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  • Writer's pictureJenni Foshey

How Climate Change Increases the Spreading of Invasive Gorse and Wildfire Risk in the Maunakea Ecosystem, Hawai’i

Updated: Jan 16

Maunakea is a sacred mountain on the Island of Hawai’i (Big Island) that is extremely important culturally, spiritually, and ecologically. Climate change is expected to impact the Maunakea ecosystem by making the region hotter and drier. These climatic conditions are likely to increase wildfire risk and the further spread of invasive gorse (Ulex europaeus) in this region. Gorse is an invasive plant that covers a large portion of the Maunakea ecosystem, spreads quickly, and does well in hot, dry, degraded, and fire-prone areas. It is important to understand the relationship between climate change, wildfire risk, and invasive gorse in the Maunakea ecosystem so that we can prevent the spread of invasive gorse, save native plant species, reduce wildfire risk, and protect Maunakea for future generations.


Photo of Maunakea.
Maunakea.

Maunakea: The Basics

  • Maunakea is one of the five volcanoes on Hawai’i Island (also referred to as the Big Island of Hawai’i)

  • Maunakea, the focus of this report, is estimated to be about 1 million years old, is the highest peak in the Pacific Ocean, and is the world’s tallest mountain towering at 4,207 meters above sea level 

  • The boundaries of the “Maunakea ecosystem” varies depending on who you talk to or what particular features or management areas you are looking at


Map of Hawai'i Island showing the locations of the 5 volcanoes.
The 5 Volcanoes on Hawai’i Island: Hualālai, Kīlauea, Kohala, Maunaloa, and Maunakea.

Map of Hawai’i Island showing the 5 volcanoes, rift zones, lava flows, and radial vents.
Map of Hawai’i Island showing the 5 volcanoes, rift zones, lava flows, and radial vents.


Who Manages the Land?

Maunakea is sectioned into different regions that are managed by different stakeholders. The summit region is managed by the University of Hawai’i and encompasses the Natural and Cultural Preservation Areas, a sacred freshwater lake called Lake Waiau, the Maunakea Ice Age Natural Area Reserve, and the Maunakea Science Reserve which houses many telescopes. Other stakeholders include: the State of Hawai’i, Parker Ranch (the largest ranch in Hawai’i), the Hakalau Forest National Wildlife Refuge, Kūkai'au Ranch, Kamehameha Schools, the Queen Lili’uokalani Trust, and the Department of Hawaiian Homelands (DHHL), which is where invasive gorse is most abundant.


Map showing the stakeholder land divisions of Maunakea (2020).
Map showing the stakeholder land divisions of Maunakea (2020).

Why is Maunakea Important to Protect?

Maunakea is important culturally, spiritually, and ecologically. Maunakea should be protected to preserve the natural beauty and life the mountain provides. 

“The health of our lands (‘āina), is the health of our people (kānaka ‘ōiwi), is the health of our nation (lāhui)” - Dr. Noa Emmett Aauwas Aluli, MD 


Cultural and Spiritual Importance 

  • Maunakea is Hawai’i’s most sacred place 

  • The Hawaiian name Maunakea translates to “White Mountain'' because it symbolizes the connection from land to the heavens 

  • Hawaiians consider Maunakea as an elder and they have a familiar relationship to it and Hawaiians believe that they come “from the mountain” because of the role Maunakea played in the Hawaiian Islands early discovery

  • Maunakea is home to many burial sites 

  • Maunakea is home to the sacred freshwater lake, Lake Waiau, which is located close to the summit


Ecological Importance

  • Maunakea is an alpine ecosystem, which is one of the most threatened ecosystems by climate change 

  • Maunakea is the only place in Hawai’i where you can find permafrost


Permafrost is a type of frozen soil that holds carbon, is in two regions of Maunakea, but is melting fast in part due to anthropogenic climate change. The relationship between climate change and melting permafrost is a dangerous cycle because as temperatures get warmer, permafrost melts which releases large quantities of carbon dioxide and methane into the atmosphere, accelerating climate change. 


Permafrost thawing cycle provided by World Wildlife Fund (2021). Increased greenhouse gas emissions lead to increased temperatures, which causes permafrost to thaw. Thawing permafrost releases more greenhouse gasses into the atmosphere, causing temperatures to increase.
Permafrost thawing cycle provided by World Wildlife Fund (2021). Increased greenhouse gas emissions lead to increased temperatures, which causes permafrost to thaw. Thawing permafrost releases more greenhouse gasses into the atmosphere, causing temperatures to increase.

How is Climate Change Impacting Hawai’i? 

Climate change is most problematic in regions that have contributed the least to greenhouse gas emissions. For example, carbon emissions across the entirety of the Pacific Islands amount to less than 0.03% of the world’s total emissions, yet these islands are some of the most at risk regions. Hawai’i and other Pacific Islands are vulnerable to climate change because of their remoteness, limited freshwater, extensive coastlines, susceptibility to impacts from natural disasters, and vulnerable food systems. The Hawaiian Archipelago has the 4th longest cumulative coastline in the United States, which means it is one of the most at-risk states to environmental tragedies like sea level rise, warming ocean temperatures (which has consequent effects of coral bleaching and declining ocean health), beach and coastal erosion, hurricanes, and other tropical storms. Hawai’i was the first U.S. State to declare a climate emergency as of 2023.


How will Climate Change Impact the Maunakea Ecosystem?

Summary

Climate projections indicate that the Maunakea ecosystem will become hotter and drier. These climate projections will: 

  1. Increase the spreading of invasive gorse 

  2. Increase wildfire risk


Climate Projections

There is confidence that climate change is projected to make droughts persist or worsen because temperatures will increase, especially at higher elevations, and precipitation will decrease making it drier in the Maunakea ecosystem. This will exacerbate wildfire risk, increase damage by feral ungulates (hooved animals like sheep and goats), cause loss of native plant species, and increase risk of soil erosion. 


To see the current drought conditions in Hawai’i, check out the U.S. Drought Monitor resource below!



Interested in learning more about climate change in Hawai'i? Watch this!



Increased Spread of Invasive Gorse 

Invasive Species in Hawai’i 

Invasive species are Hawai’i’s number one environmental threat due to the remoteness of the islands, the frequent imports of goods, and high tourism. The Hawai’i Department of Land and Natural Resources (Hawai’i DLNR) classifies an invasive species as a species that arrived to Hawai’i without the assistance of humans. A species is considered invasive if it is harmful to the environment, economy, and/or human health, and is not native to Hawai’i. Common invasive plants in the Maunakea ecosystem include: gorse (Ulex europaeus), cape ivy (Delairea odorata), fireweed (Chamaenerion angustifolium), and fountain grass (Pennisetum setaceum). 


Gorse in full bloom.
Gorse in full bloom.

Gorse Quick Facts: 

  • Gorse does well in dry and hot environments 

  • Gorse is pyrophytic (fire-resistant) 

  • Gorse can fix nitrogen, which allows it to colonize and dominate areas with poor soils 

  • Gorse reproduces through its heat-tolerant seeds, which are produced at the rate of 500-600 seeds per square meter and there can be up to 20,000 seeds per square meter in one given region 

  • Gorse seeds can remain viable in the soil for over 30 years, making it challenging to remove because it takes a long time to completely eradicate 

  • Gorse is a fire-hazard due to its woody and oily structure

  • Gorse also has a deep root system which allows them to prevent native species from establishing their roots


Gorse (yellow flowered plants) in the Maunakea ecosystem.
Gorse (yellow flowered plants) in the Maunakea ecosystem.

Where is Gorse located within the Maunakea Ecosystem?

Gorse is most prominent in the eastern region of Maunakea in the DHHL region (see map below) and is most problematic along the edges of public roads, degraded landscapes, pasture lands, cleared forests, gravelly floodplains, and areas of high human disturbance. East of the DHHL region lies the Hakalau Forest National Wildlife Refuge which is home to many endangered plants and animals. Given the proximity between these two regions, it is important to contain gorse in the DHHL region so it does not enter the Hakalau Forest National Wildlife Refuge and crowd out the flora and fauna there. If gorse is not well maintained, it can easily spread throughout the island.


Map of Hawai’i with an arrow pointing to the DHHL region where gorse (Ulex europaeus) is most abundant in the Maunakea ecosystem.

Image Source: Leary et al. (2006).


Increased Wildfire Risk

As climate change makes the Maunakea ecosystem hotter and drier, gorse is able to spread more easily as it does well in these conditions. As gorse begins to dominate the ecosystem, there will be less biodiversity in the region (because gorse will crowd out native species). Remember, gorse is a dry plant and thrives when fire is present. Gorse burns at a very high intensity and spreads quickly. With more gorse present, there is more risk for wildfires to spread because gorse acts as kindling for the fires since it is such a dry, woody plant. This is what we call a “positive feedback loop”.

Note: Despite the term "positive" in a "positive feedback loop", it does not translate to "good". A positive feedback loop indicates that as one factor increases (i.e. climate change impacts), it will cause another factor (i.e. fire risk) to increase which worsens/exacerbates the entire situation/relationship.


Positive feedback loop of climate change, fire risk, and gorse spread. Climate change impacts promote gorse spreading and increases fire risk. Increased gorse spreading increases fire risk, which further increases the spread of gorse.
Positive feedback loop of climate change, fire risk, and gorse spread. Climate change impacts promote gorse spreading and increases fire risk. Increased gorse spreading increases fire risk, which further increases the spread of gorse.

Why is this Information Relevant?

Understanding what can increase wildfire risk in Hawai’i is extremely important because it allows people to take actions that will prevent wildfires and prepare them for when they do occur. The Lāhainā wildfires that took place in August of 2023 are still being understood and people are still (and will forever be) grieving the loss of so many lives. The wildfires in Lāhainā were deemed the worst environmental disaster in Hawaiian history and was the deadliest wildfire in the U.S. in the past century, affecting 1,550 people and 2,200 structures. High winds and dry weather was the cause of the wildfires that developed and turned the entire town into shambles. While organizations, homeowners, and governmental officials are aware of the risks of wildfires, the Lāhainā wildfires have demonstrated how deadly and unstoppable they are. Efforts to mitigate and prevent wildfires need to continually be checked and planned for. Natural wildfires on Maui used to be rare, but land development and encroachment of invasive species has shrunk this ecosystem putting it more at risk for wildfires to occur. The Maunakea ecosystem shares similarities with Maui as it, too, is impacted by land development (specifically land degradation) and invasive species. This adds to the fact that wildfire risk will increase as the impacts of climate change progress.



Click below to donate to the Maui Strong Fund that provides financial resources to support the immediate and long-term recovery needs for the people and places affected by the devastating Maui wildfires.


Studying the ecology and distribution of gorse can help scientists, governmental officials, and land managers understand the relationship between gorse and climate change impacts. We cannot afford to ignore climate change, especially in Hawai’i. Now more than ever, we witness more frequent and deadly wildfires that span large areas. Because of the wildfire potential in Maunakea due to climate change and gorse, we must prioritize learning more about this relationship and taking preventative measures early on so we can protect the sacred Maunakea ecosystem for generations to come. This knowledge can influence future climate mitigation strategies, climate policies, ecological restoration practices, invasive species management, and wildfire risk prevention in the Maunakea ecosystem.


What is Currently Being Done to Protect Maunakea?

Restoration 

There have been many efforts to eradicate and control gorse in the Maunakea ecosystem, but it is still spreading and putting many endemic species at risk. There are many different ways to restore and protect an ecosystem. In the case of invasive gorse in the Maunakea ecosystem, there are two primary strategies being implemented: 1) removing invasive species 2) planting native species.


1. Removing Invasive Species

Invasive species removal entails people going out into the field to physically pull out, cut down, or spray with herbicide. 


2. Planting Native Species

The best way to remove gorse without contributing to its spread is to plant fast growing native species, like koa (Acacia koa), to shade out gorse. It is important to make sure that the area does not experience any disturbance for twenty years while trees are growing. Once the native trees are large enough, the area will become too shady for gorse and the gorse will not be able to survive.


DHHL and College of Tropical Agriculture and Human Resources at the University of Hawai’i at Mānoa pilot restoration project of planting koa trees (Acacia koa) (middle of image) in a field of gorse (yellow surrounding vegetation).
DHHL and College of Tropical Agriculture and Human Resources at the University of Hawai’i at Mānoa pilot restoration project of planting koa trees (Acacia koa) (middle of image) in a field of gorse (yellow surrounding vegetation).

Limitations to Restoration

Restoring an area through removing invasive species or planting native species is effective, but it takes time and requires regular upkeep and plenty of personnel to do the work and maintain the site for years. Restoration also requires adequate funding for the equipment, plants, permits/certifications, and personnel (ex: paychecks). 


Education and Outreach 

In addition to restoration efforts, various organizations and stakeholders of Maunakea work to educate the public about the invasive species that threaten the ecosystem through their websites, social media, meetings, and newsletters. Many organizations also do outreach work to gain support of their mission to protect/restore Maunakea. This can be done through asking for donations or by hosting volunteer work days where the public can physically help remove invasive species or plant native species.


Watch the video below to learn about Natural Climate Solutions; how we can use nature to combat climate change.


How You Can Help!

Whether you are located on Hawai’i Island or elsewhere in the world, you CAN help protect Maunakea for future generations. Check out the resources below to learn more about the missions of individual organizations. You can also show your support by following them on social media or by donating to them.  If you do ever visit Hawai’i, consider participating in an environmental restoration work day to show your love for the ‘āina (Hawaiian for land). 

Get Involved!

Additional Resources to Check Out:

Jenni (author) removing invasive ginger at a restoration site in Hawai’i with Kupu.
Jenni (author) removing invasive ginger at a restoration site in Hawai’i with Kupu.

Accounts to Follow on Instagram


 

Interested in learning more? Contact me for the full report at journey.jenni@gmail.com


Like this article if you learned something new!

Questions? Leave a comment below!

 

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