Is Fencing The Future Of Hawaii’s Native Ecosystems?

A sprawling ohai plant in northwestern Molokai clings to the earth, its leaves fluttering as gales blast off the Pacific Ocean. Its presence is a good sign.

molokai locator badgeOhai are early establishers in new ecosystems, called pioneer species, and when this plant was sighted in 2010, it marked 150 years since its last known appearance in the area.

This particular plant is the original’s progeny, part of a greater native ecosystem blanketed with mostly native flora – naupaka, aweoweo, akiaki grass to name a few. But ohai is particularly remarkable, according to William “Butch” Haase, executive director of the Molokai Land Trust.

“To see rare plants popping up on their own in your restored system, it’s kind of like the holy grail of restoration,” Haase said.

The Mokio Preserve is home to the endemic endangered Ohai plant that was growing very close to the ground with high winds whipping the landscape.
The Mokio Preserve is home to the endemic endangered ohai plant that was growing very close to the ground with high winds whipping the landscape. Cory Lum/Civil Beat/2022

He compares the pristine native area to what’s visible on the horizon: emaciated forests of gnarly invasive kiawe trees.

Between the invasive and native species is the project’s linchpin: a fence, being upgraded by a five-strong Molokai Land Trust crew. The new build is worth $1 million, spanning 1.1 miles, and will protect close to 100 acres.

Mammal-proof fencing is widely recognized as the most effective means of protecting the 1.3 million acres of native ecosystems that still exist in Hawaii, as they face overwhelming pressure from invasive species of plants and animals.

The pressure of outside influence on these ecosystems – which evolved without all the deer, pigs and goats – has left the archipelago with less than half of what existed before human contact.

Molokai Land Trust Executive Director William Butch Hasse drives his truck towards the Mokio Preserve located on the northwest side of Molokai.
Molokai Land Trust Executive Director William “Butch” Haase drives along the trail, only accessible by four-wheel drive, to Mokio Preserve. Cory Lum/Civil Beat/2022

The endemic and native species in these ecosystems play a greater role in Hawaii’s health, as they often constitute watersheds, which lie in the nexus of the state’s greatest concerns in the face of climate change: terrestrial and aquatic environments, fresh water availability and the state’s food system.

But to protect much of these ecosystems from mammals introduced since human contact, fencing appears to be the most viable resolution, as the state edges closer to its goal of protecting 30% of its important watersheds by 2030.

The state currently protects 5.6% of its native ecosystems, according to the Department of Land and Natural Resources, accounting for 17% of its important watersheds.

And given the mounting pressure of deforestation from mammalian populations, it has many now asking if the future of nature in Hawaii is to be fenced.

Building Barriers

Once a fence is built, the work is not done – trees fall, animals burrow, jump and climb, winds blow.

The trade winds that ricochet off the cliffs at Mokio Preserve corrode metal, so the new fence is made of the same material used for lobsterpots.

“It’s getting sandblasted and salt-sprayed continually,” Haase said. “We had five gauge galvanized wire disintegrate in four years.”

Map of protected Mokio Preserve boundary on Molokai
A map shows the Mokio Preserve boundary on Molokai. April Estrellon/Civil Beat/2022

In other areas around the state, watershed protection groups are tasked with reaching areas even less accessible than Mokio Point, on the tops of mountains, by helicopter.

Notwithstanding, all fences in Hawaii share the same primary function — keep invasive mammals out.

The fence that the Molokai Land Trust is currently building is expensive, designed to keep virtually everything without wings from getting in: An awning over the fence acts to keep mongoose and rodents out, while the interior mesh is buried a foot deep to keep animals from tunneling under it.

A Perilous Predicament

Once deer, pigs, goats or cattle get into an area, they cause havoc. They spread invasive plants, eat native flora and leave native trees susceptible to diseases such as rapid ohia death. They essentially upend an ecological balance formed over thousands of years without any intervention, human or otherwise.

Take feral pigs: They rub up against trees, stripping their bark — a key defense — as well as tear up forests’ understory, creating bare-soil bedding for themselves.

They also carry seeds in their hair or stomachs, depositing them in freshly degraded areas, making way for invasive plants to take hold. A University of Hawaii Hilo study published last year found that areas with invasive ungulates were up to 69 times more likely to have cases of rapid ohia death. Within the study period, a fence was breached and suspected cases of the arboreal disease rose dramatically.

In removing these multi-leveled ecosystems — which attract moisture and in turn ensure water availability — they leave bare land that is unable to retain water and nutrients, which leads to erosion, running soils off into the sea and destroying coastal marine ecosystems.

Watersheds are also the final safe haven for languishing native bird populations, of which two species — kiwikiu and akikiki — are predicted to go extinct within the next two years, according to DLNR’s Division of Forestry and Wildlife.

The consequences of losing watersheds continues though, according to Emma Yuen, manager of DOFAW’s native ecosystems program.

“These are really, really important for not only staving off the effects of climate change, but also dealing with the effects of climate change,” Yuen said.

Watersheds not only help to sequester carbon, she says, but they also help in preventing flooding by absorbing 14 times more water than barren land.

Partnering Up

DLNR currently requires about $6 million in state funding each year to reach its goal of protecting 30% of its important watershed areas by 2030, according to Yuen. The department has received $47 million in state funding for mammal-proof fencing since 2013, and $49 million in federal grants for the wider watershed program.

“Only a few years have we received that level of funding,” Yuen said. “Some years we didn’t get any. There have been lags in process that we’ll see.”

The state has recognized the importance of the archipelago’s watersheds since the early 1990s, when the first of 10 key watershed partnerships – which now collectively cover 2.2 million acres – formed between private and public landholders to protect the billions of gallons of water resources that existed within them.

It was only in 2011, when former Gov. Neil Abercrombie started “The Rain Follows the Forest” campaign to protect watersheds that the investment in fencing really started.

It was the result of years of work trying to convince lawmakers because at the time lingering doubt over the reality of climate change and the importance of the mountains was still abstract, according to then-DLNR Chair William Aila.

While in economic terms watersheds’ value is in the billions — Koolau Watershed on Oahu was estimated to be worth between $7.4 billion and $14 billion — evidence of their environmental value was mounting.

“It took a few years to get the information accepted by the decision-makers,” Aila said, adding that soon the ranchers and private landowners followed suit.

Now the future of Hawaii depends on watershed protection — and in turn fencing, he said.

The current DLNR chair, Suzanne Case, says the state is on track to meet the 30% goal by 2030 but it’s contingent on sustained funding. Watershed protection remains the department’s top capital improvement project priority.

“I think it will be close,” Yuen said. “We can’t afford to have less funding than what we need or else we’re not going to reach it.”

Of the 550 fencing projects currently underway in Hawaii, from tiny single-species fences to enormous fences encapsulating mountaintops, DLNR has funded approximately 219 miles of fencing across the islands since 2013.

“All across the entire rest of that, including 83% of our remaining old growth forest, we just have these animals eating away … as we speak,” Yuen said.

As the overall state budget bill currently stands, the Senate has so far agreed with the House in cutting almost $4 million in funding for watershed initiatives statewide next fiscal year, which starts July 1. Case told the Senate money committee, chaired by Donovan Dela Cruz, when it heard the bill last month that this would be “extremely problematic” if the funding was not restored.

Cutting that funding not only eliminates the $4 million in state money but also jeopardizes a $5 million federal grant that the department has secured which requires matching state funds.

“This statewide fencing initiative implements the most cost-effective and long-term solution to control axis deer, pigs, and other damaging animals, as well as protect forests from Rapid ʻŌhiʻa Death,” Case said in her testimony.

Though the draft budgets effectively zeroed out the watershed protection budget, the Senate inserted a nominal amount in its version which indicates it will likely be discussed further in conference committee later this month when House and Senate lawmakers negotiate a final draft.

But it's not just funding for fencing that is needed to help those areas; the community still needs to be on board.

"Now, almost 10-15 years later, the doubt about climate change is pretty much over," Aila said. "The next change is going to be convincing the hunters that we are going to have to get rid of some ungulates in some areas."


Sitting at a restaurant in Kaunakakai, Molokai's main town, Justin Luafalemana talks about managing the land over some saimin. The DLNR forestry worker's day of surveying the mountainous reaches of the island is sweated into his highlighter-yellow shirt; he was looking for rapid ohia death.

"We didn't find much," Luafalemana said. There did not appear to be any cases, meaning Molokai's clean bill of health could continue. "It's a blessing."

President of the Molokai Hunting Club Justin Luafalemana.
Molokai Hunting Club President Justin Luafalemana also works for DLNR and surveys the forests for signs of disease. Cory Lum/Civil Beat/2022

But that could be threatened by a drought-fueled mass die-off of deer last year following years of extractive ranching, plantation agriculture and invasive species presence. It led to an eastward migration of deer, with many moving towards agricultural areas and watersheds in search of food and water — potentially bringing all their issues with them.

The change in mammal dynamics has led DLNR to seek fencing upgrades on Molokai, because they're only designed to keep pigs and goats out. The Senate has budgeted approximately $1.8 million for the control of deer around Hawaii, including fencing projects.

Hundreds of flies engulf dead Axis Deer in a pit located on the Molokai Ranch property. January 15, 2021
Dead deer were tossed in pits on Molokai Ranch following the drought that killed the animal in droves last year. Cory Lum/Civil Beat/2021

Haase, who also occasionally hunts, says the invasive mammals' movement is akin to Whac-A-Mole.

Hunters are concerned about DLNR's move, fearful fencing could restrict access to an animal that plays an integral role in feeding the island's population.

Luafalemana has built a lot of the fencing around Oahu and Molokai, but he is also president of the Molokai Hunting Club.

And for Molokai, an island community that relies on the land and sea for 40% of its diet, it's a complicated situation of looking after the land and ensuring people are fed. In other parts of the state too, hunters have felt disenfranchised in invasive mammal control efforts.


A sole focus on fencing is not a fix-all solution, Luafalemana said, rather he sees the community as being one of the most important tools to dealing with the issue, at least on Molokai.

Luafalemana said early goat eradication efforts on Molokai -- combining fencing and culling animals by helicopter and making the meat available to the community for food — exemplify what is possible. Those projects included several groups, including the community, private land owners and public entities coming together.

"We've seen all those tools that were introduced," Luafalemana said. "Now, it's only fences."

Infographic of problems caused by deer on Maui

Luafalemana and the 200-member hunting club are not against fences, he said, as they recognize "ola i ka wai" (water is life), and that watersheds span from mountain peak to ocean reef.

"It's in our blood, being passed down from generation to generation," he said.

Luafalemana put away his diving gear about a year ago because he wants to focus on deer so that the community can fish for longer.

"If you're out there fishing, I want you up here hunting," Luafalemana said.

Restoring Biology And Culture

Ecologist Kawika Winter, who works for the Biocultural Initiative of the Pacific at UH, believes the tenets of Native Hawaiian land management can work together with current tactics like fencing.

Winter believes the future of native forests does not have to be penned in, he said.

In previous work at Limahuli Garden and Preserve on Kauai, Winter built fences in upper watershed areas, but he does not endorse fencing as a default option for protecting Hawaii's ecosystems.

He found ways to stop invasive mammals from moving inland by encouraging them to head in the other direction through selective fencing that allows for hunting while keeping the animals out of the watersheds.

"Now we have this amazing section of the valley that's unfenced and it's majority native trees and native understory. It's absolutely beautiful," Winter said of the Kauai preserve. "And so we were able to provide a model of how to engage in conservation that was restoration without a fence."

But what underpins everything is a place-based plan on how best to do things and to what end, which Hawaii has a blueprint for, Winter says.

That means taking Indigenous knowledge, practices and historical understanding of the land and combining it with Western scientific approaches, to inform the future of land management.

Mauka To Makai

Outside Molokai's small restoration parcel, past part of the old fence awaiting its upgrade, the distant hill is covered in sand and kiawe trees. It is the start of the watershed -- albeit a dry one.

Closer to the cliffs and within the fenced area, a small gully is filled with beach naupaka and other native flora. Rather than a flowing stream, which one might expect in a watershed, the vegetation congregating within the small channel is a sign of moisture, according to Haase.

"That mauka to makai relationship absolutely guides the work that we're doing here," Haase said. "Because in order to preserve the marine resources, we have to restore the terrestrial resources. The work of this fence is going to capture the rest of this small, tiny little watershed and allow us to complete that restoration."

Civil Beat’s coverage of Maui County is supported in part by a grant from the Nuestro Futuro Foundation.

“Hawaii Grown” is funded in part by grants from the Ulupono Fund at the Hawaii Community Foundation, the Marisla Fund at the Hawaii Community Foundation, and the Frost Family Foundation.

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