
Hawaiʻi Island
Natural Areas Weed Management Forum
For quick access to each presentation shared, click on the pdf icon below. Labeled with title, presenter and affiliation. *
*at time of presentation
2017:
Invasive Plant Management within UH Managed Lands on Mauna Kea - Darcy Yogi (OMKM Natural Resources)
Diamond Head State Monument’s interior and slopes are riddled with alien species. Our objective is to limit the growth of alien species within the crater and its outer slopes, with special concern along our trail corridor and where there is heavy foot traffic. Our priorities include controlling lion’s ear (Leonotis leonurus), bellyache bush (Jatropha gossypiifolia), fountain grass (Pennisetum setaceum), and other alien species that out compete our native species. The strategy we employ for weed control has been manual weeding, spot spraying with herbicide, and weed matting. The populations of these alien species have not been mapped nor tackled on a large scale. Some challenges we face include having a limited staff (1 park caretaker, 1 interpretive technician, 2 KUPU interns), high frequency of visitors per day, park hours of operation, and a large area of maintenance. The crater encompasses 475 acres and sits in urban Honolulu. The park is open to the public 365 days a year from 6am-6pm and is usually visited by 2,000-5,000 tourists and hikers per day. It has numerous inaccessible areas and is shared with Hawai`i State Department of Defense and the Hawai`i National Guard. There are also endangered plant species in various locations in and around the crater (Schiedea adamantis, Doryopteris takeuchii, Marsilea villosa), which also inhibit our work in controlling the spreading of these alien species.
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A Phased Approach to Improving Habitat for a Critically Endangered Species - Steve Evans & Pamela Sullivan (Natural Resources Office, Pōhakuloa Training Area, Center for Environmental Management of Military Lands, Colorado State University)
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A phased approach to improving habitat for a critically endangered species - an adaptive management lesson The PTA NRO manages 4 listed plant species in the Keʻāmuku Maneuver Area. One is Melanthera venosa, a federally endangered, low-growing, perennial herb. It is restricted to Hawaii Island puʻu in montane dry shrublands dominated by invasive grasses, at elevations from 725 to 1136 m. The species numbered approximately 4,150 individuals in the 1980's and occurred on as many as 6 puʻu. The distribution has been reduced to potentially just 1 puʻu (Nohona o Hae) with less than 100 individuals due to continued habitat degradation. Although Puʻu Nohona o Hae had been fenced and ungulates removed, M. venosa continued to decline due to increasing densities of invasive species such as Cenchrus setaceus. However, care needed to be taken to ensure that removal of C. setaceus did not negatively affect M. venosa by altering the biotic and abiotic conditions or impacting common native species. Therefore, PTA NRO implemented a tiered weed control strategy that will be followed with habitat improvement. Weed control was phased in to gradually alter conditions and allow M. venosa to acclimate. C. setaceus was gradually reduced to 1 foot and killed within 1 m of M. venosa, and cut to the ground and treated with herbicide within a 25 m buffer. Unfortunately, weed control around M. venosa coincided with a dry period and plants seemed stressed as a result, necessitating additional management. Subsequently, weed control revealed a high density of native species previously over-topped by C. setaceus throughout the weed control buffer. Going forward, the site will be monitored for natural recovery of common native species. If needed, outplanting of the less common natives will be considered, and finally augmentation of M. venosa may occur. This effort highlighted the need for a true, adaptive management approach, rather than management by trial and error, to improve management outcomes.
An Overview of the HVNP Alien Plant Control Program - David M. Benitez (Hawaii Volcanoes National Park – Pacific Islands Exotic Plant Management Team)
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An Overview of the HVNP Alien Plant Control Program The NPS is mandated to protect natural resources for future generations, and alien plant invasions present a direct threat to this mission. HVNP’s alien plant control program has expanded significantly over the past 30 years, from less than 200 to over 1,200 worker days in the field, and includes over 134 species controlled or monitored for invasiveness. Of these, at least 33 are widespread, highly disruptive species, many ranked among the world’s worst invaders. Strategic management of weeds is imperative since resources to fund operations are limited, many species are widespread, new species continue to establish, and changing climate presents long term uncertainties. HAVO’s weed management strategy is grouped into two different approaches, depending on the distribution of the target. A localized approach is employed for species with discrete populations of few individuals or a limited extent, and a Special Ecological Area (SEA) approach is employed to exclude more widespread species from high priority areas if they cannot be controlled parkwide. The high priority areas are selected based on attributes including representativeness, manageability, and value for research and interpretation. In fiscal year 2016, 1,287 worker days were spent in the field controlling invasive weeds. Staff, partners, and volunteers controlled 92,157 plants of 72 species, and 60.7 acres invasive grasses, blackberry, and ginger. NPS and cooperator crews systematically swept 25 blocks in 11 SEA units in the park. Volunteers in Parks (VIP’s) contributed 20% of program field workloads (261 worker days), and youth programs and youth volunteers contributed 17% of program field workloads (214 worker days). The high productivity of the park’s alien plant control team is a product of a sustained long term commitment and highly experienced staff, intolerance of unsafe work practices, highly leveraged workforce including partners and volunteers, and organizational support from NPS and other agencies.
Cultural Landscape Rehabilitation Through Restoration of Native Ecosystems - Jackson Letchworth, Tyler Paikuli-Campbell, & Sallie Beavers (Kaloko-Honokōhau National Historical Park)
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An Overview of the HVNP Alien Plant Control Program The NPS is mandated to protect natural resources for future generations, and alien plant invasions present a direct threat to this mission. HVNP’s alien plant control program has expanded significantly over the past 30 years, from less than 200 to over 1,200 worker days in the field, and includes over 134 species controlled or monitored for invasiveness. Of these, at least 33 are widespread, highly disruptive species, many ranked among the world’s worst invaders. Strategic management of weeds is imperative since resources to fund operations are limited, many species are widespread, new species continue to establish, and changing climate presents long term uncertainties. HAVO’s weed management strategy is grouped into two different approaches, depending on the distribution of the target. A localized approach is employed for species with discrete populations of few individuals or a limited extent, and a Special Ecological Area (SEA) approach is employed to exclude more widespread species from high priority areas if they cannot be controlled parkwide. The high priority areas are selected based on attributes including representativeness, manageability, and value for research and interpretation. In fiscal year 2016, 1,287 worker days were spent in the field controlling invasive weeds. Staff, partners, and volunteers controlled 92,157 plants of 72 species, and 60.7 acres invasive grasses, blackberry, and ginger. NPS and cooperator crews systematically swept 25 blocks in 11 SEA units in the park. Volunteers in Parks (VIP’s) contributed 20% of program field workloads (261 worker days), and youth programs and youth volunteers contributed 17% of program field workloads (214 worker days). The high productivity of the park’s alien plant control team is a product of a sustained long term commitment and highly experienced staff, intolerance of unsafe work practices, highly leveraged workforce including partners and volunteers, and organizational support from NPS and other agencies.
Getting Into the Weeds: A Summary of Invasive Plants in Hawaiʻi’s National Parks - Jacob Gross & Alison Ainsworth (National Park Service Inventory & Monitoring Program Pacific Island Network)
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Getting Into the Weeds: A Summary of Invasive Plants in Hawaiʻi’s National Parks The Pacific Islands Network Inventory and Monitoring (I&M) program monitors non-native plants within relatively intact plant communities across national parks of Hawaiʻi, American Samoa, Guam, and Saipan. Monitoring occurs every five years per park. Results from the first cycle of monitoring (2010-2013) at Hawaiʻi Volcanoes (HAVO) and Haleakalā (HALE) national parks include richness, frequency, and cover of non-native life forms and plant species at various spatial scales. Non-native plant species were documented within the wet forest and subalpine shrubland plant communities of HAVO (18,000 ha) and HALE (7,000 ha). Nearly twice as many non-native species were recorded in HAVO (108) as compared to HALE (60). However, the subalpine shrubland at HALE contained greater frequency and cover of non-native plants. Species richness, frequency, and cover were best summarized at small-scale, contiguous sampling frames rather than by plant community. Sampling frames were generally distinct in non-native species composition, likely a result of different microclimates, disturbances, adjacent land use, and accessibility. Non-native plants within HALE’s wet forest show a trend of decreasing cover with increasing elevation. Two of the most frequent invasive plants in HALE’s wet forest, Clidemia hirta and Hedychium gardnerianum, were only found as incipient populations during previous monitoring in 1988. At HAVO, five new park and two new island species were found during monitoring efforts. Continued monitoring in these areas will increase spatial coverage and allow for change detection, helping managers to prioritize existing and emerging threats.
Using Foliar Spray Volume to Estimate Area & Number of Plants Treated - Joel Brunger (Big Island Invasive Species Committee)
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In the Thick of It: Using Foliar Spray Volume to Estimate Area and Number of Plants Treated Reporting the area and number of plants treated is a typical requirement for invasive species control programs receiving grant funds. BIISC’s target species, Rubus sieboldii, is a dense ground-covering shrub, and it has proven difficult and time-consuming to accurately determine the area and count the number of plants treated during control operations. The BIISC Plant Crew has developed a method to use foliar spray volume to estimate these reporting data. A backpack sprayer was calibrated and timed while spraying 10 plots of 1 square meter of Rubus of varying canopy cover. The number of mature Rubus plants per square meter was counted in 10 plots with 100% canopy cover. The numbers of ounces and mature plants per square meter were determined, and these data were used to calculate the number of ounces per plant being sprayed. This foliar spray volume is then used in future operations to estimate both the area and number of plants treated. These estimates satisfy reporting requirements and can be used to track annual progress. Field staff can spend more time treating plants instead of collecting data, which increases a field crew’s productivity and efficiency. BIISC is employing this method on Rubus sieboldii but further applications could be useful for other species such as Pennisetum setaceum.
Invasive Species Management: Protecting watersheds one plant at a time with extreme prejudice - Leary, J., K. Burnett , C. Wada, R. Rodriguez, D. Jenkins & B. Mahnken (Dept. of Natural Resources and Environmental Management, UH Economic Research Organization, Dept. of Molecular Biosciences and Bioengineering, Maui Invasive Species Committee)
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Biology and Management of Incipient Miconia in the East Maui Watershed. Miconia (Miconia calvescens DC) was introduced to East Maui as a single horticultural specimen circa 1970. Management commenced two decades later with a 25-year history that continues today. In 2012, Herbicide Ballistic Technology (HBT) was introduced as a novel treatment platform on manned helicopter surveillance missions; virtually doubling operational efficiency by combining intelligence gathering activities with concurrent target elimination. To date, over 100 HBT missions have been conducted, approaching 500 hours of operational flight time, treating over 20,000 high-value incipient targets, protecting over 18,000 ha of the East Maui Watershed (EMW). These robust operations data allow us to explore performance analytics in a real management setting, e.g., search efficiency, herbicide use rate, etc., which can be further monetized to determine variable costs of an operation. With basic GIS, we have also determined the dispersal kernel of miconia in the EMW, spreading out to 1644 m from the maternal source, creating an impact area approaching 850 ha. Our future goal is to use these new model parameters for optimizing containment strategies with most effective impact reduction and highest return on future cost avoidance. The aerial deployment of HBT is proving to be an efficient management system reducing further impact to these fragile ecosystems. To conclude, the successful adoption of this new technology was achieved through a spontaneous form of participatory action research where scientists and practitioners shared in the responsibilities of research and management towards evolving solutions in sustainable invasive species management.
Estimating and applying biological parameters to enhance management of Rauvolfia vomitoria, an invasive tree in North Kohala, Hawai'i - Timo Sullivan (University of Hawaiʻi at Hilo, Kohala Watershed Partnership, Hauʻoli Mau Loa Foundation, Big Island Invasive Species Committee)
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Estimating and applying biological parameters to examine and enhance management of Rauvolfia vomitoria, an invasive tree in North Kohala, Hawai'i. At times, managers may plan to either contain an invasive population within—or exclude an invasive species from—a certain area. Given that neither strategy addresses the invasive source population, both will require similar, and perpetual management inputs over time to maintain their success. These inputs involve the detection and removal of immigrants from the source population either into the area of exclusion, or beyond the area of containment. Large-scale detection and removal efforts of invasive populations can be costly, and because of the perpetual nature of these strategies, costs can accumulate to significant levels. Consequently, managers practicing either strategy can either minimize or exaggerate these costs in relation to how well calibrated their management actions are to the invasive species’ characteristics. In order to successfully deal with the threat of invasive immigrants entering the zone of exclusion or leaving the zone of containment, managers must understand (1) how far these immigrants can disperse from the source population into the managed area, and (2) how quickly these immigrants can reach mature status and become an encroached source population. By understanding these phenomenon, managers can then better estimate the necessary buffer size and frequency of management input to ensure that all source populations immigrants are detected and controlled before generative status. By gathering simple growth and dispersal vector behavior data, I was able to create these types of estimates for buffer size and management frequency in regard to the invasive tree species R. vomitoria, currently found in the North Kohala region of Hawai`i island. Additionally, different tiers of predictive interval confidences—e.g., 95%, and 99.9%—were created through general linear modelling. This allowed multiple management scenarios to be compared regarding how these different confidences can affect management strategies and cumulative costs over time, e.g., management input every 4 or 5 years.
Cheap, effective control of Albizia: Yes, it can and should be done - Flint Hughes, Travis Sowards, & Kyson Dunn (USDA Forest Service) and Springer Kaye, Caitlin Morrison, Angalee Kirby, & Bill Buckley (Big Island Invasive Species Committee)
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Estimating and applying biological parameters to examine and enhance management of Rauvolfia vomitoria, an invasive tree in North Kohala, Hawai'i. At times, managers may plan to either contain an invasive population within—or exclude an invasive species from—a certain area. Given that neither strategy addresses the invasive source population, both will require similar, and perpetual management inputs over time to maintain their success. These inputs involve the detection and removal of immigrants from the source population either into the area of exclusion, or beyond the area of containment. Large-scale detection and removal efforts of invasive populations can be costly, and because of the perpetual nature of these strategies, costs can accumulate to significant levels. Consequently, managers practicing either strategy can either minimize or exaggerate these costs in relation to how well calibrated their management actions are to the invasive species’ characteristics. In order to successfully deal with the threat of invasive immigrants entering the zone of exclusion or leaving the zone of containment, managers must understand (1) how far these immigrants can disperse from the source population into the managed area, and (2) how quickly these immigrants can reach mature status and become an encroached source population. By understanding these phenomenon, managers can then better estimate the necessary buffer size and frequency of management input to ensure that all source populations immigrants are detected and controlled before generative status. By gathering simple growth and dispersal vector behavior data, I was able to create these types of estimates for buffer size and management frequency in regard to the invasive tree species R. vomitoria, currently found in the North Kohala region of Hawai`i island. Additionally, different tiers of predictive interval confidences—e.g., 95%, and 99.9%—were created through general linear modelling. This allowed multiple management scenarios to be compared regarding how these different confidences can affect management strategies and cumulative costs over time, e.g., management input every 4 or 5 years.
Keau’ohana Native Rainforest Restoration - Project of non-profit ‘Malama O Puna’
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Keau’ohana Native Rainforest Restoration Keau‘ohana Native Forest Reserve in the Puna District of Hawai‘i Island has the largest and most intact lowland wet forest remaining below 1,000 feet in elevation in the State of Hawai'i. This forest is a unique reservoir of rare native biodiversity, and is also the most optimal remaining critical habitat for the endangered ha‘iwale (Cyrtandra nanawalensis). Since 2014, the Keau’ohana Forest Reserve has undergone intensive restoration that eliminated most invasive species on > 30 acres of the most bio-diverse portion of the reserve, down-slope of Highway 130. The main target species have been waiawi (psidium cattleianum), and Clidemia hirta, however other important invasive species have included, Kukae maile (Paederia foetida), Melastoma septemnervium, thimble berry (Rubus rosifolius), and coleus (Plectranthus scutellarioides). Species in earlier stages of invasion include Cecropia obtusifolia, Trema orientalis, and Melochia umbellate. Despite damages caused by hurricane Iselle and subsequent ohi’a loss due to Rapid Ohi’a Death (ROD), Keau’ohana’s native forest is responding well to restoration measures. There is natural regeneration of numerous native species, including ohia seedlings. Species such as kopiko (Psychotria hawaiiensis), kolea (Myrsine lessertianna), lama (Diospyros sandwincensis), Hapu’u (Cibotium spp.), and mamaki (Pipturus albidus), provide sufficient shade in much of the forest. Native species such as ‘ohe (Poliscias hawaiensis), a rare yet fast growing native canopy tree, have been out-planted in open areas in need of shade. The broadcasting of mamaki seeds has proven to be an excellent restoration strategy. Having undergone intensive restoration, it is important now to follow-up with appropriate weeding efforts to eliminate the numerous invasive seedlings that are naturally regenerating due to the very abundant seed bank. Our primary goal to reconstitute the native forest composition (>90%) has been achieved. Our current goal is to maintain this, and expand upon its perimeters wherever possible. The project is currently half way through its second pass
Assessing the Detection of Miconia with sUAS - Ryan L. Perroy, Nathan Stephenson, Timo Sullivan, & Caley Saragosa (University of Hawaiʻi at Hilo)
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Assessing the Detection of Miconia with sUAS. Small unmanned aerial systems (sUAS) can facilitate the early detection and management of invasive plants, even in the understory of dense tropical forests. Here we show how overstory vegetation cover (canopy openness), imagery resolution, and camera look-angle impact the aerial detection of known individual miconia (Miconia calvescens) plants using sUAS. For our finest resolution imagery (1.37 cm ground sampling distance collected at 30 m agl), we obtained a 100% detection rate for sub-canopy plants with above-crown openness values >40% and a 69% detection rate for those with >20% openness. We were unable to detect any plants with
Using Google Earth Engine as part of a DST framework* - Heather Kimball (Pacific Science Advocates)
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Using Google Earth Engine as part of a DST framework for invasive species management. The Google corporation has recently renewed efforts to develop its Earth Engine platform. Earth Engine combines the functionality of mapping software, such as ArcMap, and remotely sensed imagery analysis software. Earth Engine has the advantages of: preloaded satellite imagery and imagery derived data products, a suite of scripts for image processing and analysis, the ability to import data sets from other platforms, and it is free to non-commercial users. Earth engine can also be called from, and send outputs to, other web applications. However, Earth Engine does not have an intuitive user interface and it requires some programing skills in JavaScript or Python to perform analyses. In this presentation, I will provide a brief demonstration on the functionality of Earth Engine and discuss options for integrating it into a geospatial Decision Support Tool (DST) platform. DSTs are platforms designed to facilitate communication, transparency and data driven decision making. DTS typically combine a knowledgebase containing the data relating to the decision, a logic model describing the relationships between decision criteria and a user interface that allows end users to further refine and evaluate criteria based on their priorities. Since Earth Engine is a JavaScript based platform, it shows promise as an integrated part of a light weight, flexible and low cost geospatial DST. I will conclude my presentation with a discussion on how an Earth Engine based DST might be designed for invasive species management applications.
A phased approach to improving habitat for a critically endangered species – An adaptive management lesson - Steve Evans & Pamela Sullivan (Natural Resources Office, Pōhakuloa Training Area Center for Environmental Management of Military Lands Colorado State University)
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Using Google Earth Engine as part of a DST framework for invasive species management. The Google corporation has recently renewed efforts to develop its Earth Engine platform. Earth Engine combines the functionality of mapping software, such as ArcMap, and remotely sensed imagery analysis software. Earth Engine has the advantages of: preloaded satellite imagery and imagery derived data products, a suite of scripts for image processing and analysis, the ability to import data sets from other platforms, and it is free to non-commercial users. Earth engine can also be called from, and send outputs to, other web applications. However, Earth Engine does not have an intuitive user interface and it requires some programing skills in JavaScript or Python to perform analyses. In this presentation, I will provide a brief demonstration on the functionality of Earth Engine and discuss options for integrating it into a geospatial Decision Support Tool (DST) platform. DSTs are platforms designed to facilitate communication, transparency and data driven decision making. DTS typically combine a knowledgebase containing the data relating to the decision, a logic model describing the relationships between decision criteria and a user interface that allows end users to further refine and evaluate criteria based on their priorities. Since Earth Engine is a JavaScript based platform, it shows promise as an integrated part of a light weight, flexible and low cost geospatial DST. I will conclude my presentation with a discussion on how an Earth Engine based DST might be designed for invasive species management applications.
2018:
Albizia Assassins - Bill Buckley (Big Island Invasive Species Committee)
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Albizia (Falcataria moluccana) is considered one of the most costly invasive species threats in Hawaii. Growing at a rate of 10-15 feet per year, it produces abundant seeds that are wind dispersed, and develops limbs that are structurally weak and can easily break off in wind events. Albizia threatens critical infrastructure such as roads, power lines, and homes. During Tropical Storm Iselle in 2014, albizia trees were the main culprit in blocking roads and emergency routes in East Hawaii, damaging or destroying dozens of homes and leaving residents without electricity for days or weeks. In 2013 Big Island Invasive Species Committee (BIISC), along with other stakeholders, created a task force specifically intended to mitigate the danger caused by albizia trees on important infrastructure. Three goals of the task force were to (1) delineate priority infrastructure; (2) Come up with a novel approach to treatment and management; (3) engage the community. Since this partnership began thousands of hazardous albizia have been mitigated along miles of priority infrastructure and almost 150,000 non-hazardous albizia trees have been treated on over 9,000 acres of land. For non-hazardous albizia treatment we use the incision point application using Milestone herbicide developed by University of Hawaii Cooperative Extension Service. This method is cost-effective, safe, quick, easy and very effective. We’ve also worked to engage community members in 7 east Hawaii Island communities to enable them to manage albizia on their property and within their community. Over 300 community members have attended a training since 2015, resulting in the volunteer treatment of thousands of albizia trees across the Big Island.
Yes, Albizia can be successfully controlled. Just ask the Samoans. - Flint Hughes (Institute of Pacific Islands Forestry, USDA-USFS), Tavita Togia (National Park of American Samoa, DOI-NPS), James Leary (University of Hawaii at Mānoa)
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It is often difficult, if not impossible to eradicate an invasive species from a given area, no matter the resources at one’s disposal. Here we describe an example of one such successful effort and the approaches used to achieve it. As of 2001, approximately 40% of the island of Tutuila, American Samoa was infested with large stands of the fast growing, N-fixing tree, Falcataria moluccana – known as Albizia in Hawaii and Tamaligi in American Samoa. Research found that when Tamaligi trees are eliminated, native Samoan forest species quickly reestablish and persist. In 2017, field crews from the National Park of American Samoa (NPAS) terminated the last remaining accessible Tamaligi population of 1,500 trees on Tutuila Island. Since the beginning of September of 2014, field crews killed a total of 12,350 mature Tamaligi trees across 19 villages and in the process restored approximately 4,120 acres of native forest. This greatly exceeded the number of Tamaligi killed by NPAS staff and their partners over the previous 13 years (i.e., 7,237 mature trees) since 2001. This dramatic increase in numbers killed came from switching from a manual approach whereby trees were laboriously girdled with machetes to a more efficient method using the highly effective herbicide, Milestone (a.i. aminopyralid). Clearing Tamaligi from these forests has protected important habitats of Samoa’s native flora and fauna and reduced the negative impacts of Tamaligi on watershed-streams and coastal habitats. Strong support of American Samoa’s village community enabled NPAS staff to accomplish the daunting and often dangerous control efforts. American Samoa’s Office of the Governor also supported and helped coordinate efforts with the traditional leadership of the affected villages. The importance of having many conversations with village communities in a respectful, candid and cordial manner cannot be overstated as a means to success. Further, these efforts have employed numerous village youth whose work has produced tangible results. Views of dead Tamaligi populations across landscapes have provided a powerful message to the Island’s communities about the importance of saving Samoa’s rainforests and that it can be accomplished by American Samoa’s people. Job opportunities to improve forest health have provided a source of income to many families, in turn, creating investments back to their villages, and justifying public support for government conservation initiatives.
Efficacy of Undiluted Herbicide Injections on Tropical Woody Species in Hawaii - James Leary, Julia Lee, & Jane Beachy (Oʻahu Army Natural Resource Program)
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There are hundreds of exotic, woody species naturalized in Hawaii, with many considered to be problematic, invasive weeds impacting natural areas and forested watersheds. Among conservation groups, the active ingredient triclopyr (TCP) is the most relied upon herbicide selection for woody species control, with a basal bark application of a 25% v/v oil adjuvant blend being the most typical method. Anecdotally, the technique is mostly successful, but without calibrations to report on effective dose, supporting the observation that effective applications are mostly compensated by high doses. Starting in 2011, field efficacy trials were initiated to determine if other registered active ingredients including: aminopyralid (AMP), imazapyr (IMZ) and glyphosate (GLY), along with aminocyclopyrachlor (ACP); would prove to be more effective in measured doses. Thus, expanding the “palette” of herbicide options and encouraging a optimized approach to pesticide use. These treatments were administered via injection with metered doses of undiluted formulations. Starting in 2011, replicated efficacy trials have been administered to naturalized stands of thirty species, all from different genera. Size was a variable among experimental units with basal diameters ranging 10-30 cm (50th percentile). Dose volumes were consistent within treatment designs and ranged from 2-4 ml per target (50th percentile) across experiments. Performance was measured by recording defoliation over time. The treatments ACP, AMP and IMZ were consistently strong performers (>80% defoliation) effective on 85%, 45% and 61% of treated species, respectively, while GLY and TCP were only effective across 21% and 27% of species, respectively. Median effective doses for ACP, AMP and IMZ were 2.0, 2.3 and 2.2 mg ae cm-2 (acid equivalent applied to area of basal cross section), respectively, while GLY and TCP were effective at 5.7 and 5.3 mg ae cm-2, respectively, with noticeable efficacy reduction at 90% defoliation observed in 90% defoliation typically observed 150-200 DAT. Effective control was determined for 73% of the species tested, with 50% of those species having a single herbicide option superior to the other herbicides and multiple options becoming less frequent among species. Furthermore, all effective options (i.e., ACP, AMP and IMZ) superseded TCP using this low-dose injection technique. The injection technique is proving to be an effective, efficient and more hygienic alternative to woody species control in Hawaii, where performance outcomes are improved with inclusion of a more diverse herbicide inventory.
Biological control of weeds: Updates for Big Island Natural Areas - Ken Puliafico, Tracy Johnson, Nancy Chaney, & Lori Bufil (Institute of Pacific Islands Forestry, USDA Forest Service, Research & Development Pacific Southwest Research Station)
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Our Forest Service team at the Institute of Pacific Islands Forestry focuses on development of natural enemies for long term suppression of invasive plants in forests of the Hawaiian Islands and elsewhere across the Pacific. Here we summarize the current status of biological control projects targeting some of the most disruptive weeds in Pacific ecosystems: Psidium cattleianum (strawberry guava), Tibouchina herbacea, Miconia calvescens, Clidemia hirta and relatives. We are collaborating with forest managers on Hawaii Island to distribute and monitor efficacy of Tectococcus ovatus, with the goal of slowing the spread of strawberry guava in native forests. We will provide updates on two agents currently proposed for biocontrol of weedy melastomes that are under review. We will also discuss our progress with other promising agents on target species such as albizia, faya tree and several others that we are working on in collaboration with local and international partners.
Responding Hard and Fast on Soft Money - Springer Kaye, Manager Joel Brunger, & Field Supervisor (Big Island Invasive Species Committee)
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Strong, stable funding for post-border management of invasive species is critical to ensure that new and sparsely established pest species do not create permanent, costly impacts to agriculture and conservation areas. Early Detection and Rapid Response capacity in Hawaii is largely tax-payer funded, and affected similarly and simultaneously at the local, state, and federal level by strong shifts in the US economy, such as the 2007 economic recession. During the past five years, for example, the Hawaii Invasive Species Council has received relatively strong and consistent funding, when compared to the previous five years (though at no point have funds been sufficient to meet statewide need). Ten years ago, the Big Island Invasive Species Committee adopted an Early Detection and Rapid Response (EDRR) approach to invasive species management, closing the chapter on Operation Miconia in favor of stopping "the next miconia." Six target species were selected to demonstrate the potential for eradicating species established, at varying degrees of severity, on the island of Hawaii. In this presentation, we will examine progress made toward eradication of each species between 2008 and 2012, during the recession, and 2013-present. We discuss effective methods for systematic eradication of species, and other factors contributing to the economic recovery of ISC programs. An encouraging picture emerges, for those optimistic about Hawaii's economic future and the adoption of the Hawaii Interagency Biosecurity Plan.
Hawaii Wildfire Management Organization - Elizabeth Pickett (HWMO Executive Director), Pablo Akira Beimler (Community Outreach Coordinator), Melissa Kunz (PFX Coordination Assistant), Orlando Smith (GIS Specialist)
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In 2015, HWMO’s Technical Advisory Committee identified Hawaii’s lack of consolidated, landscape-level information on vegetative fuels treatments used to reduce wildfire risk. In response, HWMO is developing island-by-island fire fuels management maps that will 1) provide information on existing vegetation management efforts, and 2) identify and prioritize additional future vegetation managemen projects for the purpose of fire mitigation. This goal of this presentation is to introduce the project and data collection process and provide an opportunity for Weed Management Workshop participants to provide information on their existing or desired fuels reduction projects and add to the statewide set of projects and priorities.
Restoration of tropical dry forests at Pu`uwa`awa`a Successes & Challenges - (Nāpu`u Conservation Project)
The Nāpu`u Conservation Project manages state lands at Pu`uwa`awa`a where weeds threaten some of the last remaining fragments of native tropical lowland dry forest. It is well known that invasive weeds degrade dry forests through the promotion of wildfire, competition with native species for light, water, and nutrients, and prevention of native seedling establishment through space occupation. To mitigate these impacts, dry forest restoration efforts often focus on areas with existing native tree canopies as those areas are likely to have a native seed bank and are more cost effective to restore. Successful examples of this approach include the Ka`ūpulehu Dry Forest Preserve, and Kīpuka Oweowe at Pu`uwa`awa`a. What is less well known is whether fully degraded (i.e. 100% weed-infested areas with no natives left), can ever return to native-dominated dry forest, or if those areas are too far gone, or too expensive to recover. Understanding the range of conditions over which restoration can be successful is important as the vast majority of once native dry forest areas are now mostly, or fully dominated by weeds. Moreover, we have little information regarding the distribution of native and non-native trees across the landscape to help inform placement of conservation units where native trees dominate, or to help determine where non-native tree control efforts should be targeted. Here we report on weed removal and outplanting efforts across a range of conditions from areas with native canopy trees present and a non-native understory, to 100% weed infested areas. We will discuss the successes and challenges of working in those different conditions, as well as the results from over 7 years of restoration effort. In addition, we will report on the use of different technologies at Pu`uwa`awa`a used to help inform these efforts.
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Kumaipo Fire: Lessons Learned from a Partnership for Restoration - Clay Trauernicht (UH & Pacific Fire Exchange), Amy Tsuneyoshi (Honolulu Board of Water Supply), Tamara Ticktin (UH Botany)
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We examined 14 years of Hawaiian forest regeneration after the 2003 Kumaipo Fire and subsequent weed management and outplanting efforts in the Waianae Mountains on Oahu. Abundant natural regeneration and outplants of the native tree Acacia koa formed a closed canopy across much of the burn site in 14 years. Other naturally regenerating native plants declined and nonnative species, primarily Clidemia hirta and Nephrolepis multiflora now dominate the understory. Outplanting significantly increased the native component of post-fire vegetation and contributed to some native regeneration at the final survey (in 2017). A key lesson is that restoration efforts must consider the longer-term forest dynamics. Natural declines in some nonnative species, (e.g., Buddleja asiatica) over time indicate opportunities to prioritize weed management. For re-establishing native species, although Acacia koa is excellent for short-term recovery, but other research shows that pure koa stands transition to mixed species canopies over time. Given that all of the naturally regenerating canopy trees at the final survey were nonnative (e.g., Schinus, Toona, Grevillea, Trema), it is likely that long-term persistence of native forest after fire will require not continued weed management, but active outplanting of a mix of native canopy trees.
Restoration of Keau’ohana Rainforest and the Lowland Environment 2018 - Jaya C. Dupuis (Malama O Puna)
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This presentation offers an update on the Keau’ohana Native Rainforest Restoration efforts being conducted in the Puna District since 2014, and the general status of the restoration site in light of environmental challenges such as Rapid Ohia Death, increased feral pig activity, climate change, ect… Species-specific management strategies will be discussed. Efforts include a growing outreach and education component to help student groups and community members understand how to take care of our local native rainforest. Along with restoring Hawaii’s largest and most intact lowland native rainforest (
Liko Nā Pilina Experiment: What species and treatments are having the greatest success, in terms of growth and invasion resistance - Rebecca Ostertag, Susan Cordell, Peter Vitousek, Amanda Uowolo, Nicole DiManno, Kaikea Blakemore, Shances Akima, Amy Durham, Mikkel Gantzler, Jonathon Kuntz, James Melcher, Kalena Spinola, & Israel Stillman (University of Hawaii at Hilo, USDA Forest Service, Pacific Southwest Research Station - Hilo, Stanford University)
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Restoration to a previous reference condition may not be feasible in all situations, due to lack of information, invasive species, or climate change. When site improvement is desirable, a valuable option is restoration based on functional traits, but this method requires experimentation. To meet the objectives of increased carbon storage, native biodiversity regeneration, and invasion resistance, we developed a restoration effort in a lowland wet forest in Hawai´i, employing both native and non-native (i.e., non-invasive) species with varying functional trait expression in experimental treatments. Core (n=4 per treatment) species were chosen based on expected C turnover rates (slow or moderate) while trait (n=6 per treatment) species were chosen based on functional trait redundancy or complementarity to the core species. Sixteen plots with similar vegetation structure, light levels, and soil nutrients were cleared of all invasive species and then planted into, while four additional ones were left uncleared as reference plots. The experimental restoration plots have been monitored for the last four years with a suite of parameters measured in order to evaluate the success of these hybrid communities. Topography has also been assessed across the site to examine how site conditions may influence outplant success and native recruitment. The restoration efforts at this site are being put to the test in the face of declining forest health with an 11% average annual rate of mortality being witnessed for the dominant canopy tree, Metrosideros polymorpha, due to disease caused by a Ceratocystis fungus. After four years of community development parameters measuring restoration success suggest that the MOD RED (i.e., moderate C turnover core – redundant traits) treatment is prevailing with high rates of survival, growth, canopy closure, and outplant litterfall, leading to greater invasion resistance, and thus lower plot maintenance efforts. In comparison, the SLOW COMP (i.e., slow C turnover core – complementary traits) treatment has shown greater reproduction in the early stages of this experiment, yet greater recruitment has not been recorded due to lower invasion resistance created by the outplants. Topography was found to be important with rougher plots resulting in greater sapling recruitment, and topographical depressions influencing outplant growth. In determining which of these treatments will be successful in the long-term we need not only consider the original goals of increased C storage, native biodiversity regeneration, and invasion resistance, but also which community assemblages will best mediate the impacts of a forest declining rapidly in terms of native canopy health.
Eco Census: Team ʻIke ʻike - Rebekah Loving, Morgan West, & Morgan Friend
Resources for the control and eradication of weeds are limited, while current detection and removal efforts are expensive. To increase the effectiveness of available resources, we have designed and implemented a prototype automated weed detection software system for use with sUAS (small Unmanned Aerial System)-derived imagery. sUAS platforms can produce fine resolution imagery adequate to detect invasive plants, but current approaches require hours of manual classification and processing. We have developed two key technologies to help solve the difficulties faced by weed detection efforts. For the first component, we developed a convolutional neural network for detecting weeds of interest within imagery. Creating the convolutional neural network requires manually building a database of classified segments of images which contain the different weeds of interest. The second component is an algorithm which calculates the GPS coordinates of the identified plants. A land manager now only needs to load the imagery from a sUAS onto a computer and select the weeds of interest. The output is the location of the target weeds within each image. Our training set currently includes 376 images of Miconia calvescens from a variety of locations and altitudes. This training set can be expanded to include other species of interest. Our classification specificity and sensitivity for miconia are currently 88% and 83%, respectively. Hundreds of sUAS images can now be processed in under an hour, generating a display highlighting weeds of interest and a text file of plant coordinates.
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Developing Pest Management Applications With Unmanned Aerial Systems - Roberto Rodriguez, Ken Giles, Daniel Jenkins, & James Leary (Department of Molecular Biosciences and Bioengineering University of Hawai‘i at Mānoa, Department of Biological and Agricultural Engineering University of California at Davis, & Department of Natural Resources and Environmental Management University of Hawai‘i at Mānoa)
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This is a collaborative project with a research and technology objective to develop, validate and certify unmanned aerial systems with HBT capabilities (UAS-HBT) in remote pest target elimination. We have developed a first-generation prototype HBT gimbal with controlled flight tests proving concept with a vertical takeoff and landing (VTOL) octocopter able to lift the 6 kg payload and an independent operator able to remotely engage and accurately discharge projectiles to target. Accuracy and precision of the treatment system is
Maui Nui
Natural Areas Weed Management Forum
For quick access to each presentation shared, click on the pdf icon below. Labeled with title, presenter and affiliation.*
*at time of presentation
2015:
Psidium cattleianum mapping and control efforts in West Maui- Jill LaBram (West Maui Mountains Watershed Partnership)
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Non-native, habitat modifying, Psidium cattleianum (strawberry guava), is currently among the greatest threats to the health of the West Maui Mountains Watershed. A structured plan to target infestations and prevent their spread is essential and requires various approaches given challenging terrain. P. cattleianum was brought to Hawaii in 1825 from Brazil as an ornamental plant. It is extremely fast growing, resilient, monotypic, and water thirsty. In West Maui, this species is forming dense thickets WMMWP wide, especially in historically disturbed sights around the Forest Reserve boundary and in valley bottoms. Approximately 3,000-5,000 acres are already overrun by this species (~10% of the entire WMMWP area), and habitat modeling has shown that this species has the ability to invade the entirety of the West Maui watershed if left unchecked. We have found individuals up to 4900’ elevation and small satellite populations have become established ~4,000’. This presentation will explore the reasons for targeting this species and our top-down approach to protect the core of our watershed. Our four management strategies include on the ground staff control, aerial surveys and treatment using Herbicide Ballistic Technology (HBT), volunteer service trips on the Waihe’e Ridge Trail, and release of the biological control, Tectococcus ovatus. We will also cover a preliminary evaluation of these efforts, as well as, the limitations and challenges of each strategy. Our future goals include maintaining these efforts, revisiting control sites, assessing the efficacy of treatments, and refining our herbicide techniques. Mapping P. cattleianum throughout the watershed is an on-going process which guides our current and future management decisions.
Ginger Control in the East Maui Watershed- Givonn Osterneck (East Maui Mountains Watershed Partnership)
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With the successful management of ungulates in the core east Maui watershed, the partnership has adjusted its focus to weed management. Himalayan ginger poses a devastating and irreversible habitat modifying threat to this high-elevation rainforest ecosystem. From 2008 when ginger was initially detected in the area, through the 2013- 2015 process of completing an initial first pass of control through the infestation, EMWP has learned a lot in the process. EMWP was challenged by a dense canopy making aerial detection nearly impossible, low confident detection in dense uluhe areas, rhizomes traveling underground with no vertical stocks, along with other challenges. EMWP will work in the future to define an appropriate retreatment interval, detect new populations spread by birds before they grow too large to manage, control difficult to reach epiphytic individuals and plan the next priority areas for control.
TNC Weed History and Management - Kerri Fay (The Nature Conservancy, Maui)
The goal of TNC’s weed control program is to maintain large native-dominated core areas within Waikamoi Preserve and adjacent areas that are free of the highest priority habitat-modifying weeds, and prevent the introduction and spread of problem weeds to areas where they are not currently established. The most important aspects of our weed control program are to minimize current disturbances to intact native communities, reduce infestation size of priority weeds with a focus on outliers, while first surveying for and controlling outliers, and to prevent the introduction of additional invasive plant species. The highest priority is the containment and localized eradication of Himalayan ginger, primarily due to its established range, rate of spread, and aspects of habitat modification. In FY2015 we swept 105 acres and treated 1,726 m2 for Himalayan ginger. We are challenged with a no herbicide use limitation when close to county water infrastructure. We started manual control but moved to surveying and mapping. In a 2.5 acre area we had 316 ginger patches along our new fenceline. Within the last few years we have seen a dramatic increase in Pinus species popping up across the higher elevations of the preserve. We treated 3,459 Pinus on the ground in a 23 acre area in FY15. In FY14 we treated about 400 pines in about a 1000 acre area via low volume aerial spray. Other small populations of Setaria palmifolia and Delairea oderata were treated as encountered. Low volume injection trials on 100 foot conifers proved successful resulting in less herbicide use. FY16 weed management will focus on control of 74 acres of ginger and 20 acres of Pinus.
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Invasive Pine Detection and Mapping Using High Spatial Resolution Satellite Remote Sensing - Jonathan Marshall (Haleakala National Park)
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The objective of this project is to use high spatial resolution satellite data and remote sensing analysis software to create detection maps of invasive pine trees across montane East Maui. Invasive pines pose a significant threat to the diverse native ecosystems of East Maui. To effectively manage these pines, it is important to have a complete spatial understanding of their extent. Accurate pine maps will be useful to East Maui land managers and will allow for more efficient use of limited control resources. Satellite remote sensing is a capable tool due to its ability to detect land cover characteristics across large spatial areas and with fine spatial detail. Detecting pines will rely on established remote sensing vegetation classification methodologies which take advantage of the unique spectral signatures of plants. This project has conducted preliminary research that shows that the spectral signature of pines is separable from the surrounding vegetation. Using this unique spectral characteristic, this project will map pines across montane East Maui and estimate population density and the size class of individuals. These results will be integrated with GIS, and provided to land managers as a management resource. The procedural work for the remainder of 2015, involves the core application of the pine spectral signature to vegetation classification algorithms that will classify and map East Maui. Current challenges include spectrally separating different pine species from each other and examining the viability of more spatially accurate satellite data. Resources for this project include remote sensing and GIS software available through the University of Hawai’i at Manoa’s Geospatial Analysis and Remote Sensing Lab. Management data and GPS training data for pine trees has been provided by the Haleakal ā National Park Vegetation Management team. The primary project deliverables are expected early Summer of 2016.
Efficacy of Undiluted Herbicide Injections on Tropical Woody Speciesin Hawaii - James Leary (CTAHR)
There are hundreds of exotic, woody species naturalized in Hawaii, with many considered to be problematic, invasive weeds impacting natural areas and forested watersheds. Among conservation groups, the active ingredient triclopyr (TCP) is the most relied upon herbicide selection for woody species control, with a basal bark application of a 25% v/v oil adjuvant blend being the most typical method. Anecdotally, the technique is mostly successful, but without calibrations to report on effective dose, supporting the observation that effective applications are mostly compensated by high doses. Starting in 2011, field efficacy trials were initiated to determine if other registered active ingredients including: aminopyralid (AMP), imazapyr (IMZ) and glyphosate (GLY), along with (unregistered) aminocyclopyrachlor (ACP); would prove to be more effective. Thus, expanding the “palette” of herbicide options. These treatments were administered via injection with metered doses of undiluted formulations. Starting in 2011, replicated efficacy trials have been administered to naturalized stands of thirty species, all from different genera. Size was a variable among experimental units with basal diameters ranging approximately 10-30 cm (50th percentile). Dose volumes were consistent within treatment designs and ranged from 2-4 ml per target (50th percentile) across experiments. Performance was measured by recording defoliation over time. The treatments ACP, AMP and IMZ were consistently strong performers effective (>80% defoliation) on 85%, 45% and 61% of treated species, respectively, while GLY and TCP were only effective across 21% and 27% of species, respectively. Median effective doses for ACP, AMP and IMZ were 2.0, 2.3 and 2.2 mg ae cm-2 (acid equivalent applied to area of basal cross section), respectively, while GLY and TCP were effective at 5.7 and 5.3 mg ae cm-2 , respectively, with noticeable efficacy reduction at 90% defoliation observed in 90% defoliation typically observed 150-200 DAT. Effective control was determined for 73% of the species tested, with 50% of those species having a single herbicide option superior to the other herbicides and multiple options becoming less frequent among species. Furthermore, all effective options (i.e., ACP, AMP and IMZ) superseded TCP using this low-dose injection technique. The injection technique is proving to be an effective, efficient and more hygienic alternative to woody species control in Hawaii, where performance outcomes are improved with inclusion of a more diverse herbicide inventory.
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Bocconia frutescens: Biology, Ecology & History of Invasion in the Hawaiian Islands- Chuck Chimera (PCSU)
Bocconia frutescens (Papaveraceae), commonly known as the plume poppy, is a short-statured Neotropical tree native to much of Central and South America and the West Indies. It is naturalized in dry and mesic forests on the islands of Maui and Hawaii, where it is capable of forming dense stands that can exclude the establishment of native species. It can reach reproductive maturity within four to six years, and produces tremendous numbers of seeds with fleshy arils that facilitate its dispersal by frugivorous birds. It also forms a long-lived seed bank, is able to resprout after repeated cutting and requires herbicide applications for effective control. It tolerates a broad range of environmental conditions along a large elevation gradient within its native range, suggesting that it could further encroach upon additional native and non-native habitats within the Hawaiian Islands, and has the potential to become invasive in similar tropical ecosystems worldwide. The US Fish & Wildlife Service lists Bocconia as a primary threat to a number of endangered species endemic to Maui and Hawaii. Because of the current and potential impacts, Bocconia was designated a state noxious weed, and is the target of containment and control efforts on Hawaii island and on leeward East Maui respectively. It is also recognized as a threat to similar habitats in other areas or islands outside its current invaded range, and is an early detection target of the Kauai, Oahu and Big Island Invasive Species Committees.
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Bocconia frutescens: extent and strategies for control - Keahi Bustamente (Leeward Haleakala Watershed Partnership)
Bocconia frutescens, or Tree Poppy, is a large erect shrub that has impacted native forest on the Leeward slope of Haleakalā, Maui, Hawai’I for many decades now. It was first collected in 1920 on an old road in Kanaio and by 1974 single plants were showing up in Auwahi and Kula. Although its range on Maui is currently limited to Leeward Haleakalā, it will undoubtedly threaten nearby windward preserves as it slowly increases its range via bird dispersal, prolific seeding, and an ability to germinate in a variety of conditions. Since the early 2000’s, when LHWRP began management of the species, over 30,000 plants have been controlled. Aerial surveys of the known range were completed in 2015. The Partnership is working towards creating estimates for long-term feasibility of initial control and maintenance in our project areas. Current goals are to control all mature and immature Bocconia plants that are incipient, as well as those in close proximity to rare species. A long-term goal has been to create an adult Bocconia-free fenced conservation area at Kahikinui (across DHHL and DLNR ) with a buffer to limit potential for bird dispersal has been set. However, control in this area has proven challenging as many plants occur on steep to vertical terrain, accessible only by HBT or rappel.
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13 years of Bocconia Control at Kanaio Natural Area Reserve: Evaluation and Lessons Learned - Byron Stevens (DLNR DOFAW NAR)
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Tree Poppy Bocconia frutescens (Papaveraceae) has been present on the Southern slope of Haleakala volcano since at least 1920, and is now widespread throughout dry and mesic habitats. Attempts to control this plant within the Kanaio Natural Area Reserve began in 2003, and are on-going within a 1480-acre area. Control involves crews on foot making sweeps across rugged lava terrain and basal bark herbicide treatment when Bocconia is located. Several years are required to make a complete sweep of the Reserve. Monitoring plots were established at the beginning of the effort and periodically revisited to assess trends in the infestation. The initial control effort appears to have been successful in reducing the number of mature plants, but recruitment of young plants has increased, perhaps due to recent increased rainfall and the removal of grazing animals from the area. A side benefit of the intensive sweeps has been location and control of incipient populations of other weeds, as well as the discovery of rare plants and archaeological sites.
Planning for Kiwikiu reintroduction: Habitat restoration in Nakula Natural Area Reserve - Chris Warren (Maui Nui Forest Bird Recovery Project)
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Maui Forest Bird Recovery Project has been conducting experimental restoration trials in the Wailaulau unit of Nakula NAR since 2012 to inform managers of the most efficient and effective methods for restoring the forest in the reserve. Concurrently we have been conducting large-scale outplantings throughout this same area to increase available habitat for Kiwikiu following the planned reintroduction of the species. Non-native grasses dominate large areas throughout Nakula. However, natural regeneration of some native species within grassland areas creates a mosaic of desirable and undesirable species making removal of grasses to support native recruitment challenging on the landscape-scale. Our outplanting areas are designed to provide corridors of habitat connecting existing forest patches. Prior to planting herbicide was applied only to where each seedling was to be planted. The restoration trials have shown removal of non-native grasses to significantly enhance natural regeneration of some species and we are also preparing strips where herbicide will be applied and grasses removed to enhance recruitment without outplanting. As of March, 2015 MFBRP has planted > 8 ha in outplantings corridors and we are planning an additional 5.6 ha to be planted by January 2016. An additional 2.5 ha of erosion scars have been planted throughout the unit. The remote and rugged nature of the site restricts many restoration activities to manual methods only. Unlike other parts of Nakula, natural regeneration and existing native vegetation in much of the Wailaulau unit prohibit broad-scale, aerial application of herbicide and application must be done on the ground. Our goal is to continuing our outplanting efforts in corridors and erosion scars in remaining areas. We also plan to plant additional understory species to areas with existing canopy cover to increase habitat quality and important Kiwikiu food sources.
The Perils of Pampas in Precarious Places - Mike Ade (Maui Invasive Species Committee)
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Cortaderia jubata has invaded a diverse range of habitats and forest types on the island of Maui, including dry (500 mm annual rainfall) to very wet (up to 5000 mm annual rainfall) areas, dryland, mesic, and wet koa-ohia forests, and subalpine shrublands. It threatens to exclude native understory flora and impair watershed integrity. Coordinated efforts of the Maui Invasive Species Committee (MISC) to control pampas grass began in 1998, and has included extensive aerial helicopter and ground control. The combination of aerial and ground efforts in the most densely infested area on East Maui has proven successful, reducing the average number of mature plants found per acre from >5 in 2008 to less than 1 by 2014. Other locations on Maui face different challenges to successful control, including sociological (landowner reluctance to permit control in residential areas), topographical (extreme terrain), and climatological (inclement weather). In the mountains of West Maui, inhospitable terrain has limited the ability to stage ground crews in the area to find and control plants before they reproduce. More effective aerial treatment methods need to be evaluated. GIS is used as a tool to highlight strategies, progress, and challenges associated with controlling pampas grass populations throughout Maui.
Have We Narrowed Down Priorities to Achieve Realistic Goals to Mitigate Habitat Loss? - Pat Billy (The Nature Conservancy)
Assuming most managers are in agreement on target species and strategic management approaches, we should investigate ways to collaborate to get the biggest bang for buck, especially near shared management borders. DO we have efficient 'satellite to core' approaches, most current GIS for range and mapping methodology, and best management practices in terms of chemical control? What targets are assumed to have eventual biological control and will that be enough to contain further spread to non-infested sites? Where will we draw the 'line of death' in terms of controlling outlier populations when we cannot practically take on core populations? Is there a reliable budget to continue work into a 5 year management plan?
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2016:
Gorse Management at Puu Pahu - Chris Radford (East Maui Mountains Watershed Partnership)
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Gorse (Ulex europaeus) is one of the most noxious and invasive weed species in Hawaii. This thorny, perennial shrub forms tall dense stands which shade out surrounding vegetation and displace native plants by out competing them. Gorse populations can develop into impenetrable monotypic thickets that render invaded areas completely unproductive, impassible, and extremely prone to fire due to its abundant dead material and oily, highly flammable foliage and seeds. On Maui, Gorse infestations are typically found in higher elevation pastures and natural areas, particularly on the slopes of Haleakala. The East Maui Watershed Partnership and Haleakala Ranch Company are working together to control Gorse in and around the Puʻu Pahu Reserve. The reserve encompasses roughly 1,200 acres of subalpine shrubland that is home to a number of rare and endangered native plant and animal species. It is located on Haleakala Ranch property between 6,000 and 8,000 ft and is directly adjacent to Haleakala National Park’s Crater District. Gorse control by EMWP is typically carried out in two phases. First, sweep to detect all weed populations while controlling the small populations, then target and control the higher population densities detected during the sweeps. Given the vastness of the reserve relative to our resources, we delimit what we consider reasonably sized areas to be thoroughly swept and controlled each year. The target areas range from approximately 50 to 100 acres. The area being covered each year is intended to follow a systematic approach that allows for a regular revisit interval. EMWP’s primary objectives for this project are to control Gorse inside and in the immediate vicinity of Puʻu Pahu Reserve, as well as document and control incidental priority weeds. We are supplementing these efforts with a volunteer based native plant out-planting program within the reserve.
Invasive Plant Species Management on Lanai - Mike Donoho (Pulama Lanai)
After a century of large-scale agriculture and presence by big game animals, Lāna‘i is dominated by non-native plant species, including several invasive species. On an island that is 98% privately owned, it is the responsibility of the landowner, Pūlama Lāna‘i, to not only manage established weed populations, but also prevent the introduction of new invasive species to the island to the extent possible. Lāna‘i is fortunate to be free of fountain grass (Pennisetum setaceum), ivy gourd (Coccinia grandis), or ragweed parthenium (Parthenium hysterophorus) and Pūlama is working to keep it as such through the efforts of its Natural Resources Department. Pūlama is developing its Natural Resource Management Plan, which will outline its strategies to manage, control and in some cases, eliminate established invasive species on the island.
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Miconia Ground Strategies in East Maui - Bryan Berkowitz (Maui Invasive Species Committee)
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Miconia calvescens has invaded approximately 21,000 acres on East Maui with a potential range of 119,000 acres of suitable habitat. On Maui, it grows in lowland to montane tropical rainforest at altitudes between 10 meters and 850 meters with 3,000mm - 7,000mm of rain per year, and threatens to exclude native understory flora and impair watershed integrity. Coordinated efforts of the Melastome Action Committee (MAC) to control Miconia began in 1991. This led to the formation of the Maui Invasive Species Committee (MISC) in 1999 and has included extensive aerial helicopter and ground survey and control. Recognizing the magnitude of the core infestation in Hāna, control methods are largely centered on containment and protection of high value native forest and vectors such as roads. This work seeks to describe the parameters of the Miconia project that guide and direct control methods. GIS is used as a tool to highlight strategies, progress, and challenges associated with controlling Miconia populations throughout East Maui.
Biology and Management of Incipient Miconia in the East Maui Watershed - James Leary (Natural Resources and Environmental Management)
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Miconia was introduced to East Maui as a single horticultural specimen circa 1970. The management of miconia commenced two decades later and continues on today. Native to Central and South America, this species has many biological attributes that make it a highly successful invader of Hawaii including high adult fecundity and frugivorous dispersal of progeny. In less than 40 years, incipient miconia populations have invaded remote sections of the East Maui Watershed. In 2012, Herbicide Ballistic Technology (HBT) was introduced as a novel treatment platform greatly enhancing helicopter interventions against these incipient populations. In five years of operations, we have conducted over 100 missions, approaching 500 hours of operational flight time (OFT), treating over 20,000 high-value, targets. With reliance on published science out of Tahiti and Australia and basic GIS analysis of our own empirical data, we have developed a dispersal kernel showing that 90, 95 and 99% of all incipient targets establish within 210, 302 and 602 m of the nearest mature plant, respectively, with rare (i.e., 1%) long-distance dispersal events occurring at up to 1644 m. Thus, showing a single, autogamous (self-fertile) plant directly impacting 850 ha of the watershed. Based on this new knowledge, the total area impacted by mature miconia in 2012 was 20,482 ha. In 2016, the total impact area expanded 2.2%, reaching 20,934 ha. We estimate this area impact to persist for over four decades accruing management costs approaching $150K (with inflation) in order to achieve total extirpation of progeny within the impact zone. Our goal is to use these new model parameters for optimizing containment strategies with effective impact reduction and highest return on future cost avoidance.
Designing an Herbicide Ballistic Technology Platform for Unmanned Aerial Systems (HBT-UAS) - Roberto Rodriguez (Molecular Biosciences and Bioengineering)
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Herbicide Ballistic Technology (HBT) consists of encapsulated herbicide formulations in soft-gel projectiles delivered by an electro-pneumatic marker. The HBT platform has proven to be a valuable tool to treat isolated plant targets during surveillance operations, by removing the need for an additional flight operation to treat the target. Unmanned Aerial Systems provide an on-demand platform for remote sensing and have been used for mapping in conservation. We are developing a UAS compatible HBT platform (HBT-UAS) to rapidly treat single targets from a UAS. The proposed HBT-UAS falls under the regulations contained within 14CFR§137 Agricultural Aircraft Operations and the Hawaii Pesticide Law and operations must be reviewed by relevant authorities for compliance. Adaptation of the HBT platform to provide UAS with treatment capabilities will reduce the demand for manned aerial operations in some areas allowing for these resources to be applied in areas that are not compatible with UAS limitations. In order to realize the utility of HBT-UAS, we are moving forward with developing trained aerial management teams consisting of pilots, payload operators and visual observers. The course will consist of both ground and flight training. Ground training will include topic areas required by the FAA in 14 CFR §107.73, based on the contents of 14 CFR, Aeronautical Information Manual, and Pilot's Handbook of Aeronautical Knowledge, and areas related to successful operation of UAS (e.g., filing NOTAMs, interpreting aviation weather resources, completing logbooks and reports, etc.). Flight training will incorporate maneuvers from the FAA Airplane, Glider, and Helicopter Flying Handbooks that apply to UAS including takeoffs and landings, performance maneuvers, and emergency procedures.
Web and mobile platforms for conservation and land management - Sam Aruch (Natural Resource Data Solutions)
Natural Resource Data Solutions is building a new web application to collect and mange field data, track project progress, and produce reports. This tool is the culmination of over 15 years of experience performing fieldwork and building databases for conservation mangers throughout Hawai'i. We will provide a hands on demo of the application, its functionality, and integration with GIS, mobile data collection and other tools.
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Pine Management in the Upper East Maui Watershed - Kerri Fay (The Nature Conservancy Maui)
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The goal of TNC’s weed control program is to maintain large native-dominated core areas within Waikamoi Preserve and adjacent areas that are free of the highest priority habitat-modifying weeds, and prevent the introduction and spread of problem weeds to areas where they are not currently established. The most important aspects of our weed control program are to minimize current disturbances to intact native communities, reduce infestation size of priority weeds with a focus on outliers, while first surveying for and controlling outliers, and to prevent the introduction of additional invasive plant species. Within the last few years we have seen a dramatic increase in Pinus species popping up across the higher elevations of the preserve. Since FY11 we’ve been treating Pinus species on the ground and since FY14 we’ve been treating them via aerial platform in about a 1000-acre area. Going forward weed management will focus on controlling what is left in the remote subalpine area with a probable contract with Windward Aviation to act independently.
Aerial Pine Control – Past, Present and Future - Jon Marshall (Haleakala National Park)
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Haleakalā National Park (HALE) is home to high elevation native shrubland and subalpine ecosystems that are crucial habitat for many endangered Hawaiian plants and animals. These habitats are threatened by non-native plant species such as pine trees. A 2007 fire in Polipoli State Park (is thought to have) dispersed seeds across montane East Maui. In addition, nearby forestry populations continually disperse seeds across much of the park. Pine species of concern include Monterey Pine (Pinus radiata), Mexican Weeping Pine (Pinus patula), and Maritime Pine (Pinus pinaster). Immediate control of newly established pine populations is necessary to prevent competitive exclusion of essential native habitat. HALE vegetation management and Pacific Islands Exotic Plant Management Team (EPMT) personnel have been controlling pines for decades, but recent efforts have included intensive aerial precision treatment and ground crew herbicide applications. These techniques are efficient and effective methods for controlling remote, inaccessible, and large trees. Additionally, newly implemented satellite remote sensing tools allow us to plan control operations through the precise pinpointing of target trees and can allow for post treatment monitoring of efficacy through mortality detection. Remote sensing and continued proactive ground and precision helicopter application, driven by growing understanding of the scope and complexity of the problem, will drive future management.
Calibrating a helicopter long-line sprayer treating incipient gorse patches in Humuula, Big Island - James Leary (Natural Resources and Environmental Management)
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2017:
Kahikinui and Nakula NAR Habitat Post Ungulate Exclusion - Jennifer Learned (Maui Nui Seabird Recovery Project)
Ungulate exclusion within the upper Kahikinui Forest and Nakula Natural Area Reserve began in 2014 with the completion of ungulate-proof fencing and the removal of goats from the area. Grazing by feral ungulates has altered the vegetation community and the relative abundances of native and non-native plants throughout the area, including high-elevation alpine and sub-alpine shrub habitats. We’re working to characterize the habitat and document responses to the release from grazing pressure as part of long-term monitoring of the resident Hawaiian petrel (Pterodroma sandwichensis) colony. In March 2017, we measured physical characteristics and conducted the first annual vegetation survey. We divided the upper reserve (above 6800 ft.) into 8 gradsects, each spanning 300 feet in elevation. 10m x 10m permanent plots were randomly generated within each gradsect to represent 0.01% of the total area (n=55). We estimated percent cover for all species within each plot (standard Relevé method), measured slope, aspect, altitude, and characterized surficial geology. Endemic species are more common than naturalized species (7 out of the top 10 encountered species) and contribute to greater vegetative cover (average 5.4% cover vs. 0.6%). Grasses are the most common naturalized species, and have significantly higher coverage than native grasses only at lowest elevations. Opposed to elevation alone, distance from the ridgeline determines a grass-dominated vs. shrub-dominated habitat. These data are the first attempt to characterize the vegetation community within the fenced reserves. Future annual assessments within the permanent plots will document habitat response to ungulate exclusion. In addition, we will add plots to high-density petrel burrowing locations. We will assess habitat variables in conjunction with burrow site selection to better understand landscape requirements for the colony. Continued monitoring of the habitat on leeward Haleakala will inform reserve management strategies and Hawaiian petrel protection.
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Invasive Weed Management in Highly Impacted Landscapes - Keahi Bustamente (Leeward Haleakala Watershed Restoration Partnership)
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Since 2013 LHWRP has increased its focus and efforts to manage invasive Pine species on Leeward Haleakala. With a small field crew and limited resources, for such a large area, partnerships with surrounding land owners and land managers has become an integral part of the control effort. In 2016, over 600 acres was cleared of 1200+ plants at Haleakala Ranch's Pu'u-pahu Preserve on the West slope of Haleakala. This was achieved with help from over 50 people, from multiple agencies, in less than two days. Overall, the LHWRP strategy has been simple, remove outliers and re-sweep areas every two years when possible. In 2018 another multi-agency ground sweep will be conducted on the South slope to control remaining outliers which threaten biologically sensitive areas like Auwahi and the Kanaio NAR, as well as the Nakula NAR.
Accelerating the Restoration Trajectory of Acacia koa - James Leary (Natural Resources and Environmental Management)
Restoring Hawaii’s native koa (Acacia koa, A. Gray) forests are top conservation and forestry priorities; providing critical habitat services and high-value timber products. Efforts to restore koa forests, however, are directly impeded by extensive kikuyu grass (Pennisetum clandestinum Hochst. ex Chiov.) swards occupying deforested montane landscapes. In a field study, we implemented a combination of grass suppression and seedling stocktypes to measure outplanting performance in a naturalized site on Ulupalakua Ranch property. Seedlings were grown in a nursery in two different root container sizes (111, and 207 cm3) and subsequently outplanted into grass-dominated plots that were either untreated or suppressed with a high-rate herbicide combination of imazapyr and glyphosate (1.7 kg a.i. ha-1, respectively), administered 30 days prior to planting. Across all treatments, seedling survival was high (>95%). The larger stocktype was persistently larger and at 30 months after planting was 10% taller with an 18% greater root collar diameter. Concurrently, initial grass suppression resulted in trees that were 34% taller with 66% larger root-collar diameters, 30 months after planting. Corresponding to the larger sizes, were significantly higher leaf area indices (2.6 vs. 1.8 m2 m-2), indicative of higher photosynthetic capacity and canopy closure. Grass suppression increased soil temperature and soil moisture in the first year, followed by a dramatic drop in soil moisture on the second year, which corresponded with an apparent log-phase growth response of koa after the first year in establishment. These results demonstrate how the combination of fundamental silvicultural practices in the nursery and the site can accelerate tree growth to meet restoration goals in shorter time intervals. This is a first report of koa (a leguminous species) tolerance to a high-rate, pre-plant application of the herbicide active ingredient imazapyr.
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Update on Weed Control Efforts in Waikamoi - Keoki Kanakaokai (The Nature Conservancy Maui)
The goal of The Nature Conservancy’s weed control program in Waikamoi is to maintain large native-dominated core areas within the 8,951 acre preserve and adjacent areas that are free of the highest priority habitat-modifying weeds, and prevent the introduction and spread of problem weeds to areas where they are not currently established. The most important aspects of our weed control program are to minimize current disturbances to intact native communities, reduce infestation size of priority weeds with a focus on outliers, while first surveying for and controlling outliers, and to prevent the introduction of additional invasive plant species. The highest priority is the containment and localized eradication of Himalayan ginger (Hedychium gardnerianum). The control of gorse (Ulex europaeus), pines (Pinus patula and Pinus radiata), and Blackwood acacia (Acacia melanoxylon) follow closely with the goal of suppression, while the detection and prevention of establishment by species like strawberry guava (Psidium cattleianum) and clidemia (Clidemia hirta) requires constant vigilance. Adapting strategy and incorporating innovation will be key to overcoming challenges in dealing with these highly successful invaders.
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Ginger Control Efforts by EMWP - Chris Radford (East Maui Watershed Partnership)
The East Maui Watershed Partnership (EMWP) has been conducting focused efforts to control Himalayan Ginger (Hedychium gardnerianum) since 2014, targeting populations on the windward side of East Maui. We have completed at least one sweep across approximately 167 acres since control work began. This presentation will provide some background on EMWP’s control efforts for ginger, as well as a broader outline of our management strategy for this target. Discussion will focus on our current treatment methods, recommended retreatment interval period, as well as possible resolutions to current limitations and challenges.
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Valuating Conservation Activities in Waikamoi Preserve - Chris Wada (University of Hawaii Economic Research Organization)
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The objective of this research is to estimate the value of ecosystem services protected by watershed conservation activities at The Nature Conservancy’s Waikamoi Preserve on the island of Maui. Projections of monetized benefits, together with trajectories of conservation costs, are used to calculate net present value, payback period, and return on investment. We find that conservation activities at Waikamoi Preserve protect an estimated 9,657 million gallons of freshwater yield over the next fifty years. The estimated present value of groundwater recharge benefits, calculated in terms of avoided future costs, is $7.5 million. When taking into account ecosystem services in addition to freshwater provision, the net present value is $8.5 million, and the return on investment is 26% for the planning period ending in 2067. Because much of the watershed protection costs are front-loaded while benefits are back-loaded, the payback period for investment is 41 years.
Early Movements of Tectococcus ovatus in West Maui - Chris Brosius (West Maui Mountain Watershed Partnership)
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Non-native, habitat modifying Psidium cattleianum (strawberry guava) is currently among the greatest threats to the health of the West Maui Mountains watershed. An integrated approach will be needed to control the spread given its aggressive use of habitats over challenging terrain. P. cattleianum was brought to Hawaii in 1825 from Brazil as an ornamental plant. It is extremely fast growing, resilient, animal and bird dispersed, monotypic, and water thirsty. In West Maui, approximately 5,000 acres are already monotypic (~10% of the entire WMMWP area). These dense thickets are primarily in historically disturbed areas proximate to the Forest Reserve boundary and on valley floors. Small satellite populations have become established up to 4,000’ and individuals have been found up to 4900’ elevation. Habitat modeling suggests this species has the ability to invade the entirety of the West Maui watershed if left unchecked. This presentation will briefly review our control approaches to date before focusing on early lessons learned regarding the establishment of the biological control, Tectococcus ovatus. We will explore potential T. ovatus translocation methods to help accelerate the spread of the species and propose integrated strategies which may further future P. cattelianum control efforts.
The Double Edge of Success: MISC Eradicable Species - Mike Ade (Maui Invasive Species Committee)
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In presenting an overview of Maui Invasive Species Committee’s eradicable species targets that includes a definition of an eradicable, the selection process, a slide presentation of targets, brief history of control and current coverage, Mike Ade and Christian Visoria will be discussing the success of this work and merits of continuing this program indefinitely as well as the downside of successful control work that includes lessened likelihood of staff, partners, volunteers and the public to find and identify these targets in a field setting. The overall focus of the presentation will be on the factors that contribute to problems with identifying and controlling plants in a field setting that have arisen as a result of successful control work. This will include discussion on relying on visual aids to enable crew, partners and the public to find or identify plants as opposed to identifying plants in the field and ways in which identification issues can be somewhat mitigated through successful partnerships and increased education that incorporates a strong PR component into the survey and control strategy. Also discussed is the difficulty of attaining and claiming eradication of many of our eradicable targets, not only due to the difficulties expressed in relation to the reduced visibility of these targets as successful control progresses, but also due to a variety of additional factors that include reintroduction through the landscape/nursery trade as well as imports of non-targeted plants and even potting soil amendments and difficulties with access to private land/property.
Landcover Maps for Natural Resource Management in Hawaii - Matt Lucas (Natural Resources and Environmental Management)
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Remote sensing is a powerful tool for rapidly mapping landscape scale vegetation extents and change. However, too often a disconnection exists between where, when and why remote sensing products are produced and their application to management. This means that place based managers often apply un-intended and/or outdated map products to convey or measure valued resources across their management area. This talk will focus on learning about what vegetation and land-cover products exist for Hawaii as well as an overview of the attributes, and intended use of these products. Additionally, this talk will briefly introduce Google’s cloud-based global remote sensing platform ‘Google Earth Engine’ (GEE). GEE combines a huge catalog of geospatial datasets with high-level analysis capabilities that run on remote supercomputers accessed through a web-based platform. This is making remote sensing data easily available and sharable for scientists and managers alike, thus increasing ability to track changes across any landscape. Finally, this talk will conclude with the introduction of a newly developed dynamic landcover product which identifies potential areas and rates of land cover change statewide. This new product will be used to showcase historical vegetation change and its utility for evaluating past, current, and future restoration and weed control efforts, as demonstrated at several Hawaiian management sites. Talk will conclude with a group discussion with particular focus on participant input of the utility, interface and potential applications, of this product in the context of management action evaluation, planning and reporting.
Oʻahu Weed Workshop
For quick access to each presentation shared, click on the pdf icon below. Labeled with title, presenter and affiliation at time of presentation. To read full abstracts click ʻread moreʻ.
2015:
Tibouchina control at Poamoho and pampas grass control in the upper Ko‘olau - Julia Parish (Oʻahu Invasive Species Committee) - NO ABSTRACT
Waimea Valley Native Forest Restoration Project - Laurent Pool (Waimea Valley)
Waimea Valley’s natural resource objectives are to improve the native integrity within the 15 acre mesic forest restoration site. Within the ungulate free site, are many areas dominated by a diverse set of native plants. Also within the site are areas completely inundated with ecosystem altering and aggressive invasive weeds. In early 2014, we scaled back our efforts and did not expand our work into new areas within the site. Due to the low frequency of our visits in early and other funded projects, we underestimated the work load within the site. At this point, with 4 crew-members, we have been able to greatly increase our time in the site and have a better grasp on the native and exotic recruitment and strategy within the site. The 5 mile (each way) “backwoods” commute has been very heavy on the road and many hours have been devoted to filling holes and mud pits. Our current resources include: a 6 seater UTV with tank sprayer, chainsaws, brush cutters, on-site rain catchment tanks, volunteers, plant nursery, botanical surveys, Gigapan imagery, aerial imagery, and secure funding for salaries. Our main weed control challenges lie with Chrysophyllum oliviforme, basket grass, strawberry guava, and a slew of other herbaceous weeds and grasses. Scheduling mauka time, other projects, data collection, and funding are also issues that we continue to deal with. Our strategy into some of the mixed vegetative areas could use some review. Our 2015 goals are to schedule more mauka days, more systematic and detailed weeding, and IPA and seed longevity trials for Chrysophyllum oliviforme. Systematic targeting of outlying invasive plants with the use of of Gigapan imagery and scopes will also be implemented. Alternate routes / baseyards, better data collection, and alternate sources of income will also be explored.
Controlling Weeds while Maintaining Microclimate Conditions Suitable for Rare Hawaiian Tree Snail Survival - David Sischo (DLNR-DOFAW, Snail Extinction Prevention Program Coordinator)
Predator-proof exclosure structures continue to be the only method available to prevent predation of endangered Hawaiian tree snails by all known invasive molluscivores. There are currently five such exclosure structures in the Wai`anae and the Ko`olau Mountains of O`ahu, with more slated for construction. Hawaiian tree snails need specific microclimate conditions to survive, which often includes high humidity and protection from sun exposure. A continuing challenge in regards to managing such structures is maintaining these microclimate conditions suitable for snail survival, while also reducing the presence of weeds and promoting native plant regeneration. The problem is invasive weeds, such as Christmas berry and strawberry guava, are often present inside exclosures, and provide significant contributions to canopy cover. While canopy cover is good for maintaining humidity and reducing direct sun exposure, these same weeds also prevent native plant recruitment, a “catch-22” situation. We are currently experimenting with selective pruning and use of strategic clip and drip herbicide applications to slowly phase out the invasive weeds, while encouraging native plant recovery. We will describe our current efforts, and hope to receive feedback and new ideas through discussion.
Management Options for Control of Batis within Brackish Wetlands - Katie Doyle (DOFAW-Wildlife)
Specifically my site is Hamakua Marsh in Kailua, Oahu. The State of Hawaii DLNR/ Division of Forestry and Wildlife bought the land from Kaneohe Ranchers in 1997. The site is part of Kawainui watershed. The marsh is 70% surrounded by fence (not predator proof), and 30% by Hamakua Stream. The interior mudflats are filled with pickleweed, Batis maritima, which is an invasive species. My goal is to control this plant for 3 endangered bird species. Control has occurred since 2005 by spraying the the area with the herbicide Habitat. This completely kills the plant and all other plants for about 9 months. This species was the only species present besides milo, Thespesia populnea, when I started managing this marsh 4 years ago. I decided in fall of 2013 to run experiments in managing with less herbicide to encourage natives. I ran 3 test plots: 1 was a control where I did not spray or till, 2 was mowed and tilled, and 3 was sprayed and tilled. The results from plot 2 were only native plant regrowth because of flooding. Now I manage the entire 22 acres with no control of water or flooding, trying to recreate this event. The marsh has been flooded all year, so I cannot till, and the birds are nesting within all but 3 months. My goal for spring 2015 is a combination of spraying and weedwhacking to control the regrowth until fall when I can hopefully till again.
Diamond Head State Monument - Jacob Fitzpatrick (Diamond Head State Monument)
Diamond Head State Monument’s interior and slopes are riddled with alien species. Our objective is to limit the growth of alien species within the crater and its outer slopes, with special concern along our trail corridor and where there is heavy foot traffic. Our priorities include controlling lion’s ear (Leonotis leonurus), bellyache bush (Jatropha gossypiifolia), fountain grass (Pennisetum setaceum), and other alien species that out compete our native species. The strategy we employ for weed control has been manual weeding, spot spraying with herbicide, and weed matting. The populations of these alien species have not been mapped nor tackled on a large scale. Some challenges we face include having a limited staff (1 park caretaker, 1 interpretive technician, 2 KUPU interns), high frequency of visitors per day, park hours of operation, and a large area of maintenance. The crater encompasses 475 acres and sits in urban Honolulu. The park is open to the public 365 days a year from 6am-6pm and is usually visited by 2,000-5,000 tourists and hikers per day. It has numerous inaccessible areas and is shared with Hawai`i State Department of Defense and the Hawai`i National Guard. There are also endangered plant species in various locations in and around the crater (Schiedea adamantis, Doryopteris takeuchii, Marsilea villosa), which also inhibit our work in controlling the spreading of these alien species.
To Weed or Not to Weed? That is the Question. Weed Control and Restoration Work around Rare Plants - Lara Reynolds, Mandy Hardman & Katie Doyle (Native Ecosystem Protection and Management Program)
Restoring an ecosystem with threatened and endangered (T&E) plants in the vicinity poses numerous challenges. Challenges related to weed control can range from the possible effects of altering light regimes/abiotic conditions following weed control, potential non-target herbicide impacts, and mitigation of future tree falls as treated trees die. In some cases, controlling invasive species may have more negative consequences to T & E plants in a restoration area than not controlling them. All too often the unknown impacts result in the dilemma “to weed or not to weed” - when and how do you make the decision to control weeds around rare plants? We will present an example of this decision-making process using Oahu DOFAW’s weed control efforts around a population of the endangered Cyperus trachysanthos (pu’u ka’a) in the Hamakua Marsh. We will also share a stepwise guide to aid in the decision-making process. Following the presentation will be a group discussion of other program’s experiences weeding around T&E species and an opportunity to provide feedback and suggestions that can be used to develop a set of guidelines for weed management in proximity to T&E plants.
Accelerating the restoration trajectory of Acacia koa in kikuyu grass-dominated Landscapes - Anthony S. Davis, Jeremiah R. Pinto, James J.K. Leary & Matthew M. Aghai
Restoring Hawaii’s native koa (Acacia koa, A. Gray) forests are top conservation and forestry priorities; providing critical habitat services and high-value timber products. Efforts to restore koa forests, however, are directly impeded by extensive kikuyu grass (Pennisetum clandestinum Hochst. ex Chiov.) swards occupying deforested montane landscapes. In a field study, we implemented a combination of grass suppression and seedling stocktypes to measure outplanting performance in a naturalized site on Ulupalakua Ranch property. Seedlings were grown in a nursery in two different root container sizes (111, and 207 cm3) and subsequently outplanted into grass-dominated plots that were either untreated or suppressed with a high-rate herbicide combination of imazapyr and glyphosate (1.7 kg a.i. ha-1, respectively), 30 days prior to planting. Across all treatments, seedling survival was high (>95%). The larger stocktype was persistently larger and at 30 months after planting was 10% taller with an 18% greater root collar diameter. Concurrently, initial grass suppression resulted in trees that were 34% taller with 66% larger root-collar diameters, 30 months after planting. Corresponding to the larger sizes, were significantly higher leaf area indices (2.6 vs. 1.8 m2 m-2), indicative of higher photosynthetic capacity and canopy closure. Grass suppression increased soil temperature and soil moisture in the first year, followed by a dramatic drop in soil moisture on the second year, which corresponded with an apparent log-phase growth response of koa after the first year in establishment. These results demonstrate how the combination of fundamental silvicultural practices in the nursery and the site can accelerate tree growth to meet restoration goals in shorter time intervals. This is a first report of koa (a leguminous species) tolerance to a high-rate, pre-plant application of the herbicide active ingredient imazapyr.
2016:
Trial by fire: Invasive plant management following a wildfire at the O‘ahu Forest National Wildlife Refuge - Chelsea Arnott & Alison Crowley (Ko‘olau Mountains Watershed Partnership) - NO ABSTRACT
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Control of Chromolaena odorata on O‘ahu: A bedeviling problem - Nathan Dube & Alex Bessemer (O‘ahu Invasive Species Committee) - NO ABSTRACT
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Restoration case study: Psidium cattleianum dominated forest in the Wai‘anae Mountains, O‘ahu - Jane Beachy (O‘ahu Army Natural Resources Program) - NO ABSTRACT
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Scaling up success: What might it take to achieve ecosystem-level invasive plant management in the Ko‘olau Mountains? - Richard Pender (Ko‘olau Mountains Watershed Partnership) - NO ABSTRACT
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Remote detection of invasive pines (Pinus spp.) within Haleakala National Park: Target detection and extraction - Jonathan Marshall (Department of Natural Resources and Environmental Management, University of Hawai‘i at Mānoa) - NO ABSTRACT
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Assessing the most effective weed control re-treatment interval for Clidemia hirta dominated areas at Opaeula Lower
Management Unit, O‘ahu - Michelle Akamine (O‘ahu Army Natural Resources Program) - NO ABSTRACT
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An integrated telemetry system for herbicide ballistic technology (HBT) to determine dose to target and area use rate - Roberto Rodriguez (Akamine, O‘ahu Army Natural Resources Program) - NO ABSTRACT
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Aerial search effort and intervention frequency leading to target density reduction on incipient Miconia populations - James Leary (Department of Natural Resources and Environmental Management, University of Hawai‘i at Mānoa) - NO ABSTRACT
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An integrated telemetry system for herbicide ballistic technology (HBT) to determine dose to target and area use rate - Roberto Rodriguez (Department of Molecular Biosciences and Bioengineering program at the University of Hawai‘i at Mānoa) - NO ABSTRACT
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Vegetation monitoring utilizing gigapan imagery - William Weaver & Michelle Akamine (Akamine, O‘ahu Army Natural Resources Program) - NO ABSTRACT
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Fountain grass suppression in Manuka Natural Area Reserve, Hawai‘i: 20 years later - Jennifer Randall (Department of Land and Natural Resources, Hawai‘i) - NO ABSTRACT
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Calibrating effective herbicide dose injections on tropical woody species - James Leary (Department of Natural Resources and Environmental Management, University of Hawai‘i at Mānoa) - NO ABSTRACT
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2017:
Coming Soon!
2018:
Remote sensing of invasive plants with unmanned aerial vehicles (UAV) and open-source computer vision software - Jean Fujikawa, Derek Ford, and Solomon Champion (Oahu Invasive Species Committee, Kailua, HI)
Advances in technology, increasing amounts of imagery available, and the enthusiasm of two of our field crew led us to experiment with both drone surveys and computer-aided object detection for invasive species management in this past year. We experimented with a DJI Mavic Pro, DJI GO 4 flight software, and DroneDeploy for flight planning and processing orthomosaics. UAVs were most useful for miconia (Miconia calvescens) surveys on uluhe ridges where survey quality seemed equivalent to ground or aerial surveys and in residential areas. UAVs were also useful in locating the specific location of dead ‘ōhi‘a trees when sampling for Rapid ‘Ōhi‘a Death. We used OpenCV for computer-aided object detection and experimented primarily with fountain grass (Cenchrus setaceus) classifiers, but also tried classifiers for miconia. We created Python programs to identify some of our target species in single images, in a batch of images, and in videos. Future research would involve making the video review more automated,and collecting imagery specific to our target species as well as the image collection method to created better classifiers.
Native Forest Restoration in the Kipapa Burn Response Area: Management Update - Jordan Lewis, Dylan Davis, and Will Weaver (Koolua Mountain Watershed Partnership, Honolulu, HI)
In January 2015, a forest wildfire burned 180 acres of koa/‘ōhi‘a lowland mesic forest located between 1,000 ft. and 1,500 ft. elevation along the lower western boundary of the Oahu Forest National Wildlife Refuge. Within a year of the fire, a suite of woody weeds invaded the site or resprouted from burned stumps, including: albizia (Falcataria mollucana), broomsedge (Andropogon virginicus), paperbark tree (Melaleuca quinquenervia), gunpowder tree (Trema orientalis), shoebutton ardisia (Ardisia elliptica) and white moho (Heliocarpus popayanensis). KMWP received funding from the DOI Burned Area Emergency Rehabilitation (BAER) program for initial control work and weed mapping of the burned area [referred to as the Kīpapa Burn Response (KBR) area] during 2015. KMWP mapped the affected area, identified invasive targets, designated subunits for management purposes, developed a management plan, and initiated invasive grass and woody target weed control to facilitate recruitment of native vegetation throughout the target area. Monitoring in the unit indicates that native vegetation is responding positively to continued weed control actions with further management needed. Paperbark (Melaleuca quinquenervia) was designated a high priority target weed for the KBR area during FY17 due to its aggressive domination of landscapes affected by fire and its ability to outcompete native vegetation with allelopathy exhibited by leaf litter. Control was ramped up in 2017 and treatment method trials are underway in 2018.
Accelerating the Restoration Trajectory of Acacia koa - Jeremiah R. Pinto, Anthony S. Davis, James J. K. Leary, Matthew M. Aghai (Rocky Mountain Research Station, USDA Forest Service, Moscow, ID, College of Forestry, Oregon State University, Corvallis, OR, Department of Natural Resources & Environmental Management, University of Hawaii at Manoa, Kula, HI,School of Environmental and Forest Sciences, University of Washington, Seattle, WA)
Restoring Hawaii’s native koa (Acacia koa, A. Gray) forests are top conservation and forestry priorities; providing critical habitat services and high-value timber products. Efforts to restore koa forests, however, are directly impeded by extensive kikuyu grass (Pennisetum clandestinum Hochst. ex Chiov.) swards occupying deforested montane landscapes. In separate field studies, we implemented different herbicide combination treatments for measuring grass suppression and koa seedling performance in naturalized (grass-dominated) mesic, montane sites on the Big Island and Maui. In the Maui experiment untreated plots were compared to suppression with a high-rate herbicide combination of imazapyr and glyphosate (1.7 kg a.i. ha-1, respectively), administered 30 days pre-plant. Across all treatments, seedling survival was high (>95%). Grass suppression resulted in trees that were 34% taller with 66% larger root-collar diameters, 30 months after planting. Corresponding to the larger sizes, were significantly higher leaf area indices (2.6 vs. 1.8 m2 m-2), indicative of higher photosynthetic capacity and canopy closure. Grass suppression also increased soil temperature and soil moisture in the first year, followed by a dramatic drop in soil moisture on the second year, which corresponded with an apparent log-phase growth response of koa after the first year of establishment. This is a first report of koa (a leguminous species) tolerance to a high-rate, pre-plant application of the herbicide active ingredient imazapyr. A similar experiment on the Big Island compared untreated plots against grass suppression with grass selective herbicide active ingredient fluazifop-p-butyl applied every four months for a total of five treatment applications in 20 months. We measured >70% decline in the stolon fraction after 20 months as a result of the successive applications. Furthermore, we also measured ~2-fold increase in basal diameter and canopy height of 12-month old koa saplings with the post-plant fluazifop regiment compared to the untreated control. The results of the experiments support the utility of the herbicides in grass suppression. Imazapyr and glyphosate are broad-spectrum herbicides, but are typically the most effective grass control options. There is potential for collateral injury from these herbicides if not scheduled properly in a restoration plan. Fluazifop-p-butyl is one of the few options for selective grass control in natural area restoration. It shows excellent performance as a post-plant suppression/maintenance strategy on monotypic swards of kikuyu grass positively contributes to an accelerated restoration tactic restoring koa canopy. This data was submitted in an application package by Syngenta Corp. to the Hawaii Department of Agriculture to petition for a FIFRA Sec. 24c Special Local Needs Registration for controlling invasive grass species in wildlands and restoration areas in Hawaii. The study on imazapyr and glyphosate can be referenced by searching Pinto, J. R., Davis, A. S., Leary, J. J., & Aghai, M. M. (2015). Stocktype and grass suppression accelerate the restoration trajectory of Acacia koa in Hawaiian montane ecosystems. New Forests, 46(5-6), 855-867.
Conservation Updates from Waimea Valley - Laurent Pool (Waimea Valley / Hi`ipaka LLC, Hale`iwa HI)
Since the 2008 acquisition of the 1,875-acre parcel of land on the North Shore of O`ahu, Hi`ipaka LLC has developed a functional and growing conservation program. The program currently has 3 sites to manage. Progress updates on all 3 sites highlight challenges and successes. The Forest Stewardship Management Plan has been briefly outlined. Data is presented showing overall trends of plantings, ungulate control, volunteer involvement, and restoration efforts. Available funding sources for private landowners are also discussed. A brief guide to the “home grown” style of conservation is described and includes; native plant fruiting schedules, nursery management, site preparation, out-planting and site maintenance.
Native Hawaiian Forest Restoration at Koa Ridge, Waikāne Valley, windward Ko‘olau Mountains, O‘ahu: A Progress Report - Paul L. Zweng (‘Ōhulehule Forest Conservancy, LLC)
Waikāne forest restoration projects occur in mesic-to-wet, low-to-mid elevation (~400-800 ft) ridges and gullies located in the northern portions of Waikāne Valley, windward Ko‘olau Mountains, O‘ahu. The native plant communities here have been largely degraded whereas more intact native plant communities still survive at higher elevations. A botanical survey conducted by Joel Lau (2012) recorded 97 native taxa including 31 trees, 19 shrubs, and 11 ground cover/herbs, 4 vines and 32 ferns/fern allies. Rare plants include hai‘wale (Cyrtandra kaulantha and Cyrtandra subumbellata). Remnant native forest on ridges and slopes are dominated by ‘ōhi‘a, koa, kōpiko, ‘ahakea, and lama trees. The common invasive plants occurring on ridges and upper slopes within the restoration sites include albizia, strawberry guava, shoebutton ardisia, octopus/umbrella, and white moho (trees); Clidemia and Asteraceae sp. (shrubs/ subshrubs/herbs), alien grasses such as basket grass and Hilo grass as well as alien ferns such as Cyclosorus parasiticus. “Search and destroy” sweeps in 2012-2017 have killed 1,552 albizia and 2,912 octopus trees, helping to mitigate their spread. Forest restoration at Koa Ridge has been conducted at ten sites, each occurring in close proximity to one or more “old growth” koa trees, using variations on the following steps: (1) Girdle/treat the largest of the strawberry guava trees as well as the numerous
Monitoring on a Time Budget - Jenna Masters (Division of Forestry and Wildlife, Department of Land and Natural Resources, Pearl City HI)
In programs with smaller staff and time constraints committing to a monitoring plan can be a daunting. Monitoring can be used evaluate program goals, management effectiveness and is often needed for reporting on grant deliverables. Finding a way to get reliable data while operating in a restricted time budget is one of the goals of this plan. NEPM wanted to assess two things; change in management areas over time and survivorship of ex-situ species in the Pahole Natural Area Reserve. One of our main challenges is to determine survivorship in species planted with fluctuating amounts of individuals. Some species have too many to monitor every year while others have too few. To increase the sample size of plants with too few individuals our monitoring plan will span multiple years. Monitoring will continue until 2021 where we should have up to 100 individuals from each plant species. This long-term monitoring reduces monitoring time per year while providing a larger sample sizes. We will be monitoring our first cohort of plants that were introduced in 2017 this year. Photo point monitoring is used to asses change over time. Unfortunately, photos can only be representative of the areas pictured and cannot accurately assess the area as a whole. We would like to assess the difference between weed management techniques. Two common techniques include the removal of invasive by clear cutting vs. slow killing of an area. What we can determine is the amount of time and effort spent in each area and compare them to how the pictured areas have changed over time. We would like to brainstorm more ways to monitor on a time budget and think this would make a great break out topic.
Native Ecosystem Restoration as Weed Control - Taylor Marsh (Oahu Army Natural Resources Management Program, Wahiawa, HI)
Although conservation agencies across the state have differing goals, one commonality exists: the need for ongoing control of invasive plants. What agencies replaced controlled weeds, or entire treated areas, with native plants via active restoration? Would this reduce the amount of weeds which occur in treatment areas over time? It is difficult to know if active restoration works, and there are a number of differing factors to consider that might make restoration efforts difficult or even unnecessary. In Hawai‘i, mostly qualitative observations about this have been made during restoration efforts, but it is nevertheless important to consider replacement strategies after the removal of weeds, as there are potentially some significant direct and indirect benefits to using the technique. At the O‘ahu Army Natural Resources Program (OANRP), efforts are currently underway to restore three alien-dominated mesic forest sites in the Wai‘anae Mountains to native-dominated understory and canopy. At these restoration sites, anecdotal information suggests that active restoration effort is effective and worthwhile, but also reveals lessons learned and associated challenges. This presentation is intended to show restoration successes, promote discussion and, create and perpetuate momentum for more restoration projects in the future.
Early Movements of Tectococcus ovatus, a Psidium cattleianum Biocontrol, in West Maui and Oahu - Chris Brosius, Amanda Hardman, and Will Weaver (West Maui Mountain Watershed Partnership, Lahaina, HI, Division of Forestry and Wildlife, Department of Land & Natural Resources, Pearl City, HI, Koolua Mountain Watershed Partnership, Honolulu, HI)
Non-native, habitat modifying Psidium cattleianum (strawberry guava) is currently among the greatest threats to the watershed and health of native ecosystems on the Hawaiian Islands. In Hawaii, strawberry guava thrives between sea level to 4000’ and satellite populations are observed at greater elevations. P. cattleianum was brought to Hawaii in 1825 from Brazil as an ornamental plant. It is extremely fast growing, resilient, animal and bird dispersed, monotypic, and water thirsty. An integrated management approach will be needed to control the spread given its aggressive use of habitats over challenging terrain. In West Maui, approximately 5,000 acres are already monotypic (~10% of the entire WMMWP area). Habitat modeling suggests this species has the ability to invade the entirety of the West Maui watershed if left unchecked. Almost the entire landmass on Oahu sits below 4000’ and is susceptible to invasion. Strawberry guava is one of the top causes for the destruction of the native mesic forest in the Waianae range and is currently a serious threat to the upper elevations of the wetter Koolau summit watersheds. Landscape level control methods are needed to prevent further invasion. This presentation will summarize establishment efforts of the biological control agent, Tectococcus ovatus, on the Island of Oahu and focus on early lessons learned regarding the establishment of the biological control in West Maui. We will explore potential T. ovatus translocation methods to help accelerate the spread of the species and propose integrated strategies which may further future P. cattelianum control efforts.
2019:
Considerations for Restoration Site Preparation and Planning - Jane Beachy (Army Natural Resources Program, O‘ahu) - NO ABSTRACT
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Transforming Land Back to ‘Āina - Rick Barboza (Hui Ku Maoli Ola) - NO ABSTRACT
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2020:
Coming Soon!