The Arbornaut, page 22
Citizen science expeditions to the Amazon increasingly center around one of the world’s longest skywalks, called the Amazon Conservatory for Tropical Studies (ACTS) Canopy Walkway. It spans almost one-quarter of a mile with twelve bridges and thirteen platforms that extend to a height of 125 feet. Called the eighth architectural wonder of the world by forest scientists, this treetop trail provides otherwise impossible views into the lives of millions of otherwise invisible species. Like many others built since, our first walkway back in Australia used poles to support its bridges spanning away from a slope to a height of fifty feet. But in the Amazon, no poles were tall enough, so one of two techniques was required for suspending bridges: (1) through-bolt installed through the trunk like a piercing, to hold stainless steel cables in place but with no harm to the tree; or (2) necklace of cable encircling the girth, with rubber pads to buffer the bark from damage. A through-bolt is safer for tree health, because most of the trunk is dead wood and not impacted by the hardware. A tree’s only living cells are a thin layer of vascular tissue that sits just below the bark, so a circular cable can easily damage those vital cells by strangling the trunk. Given the enormity of trees and the remoteness of base camp in the Peruvian Amazon, it was not possible to haul large generators to these sites, nor could we find long enough through-bolts. So loops of cable were gently affixed around twelve strong trunks and buoyed away from the vascular tissue by rubber grommets to minimize strangulation. It took six months to build the first platform of this walkway because the locals only had manual drills. But after a simple battery-operated drill was brought to the site, the next ten platforms were completed in just three months. This timeline is vastly different from similar construction in forests closer to big cities, where the building process of an aerial structure may take only a few weeks yet the permitting can take a year due to liability and paperwork. A creative Maryland engineer, Ilar Muul, designed the Amazon walkway using the necklace technique. This structure requires a lot of careful maintenance to constantly check for termites and fungus under all the rubber grommets encircling the trunks. Fortunately, the local villagers, proud of their ecotourism operation, inspect the structure almost daily as part of their employment as guides.
In the Amazon jungle, this extraordinary skywalk allows citizen science teams to experience the whole forest. Travelers have included students, educators, community leaders, CEOs, families, and scientists aged seven to ninety. In the eighth continent, everyone is an explorer! As a young field biologist in Australia, I had the good fortune to be indoctrinated to citizen science through Earthwatch, and after that engaged the public in many science projects as a museum leader. Perhaps my favorite citizen science program involved middle school kids and was called the JASON Project. After he found the Titanic at the bottom of the Atlantic Ocean, marine explorer Bob Ballard received thousands of letters from schoolchildren, all inquiring if they could accompany him on his next trip in the Alvin submarine (which only seats two!). Bob realized he could never directly transport thousands of young people undersea for marine research. Instead, he founded the JASON Project, named after his favorite marine hero, Jason, of Golden Fleece notoriety. Bob used satellite telecommunication to link remote field expeditions to schools and museums. When he needed a terrestrial scientist to balance his marine expertise, Bob tapped me for the role. I earned the nickname “Canopy Meg” from Bob and the millions of kids who participated in the JASON Project. Bob and I both marveled at our different worlds—my love of canopies despite the insects, perspiration, humidity, and venomous creatures versus his passion for the undersea world despite the claustrophobia in a submarine plus challenges of darkness and pressurization. Bob was a great role model for enthusiastic science communication, even if he did occasionally swat some of the insects I was trying to measure. And soon enough, we both realized this was great training for us too: if you could speak clearly to seventh graders, you could also communicate effectively to politicians, who often had about the same level of science training. We broadcast virtual expeditions in the tropical forests of Panama and Belize, where I oversaw construction of a new walkway for the broadcast and our team figuratively followed a raindrop from the canopy to the forest floor and out to a coral reef. In Panama, I partnered with a soil scientist, affectionately calling our broadcast “The Scoop on Poop” because we measured insects eating leaves and followed their frass down to the soil as part of nutrient cycling. Those early JASON expeditions cost millions of dollars; we had to ship a satellite dish via oceanic barge, transport thousands of pounds of video cameras and electronic wire to string through the forest, and hire over twenty technicians to operate a production studio. (Today, we broadcast remotely at less than a tenth of the cost using a single laptop with internet connectivity and two or three technicians.) The JASON Project hosted its 1999 broadcast season from the Amazon walkway. After fifty-three hour-long broadcasts to over three million students from a 125-foot-high platform, I was not only sunburned and bitten by bugs but also transformed into a STEM celebrity in the eyes of many middle school science teachers. Following the broadcasts, a few wrote asking if they could assist with my research. Amazon citizen science expeditions soon became an annual event. For more than twenty-five years, teachers, students, families, and CEOs have joined me in the Amazon to conduct long-term field research. Those volunteers have calculated herbivory, discovered insects, measured leaves of different species and heights, and estimated biodiversity. On these citizen science expeditions, everyone contributes to our collective knowledge of tropical jungles, which translates via real and varied ways into conservation.
The walkway itself inspires botany lessons about the majestic trees that support its twelve platforms. Each species, plus all their inhabitants, tells a story and has a function in this complex tropical forest canopy. For example, strong trunks of Inga sp. (Peruvian name shimbillo) hold up several aerial platforms and also provide timber for local people to construct huts or carve canoes. Their compound leaves have a small cuplike gland between each pair of leaflets, whose function remains unknown and a feature I never saw on any other plant. Legend has it that butterflies drink from these tiny receptacles, and my students fantasized it could also be a drinking cup for fairies. Over 350 species of the genus Inga exist throughout the Amazon, yet scientists still do not know much about its ecology, except that citizen scientists carefully calculated that its foliage was delicious to herbivores, with up to 30 percent surface area consumed. Inga grows best in moist lowland forests, but with the onset of climate change and the warming of the Amazon, scientists have observed them dying more rapidly than other, more drought-tolerant species. Another common platform support tree is Apeiba membranacea (Peruvian name peine de mono). Apeiba fruits resemble sea urchins and are coveted for use in local crafts. Its bark has a pH conducive for bromeliads and orchids to populate its branches, creating a vertical festoon of colorful greens and pink flowers.
A third species that carries its own mystery is Cedrelinga cateniformis (Peruvian name tornillo), which grows to over 150 feet high. I affectionately nicknamed this species the “green bean” tree, to remind students it is a close cousin of their dinner vegetable and a member of the legume family, which ranges from small six-inch-high vegetables to large two-hundred-foot giants. This emergent supports the walkway’s highest platform at 125 feet, high above the forest floor, which was an aerial base camp for the JASON Project. Each day for two weeks, a movie crew filmed me measuring herbivory (and swatting sweat bees that landed all over my face). The research was livestreamed to middle school students around the world while host Bob remained on the forest floor, asking questions all the while that were relayed via microphone. A family of shovel-tail lizards (Tropidurus flaviceps) lived on the branch next to my roughshod research table, and I got to know both parents and all five offspring in their aerial territory, where they feasted on insects that had feasted on me. (Descendents of that same lizard family are still there twenty-five years later.) One of the most often-asked questions by K–5 students during JASON broadcasts was, How do you manage to go to the bathroom in the canopy? Answer: a hasty trek across six bridges and five platforms to descend the stairwell to the forest floor. For girls, there were no shortcuts, although the film crew (all male) each had a jug used discreetly in situ. Relieving oneself from such a height is simply not polite, especially when there’s a well-traversed ground trail underneath.
Another unique attribute of JASON was that while millions of middle school students participated virtually, several dozen assisted the scientists during the broadcast. They were recruited from local as well as international schools. In this emergent roost, I hosted a fifth grader from Iquitos, Peru, who had never before visited her local tropical jungle. Pamela became an expert at measuring leaves and swatting sweat bees at the same time. Fifteen years later, she earned a scholarship to the University of Florida to study environmental education and ecotourism, inspired by her JASON experience. Another student achieved fame by winning our online competition to name a new species of beetle discovered during the broadcast. A panel of scientists voted on the one thousand entries submitted and selected hers: nutmeg beetle, named for the host tree (in the nutmeg family), the beetle’s color (nutmeg), and its finder (Meg), all embedded in the name.
As an emergent, the green bean tree provided a lookout from which to see the rest of the forest. A variety of tropical flora were visible from our platform, some with wonderful names and amazing medicinal uses. Oxandra xylopioides boasts cauliflorous flowering habit and attracts mid-canopy pollinators; palms Lepidocaryum tessmannii and Astrocaryum sp. are both tongue-twisters and important plants for the shaman’s jungle pharmacy. Virola sp. provides a home to Azteca ants, which give a walloping sting if you try to pluck a leaf; the elegant Symphonia globulifera with its cherrylike fruits is so colorful and distinct during flowering season that a drone could be deployed to count the local population of red crowns.
After my first summer of teacher workshops at the Amazon walkway, I devised several citizen science units so volunteers could contribute to tropical research in a meaningful way. This is tricky business. It is not useful to ask amateurs to carry out complicated actions, such as writing technical classifications of insects or finding critters that require a trained eye to detect. Instead, activities need to be simple enough that they won’t contribute erroneous data to the overall research, but interesting and meaningful enough to provide a sense of reward to the participants. In this case, I invited volunteers into the canopy to find, photograph, and sometimes collect insect herbivores. Forty eyes could see more deeply into complex foliage than just my two eyes. Working in teams, citizen scientists collected leaves and learned how to measure herbivory by a simple process of counting graph-paper squares and in turn calculating the squares of proportional leaf area missing. Back at base camp, they played out this painstaking process in a place with no electricity—the almost-primitive counting methodology became a cult of sorts. Each team adopted a tree, collected thirty leaves, and calculated its defoliation. I called it the Leaf Lovers Club, which now boasts hundreds of international members. The data were entered into a spreadsheet on my laptop, so the comparisons between species provided information about which species are most resistant to insect attack. The local shaman and I enjoyed discussing these results—we both appreciated that plants produce chemicals to repel insects. Those species with little or no herbivory are usually the most toxic, which typically translates into their being important medicinal plants.
Our first several summers were teacher-exclusive workshops, but since then my citizen science Amazon trips have been open to a diverse public. With students and volunteers, I published articles about Amazonian epiphytes and herbivory, calculated the damage of leaf miners in the canopy for the first time in the annals of science, and assessed the local economics of the walkway in creating sustainable employment for indigenous people from ecotourism instead of logging. Every expedition starts in Lima and connects via local airlines to Iquitos, a river city in northern Peru approximately twenty-two hundred miles from the mouth of the Amazon and with no road connections to the outside world. The Amazon is called the river highway since it connects everyone and everything in northern Peru, from markets to medicines to marriages. From Iquitos, we boat for about five hours downriver and then up a tributary called the Napo (close to the border of Ecuador), watching for pink dolphins at every watery intersection. Our destination, the Amazon Conservatory for Tropical Studies, is an international field station situated on the edge of a million-acre preserve of primary tropical rain forest in northern Peru. At ACTS, botanists have recorded over 750 species in one square hectare (2.47 acres), almost a world record. A research camp houses up to forty visitors at a time, without electricity or running water but with the world’s best wildlife symphonies and possibly the freshest air on the planet. ACTS partners with a local nonprofit called CONAPAC (Conservacion de la Naturaleza Amazonica del Peru, A.C.) for activities including freshwater filtration in villages, environmental education in schools, and sustainable incomes for local villagers through ecotourism.
Located at latitude 3° south, this section of the Amazon receives over two hundred inches of rain per year, and temperatures hover in the eighties with average humidity around 80 to 90 percent. According to surveys, biodiversity in Amazon forests exceeds that anywhere else on the planet and will be even higher when canopy inhabitants have been tallied. Approximately twenty thousand plant species grow in the United States, but over eighty thousand plant species live in the Amazon, along with over two million insect species, twenty-five hundred fish, and fifteen hundred birds. Why are the tropics so rich in life? Hypotheses include a mild climate, the complexity of three-dimensional niches in a tall tropical forest, and the long evolutionary timelines that have allowed radiation of many species in fairly stable environments. Living along the riverbanks, the local people, or ribereños, cultivate land, harvest food, and then move if the river floods or alters course, just as they have done for many generations. An Amerindian tribe called the Yagua lives near our base camp and share their knowledge of the forest with my teams. Two of their most important plants are chambira palm (Astrocaryum sp.) to weave bags, hammocks, and decorative jewelry, and Irapay palm (Lepidocaryum tessmannii), which grows in the understory and is harvested sustainably for roof thatching. The locals utilized an estimated five hundred thousand palm fronds to make our dining room roof, which resists the incredibly heavy rains.
The definition of citizen science is any action where nonscientists assist scientists in conducting research. Volunteers have perspired, overheated, lost sleep, and eaten bugs, all in exchange for engaging in exploration and discovery. Even in their downtime, it’s never a dull moment, from encountering tarantulas in the shower, to seeing anacondas by night, to fishing for piranhas. In this biodiverse ecosystem, more questions abound than answers. How do so many millions of species live in one place? Why don’t animals devour all the leaves, since trees cannot run away from hungry beetles, ants, and sloths? How do tiny orchid bees navigate in a sea of green to find their specific flower? What tips off a shaman to discover the best medicinal plants? In the Amazon jungle, survival of the fittest is not an abstract concept. Both plants and animals evolve strategic behaviors and defense mechanisms to avoid being eaten, overshaded, trampled, strangled, dried up, outcompeted, or infected. As with travel to most remote places, discovery lurks behind every trunk. To survive in a tropical rain forest, camouflage is the name of the game.
One notable element of Amazon field research is the heat! The uppermost canopy is extremely hot and dry, with occasional heavy rain showers that pelt and sometimes tear the leathery leaves, but droplets quickly filter through to lower foliage and the forest floor. The tree crown is like an aerial desert; downpours rapidly turn into throughfall, then the top layer remains hot, dry, and windswept. One group of tropical epiphytes includes cacti, adapted to living in blazing sun without much water, conditions found in both the desert and a tropical rain forest canopy. It is so sultry and humid that sometimes our clothing needs wringing out after becoming drenched in sweat. I occasionally daydream about transforming into an arctic biologist, so my clothes would not always be growing mildew. The locals bathe in the river several times a day, and have no fear of piranhas, many of which are vegetarian and quite harmless despite their Hollywood portrayal as bloodthirsty predators. The showers at the field station are cold but refreshing, and feature river water pumped through a simple unfiltered pipe, minus the piranhas and anacondas. (But be careful not to open your mouth in the shower lest you risk getting sick from tropical microbes to which our bodies are not adapted!)
Leaves, those trillions of tiny green machines that form the basis of all life on Earth, overwhelm our five senses in all directions in the Amazon. We see greenery, we smell decay, we touch leaf hairs, we sometimes ingest medicinal plants. The citizen science mission for my Amazon expeditions, however, is to survey insect damage as a clue to gauge forest health. After twenty-five field years, my volunteers have confirmed that herbivores annually consume over a quarter of Amazon rain forest canopies, similar to findings in Australian rain forests. Given the millions of insects in the crowns, I guess this is not really surprising, and anyone who ascends into the treetops returns with a huge admiration for “holey leaves.” Upon close inspection, it is difficult to find even one leaf not chomped or sucked or tunneled. On average, only twenty-one leaves per one thousand are intact (i.e., without a bite). The Amazon foliage has recently been nicknamed a “smoking gun” in the mystery of how moisture and rainfall affects forests. For a long time, scientists could not explain why the onset of seasonal rains began a few months before the oceanic currents brought moist air from the oceans. The leafing-out period for most tropical forests contributes significant water vapor into the atmosphere as a result of so much photosynthesis. During transpiration, leaves release moisture from small pores called stomata, enough to create low-level clouds, detectable above the forest by NASA satellites. These leaf-induced rain clouds cause showers that in turn warm the air, triggering wind patterns bringing additional moisture from the oceans, linking rainfall cycles to the leafing patterns of tropical trees. Hooray for leaves!
