Predicting the Effects of Climate Change on the Spread of Fire-Promoting Plants in Hawai‘i: Assessing Emerging Threats to Rare Native Plants and Ecosystems
A Pacific Islands CASC FY 2019 Funding Opportunity Project
2018 was a record-breaking year for wildfires in Hawai‘i with over 30,000 acres burned statewide, including the habitat of the Oʻahu chewstick, a critically endangered flowering plant with less than 50 individuals remaining. The frequency and severity of wildfire in Hawai‘i has been increasing, and this trend is predicted to worsen with climate change. Wildfires are promoted by highly flammable invasive plants, which can spread across the landscape, providing a widespread fuel source to feed large fires that are hard to control. However, different plant species vary in their flammability, so wildfire risk depends not only on climate, but also on which plants are present. A major concern is that new non-native plants are entering Hawai‘i [...]
Summary
2018 was a record-breaking year for wildfires in Hawai‘i with over 30,000 acres burned statewide, including the habitat of the Oʻahu chewstick, a critically endangered flowering plant with less than 50 individuals remaining. The frequency and severity of wildfire in Hawai‘i has been increasing, and this trend is predicted to worsen with climate change. Wildfires are promoted by highly flammable invasive plants, which can spread across the landscape, providing a widespread fuel source to feed large fires that are hard to control. However, different plant species vary in their flammability, so wildfire risk depends not only on climate, but also on which plants are present. A major concern is that new non-native plants are entering Hawai‘i every year, some of which will spread to become invasive. Some of these recently invading plants have fire-promoting traits, making their spread a serious fire hazard.
This project will assemble information on the distribution and fire-promoting traits of non-native plants in Hawai‘i in order to generate a list of upcoming fire-promoting invaders that can be targeted for eradication and management now, before they spread widely in Hawai‘i . The researchers will also use modeling to predict how climate change will affect these fire-promoting invasive plants and fire distributions, specifically in relation to locations of rare and endangered native plant populations as well as cultural resources in Hawai‘i. The main objective is to identify sites or rare native plant species in need of special fire mitigation or management attention.
The results of this project will help reduce harm caused by wildfires in Hawai‘i by identifying fire-promoting invaders that can be eradicated before they spread widely, and by identifying rare native plants that are at high risk of burning in the future due to climate change and may need special conservation attention. In particular, this project will provide information needed by the National Park Service in developing their Fire Management Plan for the new Hono’uli’uli National Monument on O‘ahu, and will inform Hawai‘i’s Island Invasive Species Committees (ISCs) in developing protocols to prioritize new species for island-wide eradication.
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Fire_HawaiiVolcanosNP_NPS.jpg “Fire in Hawaii. Credit: NPS”
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Understanding the interaction between climate change and the spread of fire-promoting invasive plants is critical for wildfire prevention and management planning. This research proposes to unite existing predictive models for fire probability and invasive plant distributions with a new comprehensive plant biodiversity data set, enabling us to assess how patterns of invasive plants species and fire probability are likely to be affected by climate change statewide. These patterns will be mapped onto endangered plant and habitat locations, providing prediction as to which rare native species are likely to be increasingly threatened by wildfires in the future. A list of all fire-promoting invaders, identified by their specific fire-promoting traits, will be generated and cross-referenced with distribution data of naturalized and escaping plants in Hawai‘i, allowing us to determine which fire-promoting alien plants currently have limited distributions (emerging invaders) versus those that are thoroughly established. Ecological Niche Models will be used to forecast the range limits of fire-promoting species, taking into account projected changes in climate in Hawai‘i, particularly increasing temperature, declining precipitation trends, and increasing frequency of drought events. Wildfire probability maps informed by a dataset of large fires (> 20 ha) and 20-year fire history for Hawai‘i, will provide a quantitative, spatially explicit assessment of wildland fire probability statewide as predicted by climate, land cover and ignition density. Areas of overlap among the spatial layers generated from wildfire and fire-promoting invasive plant models, endangered species locations and key cultural resource locations will be identified to highlight lands that are of particular management concern. This information will be disseminated to conservation and cultural resource land managers to help implement wildfire mitigation planning. Fire-promoting invasive plants that currently have restricted distributions in Hawai‘i will be identified to raise awareness among invasive species managers and to help identify target species that may be eradicable before they spread further.