Thursday, June 29, 2017

The Botanists’ Last Stand

Steve Perlman doesn’t take Prozac, like some of the other rare-plant botanists he knows. Instead, he writes poetry.

Either way, you have to do something when a plant you’ve long known goes extinct. Let’s say for 20 years you’ve been observing a tree on a fern-covered crag thousands of feet above sea level on an island in the Pacific. Then one day you hike up to check on the plant and find it dying. You know it’s the last one of its species, and that you’re the only witness to the end of hundreds of thousands of years of evolution, the snuffing out of a line of completely unique genetic material. You might have to sit down and write a poem. Or at least bring a bit of the dead plant to a bar and raise a beer to its life. (Perlman has done both.) You might even need an antidepressant.

“I’ve already witnessed about 20 species go extinct in the wild,” Perlman says. “It can be like you’re dealing with your friends or your family, and then they die.”

Perlman tells me this as we drive up a winding road on the northwestern edge of Kauai, the geologically oldest Hawaiian island. Perlman is 69 with a sturdy build and white hair. That’s been enough to last him 45 years and counting on the knife’s edge of extreme botany.

The stakes are always high: As the top botanist at Hawaii’s Plant Extinction Prevention Program (PEPP), Perlman deals exclusively in plants with 50 or fewer individuals left—in many cases, much fewer, maybe two or three. Of the 238 species currently on that list, 82 are on Kauai; Perlman literally hangs off cliffs and jumps from helicopters to reach them.

Without him, rare Hawaiian plants die out forever. With him, they at least have a shot. Though now, due to forces beyond Perlman’s control, even that slim hope of survival is in jeopardy. Looming budget cuts threaten to make this the final chapter not only in the history of many native Hawaiian species, but in the program designed to keep them alive.

The silver lining: even if a species does go extinct in the wild, chances are Perlman has already collected enough seeds and genetic material before the last plant disappeared to grow others in a greenhouse. Extra seeds are shipped to a seed bank, where they sit, dehydrated and chilled, awaiting a more hospitable future. There may not be a viable habitat for that plant now, but what about in 50 years? Or 150? “Part of it is saving all that genetic information,” he says. “If your house is on fire, you run in and grab the kid.”

Most people probably wouldn’t speak about obscure threatened plants with this much regard. But we don’t necessarily know what we’re losing when we let a plant species die, Perlman says. Could it have been a source of medicine? Could it be supporting a food chain that will come tumbling down in its stead? Our foresight on this kind of thing has been abominable so far; one only has to look at what happened when wolves were driven out of Yellowstone National Park, only to cause a massive boom in the newly predator-free elk population, which in turn ate every plant and baby tree in sight, starving bears of their berry supply, birds of their nest sites, and bees of flowers to feed on.

Everything was beautiful, and nothing hurt

Every native plant on Kauai is an insane stroke of luck and chance. Each species arrived to the island as a single seed floating at sea or flying in a bird’s belly from thousands of miles away—2,000 miles of open ocean sit between Kauai and the nearest continent. “We think…probably one or two seeds made it every 1,000 years,” says botanist Ken Wood, Perlman’s longtime field partner.

Once a seed took root, the plant would evolve into a completely new species, or several, all of which came to be “endemic,” or found exclusively on the island. Any defenses the plant’s predecessors may have had—thorns, or poison, or repellent scents—were completely dropped. No large mammals or other potential predators made the journey from mainland to the remote island chain. From the plant’s perspective, there was no reason to spend energy on defenses when there were no predators to fend off. So stinging nettles no longer stung. Mint lost its mint oil. Scientists ominously refer to this process as species becoming “naive.”

The same was true for animals like birds and insects when they began to arrive. Famously, when a species of duck made it to the Hawaiian islands, it evolved to drop the concept of flying altogether. Its wings became little nubs. After all, there were no large mammals around to fly away from. The bird grew very large; “gigantism” is an evolutionary phenomena common to islands. Predictably, this huge, flightless duck, known as the “mao-nalo,” went extinct once humans showed up, likely finding them an easy-to-catch source of meat.

Fatal naiveté

When plants are allowed to evolve without fear, they get really, really specific. Take the Hibiscadelphus, for example. Found only in Hawaii, members of this genus of plant have flowers custom-shaped to fit the hooked beak of the honeycreeper, the specific bird that pollinates them. “They’re extremely rare. There were only about seven species described ever, and six were already extinct when I found a new one,” says Perlman. He published the discovery in 2014—it was his 50th new plant species discovery.

Almost 15% of the plants of Hawaii evolved to have separate male and female populations—a very high percentage, says Wood, compared to mainland plants. Under normal circumstances, that trait is good for island plants: it forces them to cross-pollinate, keeping the gene pool relatively diverse even if the population is small. But by “small,” evolutionary forces were probably thinking at least 200 individuals—not four or five. When you can count the number of individual plants on one hand, it’s almost certain that the few remaining males and females won’t be anywhere near each other. In those cases, Perlman and Wood painstakingly gather pollen from the males and bring it to the females.

They have to time this just right—or at least try. There is no perfect math to predict what day an individual plant will decide to flower. “And often you need to dangle off helicopters to get to them,” Wood adds. So missing the mark by a day or two and arriving to a flower that is still closed can mean having leapt from a helicopter and rappelled off a cliff and possibly camped for a day or two for naught.

“That’s what Ken doesn’t like—he likes to go in and go out,” Perlman tells me later. He proudly points to a photo on his laptop screen. It shows him collecting seeds from the last-known member of the endemic fan palm species Pritchardia munroi. The palm was clinging to a slope 2,000 feet up in the air on the tiny Hawaiian island of Molokai. “I had to go there three times to get the seed when it’s ripe,” Perlman says.

by Zoë Schlanger, Quartz | Read more:
Image: Steve Perlman