field site contained many morphospecies that were rare and locally distributed across plots, and only a few that were very common and widely distributed. The majority of the morphospecies identified were mites. This photoguide is designed to help identify arthropods found in plant litter in Hawaiian lowland forests and it may assist with research and education efforts concerned with the diversity, ecology, or conservation of litter arthropods across the Hawaiian archipelago and other Pacific islands.Item Status and trends of forest bird populations at Hakalau Forest National Wildlife Refuge, 1987–2024(University of Hawai'i at Hilo, 2025-06-10) Hunt, Noah J.; Kendall, Steven J.; Bak, Trevor M.; Camp, Richard J.; Nash, SarahSince 1985, the Hakalau Forest Unit of the Big Island National Wildlife Refuge Complex (hereafter, Hakalau) has protected the largest endemic forest bird diversity in the State of Hawaii. This includes three endangered and one threatened species and their habitats. Hakalau’s vast area (155 km2), mostly high elevation (>1500 m) montane forest, provides refuge from avian malaria (Plasmodium relictum) vectored by introduced southern house mosquitoes (Culex quinquefasciatus). However, increases in the seasonal temperatures optimal for disease carrying mosquitoes associated with climate change have coincided with recent downward trends of native species in the closed forest area of the refuge (1450–1750 m), where disease is most likely to occur. Therefore, to inform refuge management with the most updated information on these populations and their trends, we analyzed forest bird survey data collected using point transect distance sampling with new survey data from 2021–2024. We stratified our analysis across management units, including the open forest and pasture since 1987, and the closed forest since 1999, and across four elevation ranges (<1500, 1500–1700, 1700–1900, and >1900 m) since 1999. We used distance sampling to estimate species- and strata-specific abundances and applied log-linear regression to detect trends across the timeseries. We found a continuation of previous trends, wherein most native forest birds declined in the closed forest strata (mostly below 1700 m) and increased in the highest elevation and pasture strata. Patterns were highly species-specific for the three lower elevations and open forest strata. ‘Apapane (Himatione sanguinea) and warbling white-eye (Zosterops japonicus), the most abundant native and introduced bird species, respectively, increased in nearly all strata. ‘I‘iwi (Drepanis coccinea) and Hawai‘i ‘amakihi (Chlorodrepanis virens virens), also common, decreased in closed forest, were stable in open forest, and increased in pasture. Both species were generally stable or increasing across all elevation bands, except Hawaiʻi ʻamakihi decreased in the below 1500 m and the 1500–1700 m elevation bands. All three of the federally endangered forest bird species declined in closed forest. Hawai‘i ‘ākepa (Loxops coccineus) also declined in the open forest and 1700–1900 m band and was the only species to decline overall. ‘Akiapōlā‘au (Hemignathus wilsoni) declined in closed forest but increased overall. ‘Alawī (Loxops mana, also known as Hawai‘i creeper) also decreased in the closed forest, but was stable to increasing in most strata and remained stable overall. Hawaiʻi ʻelepaio (Chasiempis sandwichensis) declined in closed forest, was stable in open forest and most elevation strata, and increased in pasture. ʻŌmaʻo (Myadestes obscurus) was stable in open and closed forest and at middle elevations and increased in the pasture. Introduced red-billedleiothrix (Leiothrix lutea) declined in closed forest, was stable in the open forest and at most elevations, and increased in the pasture. Coinciding with these changes, seasonal conditions for vector occurrence have continued to lengthen in the lower elevation strata through 2024, while Hakalau’s outplanting efforts continued to increase forest cover in the pasture, suggesting that disease-free habitat may have decreased in the closed forest and increased in the pasture. The declines in the closed forest and mixture of trends in the open forest and middle elevations bands suggest emigration into the higher elevation strata from lower elevation strata, and that possible threats have suppressed forest birds even at elevations >1500 m.Item Wake Atoll: Evaluation of plant biosecurity(University of Hawai'i at Hilo, 2025-06-08) Yanger, Corie M.; Jacobi, James D.; Yelenik, Stephanie G.; Hathaway, Stacie A.; Nash, SarahIntroduced organisms can cause substantial effects across most landscapes. Island ecosystems, especially tropical islands, are at elevated risk from introduced organisms. The risks are even higher for tropical islands with moderate or high levels of transit, yet this can be minimized by application of appropriate biosecurity requirements. In this study, we examined the potential for non-native plant species introductions, especially invasive plants, via shipping containers to be transported to Wake Atoll, one of the most remote terrestrial land masses in the Pacific Ocean. We sowed debris collected from 30 shipping containers in a greenhouse experiment to determine if any live plants could be germinated, identify any species that germinated, and ascertain if they posed a threat if they were to be transported to Wake Atoll and became established there. During this study 23 plant species were identified, including ferns, monocots, and dicots. Fifteen of these species reached reproductive maturity over the course of seven months. From previous plant surveys on the atoll, we know that 13 of the 23 identified species were not previously recorded, and four species are already known to be invasive on Wake Atoll. This study provides insight into the potential for debris found in shipping containers to contribute to the spread of non-native, possibly invasive species. This information may help with the refinement of biosecurity strategies to prevent the accidental introduction of invasive species into sensitive natural areas such as Wake Atoll.