One of the best places in america is Mount Waialeale on the Hawaiian island of Kaua’i. The 5,148-foot peak receives an average of 374 inches of rain each year, but even with that annual deluge, the island state as a whole is in a period of prolonged drought.
Nearly all of Hawaii is experiencing some degree of “moderate” to “exceptional” drought, according to federal monitoring data. While this year is not as severe as the 7-year dry spell that ended in 2015, it coincides with a larger pattern of the decrease in flooding in Hawaii over the last 30 years. To make matters worse, the drought has also corresponded with a increase in average temperatureswhich speeds up evaporation.
“Globally, we’re seeing more novel types of drought,” says Abby Frazier, an assistant professor of geography at Clark University in Worcester, Massachusetts, who studies climate change and Hawaiian habitats. “One concern is that we don’t know the potential for drought to have transformative impacts on our ecosystems.” As droughts They are becoming Longer, more severe and more frequent, researchers like Frazier are concerned that ecosystems may be irreparably changed and may not recover even if regular rains start again.
There are many scientists who still don’t know how Hawaii’s unique ecosystems are responding to the prolonged lack of rain, which is closely related to changing weather conditions in general. But it is clear that the dynamics of invasive species management and endangered species protection are changing along with the ecosystem.
Despite the threat that droughts pose to the health of forests, biologists know that maintaining forests is one of the best ways to lessen the impacts of drought and keep as much water as possible in the ecosystem. Hawaii’s forests have adapted to capture moisture from the air in the form of fog or low clouds. “Water harvesting from clouds is just as important as rain,” says Emma Yuen, program manager for the state Department of Land and Natural Resources. “But if you don’t have the native vegetation there to collect moisture, you’re going to have a huge decrease in water going into the groundwater supply.”
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But lack of water is not the only threat to forests: invasive animals, mainly ungulates such as deer and pigs, damage native vegetation. Uncontrolled and without natural predators, wild deer, hogs and goats can cause serious damage, especially during a drought when herds have been destroyed. viewed Aggressive grazing of integral native plants. When patches of land are left bare, it allows dry, invasive grasses to move onto the cleared land, serving as fuel and increasing the risk of wildfires.
“Hawaii doesn’t get national press on wildfires, but we’re on par with Western states in percentage of land burned,” says Yuen. In 2021, the largest fire in Hawaiian history burned. nearly 40,000 acres—which may sound small compared to the nearly 180,000 acres that burned in california that same year. But when you compare the size of the fires relative to the size of the states, a much larger portion of Hawaii’s total land mass burned. Weather conditions and invasion by invasive grasses on the islands were beginning to resemble the most fire-prone mainland states, Hawaii Public Radio reported in 2019.
Wildfires also fuel a negative cycle, Yuen explains, as invasive weeds regrow in the space created by the fire and become fuel for larger ones in the future. Additionally, wildfires can make drought worse: in addition to removing vegetation that collects moisture from clouds, the flames and heat make the burned land less permeable so that precipitation doesn’t sink into it and instead runs off. to streams and watercourses. That means less water to replenish groundwater aquifers and a higher risk of more frequent and destructive flooding.
Since fire is not a normal historical event in Hawaii’s forests, wildfire mitigation approaches include prescribed burns (a commonly used tactic in the West), are not an option. A burn ban has been in place in Hawaii since 2012, limiting all practices of burning and requires permissions of agricultural industries or land management. And unlike California and other parts of the American West, where many species of trees and other plants are well adapted to weather some flames and regenerate healthily, native Hawaiian vegetation is not destined to burn. Prescribed fires would be destructive rather than healthy and regenerative, as Hawaiian trees and plants might not get any stronger (if at all). Instead, the main tools available to fight wildfires are firebreaks: gaps cut into the vegetation to contain the spread of flames.
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The drought, combined with Hawaii’s unique topography and geography, also makes managing invasive species and protecting endangered species particularly challenging. As an island state, it is home to a number of endemic species, organisms that evolved on the islands and exist nowhere else. Some species may be hyper-specialized to live in a specific ecosystem. While this is true for many species around the world, on the confined islands of Hawaii, those particular ecosystems can be very small. There’s a disproportionately large number of endangered species relative to the available land mass in the Hawaiian Islands, which has only been exacerbated by pressures from climate change and invasive species.
“Over the course of six miles, the average annual rainfall in Hawaii can range from 15 inches to 366 inches in a year,” says Frazier. The wide variability can leave many species stranded. Flora and fauna have nowhere to reasonably relocate if habitable habitats disappear year after year due to wildfires, droughts, or invasive species, if they can move at all.
Local organizations are working on conservation efforts to preserve native wildlife from recent periods of drought. Frazier is part of the Pacific Drought Knowledge Exchange, a network of regional ecological researchers, natural resource managers, and other experts who share information about the impacts of drought and how to mitigate them. She says there are many conservation managers looking for creative solutions, such as replacing lost native species with different native plants that might better adapt to a region’s changing climate. However, she adds that there is a dearth of future climate information needed to inform good planning and a lack of awareness of Hawaii’s particular challenges in the continental US.
The islands may be known for their waterfalls and lush tropical forests, says Frazier, but “we need to let people know that we also have a drought.”