Survey for ants on the island of Maui, Hawaii, with emphasis on the little fire ant (Wasmannia auropunctata)

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The little fire ant (LFA), Wasmannia auropunctata, is an aggressive pest ant with a painful sting that has spread to many parts of the world through human commerce. In the State of Hawaii, LFA had been intercepted previously as early as 1930, but only recently, in 1999, were established populations found in the Puna District, on the island of Hawaii (Big Island), occupying residential and agricultural sites, such as fruit orchards and plant nurseries. A single population was found on Kauai in 1999, but it has been contained and nearly eradicated. However, on Hawaii island, LFA is now well established in the Puna/Hilo area, with at least 50 sites covering at least several hundred acres. Even though nursery shipments leaving Hilo are checked for LFA by inspectors of the Hawaii Department of Agriculture, it is likely that LFA-infested shipments have reached Maui. This study surveyed portions of the island of Maui for ants, with a main goal of finding populations of LFA. Since much of the nursery material sent from Hawaii to Maui is promptly planted in new developments, searches were focused on newly developed/landscaped areas. During the survey, over 18,000 ants were collected on 4,300 peanut butter baited chopsticks at 360 sites, resulting in 823 locations with 23 ant species but no LFA. The big-headed ant (Pheidole megacephala) was by far the most abundant ant encountered in the survey and present at 55% of the sampling sites. However, since not all ant species are equally attracted to the peanut butter bait used in this survey, the relative abundance of ant species encountered may be biased, and 12 species of ants previously recorded for Maui were not collected in the survey.Primary funding for the study was from the U.S. Fish and Wildlife Service. Funding was also received from the US Geological Survey, Invasive Species Program

The Haleakala Argentine ant project: a synthesis of past research and prospects for the future

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.1. The Haleakala Argentine Ant Project is an ongoing effort to study the ecology of the invasive Argentine ant in the park, and if possible to develop a strategy to control this destructive species. 2. Past research has demonstrated that the Argentine ant causes very significant impacts on native arthropods where it invades, threatening a large portion of the park’s biodiversity in subalpine shrubland and alpine aeolian ecosystems. 3. Patterns of spread over the past 30+ years indicate that the invasion process is influenced to a substantial degree by abiotic factors such as elevation, rainfall and temperature, and that the ant has not reached its potential range. Predictions of total range in the park suggest that it has only invaded a small fraction of available suitable habitat, confirming that this species is one of most serious threats to the park’s natural resources. 4. Numerous experiments have been conducted since 1994 in an attempt to develop a method for eradicating the Argentine ant at Haleakala using pesticidal ant baits. Thirty baits have been screened for attractiveness to ants in the park, and ten of these were tested for effectiveness of control in field plots. While some of these baits have been very effective in reducing numbers of ants, none has been able to eliminate all nests in experimental plots. 5. Research into a secondary management goal of ant population containment was initiated in 1996. By treating only expanding margins of the park’s two ant populations with an ant pesticide, rates of outward spread were substantially reduced in some areas. While this strategy was implemented from 1997 to 2004, it was ultimately discontinued after 2004 because of the difficulty and insufficient effectiveness of the technique. 6. In order to achieve the types of results necessary for eradication, the project would probably need to explore the possibility of developing a specialized bait, rather than relying on a commercially produced bait. An alternative would be to pursue approval to use Xstinguish bait, a commercial bait manufactured in New Zealand and not registered for use in the US, which has yielded good results against Argentine ants. Either route would involve significant regulatory hurdles. Because the baits ultimately used would likely be liquid or paste in form, there would also be major logistical challenges in devising methods to successfully apply the baits across the two large ant populations at Haleakala.I would like to thank S.M. Joe for help in the field, and the Hawaii Invasive Species Council and Haleakala National Park for funding and logistical support. A. Bernard of Innovative Pest Control Products provided the Gourmet Liquid Ant Bait and made helpful comments on an earlier version of this report. Any use of trade, product, or firm names in this publication is for descriptive purposed only and does not imply endorsement by the U.S. Government

Climatology of Haleakalā

The steep mountain slopes of Haleakalā Volcano (Maui, HI) support some of the most spatially diverse environments on the planet. Microclimates found across vertical gradients on the mountain slopes can change over relatively short differences in slope exposure and elevation and are strongly influenced by a persistent temperature inversion and northeast trade winds that are characteristic of this region. Eleven climate stations, which comprise the HaleNet climate network, have been monitoring climatic conditions along a 2030-m leeward (960 to 2990 m) and a 810-m windward (1650 to 2460 m) elevational transect, beginning as early as June of 1988. Hourly measurements of solar radiation, net radiation, relative humidity, wind speed, temperature, precipitation and soil moisture, and derived variables including potential evapotranspiration, vapor pressure deficit, soil heat flux, and daytime cloud attenuation of sunlight are analyzed in this study. This report documents the annual, diurnal and elevational characteri tics of these climatic variables as well as their behavior over the period-of-record (~1988 to 2013) in both the 6-month dry (May – October) and wet (November to April) seasons. Results show that the climate gradients along both leeward and windward elevation transects are highly influenced by the trade wind inversion in both dry and wet seasons. Period-of-record trends in the dry-season, show increases in energy and decrease in moisture at high elevations (>2000 m). Significant dry season changes include: decreases in precipitation (5 to 8% decade-1), relative humidity (3 to 5% decade-1) and cloud attenuation of sunlight (-2 to -5% decade-1) and increase in solar radiation (2 to 4% decade-1), vapor pressure deficit (9 to 10 % decade-1), zero precipitation days (4 to 5% decade-1) and potential evapotranspiration (3 to 7% decade -1). For the wet season, an opposite signal of change was observed at high elevation although trends were not as robust as the dry season trends. Reported dry season trends are potenti lly explained by a 4% significant increase in TWI frequency identified over a similar observation period (1991-2013). In addition to a climate variable analysis, this report also highlights other past and ongoing research projects that have taken place on the mountain and provides a summary of the history of the HaleNet climate network, the people and organizations that have contributed to its operation, and a list of publications that have made use of HaleNet climate data. It is the authors’ hope that this information will aid resource managers in protecting the ecosystems and other natural resources, and provide insight into ongoing and future climate changes on Haleakalā.The data analysis presented here and the preparation of this report were supported by the acific Island Climate Science Center (PICSC) and the Pacific Island Climate Change Cooperative (PICCC) and the Pacific Island Ecosystem Research Center (PIERC). We also thank Paul Krushelnycky, Shelley Crausbay, Abby Frazier, Henry Diaz, Erica von Allmen, Thomas Schroeder and Ross Sutherland for their contributions to this report. In conducting fieldwork on Maui, the authors were given support, encouragement, and assistance by numerous ndividuals. We extend our gratitude especially to Jotoku and Doris Asato, Dennis Nullet, Bill Minyard, Ryan Mudd, Dave Penn, Ron Nagata, Ted Rodrigues, Timmy Bailey, Matt Brown, Pamela Waiolena, Chuck Chimera, Kathy Wakely, Philip Thomas, and Sabine Jessel. We thank Haleakalā National Park and PIERC, and the USGS, for their long support of the HaleNet system. We owe a special debt of gratitude to Gordon Tribble of PIERC for his unwavering commitment to sustaining HaleNet. We would also like to thank Jeff Burgett of PICCC, Deborah Solis of the U.S. Army Corps of Engineers and Neil Fujii and Jeremy Kimura of the Commission on Water Resource Management. Over the years, HaleNet research has also been supported with funding from the University of Hawai‘i Research Council, the Water Resources Institute Program of the U.S. Geological Survey, the Cooperative National Parks Resources Study Unit, NSF EPSCoR (under award 0903833), and PICCC

Non-Indigenous Bamboo along Headwater Streams of the Luquillo Mountains, Puerto Rico: Leaf Fall, Aquatic Leaf Decay and Patterns of Invasion

The introduction of bamboo to montane rain forests of the Luquillo Mountains, Puerto Rico in the 1930s and 1940s has led to present-day bamboo monocultures in numerous riparian areas. When a non-native species invades a riparian ecosystem, in-stream detritivores can be affected. Bamboo dynamics expected to influence stream communities in the Luquillo Experimental Forest (LEF) were examined. Based on current distributions, bamboo has spread downstream at a rate of 8 m y -1 . Mean growth rate of bamboo culms was 15.3 cm d -1 . Leaf fall from bamboo stands exceeded that of native mixed-species forest by c. 30(k = -0.021), and leaves from another abundant riparian exotic, Syzygium jambos (Myrtaceae) (k = -0.018), decayed at relatively slow rates when submerged in streams in fine-mesh bags which excluded macro-invertebrate leaf processors. In a second study, with leaf processors present, bamboo decay rates remained unchanged (k = -0.021), while decay rates of S. jambos increased (k = -0.037). Elemental losses from bamboo leaves in streams were rapid, further suggesting a change in riparian zone/stream dynamics following bamboo invasion. As non-indigenous bamboos spread along Puerto Rico streams, they are likely to alter aquatic communities dependent on leaf input

Economic analysis of the proposed rule to prevent arrival of new genetic strains of the rust fungus Puccinia psidii in Hawai‘i

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.Since its first documented introduction to Hawai‘i in 2005, the rust fungus P. psidii has already severely damaged Syzygium jambos (Indian rose apple) trees and the federally-endangered Eugenia koolauensis (nioi). Fortunately, the particular strain has yet to cause serious damage to ‘ōhi‘a, which comprises roughly 80% of the state’s native forests and covers 400,000 ha. Although the rust has affected less than 5% of Hawaii’s ‘ōhi‘a trees thus far, the introduction of more virulent strains and the genetic evolution of the current strain are still possible. Since the primary pathway of introduction is Myrtaceae plant material imported from outside the state, potential damage to ‘ohi‘a can be minimized by regulating those high-risk imports. We discuss the economic impact on the state’s florist, nursery, landscaping, and forest plantation industries of a proposed rule that would ban the import of non-seed Myrtaceae plant material and require a one-year quarantine of seeds. Our analysis suggests that the benefits to the forest plantation industry of a complete ban on non-seed material would likely outweigh the costs to other affected sectors, even without considering the reduction in risk to ‘ōhi‘a. Incorporating the value of ‘ōhi‘a protection would further increase the benefit-cost ratio in favor of an import ban

Food Habits of Introduced Rodents in High-Elevation Shrubland of Haleakala National Park, Maui, Hawai'i

Mus musculus and Rattus rattus are ubiquitous consumers in the high-elevation shrubland of Haleakala National Park. Food habits of these two rodent species were determined from stomach samples obtained by snap-trapping along transects located at four different elevations during November 1984 and February, May, and August 1985. Mus musculus fed primarily on fruits, grass seeds, and arthropods. Rattus rattus ate various fruits, dicot leaves, and arthropods. Arthropods, many of which are endemic, were taken frequently by Mus musculus throughout the year at the highest elevation where plant food resources were scarce. Araneida, Lepidoptera (primarily larvae), Coleoptera, and Homoptera were the main arthropod taxa taken. These rodents, particularly Mus musculus, exert strong predation pressure on populations of arthropod species, including locally endemic species on upper Haleakala Volcano

Prevention, early detection and containment of invasive, nonnative plants in the Hawaiian Islands: current efforts and needs

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The threat of invasive plants has long been recognized in Hawaii and is well documented. In many respects, Hawaii may be near the forefront among national and international efforts to address the burgeoning threat of invasive plants, perhaps especially in the field of outreach and education. However, given the scale of the problem many challenges still need to be addressed and gaps in the existing management system need to be identified. In particular, it appears that new non-native plant species are still introduced to the Hawaiian Islands at a high rate with little or no regard for their potential invasiveness. This report documents these achievements and experiences and provides a range of perspectives on how to further develop prevention, early detection and containment of invasive species in Hawaii. The report is based on a symposium and workshop held at the 2008 Hawaii Conservation Conference in Honolulu on 31 July 2008.USDA Cooperative Research, Education, and Extension Service Award Grant #2006-35320-1736

Impacts of Biological Invasions on the Management and Recovery of Rare Plants in Haleakala National Park, Maui, Hawaiian Islands

Biological invasions assisted by humans are impoverishing biological diversity worldwide (MacDonald et al. 1989, Diamond 1989). Such invasions are particularly devestating to the biota of oceanic islands such as Hawaii (Williamson 1981, Brockie et al. 1988, Hawaii Department of Land and Natural Resources et al. 1991). Ecosystems of the Hawaiian Islands are much more vulnerable to biological invasions than are continental ecosystems, because the organisms in them have evolved in isolation from many of the forces that have shaped continental organisms, including foraging and trampling by herbivorous mammals, predation by ants and mammals, virulent diseases, and fires (Loope & Mueller-Dombois 1989). Lowland ecosystems of the Hawaiian Islands were substantially modified by Polynesians prior to western contact (Kirch 1982); after Cook\u27s \u27discovery\u27 of the islands in 1778, the rate of modification accelerated and extended to higher elevations (Cuddihy & Stone 1990)

Status of the silversword in Haleakala National Park: past and present

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The Haleakala silversword, Arhyroxiphium sandwicense DC. ssp. macrocephalum (Gray) Meyrat, declined markedly in the late 1800's and early 1900's due to browsing by goats and cattle and to vandalism by humans. During the 1930's, after protection was provided by the national park, much concern arose over the high level of seed predation by native insects. Nevertheless, following protection, silversword numbers have increased and now total about 50,000 individuals. Although total crater-wide numbers remained stable between censuses in 1971 and 1982, large fluctuations have occurred on individual cinder cones. Plots for long-term study of silversword population dynamics have been established, with data taken annually. Preliminary results after three years suggest that many seedlings establish in some years, few or none in others; that substantial natural mortality occurs in some years; and that wide population fluctuations from year to year are occurring. The greatest threats to the Haleakala silversword today are thought to be the Argentine ant (Iridomyrmex humilis) and the western yellow-jacket (Vespula pensylvanica), aggressive alien predators (of insects) which could disrupt ecosystem processes, especially pollination. Park managers now recognize the need for preservation of the entire complex of organisms belonging to the silversword ecosystem.National Park Servic