Arguing Pigs Are Naturalized in Hawai`i, Professor Calls for More Research, Less Control

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To some of the participants at the ungulate control workshop at the 2006 Hawai`i Conservation Conference, the discussion was déjà vu all over again.

“We’re always doing Groundhog Day on ungulates,” Earl Campbell of the U.S. Fish and Wildlife Service complained, invoking the film whose premise is the nightmare of reliving the same experiences day after day. “We’ve got to get out of doing this thing over and over again every year at the Hawai`i Conversation Conference,” Campbell told the workshop, part of the annual conference held at the Honolulu Convention Center in late July.

Campbell’s frustration was shared by many others at the table, including public land managers, researchers, and environmentalists. For years, the state Department of Land and Natural Resources has been attempting to come up with methods to satisfy both hunters, who claim to have a cultural right to hunt pigs, and conservationists, who argue that the pigs damage and destroy native plants and, with their wallows, allow mosquitoes to invade the forest and spread life-threatening disease to Hawaiian forest birds.

Adding a new twist to the Groundhog Day script this year was the presence of José Fragoso, a mammalian zoologist with expertise on pigs and peccaries who joined the University of Hawai`i’s botany faculty two years ago. Fragoso, who studies the hunting practices of indigenous people in the Amazon, antagonized many of the conference participants with statements that set him apart from most of the scientists who have been working on Hawaiian conservation issues for years and for whom pigs and other ungulates are anathema to native flora and fauna. Fragoso’s emphasis was not so much on the need for controlling pigs and other pests of Hawaiian forests, but on what he claimed was a need for more research, including looking into the possibility that removal of ungulates might bring about greater harm than the ungulates themselves cause.

Fragoso complained about what he said was a dearth of peer-reviewed, published studies. He hauled out two cartons of reports documenting work related to ungulate issues in Hawai`i, but said his exhaustive literature search had turned up only two “real, solid publications” on pigs in Hawai`i – by Jon Giffin, in 1978, and by Cheong Diong in 1982 – and both of those, he noted, “are more than 20 years old” (though he did not explain why age alone should invalidate or undermine the conclusions).

“How long does an animal have to be in a place to be a part of the community?” Fragoso asked. “Pigs have been here more than a thousand years,” he claimed, arguing that they have “co-evolved linkages” with the native plant community.

David Burney, director of the National Tropical Botanical Garden, was among many who voiced their disagreement with Fragoso. “Those were little pigs” that the Polynesians brought with them in their canoes, he said – “pretty different from Arkansas razorbacks.”

When Fragoso claimed that no less an authority than the late Alan Ziegler supported his view that the Hawaiians allowed pigs to run freely in the forests, he was called on it by Marjorie Ziegler, director of the Conservation Council for Hawai`i.. “I don’t want to second-guess my dad,” she said, “but while he may have said pigs occasionally escaped, they were far too valuable as a food source for Hawaiians to release them into the forest.”

Fragoso continued to insist that without exhaustive, peer-reviewed, and published studies on the specific interactions between pigs and the forest in Hawai`i, any decision on management or control options would be uninformed and premature – and possibly dangerous as well. He freely expressed his identification with subsistence hunters: “I was born on an island. I grew up on an island. My family has over a thousand years on that island. We have known periods when … we could experience a lot of hunger on that island, when for whatever reason food became difficult and even though there’s fish around the water the fish disappeared. We knew what it was like to suffer without food for a while. Even though my generation did not, my grandparents told me about it.

“It’s very difficult for people who have gone through periods like that – and I think most island people go through that at some time or another – to deal with what we see sometimes as the waste of food when we’re exterminating animals.”

Fragoso also stated his view that that the fact that pigs may have been introduced at different times requires specific studies on the role of each of these cohorts in the forest. “Not all ungulates are the same,” he said. “You may have pigs that have been here for maybe over a thousand years and some here for just 50 years. And so their effects are going to be different. I stress again that we’re trying to understand the interaction, and to understand that interaction, that will be different for each ungulate depending on how long it’s been here.”

When Giffin was told that Fragoso saw a need to study each cohort of pigs introduced into Hawai`i, he was blunt: “That’s hogwash! Pigs exhibit similar behavior whenever they become feral. Domestic pigs that run wild probably all have the same behavior when they’re free-ranging.”

“Further,” he continued, “a huge body of evidence already exists on the damage pigs do in the forest. There’s no question in the minds of scientists that pigs aren’t good for the forest. This may be disputed by hunting community, but there has been so much research, so many studies to show these animals are not compatible with native forests, and not only in Hawai`i. In fact, they are a nuisance wherever they become established.”

Pig-hunting may have a place in Hawai`i, Giffin says, but if so, it is only on well-fenced game reserves. In areas designated for protection, he says, pigs and other ungulates have no place at all.

East Hawai`i, West Maui
While Fragoso’s insistence on exhaustive research may sound like a full-employment scheme for academics and researchers over the next half century, others involved in the discussion focused on how to deal with ungulates, especially pigs, in the present. At one of the conference presentations, Steve Hess of the U.S. Geological Survey’s Biological Research Division summarized his findings of studies on pigs at Hakalua Forest National Wildlife Refuge, on the Big Island. There, he said, he found that just to maintain a pig population at a given level required removal of up to 40 percent of their population annually. To reduce the population effectively, you need to cull 70 percent a year. “It takes a heckuva lot of effort to eradicate,” he noted, along with effective methods. At Hakalau, after public hunting was used, areas within the refuge were fenced and pigs removed through staff hunting and, ultimately, snares to capture the last few animals inside fenced areas.

Chris Buddenhagen described how Maui Land and Pineapple had used strategically placed, relatively short lengths of fencing – instead of huge swaths of fence up and down gulches and across ridges – to reduce pig populations in the Pu`u Kukui area of West Maui. Perhaps anticipating Fragoso’s argument that removing pig populations that have co-evolved with Hawaiian plants could cause dire unintended consequences, Buddenhagen noted that pigs in the West Maui mountains are relative latecomers, having been introduced only in the 1960s by pineapple workers.

By 1987, pig damage in the area was extensive. To address it, in 1998, ML&P began erecting fences across ridges at high elevations and snaring pigs that remained above the fence, with public hunting allowed below. Once most of the pigs had been removed, another fence would be built at a lower elevation and the process would begin again. From 2004 to the present, Buddenhagen said, 154 pigs – 7 tons of pork – had been removed and given to hunters.

As a result of those efforts, he said, 80 percent of the 3,000-hectare reserve has been pig-free for more than five years, with much of that pig-free for more than 10 years.
Fragoso asked Buddenhagen how reliable the hunters’ information was on pig weight and other aspects of the population of pigs taken. “I don’t worry too much about the [specifics],” he responded. “The main thing is, the pig is dead.”

Elsewhere in Hawai`i
Hakalau and West Maui are two of just a handful of areas in the state where high-quality native ecosystems have been fenced and protected from damage from introduced ungulates. To get a better handle on how much high-quality forest land has been protected, how much is planned for protection, and how much is out there, Theresa Menard of The Nature Conservancy conducted an exhaustive survey of land owners and managers, both public and private.

What she found is that Hawai`i has about 1.9 million acres – roughly 48 percent of the state’s land area – in relatively intact native ecosystems. Of that, 105,400 acres, or 5 percent, is fenced and virtually ungulate-free. If all plans for fencing and ungulate management are implemented, the total would rise to 612,000 acres, or 31 percent of the remaining ecosystems. Hardly any of the ungulate-free areas are on Kaua`i: according to Menard, just 100 acres have been protected from ungulates on that island.

By contrast, some 900,000 acres of state land in Hawai`i have been set aside in 63 game management areas, according to Ed Johnson, the chief wildlife biologist for the Division of Forestry and Wildlife. Johnson noted, however, that roughly half of the areas so designated remain inaccessible to hunters, frustrating both hunters and members of the public, who lately have been reporting increasing numbers of pigs in residential and agricultural areas.

One of the newest areas to come under protection is The Nature Conservancy’s Kona Hema preserve, in South Kona. In a poster presentation, TNC’s Laura Nelson described the removal of 420 pigs from the 1,800-acre Kapu`a unit of the Kona Hema preserve. In three years’ time, the area was fenced and pigs were completely eradicated from the area. Pig removal was not always accompanied by a proportional decrease in pig damage, however. As Nelson explains it, “the percentage of plots [in the fenced areas] containing a high level of ground disturbance … increased during the first year from a baseline of 38 percent of the plots to a high of 66 percent even though the estimated number of pigs decreased nearly 30 percent.” This, she says, was caused “by the pigs’ inability to disperse out of the unit and the breakdown of established territories.” Within a year and a half, however, when the number of pigs had been reduced to 40 percent of the original population, just 11 percent of the plots showed heavy ground disturbance.

The project was intensive, but Nelson argues that it was cost-effective. TNC spent $40,000 a year to eradicate the pigs (not including the cost of the fence) in the unit. Had the effort been reduced by just a quarter, costs would have been proportionate ($30,000 a year), but the time needed to eradicate would have more than tripled, to 10 years. Total costs would have been $300,000 instead of $120,000. According to the VORTEX model used to develop these estimates, anything less than 60 percent of the actual effort used would never achieve the goal of eradication.

According to Giffin, who works part-time for TNC, just a few dozen pigs are left in all three units of the 8,000-acre Kona Hema preserve. “The 4,000-acre Honomalino unit is now pig-free,” Giffin told Environment Hawai`i, “and in the 2,200-acre Papa unit, we’ve reduced the numbers to the low teens.”

Jim Jacobi gave an overview of a larger picture – “ridge to reef” – in describing work that he and others at the USGS BRD have been doing to assess sediment loads on reef areas on the south shore of Moloka`i and at Hanalei, on the north shore of Kaua`i. Jacobi said he began his analysis using a U.S. Department of Agriculture model for non-point source pollution. The limits of this model soon became apparent, he said, when he and his colleagues realized that it does not take into account landslides. Working with USGS landslide expert John Stock, Jacobi and his team developed a new model for analyzing non-point source runoff and transport of fine sediments along the coast.

The challenge he faces at Hanalei, Jacobi said, is to sift out what is human-caused (such as introduced ungulates) versus what is natural. “There are landslide scars everywhere on the slopes of Hanalei Valley… The presence of ungulates on Moloka`i has really changed the ecosystem as a whole.”

— Patricia Tummons

Volume 17, Number 3 September 2006

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