Hawaii Invasive Species Council

Ants are not an endemic component of Hawaiian ecosystems and cause significant ecological, economic and social impacts (Krushelnycky et al. 2005). Wasmannia auropunctata (the Little Fire Ant, or LFA) is an invasive ant species native to South America. Over the last century it has spread to the mainland US (Osburn 1948; Spencer 1941), Africa (Wetterer et al. 1999), Australia and the Pacific (Wetterer and Porter 2003). In the last two decades, LFA appears to be spreading more rapidly than before facilitated by increased trade within the Pacific region. Since the 1990s, new infestations have been discovered in Vanuatu (Vanderwoude 2007), Cairns, Tuvalu, Hawai’i (Wetterer and Porter 2003; Krushelnycky et al. 2005) and more recently, Papua New Guinea (Vanderwoude 2008).

First reported in 1999 on the east side of Hawaii and Kauai (Conant and Hirayama 2000), LFA is regarded as one the “worlds 100 worst invasives” (Lowe et al. 2000). Little Fire Ants over-run forest and urban ecosystems developing huge interconnected super-colonies that occupy both the ground and arboreal strata (Le Breton et al. 2004). The species negatively impacts wildlife populations (Jourdan 1997; Le Breton et al. 2003; Walker 2006), domestic animals, and public health. There is considerable anecdotal evidence that LFA sting domestic and wild animals especially on the eyes, causing blindness (Theron 2005). They are a serious agricultural pest, enhancing homoptera populations, stinging agricultural workers (Wetterer and Porter 2003) and interfering with beneficial insects introduced for biological control (Fabres and Brown 1978). Workers have refused to harvest or tend orchards infested with this species in Hawaii.

Although eradication efforts have been underway for the small population of LFA on Kauai, LFA has spread rapidly on east Hawaii (Hawaii Ant Group 2007). Control of nests on the ground has been achieved through the use of granular baits developed for another invasive species, Solenopsis invicta (Red Imported Fire Ant or RIFA). While there is scope for improvement in ground-level control, there is currently no known method to control LFA in arboreal situations, their preferred habitat. Developing a practical method for control of Little Fire Ants in arboreal situations is therefore before a response to this invasive species can be considered.

As LFA spreads in Hawaii, agricultural and landscaping industries will be affected to varying degrees. The potential impact on perennial tree cropping industries such as macadamia, coffee, and bananas could be catastrophic. Recently, LFA have been discovered in Hawaiian Peach Palm (Bactris gassipaes) plantations which form the basis of the fledgling heart of palm industry (personal communication). A real, but difficult to quantify potential impact is the effects of LFA on the quality of life of residents and the “Hawaii experience” for visitors as outdoor recreational activities will be negatively impacted by LFA. It must also be stated that LFA is currently impacting pets—cats and dogs have been blinded in the Hilo area by LFA stings.

Invasive weeds are a major detriment to the natural areas of Hawaii. An important component of all invasive weed management strategies is to efficiently and effectively mitigate the spread of incipient satellite populations from becoming major infestations. Many of these natural areas consist of extremely steep, densely vegetated, or otherwise inaccessible terrain, thereby requiring a significant amount of time and energy that may even expose field personnel to hazardous conditions while applying herbicide with conventional application equipment. New technologies are being developed at the University of Hawaii that can accurately deliver effective herbicide doses from safer long-range distances. The recreational paintball industry has contributed to the technological advancements of liquid encapsulation and pneumatic ballistics. These technologies have been adopted for developing a new tool in invasive weed management called Herbicide Ballistic Technology (HBT). The basic concept is to encapsulate aliquots of herbicide into 0.68 caliber starch gel projectiles that can be delivered to specific weed targets with a pneumatic applicator. There are three key accomplishments that have contributed to the development and progress of HBT. The first accomplishment was the development of a procedure for encapsulating an herbicide formulation into 0.68 caliber projectiles. The biggest challenge with this procedure was ensuring compatibility of the fill with the polysaccharide shell. The second accomplishment was a field demonstration of HBT effectively administered to weed targets with long-range accuracy (> 20 m) from both ground and aerial applications. The first prototype batch of HBT capsules consisted of the herbicide active ingredient imazapyr and was highly effective in trials to control Australian Tree Fern (Sphaeropteris cooperi) and banana poka (Passiflora mollissima). The third accomplishment was US Environmental Protection Agency interpretation of HBT as a legal application. According to § 167.3 of CFR title 40, the process of HBT encapsulation is technically a custom blend of EPA-registered pesticide, adjuvant and inert products. In fact, all of the components used in paintball manufacturing are pharmaceutical-grade and safe for consumption. Furthermore, an HBT application is compliant with FIFRA sec. 2(ee) in that it is consistent with (1) applying a pesticide at any dosage, concentration, or frequency less than that specified on the labeling unless the labeling specifically prohibits deviation from the specified dosage, concentration, or frequency and (2) employing any method of application not prohibited by the labeling unless the labeling specifically states that the product may be applied only by the methods specified on the labeling.

Conservation and land management organizations in Hawaii dedicate a significant amount of resources to field operations in weed control. HBT is a new technology for assisting field crews with safer pesticide handling, improved application technique and an enhanced management strategy. Encapsulated HBT capsules are by design ready-to-use and will eliminate the need for handling and mixing liquid pesticides in the field. Furthermore, there is also a reduction in water requirements needed in field operations. Improvements in herbicide application result from the ability to treat weed targets with long-range accuracy. Conventional directed applications require a significant amount of travel to and from each target species, while HBT applications will allow for the application of multiple targets within a 20 m radius from a single reference point, which increases efficiency and reduces the disturbance to a site. We have demonstrated the ability to target incipient weed populations residing on steep cliffs and deep ravines expanding the range of weed targets that would otherwise be untreatable and without putting the applicator at risk. We have also successfully demonstrated the use of HBT as a compliment to helicopter spray ball operations, which can contribute to flight safety and lower operating costs. Pilot fatigue can be reduced by diverting application responsibilities to a dedicated HBT applicator, while flight time and fuel costs may be reduced as a result to increasing target efficiency. Consider your cost for helicopter flight time? Currently, the going rates for helicopter flight time are $12-$15 per minute. If HBT applications can increase target efficiency by 10-20 plants per hour, this could translate into savings of $1000’s in weed management costs.

Problem Statement:

Protecting large areas of Hawaii’s remaining native forests from invasive plant species requires a landscape-scale weed control approach applied in a rapid and precise manner combined with a mapping system able to identify outlying weed individuals within large expanses of native forest. Ideally, this mapping system, applied incrementally over time, could also monitor the efficacy of the control program and the spread of the target weeds. The sooner managers are able to determine whether or not the spread of the target weeds are outpacing weed control efforts, the faster they are able to adapt and respond. Clearly, this real-time monitoring capability is essential to controlling a landscape-scale weed infestation. However improvements to the accuracy of a new, remote sensing-based weed mapping technology need are needed before this capability materializes.

Helicopter surveys conducted from 2003-2006 detected Australian tree fern (ATF) distributed throughout Kauai’s 142,000-acre watershed, with numerous outlying individuals established in the most remote native forest core. Realizing the urgency of the infestation The Nature Conservancy’s Kauai Program (TNC-Kauai), working with scientists and contractors, began an intensive research and development program in 2006 to map and control ATF in the 10,000-acre core of Kauai’s native forested watershed. This two-pronged program focused on developing a high-precision aerial herbicide application techniques and a cutting-edge remote sensing approach to map and monitor the ATF.

The next step is to upgrade the current weed mapping system to a weed monitoring system, capable of measuring the near-term efficacy of the herbicide treatments and the long-term rate of weed recruitment and re-colonization into the treated areas. This would entail re-flying the treatment areas to collect images after the herbicide has had a chance to kill the target weeds and comparing the before and after images, with the treatment data collected by the GPS in the helicopter. While this may sound simple enough in concept, there are some technical issues that need to be understood and addressed and a couple of different approaches need to be tested for TNC and RMH to use this system as monitoring tool.

The Hedychium or wild ginger species complex encompasses 3 highly invasive species in the family Zingiberaceae: H. gardnerianum (Kahili or “wild”ginger), H. flavescens (yellow ginger) and H. coronarium (white ginger).

Native to the North Eastern slopes of the Indian Himalayas (with H. coronarium also reported endemic to Southern China) these fragrant, showy, rhizomatous perennial herbs have been widely introduced as ornamentals to various regions of the world. They have subsequently escaped to become serious weeds of riverbanks, natural/managed forests, montane rainforests and wetlands, where they form large and dense thickets, crowding out vegetation and preventing the establishment of native shrubs and trees as well as contributing to erosion on steep slopes.

H. gardnerianum is considered the most invasive species of the genus; its biological characteristics, threat to endangered taxa and impact on biodiversity have earned it distinction as one of the “World’s 100 worst invasive alien species” and was high scoring in a 2005 PIER Risk Assessment for Hawaii and other Pacific Islands where it was identified as “likely to cause significant ecological or economic harm”.

Introduced to Hawaii by the horticultural industry, Kahili ginger escaped cultivation and was first recorded in Hawai’i Volcanoes National Park (HVNP) in 1954. Populations have now naturalised and spread to all islands in Hawai’i between sea level and 1700m. A large, aggressive, nitrogen-demanding and a shade-tolerant coloniser, its biogeochemical effects are compounded by the dense shade and network of tubers and roots formed in invaded areas. These combine to act as an effective barrier to native plant establishment and can thus alter successional pathways. Not only is the viability of undisturbed, pristine native rainforests such as those currently dominated by ohia-lehua (Metrosideros polymorpha) under threat, but also rare endemic species such as Clermontia samuelii and Labordia tinifolia var. lanaiensis. Kahili ginger currently covers over 500 ha from 1000-1300 m elevation in HVNP, and especially large populations occur in South western Kipahulu Valley between 1,070 to 1100m and Kohala state and private lands. A preliminary estimate for the cost of conservation management programmes, in 2007-2008, against Kahili ginger in the Hawaiian Islands, has been conservatively calculated at $1 million. The infested area is estimated at close to 50,000 acres, although this is likely to be an underestimate as it does not include the full range of invading outlier populations (Pat Bily, TNCH, Pers. Comm.). Many areas infested with monotypic ginger are deemed lost causes and intensive mapping and scouting missions are now concentrating efforts on mitigating incursions into high value natural areas.

Prolific seed production, regrowth of rhizomes and inflorescences subsequent to shoot removal and poor accessibility can all compromise the mechanical control of this plant. Environmental concerns such as soil leaching, contamination of ground water and non-target effects coupled with ginger’s widespread distribution with some large infestations also limit and/or preclude the use of herbicides in many areas. H.flavescens and H. coronarium are also weedy in Hawaii but are usually confined to forest edges and wet habitats on all islands (large infestations on Nahiku, Maui, Puna and Kohala mountains in particular) rather than the forest understorey. Hybrids between H. coronarium and H. gardnerianum are also reported and favour the simultaneous seed production of H. gardnerianum.

In April 2005, a strain of the Neotropical rust fungus Puccinia psidii was first found on an ohia (Metrosideros polymorpha) plant in the Hawaiian Islands and given the name “ohia rust” by Hawaii Department of Agriculture. However, although the rust has spread throughout the islands, the damage of the rust to ohia is so far minimal. This rust, notorious for a broad host range for plants of the Myrtle family (Myrtaceae), destroyed the allspice industry on Jamaica in the 1930s and devastated large non-native Eucalyptus plantations in Brazil (where the rust is native and common on guava, Psidium guajava) in the 1970s (Coutinho et al. 1998). Fortunately, the strain of P. psidii that invaded the Hawaiian Islands most virulently infects the non-native rose apple tree Syzygium jambos. Two rare native species of the genus Eugenia have also been seriously damaged by the rust, E. koolauensis and E. reinwardtiana, both known as nioi in Hawaiian. Unfortunately, many different strains of P. psidii exist and could virulently infect other members of the Myrtle family; forests of native ohia are at risk of being decimated (Loope and La Rosa 2008).

The ohia plant, Metrosideros polymorpha, comprises nearly 80% of the native Hawaiian forests and covers approximately 400,000 hectares on the Hawaiian Islands. It provides habitat to a wide range of Hawaiian fauna including a majority of its native bird species. Not surprising in view of its dominance in the forest, its importance to Hawaiian culture is paramount.

On August 28th, 2007, the Hawaii Department of Agriculture placed a temporary ban on imports of Myrtaceae from California, Florida, and South America to avoid possible new strains of P. psidii infecting the islands (Tanji 2007). The ban recently expired and Myrtaceae are again being imported to the islands. Now the Department of Agriculture is faced with the need for an appropriate permanent rule. However, the relative costs and benefits of a ban vs. a standard agricultural quarantine have yet to be explored. It is the purpose of this research project to quantify more accurately the costs and benefits of the sale of imported Myrtaceae in the Hawaiian Islands. Furthermore, we will examine the relative advantages and disadvantages of implementing either a quarantine policy or a full ban on imported Myrtaceae.

The West Maui Mountains Watershed Partnership has completed its work for the 2009 Hawaii Invasive Species Committee Grant. The following report attempts to summarize our achievements. Although the some of the deliverables of this grant were not achieved as well as we would have liked due to technological limitations, we feel that we used the resources successfully for their best and highest use. One of the main thrusts of this grant was to use imagery from Resource Mapping Hawaii to identify priority weed species, however, since we had issues with our imagery due to poor weather and rugged terrain, our analysis and ground truthing was limited. On September 20, 2012, a total of $13,348.41 was approved for a re- budget from the categories of “image collection/ analysis, data management, and training” to a new budget category for “helicopter operations” as well as the movement of monies from the “technical report” budget category to a “weed management plan” category. With this, we were able to complete our WMMWP 5-year Weed Management Plan as well as mapping of Macaranga tanarius and Toona ciliata using helicopter surveys. We were able to purchase a new GIS workstation and have continued our participation and made significant strides within our Maui Data Hui to standardize data systems within island programs. The overarching lesson learned is that technological advances in image collection are still in development and that technology may not perform to expectations in challenging environments like those found in West Maui. We are still hopeful that new developments will make weed control easier and will continue to attempt to integrate these advances when possible.

One of the biggest challenges with managing the invasive species crisis in Hawaii is the limited ability by managers to detect unwanted pests, especially in the remote and rugged terrain characteristic of Hawaii’s native watershed areas. For the most part, the only reliable tools for detecting and assessing invasive species in these areas are helicopter surveys and exhaustive on-the-ground searches by field staff. Generally, both methods are effective but have serious limitations: they are expensive, potentially dangerous, extremely time consuming and, often times, cause significant damage to non-target resources. As a result, many high priority pests go undetected, and managers are unable to identify or respond to these threats until they expand to larger “detectable levels” which are far more difficult to manage or are beyond the means of conventional control techniques. It is imperative that the conservation community continually develop better tools to more effectively detect and rapidly respond to invasive species before they reach unmanageable levels.

Resource Mapping Hawaii (RMH) is a Kauai-based firm that is currently developing remote sensing technologies to address this issue. RMH conducts fixed-wing aerial surveys which provide multi-spectral and detailed natural color images at extremely high spatial resolution. These geo-rectified images can be analyzed to identify specific plant or animal species (including individual plants) across large landscapes and rugged terrain. RMH has been able to consistently identify a number of highly invasive plant species in Hawaii, including Strawberry guava (Psidium cattleianum), and Australian tree fern (Cyathea cooperi), and is developing this capacity for other weeds. This technology, when fully developed, will allow managers to quickly and safely assess large areas for invasive weed presence, as well as provide useful baseline data for long-term vegetation composition, health, and change over time.

The East Maui Watershed Partnership (EMWP) proposes to contract RMH to provide data and training to assess weeds and vegetation across approximately 20,000 acres of State and private lands on East Maui. These lands are the site of on-going and future management efforts and have been identified as the highest priority for protection by the Partnership.

The Nature Conservancy (TNC), The National Park Service (NPS), the Division of Forestry and Wildlife (DOFAW), the Maui Invasive Species Committee (MISC), and other regional managers have expressed their interest in collaborating on this project. Haleakala National Park has applied for project funding, that, if granted, would be used to expand the coverage of this proposal to include portions of the Park’s rainforest as well as areas of East Maui most threatened by Miconia (Miconia calvescens) and Pampas grass (Cortaderia jubata). TNC Maui is also seeking in-house funding for a similar RMH project in portions of Waikamoi Preserve, Koolau Forest Reserve, and on lands owned by East Maui Irrigation (EMI). The exact survey boundaries for this (HISC) proposal may be slightly modified, and will depend on whether or not the funding requests of these other agencies are successful. To avoid redundancy, all survey work will be coordinated amongst the various stakeholders. It is the hope of the Partnership that, eventually, data sets will be obtained for all of East Maui so that multi-agency management efforts can be coordinated on a landscape level.