Geology topics

Seth W. Judge

Publications and source records attributed to Seth W. Judge.

8 recordsLinked to original sources

USGS2018

Population estimates of the Endangered Hawaiʻi ʻĀkepa (Loxops coccineus) in different habitats on windward Mauna Loa

Endangered Hawai‘i ʻĀkepas ( Loxops coccineus ) are endemic to Hawai‘i island, where they occur in five spatially distinct populations. Data concerning the status and population trends of these unique Hawaiian honeycreepers are crucial for assessing the effectiveness of recovery and management actions. In 2016, we used point‐transect distance sampling to estimate the abundance of Hawai‘i ʻĀkepas in portions of Hawai‘i Volcanoes National Park (HAVO) and the Kaʻū Forest Reserve (KFR) on Mauna Loa volcano. We then compiled the survey data from four other populations to provide a global population estimate. In our HAVO and KFR study area, we mapped habitat classes to determine the population densities in each habitat. Densities were highest (1.03 birds/ha) in open‐canopy montane ʻōhiʻa ( Metrosideros polymorpha ) woodland. In contrast, densities of the largest ʻĀkepa population on Mauna Kea volcano were highest in closed‐canopy ʻōhiʻa and koa ( Acacia koa ) forest where the species is dependent on nest cavities in tall (> 15 m), large (> 50‐cm diameter at breast height) trees. We surveyed potential nesting habitat in HAVO and KFR and found only one cavity in the short‐stature montane ʻōhiʻa woodland and five cavities in the tall‐stature forest. Differences in densities between the Mauna Kea and Mauna Loa populations suggest that Hawai‘i ʻĀkepas may exhibit different foraging and nesting behaviors in the two habitats. The estimated overall population density in the HAVO and KFR study area was 0.52 birds/ha, which equates to 3663 (95% CI 1725–6961) birds in their 11,377‐ha population range. We calculated a global population of 16,428 (95% CI 10,065–25,198) birds, which is similar to an estimate of 13,892 (95% CI 10,315–17,469) birds made in 1986. Our results suggest that populations are stable to increasing in the two largest populations, but the three other populations are smaller (range = 77–1443 birds) and trends for those populations are unknown.

Hawai'i↗

USGS2016

Changes in habitat use and distribution of mouflon in the Kahuku Unit of Hawai‘i Volcanoes National Park

European mouflon sheep ( Ovis gmelini musimon ) were introduced to Kahuku Ranch on Hawai‘i Island in 1968 and 1974 for trophy hunting and have been detrimental to the native ecosystem by trampling, bark stripping, and browsing vegetation. In 2003, Hawai‘i Volcanoes National Park acquired Kahuku Ranch and managers began removing mouflon. The objective of this project was to determine whether hunting has changed the distribution of mouflon in Kahuku, to better understand mouflon behaviour and to expedite eradication efforts. Locations from hunting and GPS telemetry data during 2007–14 were used to determine the effect of hunting on mouflon distribution by examining distance to roads and habitat use. Mouflon seemed to avoid roads after hunting pressure increased and their distribution within vegetation types changed over time. Mouflon without hunting pressure were detected in native shrub habitat in 68% of all observations. Hunted mouflon were encountered less in native shrub habitat and more in other habitats including open forest, closed forest, and areas with no vegetation. These changes suggest that hunting has influenced the distribution of mouflon over time away from native shrub and into other vegetation types where they may be more difficult to control.

Hawai‘i↗

USGS2016

Evaluating detection and monitoring tools for incipient and relictual non-native ungulate populations

Hawai‘i Volcanoes National Park (HAVO) encompasses 1,308 km2 on Hawai‘i Island. The park harbors endemic plants and animals which are threatened by a variety of invasive species. Introduced ungulates have caused sharp declines of numerous endemic species and have converted ecosystems to novel grazing systems in many cases. Local ranchers and the Territorial Government of Hawai‘i had long conducted regional ungulate control even prior to the establishment of HAVO in 1916. In 1995 the park’s hunting team began a new hunt database that allowed managers to review hunt effort and effectiveness in each management unit. Target species included feral pigs (Sus scrofa), European mouflon sheep (Ovis gmelini musimon), feral goats (Capra hircus) and wild cattle (Bos taurus). Hunters removed 1,204 feral pigs from HAVO over a 19-year period (1996‒2014). A variety of methods were employed, but trapping, snaring and ground hunts with dogs accounted for the most kills. Trapping yielded the most animals per unit effort. Hunters and volunteers removed 6,657 mouflon from HAVO; 6,601 of those were from the 468 km2 Kahuku Unit. Aerial hunts yielded the most animals followed by ground hunt methods. Hunters completed eradications of goats in several management units over an 18- year period (1997‒2014) when they removed the last 239 known individuals in HAVO primarily with aerial hunts. There have also been seven cattle and five feral dogs (Canis familiaris) removed from HAVO. Establishing benchmarks and monitoring the success of on-the-ground ungulate removal efforts can improve the efficiency of protecting and restoring native forest for high-priority watersheds and native wildlife. We tested a variety of methods to detect small populations of ungulates within HAVO and the Hō‘ili Wai study area in the high-priority watershed of Ka‘ū Forest Reserve on Hawai‘i Island. We conducted ground surveys, aerial surveys and continuous camera trap monitoring in both fence-enclosed units and unenclosed units where populations of introduced mouflon and feral pigs threatened sensitive native plants and forest bird habitats. Beginning in June 2014, twenty infrared camera traps were positioned in areas occupied by ungulates. The cameras were active for at most 198 days, and then half of the cameras were baited with oats and salt blocks for 126 days. There were a total of 1,496 observations of mouflon captured on camera, totaling 2,592 individuals: 1,020 ewes, 900 rams, 276 lambs, and 396 sheep of unknown sex. There were no detections of the illegally introduced axis deer (Axis axis). There were 11 observations of feral pigs and 109 observations of other animals (birds, rats, and other small mammals), including one detection of the federally endangered Hawaiian hawk (Buteo solitarius). Mouflon detection rates did not increase near baited cameras until three months after the initial baiting. Ground-based surveys for ungulate presence were conducted along six transects in Kahuku in October 2014. Evidence of ungulates were detected in 27.5% of plots surveyed within an unenclosed unit, while an enclosed unit had sign in only 3.6% of plots surveyed. An aerial survey by helicopter was conducted in October 2014. A total of 378 mouflon were detected during the survey: 192 in the Kahuku Paddocks, 186 in the Kahuku East unit and no mouflon were detected in the actively controlled Mauka unit. Two baseline ungulate surveys have been completed at the Hō‘ili Wai study area in the highpriority watershed of Ka‘ū Forest Reserve adjacent to Kahuku prior to the completion of an exclusionary ungulate fence. Ground-based surveys were conducted on four transects within a 4.99 km2 area on 5 August and 5–6 November 2014. In August, 20.71% of 565 plots surveyed 2 had fresh or intermediate ungulate sign. In November, 17.41% of 557 plots surveyed had fresh or intermediate ungulate sign. These surveys represent baseline levels of ungulate activity prior to management; therefore comparative inferences can be made about ungulate distribution and relative abundance, but inferences about absolute abundance cannot be made until all ungulates have been removed from the enclosed area. Additional ground-based surveys will be conducted when the fenced area has been fully enclosed, and until ungulate removals have been completed.

Hawaii↗

USGS2016

Abundance, distribution, and removals of feral pigs at Big Island National Wildlife Refuge Complex 2010–2015

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/km 2 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.

Hawaii↗

USGS2013

Pacific island landbird monitoring annual report, National Park of American Samoa, Ta‘u and Tutuila units, 2011

The National Park of American Samoa (NPSA) was surveyed for landbirds and habitat characteristics from June through August, 2011. This information provides the first data in the time-series of landbird monitoring for long-term trends in forest bird distribution, density, and abundance within the NPSA. The NPSA survey area was comprised of the terrestrial portions of the Ta‘u and Tutuila Units. Each Unit was surveyed using point-transect distance sampling to estimate bird abundance. Sampling was conducted using a split-panel design where legacy transects are visited during each sampling occasion and newly, randomly located transects are visited only during one sampling occasion. This design optimizes trend detection while allowing for measuring and correcting for estimator bias. A total of 2,516 birds was detected from 13 species in both Units. All species were either endemic or indigenous to the islands of American Samoa. Numbers of detections ranged from 7 to 1,111. Nearly every species detected was broadly distributed in the predominantly native forests of NPSA. Sufficient detections were made of seven species, allowing for density estimation. Densities of species were higher in the Tutuila Unit; with the exception of the Wattled Honeyeater ( Foulehaio carunculata ), which was the most abundant species in both Units. The species occurred at nearly every station sampled and had densities much higher than the Samoan Starling ( Aplonis atrifusca ), Polynesian Starling ( Aplonis tabuensis ), and Collared Kingfisher ( Halcyon chloris ) which occurred in modest densities. The remaining species detected occurred at less than 20% of stations sampled and we were only able to determine the number of birds per station and percent occurrence. The White-rumped Swiftlet ( Aerodramus spodiopygius ) and Cardinal Honeyeater ( Myzomela cardinalis ) were detected in small numbers, but both species can be difficult to detect in closed canopy forests. The Purple Swamphen ( Porphyrio porphyrio ) and Banded Rail ( Gallirallus philippensis ) were most often detected in areas close to villages and agroforestry plantations. The Blue-crowned Lorikeet ( Vini australis ) and Fiji Shrikebill ( Clytorhynchus vitiensis ) only occur in the Manu‘a Island Group. The former was detected in most survey areas and the latter was patchily distributed in the Ta‘u Unit. The Many-colored Fruit-dove ( Ptilinopus perousii ), a species of concern, was detected in very small numbers in both Units. The Spotless Crake ( Porzana tabuensi ), which is extirpated on Tutuila Island, has been incidentally detected in small numbers on Ta‘u Island. However, the species was neither seen nor heard during this survey and remains a species of concern. NPSA canopy and understory composition was predominantly native, and trees formed a dense closed canopy at nearly 90% of the stations sampled. More than half of the tree heights in both units were taller than 5 m and the majority of slopes were steeper than 20 degrees. There were no clear dominant tree species in the mixed native forests. The most common tree species documented included Syzygium spp., Dysoxylum spp., Ficus spp., Hibiscus tiliaceus and Rhus taitensis (among others). There were significant differences in the distribution of bird densities between legacy and random transects. Determining differences in detection probabilities cannot be definitively assessed from a single survey. We recommend both panels be sampled in the future until bias in density and abundance can be evaluated, or if sampling may be reduced.

American Samoa;National Park Of American Samoa↗

USGS2013

Pacific Island landbird monitoring annual report, Haleakalā National Park, 2012

Haleakalā National Park (HALE) was surveyed for landbirds and habitat characteristics from March 20 through July 26, 2012. This information provides data in the time-series of landbird monitoring for long-term trends in forest bird distribution, density, and abundance. The Kīpahulu District of eastern Haleakalā Volcano was surveyed using point-transect distance sampling to estimate bird abundance. We surveyed 160 stations and detected a total of 2,830 birds from 12 species. Half of the species were native and half were non-native. Numbers of detections per species ranged from 1 to 849. There were sufficient detections of seven species to allow density estimation. Āpapane ( Himatione sanguinea ) was the most widely distributed and abundant native species detected in the survey. ‘Alauahio ( Paroreomyza montana newtoni ), Maui ‘Amakihi ( Hemignathus virens wilsoni ), and I‘iwi ( Vestiaria coccinea ) were widespread and occurred in relatively modest densities. Only eight Kiwikiu ( Pseudonestor xanthophrys ) and 20 ‘Ākohekohe ( Palmeria dolei ) were detected and were restricted to high elevation wet forest. We estimated an abundance of 495 ± 261individuals of Kiwikiu in a 2,036 ha inference area which likely includes the entire suitable habitat for this species in HALE. For ‘Ākohekohe, we estimated an abundance of 1,150 ± 389 individuals in the 1,458 ha inference area. There was a strong representation of non-native landbirds in the survey area. The Japanese White-eye ( Zosterops japonicus ), Japanese Bush-warbler ( Cettia diphone ), and Red-billed Leiothrix ( Leiothrix lutea ) accounted for nearly half of all landbird detections. Each species was common in predominantly native forests. Vegetation and topographic characteristics were recorded on 160 landbird monitoring stations. HALE canopy and understory composition was predominantly native, especially at elevations above 1,100 m. Much of the forest canopy was comprised of `ohi`a ( Metrosideros polymorpha ) interspersed with mature olapa ( Cheirodendron platyphyllum ). This canopy class occurred at 92.5% of the stations surveyed. More than three-quarters (77.5%) of the monitoring stations had a dense canopy with most crowns interlocking (> 60% cover). More than half (52%) of the stations surveyed had trees taller than 10 m, while almost a third (31%) had trees 5-10 m. Only 17% of the stations had a canopy shorter than 5 m. The native shrubs Vaccinium calycinum , Broussaisia arguta , and Leptecophylla tameiameae were the most common understory plants recorded, occurring at more than 30% of the stations sampled. Native mosses and ferns were also common at stations, occurring at more than 90% of the stations sampled. The invasive Psidium cattleainum , Clidemia hirta , and Hedychium gardnerianum occurred at approximately 14% of the stations sampled, predominantly at elevations below 1,100 m.

Hawai'i↗

USGS2012

Reoccurrence of 'Ōma'o in leeward woodland habitat and their distribution in alpine habitat on Hawai'i island

The endemic solitaire, 'Oma'o (Myadestes obscurus), is common in windward forests of Hawai'i Island, but has been historically extirpated from leeward forests. The last detections of 'Oma'o on the leeward side of the island were in woodland habitat on the western flank of Mauna Loa in 1978. 'Oma'o were detected in woodland habitat in relatively low densities during a 2010 forest bird survey of Hawai'i Volcanoes National Park. The source of the population is unknown. It is probable they originated from a documented but unsurveyed population of 'Oma'o in scrub alpine lava. Alternatively, the birds may have persisted undetected for nearly 35 years, or expanded from windward mesic forests on southeast Mauna Loa. There is no evidence 'Oma'o recolonized the wet mesic forests of leeward Mauna Loa. The 'Oma'o can occupy diverse native habitats compared to other species in the Hawai'i Myadestes genus, of which most species are now extinct. The connectivity of each population is not understood but we assume there are significant geographic, physiological, and behavioral barriers for scrub alpine and wet mesic forest populations. The expansion of 'Oma'o to leeward woodlands is encouraging as the species is Hawai'i Island's last native frugivore capable of dispersing small and medium sized seeds of rare angiosperms, and could have an important role in re-establishing ecosystem function.

Hawaii↗

USGS2012

Birds in Hawai'i Volcanoes National Park: Summary of the 2010 inventory and monitoring program survey

The National Park Service (NPS) created the Inventory and Monitoring (I&M) Program in 1998 to establish baseline information and assess long-term trends in "vital signs" or key abiotic and biotic elements of National Parks (Fancy et al. 2009). The Pacific Island Network of the I&M Program developed a Landbirds Monitoring Protocol (LMP; Camp et al. 2011) to estimate species-specific status and monitor longterm trends in landbird distribution and abundance. Parks included in the LMP that harbor habitat critically important to native forest birds are Haleakala National Park (Maui Island), Hawai'i Volcanoes National Park (HAVO; Hawai'i Island), and the National Park of American Samoa (American Samoa). In 2010, the LMP was implemented in HAVO to survey landbird density and abundance. This implementation was the first anywhere in the Pacific Islands by the I&M Program, and continued monitoring is planned every five years in all three parks.

Hawai'i↗