Early Detection of Invasive Plant Species & New Plant Records: Hawaiʻi Volcanoes National Park

Gross, Jacob; Faccenda, Kevin; Akamine, Kathryn

The Pacific Island Inventory and Monitoring Network (PACN) lists four objectives within the Early Detection (ED) of Invasive Plant Species Monitoring Plan (Ainsworth et al. 2017): 1) Survey dispersal corridors and other high-risk sites for incipient populations of potentially invasive plants. 2) Provide timely information to park managers regarding the resence of new and potentially invasive plant species in order to facilitate a rapid management response. 3) Update and maintain NPSpecies (https://irma.nps.gov/NPSpecies/), the plant species database for each park, including new species detected during field surveys. 4) Develop and distribute invasive plant outreach materials to park staff to increase awareness and reporting capability. This report summarizes the new and potentially invasive plant species detected within Hawaiʻi Volcanoes National Park (HAVO) during PACN Early Detection surveys from August 12th-19th, 2022. Weed Risk Assessment (WRA) scores were utilized to help predict each newly detected plant species’ level of invasiveness and potential to spread and disrupt ecosystems (HPWRA 2023). When WRA scores were unavailable for a given plant species, the authors utilized any available information on naturalization and spread in other locales along with invasiveness of related species, lifeforms, or traits in Hawaiʻi to subjectively weigh invasiveness potential relative to other species with WRA scores. Plant species were then ordered according to their relative invasiveness potential, with the greatest WRA scores (i.e., riskiest species) listed first. In addition, species of particular concern are highlighted in the box below titled “Highlighted Species for Management Action.” All species included in this report were previously not listed within the park’s species checklist (NPSpecies) or listed as “Unconfirmed” on the checklist. In addition to early detection, some new plant species records were documented within the park by other means (other projects, herbarium records, etc.)—these species are reported here also under the section “Other New Species.” Finally, some plant species known to occur in the park were previously lumped together or otherwise mislabeled with incorrect species names, these corrections are listed under the “Misapplied” section.