Hawai‘i has more threatened and endangered species than any other state in the country. Of the approximately 1,670 endangered plants and animals listed by the U.S. Fish and Wildlife Service, almost a third are found in Hawai‘i. This has led the Islands to be described in apocalyptic terms: “ground zero” for the planet’s extinction crisis and the “extinction capital of the world.”

But how do we decide what to save? The answer, it turns out, is as difficult for biologists to answer as it is for philosophers. I asked conservationists: Of Hawai‘i’s threatened species, which, if they were to disappear completely, would have the most widespread or catastrophic effects? We talk of so many losses in Hawai‘i, and while some are intangible, I was hoping for a scientific model for concrete answers. But there is none.

“We are thinking about this whole thing as a forest ecosystem,” says Julia Diegmann, a planner at the Kaua‘i Forest Bird Recovery Project. “​​The analogy I always use is that it’s like a Jenga game. You have this tower, and it’s a solid tower if all the parts are there, but then you start removing pieces. And it becomes more and more unstable, but you don’t really know which one is going to be the piece that brings this whole tower to collapse. We don’t have enough knowledge to determine which is the species that we should save.”

And just as the forest ecosystem is interconnected, so too are physical and cultural worlds. Hawai‘i is one of the most ecologically diverse regions in the world, “and it’s that ecological richness that created the biological richness that created the cultural richness of Hawai‘i,” says Sam ‘Ohu Gon III, scientist and cultural adviser at The Nature Conservancy of Hawai‘i. In addition to the utility provided by Hawai‘i’s endemic plants and animals—for example, the wood of lama trees was used to build temples, and the leaves and berries of pōpolo plants to treat illnesses—there are also the “intellectual and spiritual values” associated with them, Gon says. “Whenever you look at an ancient chant, more often than not there will be mention of native plants and animals for emotions, for love.”

He points to ‘Ōlelo No‘eau, a book of Hawaiian proverbs and sayings compiled by Mary Kawena Pukui, which contains separate indexes for birds, marine life and plants, “because plants and animals were so important in the metaphors that were being used by Hawaiians and are still being used by Hawaiians to describe everyday things,” Gon says.

It’s not a coincidence that a place with such ecological diversity is also the place with the most extinctions: The more you have, the more you have to lose. Over the 40 years Gon has worked in conservation, he says he’s seen five species native to Hawai‘i go extinct.

“I’ve seen them, heard their songs and seen their beauty in the forest. And … it’s a horrible thing [when they go extinct]. When I was young, I used to see the ‘alalā, the Hawaiian crow, in Hawai‘i Volcanoes National Park, sitting on the fence posts, and now they’re extinct in the wild and only being raised in captivity. Or you can remember walking on a trail that was completely filled with native plants. And then now when you walk on that same trail, it’s filled with invasive weeds from all over the world. That changes the whole cultural background of what you’re walking through.”

False Killer Whales

Among the characteristics that make false killer whales unique: They share their food, not only with their companions, but even with humans—in Hawai‘i, they’ve been known to offer their fish to snorkelers and divers. And like humans, they go through menopause.

False killer whales live in warm oceans around the world, but of the insular population that lives around the main Hawaiian Islands, there are only about 140 left, making them the rarest of the 18 species of toothed whales and dolphins in Hawai‘i’s waters. Their numbers have plummeted since the 1980s. Factors contributing to their decline include slow reproductive rates (they have just one calf every six or seven years). Also, because they’re top predators and can live into their 60s, they accumulate high levels of toxic pollutants over the years. And they’re at risk from human fisheries because they go after fish on hooks.

It’s unclear how losing false killers would affect our ecosystem, “but we have a lot of examples within different ecosystems that show what happens when you lose a top predator,” says Jeannine Rossa, acting lead for the state’s Department of Land and Natural Resources’ Protected Species Program.

The classic example she cites is of the wolves in Yellowstone. They were hunted to near extinction by 1930, and their prey, the elk and deer, ballooned in numbers​.​ Grazing by the elk and deer decimated the streamside vegetation, destroying bird habitats and eroding the stream banks. When wolves were reintroduced to the park in 1995, plant life returned to the stream banks, as did birds, fish and other animals. “There are similar cascading effects with losing a species within the marine ecosystems as well,” Rossa says.

‘I‘iwi  

Of the 50 or so species of Hawaiian honeycreepers, less than half remain. The brilliantly red ‘i‘iwi, an important ‘ōhi‘a pollinator, is vulnerable to ​​the same threats that wiped out other forest birds: habitat loss, predation by non-native mammals, and avian malaria. Gon says, “Of the birds that provided for all of the Native Hawaiian featherwork, the beautiful, brilliant capes and helmets that we can see in the Bishop Museum and other museums worldwide, only the ‘i‘iwi still exists, and it is on the verge of endangerment.” The bird’s cultural significance is huge, and so would be its loss, he says. 

Gon notes that the ‘i‘iwi is also “symbolic of a beloved person”: The bird features in “Ipo Lei Manu,” the love song that Queen Kapi‘olani ​​wrote for her husband King David Kalākaua when he traveled to San Francisco, but became a mourning song when he died there.  

He mana‘o healoha 

No ka ipo lei manu 

He manu ku‘u hoa 

Noho mai i ka nahele 

‘I‘iwi o uka 

 

I have a feeling of love 

For my cherished sweetheart 

My companion is a bird 

Who dwells in the forest 

The ‘i‘iwi bird of the uplands

Native Yellow-Faced Bees

“The native yellow-faced bees”—of which there are 63 species, seven of them listed as endangered—“are an important part of maintaining the whole ecosystem,” entomologist Karl Magnacc​a says. “The bees are key pollinators of many of the common native plants that make up intact native landscapes, like ‘ōlapa, ‘a‘ali‘i, pūkiawe, māmane, naupaka, etc. A big problem that native forests face is low reproduction of native plants in the face of invasive ones, so the more native seeds produced, the better.”

Some of these solitary, native bees have adapted alongside the plants. “We think about pollen as being just small, but it varies a lot in size,” Magnacca says. Unlike honeybees, which carry pollen on their legs, the yellow-faced bees bring pollen back to their nests by swallowing it. “So if you think of a typical size of a native bee, swallowing some of these pollen would be like swallowing an aspirin. Trying to swallow one of these ‘ilima would be like trying to swallow a baseball. And so these ones that specialize on ‘ilima are much bigger.”

‘Ōhi‘a Lehua

“It’s really difficult to talk about any single plant as being vitally important, but ‘ōhi‘a comes pretty close,” Gon says. While ‘ōhi‘a is not listed as endangered, it is under threat by the fungus Rapid ‘Ōhi‘a Death, which has already killed thousands of the trees and has the potential to wipe them out across Hawai‘i. And that’s a problem because ‘ōhi‘a is a keystone species, one that holds an entire ecosystem together.  

​​If we lose ‘ōhi‘a, we lose not only food and habitat for native birds, as well as the layers of plants that have coexisted under ‘ōhi‘a’s canopy, we also lose our water. “‘Ōhi‘a are enormously important for our water system,” DLNR’s Rossa says. Everything about the tree functions to hold onto water, from its rough bark to the fuzzy leaves that resemble “the potato chips that are like little cups for you to scoop stuff with,” she says. The effect is a slow release of water into the soil and into our aquifer, our source for fresh water. Contrast the ‘ōhi‘a with introduced species like the strawberry guava or eucalyptus, with smooth bark and slick leaves. Without ‘ōhi‘a, water would rush down the mountains, “take mud and silt and destroy the reefs and not go into our underground aquifers, and we would all be in a lot of trouble,” ​​Gon says.​​​ 

Porites Coral 

In the Kumulipo, or Hawaiian creation chant, the ko‘a, or coral polyp, is the first organism born. It’s the foundation of life in Hawai‘i.

Hanau ka ‘Uku-ko‘ako‘a, hanau kana, he ‘Ako‘ako‘a, puka 

Born was the coral polyp, born was the coral, came forth

In particular, two varieties—finger corals and mound corals, both of the genus Porites—are the slowest growing and make up the bulk of our reefs. They are the equivalent of the old-growth redwood trees in California and ‘ōhi‘a in Hawai‘i: They provide the main structure and habitats of entire ecosystems.

These corals are not listed as endangered, but they are currently under stress from rising ocean temperatures: “In 2015 around Maui, the temperature threshold was exceeded dramatically, and we had large 400-year-old lobe coral colonies die. Just completely die,” says Russell Sparks, a Maui district aquatic biologist at the DLNR.​ “​Corals that had survived all kinds of stresses and events over the last 400 years just couldn’t handle that. The forecast is that the temperature threshold will be exceeded every year from 2030 on. So that’s a dire forecast for our corals.” Other threats include overfishing, which decreases the fish populations that help manage seaweed around the corals—without parrotfish and other species, coral growth is smothered.

If Hawai‘i loses its Porites coral, it loses “the dominant reef-building coral,” Sparks says, and “over time, the reefs would start to erode and become flat and featureless, and you have a flat pavement with a layer of sand that comes and goes. Not even other corals can really grow because there’s not enough vertical relief above the sand. If you don’t have coral reefs actively growing, then they’re gonna be eroding.” And if Hawai‘i doesn’t have its reefs, its coasts are also more vulnerable to erosion.