Even the Weather Channel got interested enough to fund a few such probes (“It’s 79 degrees in Boston, partly cloudy, andthis just in, folks: the live weather from Mount Everest is”). This work is still at the stage in which computer engineers are probably learning more than ecoscientists, but it’s a valuable start.More recently, a team of ecologists from the University of Hawaii was introduced to engineers at MIT. The group’s tactical mission: gather information about the extremely rare Silene hawaiiensis, a plant that lives in the southwest rift zone of the Halemaumau crater amid the volcanoes on the big island of Hawaii.
Island ecosystems are known for the starkly drawn lines between species. This is why Darwin discovered a living laboratory in the Galpagos, and why Alfred Russel Wallace was bowled over by the Indonesian archipelago. The island of Hawaii is home to a number of intriguing species, including curiosities like thornless berries and nettleless nettles: plants that enjoyed the paradise so much that they relaxed their natural defenses. In recent decades, though, Hawaii has become an ecological battlefield as alien species invade and disrupt the old balance.
Fieldwork for this project began on the northeast shore of Hawaii, in Hilo, the United States’ rainiest city. But a 50-kilometer drive southwest to Hawaii Volcanoes National Park brings you into a desert microclimate. Going from rain forest to desert in the space of a few kilometers makes this one of the world’s more sharply delineated climate zones.
There, around the ash-crusted rim of the massive Kilauea caldera, a few hundred scrappy little Silene plants are growing. They’re an endemic species, and not much is known about them. We don’t know how they pollinate, and we don’t really have a handle on the very particular climate in the area in which they’re growing.
Not too far from the Silene, you’ll find another extremely rare plant, the Portulaca sclerocarpa. There are perhaps only a hundred of these on earth, and they grow in one tiny patch in a place called Puhimau. What’s especially interesting about their little grubstake is that if you walk a few hundred meters away from the Portulaca and stick a thermometer five or six centimeters into the ground, the temperature reads 85 C. And when you look around, you see the charred remains of a forest. What’s happening is that an underground lava flow is heating the soil, killing the plants above, and it could easily wipe out the precarious Portulaca patch.
These sorts of phenomena require time-lapse logic, and time-lapse thinking. Because we’re in a wilderness within a national park, any instrumentation needs to be autonomous and wireless and very unobtrusive. So the combined MIT and Hawaiian teams came up with a novel approach. Students Andy Wheeler, Roshan Baliga, Ben Brown and Paul Pham built a tiny computerized climate sensor to measure light, temperature, humidity and wind speed. The nodes look like eight-by-eight-by-three-centimeter blocks, and they have radio links designed to self-aggregate into a wireless network. By sprinkling enough of these in an area, you can blanket a critical piece of territory with all the sensing required to form a much more detailed picture of what’s going on ecologically. And with clever camouflage that looks like logs and rocks, the sensors blend into the ecosystem.
Biology professor Mike Huddleston, associate professor of botany Kim Bridges, and their team at the University of Hawaii built some remarkable faux rocks and logs to hold the assorted electronics. In principle, a scientist simply walks out from the observatory with a bag of these high-tech rocks and drops one every 15 meters or so to form a daisy chain that leads out to the nearby Silene patch. The rocks look uncannily like the local chunks of tephra that are blasted out of volcanoes, and that’s how this first tephranet got its name. If it works, it should run for several months, producing the first intimate data snapshot of this extraordinary ecosystem.
Lush plants are a healthy part of life. Whether it’s a happy plant on the office window ledge, or a deeper understanding of how the last few members of a species are clinging to life, directing new capillary sensor networks into ecosystems can bring us real insight into problems that matter. Maybe the idea of a joint venture between Hewlett- Packard and seed giant Burpee seems a little far-fetched. But when I saw MIT student Andy Wheeler with his laptop walk over to an unsuspecting pumice rock and log into it via the tephranet radio, it was as if he’d opened a door to a new world.