A certain village in Phobjikha Valley, Bhutan, has been covered in the Japanese media fairly often; the story is that the villagers choose to live without electricity because not installing an electricity grid with overhead wires helps conserve Black-necked Cranes that migrate to the valley. A book about Bhutan records an interview: To the question, “Would you really prefer to have electricity, or is conserving more cranes important to you?” Villagers answered, “It’s good to have electricity, but we can do without it. But cranes are different from electricity. We feel happy when they visit this valley. We’ve seen them every year since childhood.”

More recently, I heard that solar lighting facilities had already been introduced and installed in Phobjikha a few years ago, but that subsequently, electricity was provided through underground cable. In January 2013, I visited Bhutan to participate in a meeting of an international experts’ working group for the “New Development Paradigm” being promulgated under a royal edict issued by the King of Bhutan. Before the meeting, I had the opportunity to visit Phobjikha Valley myself and heard about the efforts of the Bhutanese Royal Society for Protection of Nature (RSPN), which works to save the endangered cranes by involving local people in projects designed to help them live sustainably together with the birds. We would like to introduce this story from another part of Asia to our global readers. Responding to JFS’s request, Tshering Choki of RSPN contributed the article below.

Phobjikha Valley, in the district of Wangduephodrang in the Kingdom of Bhutan, is a beautiful valley situated at an altitude of over 2,900 meters above sea level. The valley is divided into two administrative blocks, Gangtey and Phobji.

Both Bhutanese and foreign visitors are aware of its status as a winter habitat for the globally endangered Black-necked Cranes (Grus nigricollis), listed as Vulnerable in the IUCN (International Union for Conservation of Nature and Natural Resources) Red List and also as destination of cultural and religious significance. The valley also lies on the periphery of Jigme Singye Wangchuck National Park.

Since its inception in 1987, the Bhutanese Royal Society for Protection of Nature (RSPN), a non-profit, non-government organization dedicated to supporting environmental conservation in Bhutan, has been a key player in conserving the Black-necked Cranes in Phobjikha Valley.

The RSPN has about 30 staff with its headquarters based in Thimphu and field offices in Phobjikha, Shemgang and Wamrong, Trashigang. Its mission is to inspire the personal responsibility and active involvement of the people of Bhutan in the conservation of the Kingdom’s environment through education, research and sustainable livelihood opportunities.

The RSPN’s strategic plan for 2010-2015 calls for:

1. Contributing to environmental conservation through sustainable livelihood approaches.
2. Increasing the level of environmental awareness through education, advocacy and public participation in conservation.
3. Developing a research strategy for the RSPN that will support environmental conservation, sustainable development, countermeasures to deal with emerging issues and education.
4. Strengthening the institutional and organizational capacity of the RSPN to support conservation, sustainable development, research and education.

The RSPN’s initial step towards putting conservation initiatives into practice in Phobjikha was a project to count and monitor Black-necked Cranes. In 1999 the RSPN initiated a conservation/sustainability program with a view to encouraging the local community’s participation and support for conservation. The program’s ideal goal is for Phobjikha to become an area where the human population is prospering economically while living in harmony with nature. It hopes to achieve this through strategies that enhance economic benefits without compromising conservation.

One of the projects introduced in 2003-2004 by the RSPN as part of this program focused on alternative energy. The goal was to encourage local communities to understand the importance and utility of different alternative energy sources and technology for mitigating negative environmental impacts.

The government had no plans at that time to provide electricity to the area, and so the project focused on distributing and installing solar panels in the valley. Many local people held the opinion that electricity had not been introduced in the valley in order to safeguard conservation priorities, but the truth mainly involved the economic non-feasibility of providing electricity to the area.

The project lent support to 198 households and 22 institutions (including government and community institutions as well as temples and monasteries) in Phobjikha.

The RSPN alternative energy project offered to distribute solar lighting equipment to the community based on a four-year installment payment plan charging 7 percent interest. They decided not to offer the solar lighting equipment for free because they wanted the community to grasp the meaning of owning the benefits by incurring the costs, as opposed to depending on free benefits.

The interest earned goes to a Phobjikha conservation fund that will support small community projects in the future. The fund is managed by a local environment management committee comprised of representatives from the local government, the local community and women, as well as national government bodies and monastic institutions. This committee plays an important role in coordinating and representing local interests.

However, in 2006, the Department of Energy initiated a proposal for Phobjikha electrification and submitted it to the Austrian Government, which showed an interest in supporting conservation initiatives in Phobjikha by funding a project to put electric wires underground.

Part of this electrification project was implemented by the Bhutan Power Corporation Ltd. (BPC) with the involvement of the RSPN in site identification and environmental impact assessment to identify important crane habitats where wires needed to be underground.

A memorandum of understanding was also signed between the BPC and the RSPN to make sure that the project is implemented in a safe, reliable and aesthetically conscious manner, in order to safeguard the existence of the Black-necked Cranes and to enhance the socio-economic development at Phobjikha. In 2009 the BPC took on the responsibility of executing this work in the area to completion, while the RSPN was responsible for monitoring the project and confirming that it was executed in the most environmentally friendly way, in order to safeguard the habitat of the endangered species.

Also, to encourage environmentally viable tourism while helping people benefit from conservation, the RSPN has been promoting community-based sustainable tourism (CBST) in Phobjikha.

For the past few years, the RSPN has been helping set up basic ecotourism facilities, such as a visitor information centre (the Black-necked Crane Information Centre) and nature trails, etc. The RSPN has also been working with the communities to develop local tourism products and services, such as local guides, cultural programs, campsites, local souvenir products, etc. The Black-necked Crane festival, started in 1998, forms an important part of the CBST program.

Currently the RSPN, in partnership with the Japan Environmental Education Forum (JEEF) and with financial support from the Japan International Cooperation Agency (JICA), is implementing a CBST project. Part of the project will involve training of local guides, supporting souvenir prodution and developing homestay facilities so that visitors can stay at homes of local people in order to enjoy experience the local food and learn about local customs.

While listening to locals describe these conservation efforts, I was able to observe cranes relaxing in Phobjikha Valley through a telescope at the information center. Afterwards, I had a great time staying with a farmer’s family and enjoying local food and drink under a stadium of stars. Having enjoyed this first-hand CBST experience, I hope the RSPN’s efforts will continue to bear fruit. JFS will be keeping an eye on RSPN’s efforts to attach importance to dialogue with local villagers while supporting sustainable coexistence between villagers and endangered cranes.

Of the seven known species of sea turtles, six live in the water off the coasts of the United States, Mexico and Canada: Kemp’s ridley, green, hawksbill, leatherback, loggerhead, and olive ridley. The seventh species, the flatback sea turtle, is only found in Australia.

Millions of sea turtles once graced our oceans, but now all six of the North American species are are included on the International Union for the Conservation of Nature’s Red List of Threatened Species. Scientists warn that the giant Pacific leatherback sea turtle could vanish in the next 5 – 30 years if current threats from industrial fishing are not halted.

Major Threats to Sea Turtle Survival:

• Poaching of adult turtles and turtle eggs
• Industrial fishing impact, such as being caught in nets and being dragged by longline hooks
• Development and destruction of beach nesting habitats
• Eating and being caught in plastic ocean debris
• Ocean pollution and oil spills
• Climate change impacts, such as sea level rise that effects nesting beaches and food supply

World Turtle Day, May 23rd every year, was established to highlight awareness, knowledge and respect for the world’s turtles and tortoises, while encouraging action to ensure their survival. Enjoy this gallery of Sea Turtle photos in honor of World Turtle Day.

Green Turtle (Chelonia mydas) Photo: Andy Bruckner, NOAA

Green Turtle (Chelonia mydas) Photo: Jeff Seminoff, NOAA

Green Turtle (Chelonia mydas) Photo: NOAA Fisheries.

Green Turtle (Chelonia mydas) Photo: Caroline S. Rogers, USGS

Hawksbill Turtle (Eretmochelys imbricata) Photo: Johan Chevalier, NOAA

Leatherback Turtle (Dermochelys coriacea) Photo: Scott R. Benson, NMFS Southwest Fisheries Science Center

Olive Ridley Arribada in Mexico (Lepidochelys olivacea) Photo: Michael P. Jensen

For More Information:

Introduction to Sea Turtles – Sea Turtle Conservancy

Sea Turtle Fact Sheet – Sea Turtle Restoration Project

Sea Turtle Restoration Project

Sea Turtle Preservation Society

How You Can Help Protect Sea Turtles – National Park Service

New discoveries of the way plants transport important substances across their biological membranes to resist toxic metals and pests, increase salt and drought tolerance, control water loss and store sugar can have profound implications for increasing the supply of food and energy for our rapidly growing global population.

That’s the conclusion of 12 leading plant biologists from around the world whose laboratories recently discovered important properties of plant transport proteins that, collectively, could have a profound impact on global agriculture. They report in the May 2nd issue of the journalNature that the application of their findings could help the world meet its increasing demand for food and fuel as the global population grows from seven billion people to an estimated nine billion by 2050.

“These membrane transporters are a class of specialized proteins that plants use to take up nutrients from the soil, transport sugar and resist toxic substances like salt and aluminum,” said Julian Schroeder, a professor of biology at UC San Diego who brought together 11 other scientists from Australia, Japan, Mexico, Taiwan, the U.S. and the U.K. to collaborate on a paper describing how their discoveries collectively could be used to enhance sustainable food and fuel production.

Schroeder, who is also co-director of a new research entity at UC San Diego called Food and Fuel for the 21st Century, which is designed to apply basic research on plants to sustainable food and biofuel production, said many of the recent discoveries in his and other laboratories around the world had previously been “under the radar”—known only to a small group of plant biologists—but that by disseminating these findings widely, the biologists hoped to educate policy makers and speed the eventual application of their discoveries to global agriculture.

“Of the present global population of seven billion people, almost one billion are undernourished and lack sufficient protein and carbohydrates in their diets,” the biologists write in their paper. “An additional billion people are malnourished because their diets lack required micronutrients such as iron, zinc and vitamin A. These dietary deficiencies have an enormous negative impact on global health resulting in increased susceptibility to infection and diseases, as well as increasing the risk of significant mental impairment. During the next four decades, an expected additional two billion humans will require nutritious food. Along with growing urbanization, increased demand for protein in developing countries coupled with impending climate change and population growth will impose further pressures on agricultural production.”

“Simply increasing inorganic fertilizer use and water supply or applying organic farming systems to agriculture will be unable to satisfy the joint requirements of increased yield and environmental sustainability,” the scientists added. “Increasing food production on limited land resources will rely on innovative agronomic practices coupled to the genetic improvement of crops.”

One of Schroeder’s research advances led to the discovery of a sodium transporter that plays a key role in protecting plants from salt stress, which causes major crop losses in irrigated fields, such as those in the California central valley. Agricultural scientists in Australia, headed by co-author Rana Munns and her colleagues, have now utilized this type of sodium transporter in breeding research to engineer wheat plants that are more tolerant to salt in the soil, boosting wheat yields by a whopping 25 percent in field trials. This recent development could be used to improve the salt tolerance of crops, so they can be grown on previously productive farmland with soil that now lies fallow.

Another recent discovery, headed by co-authors Emanuel Delhaize in Australia and Leon Kochian at Cornell University, opens up the potential to grow crops on the 30 percent of the earth’s acidic soils that are now unusable for agricultural production, but that otherwise could be ideal for agriculture.

“When soils are acidic, aluminum ions are freed in the soil, resulting in toxicity to the plant,” the scientists write. “Once in the soil solution, aluminum damages the root tips of susceptible plants and inhibits root growth, which impairs the uptake of water and nutrients.”

From their recent findings, the plant biologists now understand how transport proteins control processes that allow roots to tolerate toxic aluminum. By engineering crops to convert aluminum ions into a non-toxic form, they said, agricultural scientists can now turn these unusable or low-yielding acidic soils into astonishingly productive farmland to grow crops for food and biofuels.

Other recent transport protein developments described by the biologists have been shown to increase the storage of iron and zinc in food crops to improve their nutritive qualities. “Over two billion people suffer from iron and zinc deficiencies because their plant-based diets are not a sufficiently rich source of these essential elements,” the biologists write.

The scientists also discovered transporters in plants and symbiotic soil fungi that allow crops to acquire phosphate—an element essential for plant growth and crop yield—more efficiently and to increase the uptake of nitrogen fertilizers, which are costly to produce. “Nitrogen fertilizer production consumes one percent of global energy usage and poses the highest input cost for many crops,” the scientists write. “Nevertheless, only 20 to 30 of the phosphate and 30 to 50 percent of the nitrogen fertilizer applied are utilized by plants. The remainder can lead to production of the greenhouse gas nitrous oxide, or to eutrophication of aquatic ecosystems through water run-off.”

The biologists said crops could be made more efficient in using water through discoveries in plant transport proteins that regulate the “stomatal pores” in the epidermis of leaves, where plants lose more than 90 percent of their water through transpiration. Two other major goals in agriculture are increasing the carbohydrate content and pest-resistance of crops. A recent discovery of protein transporters that move sugar throughout the plant has been used to develop rice plants that confer pest resistance to crops, the biologists said, providing a novel way to simplify the engineering of crops with high yields and pest resistance, which could lead to reduced use of pesticides in the field.

“Just as our cell phones will need more advanced technology to carry more information, plants need better or new transporters to make them work harder on existing agricultural land,” said Dale Sanders, director of the John Innes Centre in the U.K. and a corresponding co-author of the paper. “Synthetic fertilizers and pesticides are the current solution, but we can make plants better at finding and carrying their own chemical elements.”

These recent developments in understanding the biology of plant transporters are leading to improved varieties less susceptible to adverse environments and for improving human health. Says Schroeder, “More fundamental knowledge and basic discovery research is needed and would enable us to further and fully exploit these advances and pursue new promising avenues of plant improvement in light of food and energy demands and the need for sustainable yield gains.”

In addition to Schroeder and Sanders, the co-authors of the paper are Emmanuel Delhaize of CSIRO in Canberra, Australia; Wolf Frommer of the Carnegie Institution of Science; Mary Lou Guerinot of Dartmouth College; Maria Harrison of the Boyce Thompson Institute for Plant Research in Ithaca, NY; Luis Herrera-Estrella of the Center for Research and Advanced Studies of the National Polytechnic Institute in Iraputo, Mexico; Tomoaki Horie of Shinshu University in Nagano, Japan; Leon Kochian of Cornell University; Rana Munns of the University of Western Australia in Perth; Naoko Nishizawa of Ishikawa Prefectural University in Japan; and Yi-Fang Tsay of the National Academy of Science of Taiwan.

“In [Western] medicine, we believe that one hormone can fix a problem as complicated as obesity, one neurotransmitter can fix something as complicated as depression, or one DNA strand can heal a cancer,” said Daphne Miller, MD, before a packed audience at the Ferry Building, in San Francisco.

“What attracted me to sustainable agriculture,” the Harvard-trained family physician continued, “was looking outside of that reductionist approach and seeing colleagues who were thinking about the sun, moon, rain, microbes, animals, and humans in this incredible, complex ecosystem. They were thinking in a way that I, as a physician, wanted to think.”

Jaded by modern medicine’s emphasis on isolating symptoms rather than treating the whole patient, Dr. Miller went back to the land to inspire her practice and set out on a journey to visit farmers who are eschewing business as usual. She shares her stories and discoveries in her new book, Farmacology: What Innovative Family Farming Can Teach Us about Health and Healing.

In her travels, she met Erick Haakenson of Jubilee Biodynamic Farm, who transformed a depleted plot of land into a thriving vegetable and fruit farm. As a beginning farmer, Haakenson at first followed the conventional “test-and-replace” method of soil management, sending samples to a lab for testing and then adding nutrients and minerals to compensate for deficiencies.

After dumping some 50 tons of amendments in the earth and seeing little progress, he turned to the holistic farming methods of Biodynamic pioneers such as Rudolph Steiner. He traded in nitrogen-based fertilizers for cows and compost and started farming in concert with nature’s cycles. Over time, he was able to build healthy, bioactive soil yielding vibrant, nutrient-dense plants.

Dr. Miller shared a parallel story from her medical practice. A patient named Allie had shown up at her office plagued by exhaustion and gastrointestinal problems, caught in a diet of energy bars, prescription pills, and over-the-counter supplements. Rather than take the test-and-replace approach that many of Allie’s previous doctors had used, Dr. Miller prescribed lifestyle and diet changes such as subscribing to a CSA program and gardening. Just as Haakenson’s farm sprang back to life, Allie’s health improved.

Like any farm or ecosystem, the human body is greater than sum of its parts, and according to Dr. Miller, the similarities between farm ecology and human health run deep. For example, the ideal pH and the carbon-to-nitrogen ratio in humans and soil are almost identical. The interplay of micoorganisms in healthy soil is not unlike our own human microbiome. And where do those carbs, fats, and proteins that compose our bodies come from? The food we eat and the soil it’s grown in, naturally.

Reconnecting with the soil is one of the most basic ways we can support our bodies to heal and stay healthy. Dr. Miller provided a few pointers:

1. Eat a little dirt (and even a couple bugs). If you’re eating from healthy soil,don’t scrub your vegetables. The nutrients and beneficial microorganisms are not just in the food itself, but they’re also in what the food was grown in. Conversely, unhealthy, chemically treated soil can contain toxins.
2. Buy with your nose and taste buds, not with your eyes. Pick your food up and smell it. Smell is an indicator of nutritional value, and good food should smell good. If it doesn’t smell, it might be because the seed it was grown from was selected for productivity or ease of transport instead of taste and nutrition. Food that comes from sustainable agriculture might look imperfect, but those bug-nibbled bits can be the most nutritious and delicious.
3. Choose food that has a story. Know the faces behind your food. Wendell Berry says a good way to find healthy food is to ask whether the farmer lives on the land. Farmers who live on and eat from the land, and who want to pass it down to their children and grandchildren, are more likely to take care of their soil than farmers who live off site.
4. Cook. Put simply, cooking is a way to get to know your raw ingredients and connect with the farms. See Michael Pollan’s new book to learn more about why cooking matters.
5. Give back to the soil and farms. Even if you live in the city, you can contribute to the soil cycle by joining a composting program, so your greens go back to the farm. You can also conserve water in the home, so that it can be saved for agricultural use.
6. Bring the farm to you. Whether it’s tending a vegetable garden or bringing plants into your school or workplace, being around plants can actually make people happier and healthier (a phenomenon known as biophilia).
7. Treat your body and your house with things that you don’t mind finding in your food. Sunscreens with lauryl sulfate and paint with VOCs not only enter our bodies through our skin and lungs, but they eventually wind up in our water supply. Those chemicals make their way back to the farm and ultimately into our food.
8. Enjoy fermented foods. Instead of taking expensive probiotics in pill form, eat fermented vegetables. Fermentation is controlled rotting that uses the beneficial bacteria that live on foods and in the soil they were grown in. Ferment vegetables yourself or support a local fermenter. You only need a tablespoon a day to support healthy microflora in your gut.

Modern medicine has its place in treating many diseases and health issues, Dr. Miller acknowledges, but ideally, there should be a balance between holistic and scientific approaches. “There are two ways to get your information both in healing and in farming,” she said. “One is through experience and one is through scientific method. The true art for both the physician and the farmer is knowing when to use one, when to use the other, and when to meld them.”

Learn more about Farmacology. Listen to a recording of the talk here.

By Andrew Bach and Bradley Smith

Looking over the edge of the Glines Canyon Dam in February 2012, six months after the dam removal project had started. Photo National Park Service

As the last block of concrete was pulled from the riverbed, the Elwha River in the Olympic Mountains of Washington State flowed freely for the first time in over 100 years. The river was historically one of the most productive salmon streams for its size in the Pacific Northwest. Four hundred thousand salmon once swam its length each year but, in the century since the dam’s construction, that number had fallen to a few thousand.¹ Within months of the dam’s removal, nature has rushed back: over 200 salmon have already returned. The prospect of a river teeming with silverbacked salmon weighing over 45 kilograms each may no longer remain a hazy memory of local Native American tribes.

The Elwha dam removal project stands as one of the first large dams ever removed. The intent of removing the dams is to fully restore the Elwha River ecosystem and its native migratory fish species. In doing so, the Elwha dam project revived the debate of how to balance the conflicting demands of humans for both clean energy and healthy ecosystems. Previously, that debate has been weighted decisively in favor of dam projects. But with a greater understanding of the value of ecosystem services, the Elwha dam project may represent the start of a revolution in how we assess the West’s aging dam infrastructure.²

The Tribe

The Elwha watershed was the traditional homeland of the S’Klallam Tribe, whose culture flourished on salmon from the river, among other natural resources. Against tribal will, construction of the Elwha Dam began in 1910 for the sole purpose of generating the first electricity in the region. The electricity powered several lumber mills and fueled economic development, resulting in construction of a second dam, the Glines Canyon Dam farther upstream, in 1927. The lower Elwha Dam did not have fish passage and the salmon runs declined from 400,000 per year to about 3,000 fish in the lowest eight kilometers of the river. Tributaries in the headwaters of the Elwha River were protected from further development in 1938 with the establishment of Olympic National Park. The impact on the S’Klallam Tribe was devastating for their culture and livelihood. A fishery that could be worth over $10 million was lost. The near disappearance of salmon in the watershed also had a cascading effect on the terrestrial ecosystem, where some 22 species of resident wildlife were affected, and over 90 species of migratory birds. The decomposing salmon carcasses have been shown to significantly contribute to the biomass of the forest itself, accounting for 20–60 percent of riparian biomass.¹

Newly mobilized sediment near Ediz Hook after the Elwha dams were removed. Photo Tom Roorda/USGS

The dams also stopped the movement of sediment through the river system, resulting in deposition in the reservoir deltas.¹ As a result, the river incised its channel, armored its bed with boulders (instead of sand and gravel where salmon could lay eggs), and reduced the sediment delivery to the coastal environment, causing beach erosion for at least 30 kilometers along the shore.³ Some of the most intense erosion occurred on Ediz Hook, which creates an important lumber shipping port at Port Angeles. From the 1970s through the 2000s, the Army Corps of Engineers spent hundreds of millions of dollars each year to protect the Ediz Hook from erosion.

In 1968 the S’Klallam Tribe and numerous environmental groups tried to stage a comeback by opposing relicensing of the dams by the federal government, citing loss of the salmon fishery, negative environmental impacts within the watershed, and submersion of a tribal sacred site under the reservoir.

But despite the strong case against the dam, the local nontribal community strongly favored relicensing it. The electricity from the dams continued to play an important role in powering the region’s timber-based economy. There were additional challenges in assessing the possible impacts of removing the dam, given the amount of sediment that had built up, and on the potential impact on the City of Port Angeles’ water supply. Even a U.S. Department of the Interior study in 1991, which recommended the removal of the dams, failed to energize foot-dragging state officials and local interest groups. The removal was legislated by Congress with the passage of the Elwha River Ecosystem and Fisheries Restoration Act P.L. 102-495.

Federal Laws Kick In

However, in the nearly two decades that followed the passage of the 1992 federal law mandating the dams’ removal and the release of funds to begin work, a generational shift took place. Dams—for so long seen as symbols of development and progress—were increasingly being criticized for their social and environmental impacts. The issue came into focus internationally following protests over the forced evictions of hundreds of thousands of people in India and China due to dam projects. In the United States, aging dam infrastructure was pushing local governments to repair or remove many of these structures. The 85,000 large dams in the United States have an average age of 53 years, and over 4,000 of the large dams are considered structurally unsound.⁴ An additional problem with dams is that, as they age, they fill with sediment, reducing storage capacity.

For these reasons, hundreds of small dams (less than 7.5 meters in height) have been removed in recent decades. With smaller structures, there is little question that rivers can return to their pre-dam flow characteristics.^5,6 Successful dam removals and ecosystem recovery have been seen with the Edwards Dam in Maine, and the Marmot and Condit Dams in Oregon. But as the Elwha dam saga continued to rumble into the new millennium, the question remained whether dam removal would be successful for large structures.

A major concern when removing a dam is managing the remobilized sediments from the lake delta, which are now exposed to flowing water. The Elwha River dams have accumulated over 34 million cubic meters of sediment. The reservoirs of the Glines Canyon and the Elwha Dams had no drains and were too large for a single, explosive removal. Each dam had unique characteristics and required its own removal plans, time frames for safety concerns, and strategies for managing the massive amounts of sediment in the reservoirs. Careless removal of the dams could cause large amounts of sediment in the reservoir deltas to flow down the river.⁷ Even though the Elwha Dam is the older of the two dams, the majority of sediment lay trapped upstream behind Glines Canyon Dam (GCD). Thus, the GCD removal progressed slowly in order to manage the sediment through the river system. Further complicating matters, sediment behind the GCD was located in a federally designated wilderness area of Olympic National Park, where machinery is banned.

In September 2011 work began on removing both dams. The Elwha Dam was structurally unsound, due to poor construction, and required a complex removal process to avoid a catastrophic failure. First, a cofferdam moved the river to the left side of the dam; an artificial channel cut through the bedrock where the dry right spillway is located. Then a second cofferdam directed the river into the artificial channel for removing water from behind the main dam, which was subsequently removed by jackhammering and blasting. By contrast, the Glines Canyon Dam was structurally sound, allowing for a large jackhammer to be used directly on the dam face. Both dams were removed within 13 months. However, the Elwha Dam was removed first, and muddy sediment poured down the river and into the ocean for the first time in over 100 years. Beaches near the river’s mouth experienced immediate growth, even faster than expected. After the Glines Canyon dam was fully breached, even larger amounts of sediment began moving through the river. Logs and other floating debris created logjams, causing the river to erode its banks and migrate across its floodplain as it had before the dams were installed. Sediment levels are expected to return to normal in one to three years.

A First Step

A map of the Elwha River watershed in Washington state, where the country’s first large dam removal project was recently completed. Photo National Park Service

Of course, removing the dam was only the first part of the first step of the real goal of restoring salmon fisheries. During the decade prior to removal, scientists surveyed fish populations in the river to inventory populations of native and migrating fish species.⁷ Fisheries biologists also captured Elwha River fish stock for transport to hatcheries and nearby streams for rearing in order to preserve genetic diversity. The schedule of work during the process of removing dams was periodically halted to protect fish during their seasonal runs, and provided windows for their capture and transport to safe rearing sites. Fish stocks will recover following complete deconstruction of the dams, stabilization of sediment transport, and the recovery of the ecosystem food chain that provides food for juvenile salmon that will grow in the Elwha River before migrating to the ocean. However, even in the short time (less than six months) following removal of the Elwha Dam, some wild salmon found the new habitat and spawned, in spite of turbid water. The premature appearance of the native salmon population is a positive signal forecasting the recovery of the salmon population.

The exposed reservoir lakebed represents another restoration problem. Without vegetation cover, the soft lake sediments are subject to erosion during the rainy season. For approximately 10 years, the Park Service has been collecting and saving native seeds, and rearing plants to revegetate the lakebed. As soon as lake levels were drawn down, crews were planting seeds and seedlings in order to head off invasive species. Luckily, this winter has been mild with few erosive rainstorms, and the seed bank in the sediments produced a nearly continuous cover of vegetation. The invasive species will be monitored in coming years, but the soil was more stable than expected during this first critical year.

The removal of dams on the Elwha River offers a unique opportunity to evaluate the effects of large dam removal and subsequent recovery of formerly productive aquatic ecosystems that supported large populations of salmon and a related complex ecosystem.⁸ Although intentional dam removal of this magnitude is unique, it could become more common as those in the United States and other nations manage an aging system of dams. An essential step in removing both small and large dams is assessing watershed scale features before and after dam removal. A comprehensive plan designed to evaluate the effects of dam removal on existing fish populations, food webs and habitats, sediment flow, and many other factors is essential before removing dams. Now, we are well positioned to see exactly how the system responds.

References

1. Winter, BD & Crain, P. Making the case for ecosystem restoration by dam removal in the Elwha River, Washington.Northwest Science 82, 13–28 (2008).
2. Doyle, MW, Harbor, JM & Stanley, EH. Toward policies and decision-making for dam removal. Environmental Management 31, 453–465 (2003).
3. Duda, JJ, Warwick, JA & Magirl, CS, eds. Coastal Habitats of the Elwha River, Washington: Biological and Physical Patterns and Processes Prior to Dam Removal. U.S. Geological Survey Scientific Investigations Report 2011–5120(2011).
4. American Society of Civil Engineers. 2009 Report Card for America’s Infrastructure (ASCE, New York, 2009).
5. Graf, WL. Damage control: Restoring the physical integrity of America’s rivers. Annals of the Association of American Geographers 91, 1–27 (2001).
6. Bednarek, AT. Undamming rivers: A review of the ecological impacts of dam removal. Environmental Management27, 803–814 (2001).
7. McHenry, ML & Pess, GR. An overview of monitoring options for assessing the response of salmonids and their aquatic ecosystems in the Elwha River following dam removal. Northwest Science 82, 29–47 (2008).
8. Poff, NL, Olden, JD, Merritt, DM & Pepin, DM. Homogenization of regional river dynamics by dams and global biodiversity implications. Proceedings of the National Academy of Sciences 104, 5732–5737 (2007).

Originally published in The Solutions Journal; republished through a Creative Commons-Share Alike license.

Many of us might spend up to 90 % of our day indoors — at home, work or school. The quality of the air we breathe indoors also has a direct impact on our health. What determines indoor air quality? Is there any difference between outdoor and indoor air pollutants? How can we improve indoor air quality?

It may come as a surprise to many of us that the air in an urban street with average traffic might actually be cleaner than the air in your living room. Recent studies indicate that some harmful air pollutants can exist in higher concentrations in indoor spaces than outdoors. In the past, indoor air pollution received significantly less attention than outdoor air pollution, especially outdoor air pollution from industrial and transport emissions. However, in recent years the threats posed by exposure to indoor air pollution have become more apparent.

Imagine a newly painted house, decorated with new furniture… Or a workplace filled with a heavy smell of cleaning products… The quality of air in our homes, work places or other public spaces varies considerably, depending on the material used to build it, to clean it, and the purpose of the room, as well as the way we use and ventilate it.

Poor air quality indoors can be especially harmful to vulnerable groups such as children, the elderly, and those with cardiovascular and chronic respiratory diseases such as asthma.

Some of the main indoor air pollutants include radon (a radioactive gas formed in the soil), tobacco smoke, gases or particles from burning fuels, chemicals, and allergens. Carbon monoxide, nitrogen dioxides, particles, and volatile organic compounds can be found both outdoors and indoors.

Policy measures can help

Some indoor air pollutants and their health impacts are better known and receive more public attention than others. Smoking bans in public spaces is one of them.

In many countries, smoking bans in various public places were quite controversial before relevant legislation was introduced. For example, within days of the entry into force of the smoking ban in Spain in January 2006, there was a growing movement to assert what many considered their right to smoke in indoor public places. But the ban has also led to greater public awareness. In the days following its entry into force, 25 000 Spaniards per day sought medical advice on how to quit smoking.

Much has changed in public perception when it comes to smoking in public places and on public transport. Many airlines started to ban smoking on short-haul flights in the 1980s, followed by long-haul ones in the 1990s. It is now unthinkable in Europe to allow non‑smokers to be exposed to second-hand smoke on public transport.

Today many countries, including all the EEA countries, have some legislation to limit or ban indoor smoking in public places. After a series of non-binding resolutions and recommendations, the European Union also adopted in 2009 a resolution calling on EU Member States to enact and implement laws to fully protect their citizens from exposure to environmental tobacco smoke.

Smoking bans appear to have improved indoor air quality. Environmental tobacco smoke pollutants are declining in public places. In the Republic of Ireland, for example, measurements of air pollutants in public places in Dublin before and after the introduction of a smoking ban showed decreases of up to 88% for some air pollutants found in environmental tobacco smoke.

As in the case of outdoor pollutants, the impacts of indoor air pollutants are not limited to our health only. They also come with high economic costs. Exposure to environmental tobacco smoke in EU workplaces alone is estimated at over EUR 1.3 billion in direct medical costs, and over EUR 1.1 billion in indirect costs linked to productivity losses in 2008.

Indoor pollution is much more than tobacco smoke

Smoking is not the only source of indoor air pollution. According to Erik Lebret from the National Institute for Public Health and the Environment (RIVM) in the Netherlands, ‘Air pollution does not stop at our doorsteps. Most outdoor pollutants penetrate into our homes, where we spend most of our time. The quality of indoor air is affected by many other factors, including cooking, wood stoves, burning candles or incense, the use of consumer products like waxes and polishes for cleaning surfaces, building materials like formaldehyde in plywood, and flame retardants in many materials. Then there is also radon coming from soils and building materials.’

European countries are trying to tackle some of these sources of indoor air pollution. According to Lebret, ‘we are trying to substitute more toxic substances with less toxic substances or to find processes that reduce emissions, as in the case of formaldehyde emissions from plywood. Another example can be seen with the reduction of certain radon-emitting materials used in wall construction. These materials were used in the past but their use has since been restricted.’

Passing laws is not the only way to improve the quality of the air we breathe; we can all take steps to control and reduce airborne particles and chemicals in indoor spaces.

Small actions such as ventilating enclosed spaces can help improve the quality of the air around us. But some of our well-intended actions might actually have adverse effects. Lebret suggests: ‘We should ventilate, but we should not over ventilate as this is a substantial loss of energy. It leads to more heating and use of fossil fuels, and consequently means more air pollution. We should think of it as making more sensible use of our resources in general.’

More Information:

World Health Organization on indoor air quality
Joint Research Centre on indoor air quality
European Commission on public health

Nouabale-Ndoki National Park in Central Africa, site of the scientists' research. Credit: Wikimedia Commons

Ecologists discover when, how tropical trees regenerate

Nouabale-Ndoki National Park is a tree-dotted enclave in Central Africa’s Republic of Congo. Heavy logging surrounds the park, but it still has one of the largest intact forests in Africa. In recognition, it recently became a UNESCO World Heritage Site.

Trees–thousands of them–make up a forest. How did Nouabale-Ndoki’s trees become so numerous, and how do they stay that way?

The answer, say biologists, lies far below the tree canopy, in the soil where seedlings sprout.

Reaching toward the sky: a canopy tree in Nouabale-Ndoki National Park. Credit: Connie Clark

Recently, in the journal PLOS ONE, scientists report results of an extensive seedling experiment in Nouabale-Ndoki National Park. The research, which involved sowing 40,000 seeds of five tree species, is a new look at “seeing the forest for the trees.”

The findings, which show what limits seedling growth, are important to reforestation efforts in areas that have been logged.

Every tree can produce hundreds of thousands of seeds in its lifetime, but on average, only one seed survives to adulthood, says John Poulsen of Duke University, a co-author of the journal paper.

Other paper co-authors are Connie Clark, also of Duke, and Doug Levey, formerly of the University of Florida and now a program director in the National Science Foundation’s (NSF) Division of Environmental Biology.

Which seeds have the best chance of making it to old age?

“There are basically two ways to look at successful seedling recruitment [survival],” says Levey. “Species may be seed-limited or establishment-limited.”

Two-year-old seedlings of a species known as African mahogany survive in the tropical forest. Credit: Connie Clark

A tree species is seed-limited if its ability to grow is determined by whether its seeds reach a particular location on the ground. The seeds may arrive on the wind or simply by falling from trees.

Establishment-limited trees are those that depend on the environment around them, rather than on seeds landing in just the right spot. If the soil is too wet or there is too much shade, a species is establishment-limited.

To test the importance of these two limitations on seedling recruitment, the scientists sowed tens of thousands of seeds. They chose the species randomly, which allowed the results to be generalized to all tree species, not just the most common ones, says Poulsen.

The seeds were planted in different amounts in plots that stretched across an area the size of the state of Rhode Island. Latter-day Johnny Appleseeds, the researchers couldn’t do it alone, however.

Gaston Abeya, a Mbendzele research assistant, measuring tree seedlings. Credit: Connie Clark

“We hired a small army of indigenous, Mbendzélé hunter-gatherers,” says Clark. “These families could easily locate seeds, and we were the beneficiaries of their intimate knowledge of the forest’s natural history.”

After the seeds were planted, the ecologists watched them grow into seedlings over two years.

They found that only a small fraction of seeds, some 16 percent, became seedlings. An even smaller amount, about six percent, survived to reach their second birthdays.

When numbers of seeds were at one end of a spectrum–rare or abundant–the trees’ recruitment was seed-limited.

“When seeds were at intermediate densities,” says Levey, “the chance of recruitment was influenced by environmental factors such as soil type and sunlight.”

The importance of seed- and establishment-limitation changes over time, Levey says. “As individual trees get older, they need the correct soil and light exposure [become more establishment-limited].”

Not that different from our changing needs for the right nutrients and enough light as we reach our sunset years.

Source: National Science Foundation

Originally published in Development Roast.

An INBAR project in Ecuador, financed by the World Bank, builds flood-resistant houses using a native species of bamboo. Photo credit: World Bank

Efforts to thoroughly study the role that plants play in climate change mitigation are increasing. Most researchers focus on the promise of large, leafy forest trees to help remove carbon from the atmosphere; for example Lal (1998) in India, Chen (1999) in Canada, Zhang (2003) in China, and Monson ( 2002) in the United States. This is because, generally speaking, the bigger the plant, the more CO₂ it absorbs - and trees are the most obvious large plant species. However, there are some very large non-tree plants in the world and increasing evidence points to a surprising grassy climate change warrior: bamboo.

One species of bamboo, the guadua angustifolia, found in Venezuela, Ecuador, and Colombia, has been shown to grow up to 25 meters in height and 22 centimeters in diameter, with each plant weighing up to 100 kilograms (Rojas de Sánchez, 2004). This doesn’t match the stature of many trees, but it is still big enough to be significant. It is not all about size, however. How fast a plant grows has a part in determining how much CO₂ it can absorb in a given time. In this respect, bamboo wins hands-down: it grows faster than many trees, growing up to 1.2 meters per day. In fact, bamboo holds the Guinness World Record for the world’s fastest growing plant.

Tall bamboo. Photo: By 13dede on sxc

Bamboo’s other advantage is that it has great strength and flexibility, making it an ideal low-cost building material in many parts of Africa, Asia, and Latin America, areas where it is native. This means that bamboo in a plantation can regularly be chopped down and used to build houses and other structures, where the carbon remains sequestered for an average of 80 years (Castañeda, 2006), and that the plantation will recover quickly due to the fast growth rate. Because of this, the World Bank recently financed a project in Ecuador proposed by the International Network for Bamboo and Rattan (INBAR), an intergovernmental organization dedicated to improving the livelihoods of the poor producers and users of bamboo and rattan. The project is called ‘Elevated bamboo houses to protect communities in flood zones’ and has so far succeeded in developing and implementing techniques to construct ecological flood-resistant housing for low-income families using a type of bamboo that is native to Ecuador. The results currently include five, three classrooms, and two shelters. Elsewhere in the world, bamboo is also used to make boats (most commonly in Asia, but also in Ethiopia), furniture, flooring, clothing, paper, plastics, water pipes, and a very long list of other products. In cases such as furniture and flooring, bamboo provides an attractive and practical alternative to slower growing and less sustainable tree timber.

Bamboo’s carbon sequestration properties have been studied in countries where it naturally forms wild forests, such as Mexico (Castañeda, 2006) and China (Song, 2011). Contributing to these efforts, Ricardo Rojas Quiroga—an environmental engineering student at the Universidad Nuestra Señora de La Paz—studied Guadua angustifolia, a species of bamboo that grows in the Carrasco National Park of Bolivia. He measured the density and masses of bamboo plants in the forest, estimating the amount of carbon stored per hectare. Rojas concluded that, in addition to forming part of one of the most biodiverse ecosystems in the world, each hectare of the bamboo forest of Carrasco National Park stores levels of carbon comparable to some large tree species such as Chinese fir and oak. This finding is consistent with that of many previous studies, a review of which can be found in this 2010 report by INBAR.

Bamboo growing in big clumps. Photo: By revati_me on sxc

This research is important because concrete numbers can more easily persuade policy-makers of the importance of bamboo forests, as well as other natural resources, in mitigating and adapting to climate change. For example, China has a native giant species of bamboo called Moso bamboo. One hectare (an area roughly the size of an athletics track) of this species can store up to 250 tons of carbon (Qi, 2009). Using data on CO₂ emissions from the World Bank, this translates into the amount of carbon that was produced in 2009 by around 160 people in China (or, equivalently, 50 people in the U.S.A.). Each year, a hectare of Moso bamboo absorbs 5.1 tons of carbon, which can compensate for the CO₂ emissions of three people in China (or one person in the U.S.A.). For reference, China has 3.37 million hectares of Moso bamboo (according to the State Forestry Administration of China) which accounts for around three percent of China’s total forest area.

Once the relevant data has been collected, similar calculations can and should be performed for more countries, enabling politicians to allocate resources and priorities more effectively. It is important to note that INBAR and the other studies do offer a word of caution. Prioritization of one species over another for the purposes of carbon sequestration must take care, as figures are highly dependent on geographical and climatic conditions. It must also take into consideration the compatibility of the plants with the ecosystems in question.

Ultimately, the most effective solution to climate change is to decrease CO₂ emissions by reducing dependence on fossil fuels. But, since a stage of zero emissions is highly unlikely in the near future, forests play a vital role in drive towards a more achievable state of carbon neutrality. Additionally, if countries such as those in South America can prove that their forests are removing not just their own country’s CO₂, but also a lot of the carbon produced by other countries, it could be used to provoke rich, highly-polluting countries into contributing more towards the protection of these precious resources.

Tracey Li is a Senior Research and Communications Intern with INESAD.

Paul Rosolie checking the camera trap videos on a laptop in the Amazon, Photo: Mohsin Kazmi

Visiting a rainforest can be an exercise in challenged expectations. Everyone knows that rainforests are full of life: they teem with species, act as stages for unimaginably intricate food webs, and provide refuge for rare and even undiscovered organisms that exist nowhere else in the world. And yet . . . dense tropical forests can appear deceptively devoid of animals. One can spend hours and even days hiking through the Amazon’s cathedrals of green without spotting many animals beyond buzzing insects and snatches of birdsong from overhead. There are millions of organisms around, to be sure, yet they are all woven so tightly into their environment as to be almost indistinguishable from the forest itself.

Through the camera lens

Red howler monkey in the Las Piedras region. Photo: Mohsin Kazmi

Although it seems as though obtaining glimpses of the forest’s large and rare fauna might be a hopeless endeavor, there are a few tricks of the trade that researchers use to tease out evidence of even the most elusive species. Recently, advances in remote camera technology have provided scientists and photographers with new and exciting options for detecting wildlife—a way to put eyes in the forest without disturbing animals’ natural behaviors or movement patterns. When viewed through a camera lens, the forest comes to life. Case in point: the work of Paul Rosolie, a wildlife researcher who has done extensive research along Peru’s lower Las Piedras River. Rosolie has put concerted effort into documenting animals in the region’s forests. He often strategically places his cameras at mineral deposits—hotspots for wildlife seeking critical nutrients—and Rosolie’s photos have provided a valuable window into forest diversity and activity.

Rosolie’s film, An Unseen World, a collection of stunning camera trap footage from the Peruvian Rainforest, was a winner in the 2013 United Nations Forum on Forests (UNFF) short films contest, Forests for People.

There is a dark side to this story. The animals captured by Rosolie’s cameras cannot comprehend that their forest is on the brink of vast and potentially devastating changes. But Rosolie can, and this is what drives his efforts to document and publicize the region’s incredible biodiversity. He conducts his research knowing that every day, development encroaches a little bit farther into this delicate ecosystem, largely facilitated by road development designed to ease the process of extracting resources from South America’s rich interior.

Paving Peru

The Trans-Amazonian highway was an ambitious and ill-conceived project initiated by General Medici, one of Brazil’s military rulers, in 1970. He observed that the northeastern parts of Brazil faced extreme resource scarcity, and his solution was to build a 5,000 km road spanning South America from east to west—crossing some of the most intimidating terrain on the planet. It was cut through thousands of kilometers of steaming tropical forest, up steep and winding mountainsides, and across dizzyingly high Andean passes.

The highway was assembled at a breakneck pace—the entire road was laid over the course of just 18 months. Unfortunately, someone managed to overlook the fact that the rainforest gets a lot of rain. A lot of rain. Enough rain to make the new highway, covered in just a thin veneer of gravel, virtually impassable for up to six months of the year.

Logging truck near the lower Las Piedras.

Although the road failed as a reliable route of commerce, it has created lasting impacts. It resulted in previously isolated indigenous communities being exposed to new diseases, costing thousands of human lives and even broader cultural losses. The Brazilian government sponsored a large resettlement movement to populate South America’s interior after the road was built. Inevitably, settlers left stranded during rainy periods had to clear fast swaths of forest to eke out a living, due to the Amazon’s low soil nutrient content. And during the months the road was actually passable, it served as a conduit for logging—both illegal and otherwise—and rampant wildlife poaching in a region that is teeming with rare and unique species, including many that are likely unknown to science.

Humankind’s urge to conquer nature knows no bounds, however. Although the Brazilian government largely abandoned the road a few years after it proved to be a maintenance nightmare, there has recently been a new push to pave the entire thing, in an effort to keep it passable and facilitate more resource extraction from the heart of South America. It also provides a convenient corridor for moving drugs from one coast of the continent to the other, although that was not included in the official economic analyses.

This new and “improved” version of the highway—now experiencing dramatic increases in traffic—passes through the Las Piedras river area. The consequences are becoming more and more evident by the day. New logging roads are sprouting off of the main road into the pristine forest, and Rosolie and his team have seen a marked uptick in wildlife fatalities for species ranging from jaguars to macaws.

Protecting the Las Piedras region

One reason the region is reeling from the new road is that none of its land is formally protected—making it nearly impossible to enforce penalties for killing or disturbing wildlife. Thus, Rosolie is spearheading the effort to obtain formal protection of the land. “It’s no small task to create a national park, but…the truly unique element of the Piedras plan is the once-in-history opportunity to protect the area before it is degraded, and before it is filled with too many people to make a park viable.”

“Protecting this river would create ecosystem connectivity between large, famous protected areas. I think that connecting the already-existing parks to create a mega-reserve would be something for Peru to be proud of; an important example for the rest of the world.”

Protecting the Las Piedras region would yield compound benefits by creating a corridor system between other vital biodiversity hotspots. “Protecting this river would create ecosystem connectivity between large, famous protected areas. I think that connecting the already-existing parks to create a mega-reserve would be something for Peru to be proud of; an important example for the rest of the world.” While fighting to protect the region from further disturbance, Rosolie continues to document the rich diversity of Las Piedras. His cameras have yielded footage of dozens of rare and unique mammal species, including the short-eared dog (Atelocynus microtus), one of the Amazon’s rarest mammals.

Rosolie has also documented a tiny marsupial known as the “mouse opossum” (Marmosa murina), the bellow-lunged red howler monkey (Alouatta sara), the elusive pale-winged trumpeter (Psophia leucoptera), and the virtually unstudied twist-necked turtle (Platemys platycephala), just to name a few highlights. Conservation work can be disheartening, especially for researchers that spend much of their time out in the field, confronting the effects of habitat destruction and poaching first-hand every day. Rosolie remains undaunted, and is putting effort into developing ecotourism-based conservation efforts around the lower Las Piedras. He has also written a book, Mother of God, which will be published by Harper Collins in early 2014. Rosolie hopes that the book’s tales of adventure and descriptions of the rich biodiversity of Peru’s forests will bring more attention and support to his efforts to protect wildlife in the region. In the mean time, he continues to cook up new and innovative ways to bring much-needed attention and support in order to save one of the jewels in South America’s crown of biodiversity.

Species in Las Piedras Colpa Camera Trap Study:

1. Red Brocket Deer: Mazama Americana
2. Grey Brocket Deer: Mazama gouzoubira nemorivaga
3. White-lipped Peccary: Tayassu pecari
4. Collared peccary: Tayassu tajacu
5. Tapir: Tapirus terrestris
6. Ocelot: Leopardus pardalis
7. Puma: Puma concolor
8. Giant Anteater: Myrmecophaga tridactyla
9. Giant Armadillo: Priodontes maximus
10. Nine-banded Armadillo: Dasypus kappleri
11. Red Squirrel: Sciurus igniventris
12. White Capuchin Monkey: Cebus albifrons
13. Howler Monkey: Alouatta sara
14. Paca: Cunniculus paca
15. Agouti: Dasyprocta punctate
16. Anuje: Myoprocta pratti
17. Porcupine: Coendou bicolor
18. Jaguar: Panthera onca
19. Tyra: Eira Barbara
20. Amazon Coati: Nasua nasua
21. Rabbit: Sylvilagus brasiliensis
22. Spider Monkey: Ateles chamek
23. Squirrel Monkey: Saimiri boliviensis
24. Amazonian Red Sided Opossum: Monodelphis glirina
25. Mouse opossum: Marmosa murina
26. Spixes Guan: Penelope jacquacu
27. Razor-billed Curosaw: Mitu tuberosum
28. Pale Winged Trumpeter: Psophia leucoptera
29. Yellow-footed Tortoise: Geochelone denticulata
30. Side Necked Turtle: Atemys platycephala

More Information:

Tamandua Expeditions

Even as the U.S. East Coast braces for the arrival of the bizarre infestation of cicadas that happens with clockwork precision every 17 years, we’re already seeing an infestation of cicada stories, everything from how to grill a cicada to how to make a refreshing cicada cocktail. And that’s even before the Internet Meme Machine gets started. This will be the first arrival of the 17-year cicadas during the modern social media era, so get prepared for cicada hashtags (e.g. #Swarmageddon), “insect porn” of cicadas mating on Instagram and round-the-clock tweets documenting their arrival. But here’s one thing maybe you haven’t thought of: Why every 17 years? Why not every 18 years or every 16 years or every 15 years? What’s so special about the number 17?

The answer has to do with the mathematical brilliance of nature, the power of prime numbers and the mysterious process of natural evolution.

In 1977, Stephen Jay Gould was the first to examine what was so magical about the 17-year reproduction cycles of cicadas and the potential link with the mathematics of prime numbers. In the famous essay “Of Bamboos, Cicadas, and the Economy of Adam Smith” (which appeared in Gould’s first book Ever Since Darwin), the legendary Harvard scientist looked for examples of other species that take excessively long periods of time between reproductive cycles for clues. He found a potential counterpart to the cicada in the flowering cycles of Japanese bamboo. Somehow, both bamboo and cicadas were able to “time” their episodes of sexual reproduction over extended periods. There was one species of bamboo, for example, that first flowered in China in the year 999 and continued to flower and seed every 120 years. Even when this bamboo species was transplanted to places like Japan and Russia, it still kept rigorously to its 120-year cycle.

For Gould, the regular 17-year cycle of cicadas was even more puzzling. How was it possible that three different species of cicadas from different parts of the country could keep to their 17-year cycles, all while living underground the whole time while sucking juices from the roots of forest trees? How could they then emerge precisely at the same time, become adults, mate, lay their eggs and die — all within a span of a few weeks? That’s a long time to be dormant, and an incredibly short period to live and mate.

It turns out that the 17-year period is mathematically significant, since 17 is a prime number, as is 13 (the duration of the reproduction cycle followed by the 13-year cicadas in the South). By waiting 17 years, cicadas were basically gaming the evolutionary system. As Gould points out, most predators have 2-to-5 year life cycles, so the easiest way for cicadas to avoid regular predations over time was so minimize the number of coincidences when both life cycles overlapped. As Gould explains, the way to do this was to reproduce at exactly 17-year intervals, so that predators couldn’t feast on them at regular intervals:

“I am most impressed by the timing of the cycles themselves. Why do we have 13 and 17-year cicadas, but no cycles of 12, 14, 15, 16, or 18? 13 and 17 share a common property. They are large enough to exceed the life cycle of any predator, but they are also prime numbers (divisible by no other integer smaller than themselves). […]

Consider a predator with a cycle of five years: if cicadas emerged every 15 years, each bloom would be hit by the predator. By cycling at a large prime number, cicadas minimize the number of coincidences (every 5 x 17, or 85 years, in this case). Thirteen- and 17-year cycles cannot be tracked by any smaller number.”

Of course, in the 30 years or so since Gould first wrote about the bamboo and the cicada in his book Ever Since Darwin, there have been the skeptics. Some say that the long reproduction cycles of the cicadas are due to weather patterns. They point out the fact that cicadas date back nearly 2 million years, back to the Pleistocene epoch, when their was a need to burrow underground and remain for long periods of time until the glaciers melted. But that doesn’t explain the strange synchronicity of the 17-year incubation period. Why 17 years? Can it be any coincidence that 17 is a prime number?

So there you have it – the primary survival dynamic of the cicada – being “eminently and conspicuously available, but so rarely and in such great numbers that predators cannot possibly consume the entire bounty” – owes its success to the mathematical brilliance of nature. As long as cicadas keep to 17-year cycles, they can avoid their predators for as long a period of time as possible. Who knew that nature’s innate knowledge of prime numbers could be such a valuable survival skill?

Dominic Basulto is a digital thinker at Electric Artists in New York City and a contributor to The Washington Post’s Ideas@Innovations blog. He is working on a new book called “Endless Innovation, Most Beautiful and Most Wonderful”, exploring how Charles Darwin’s ideas on natural selection and the “survival of the fittest” apply to business in the digital age.

This article is shared by permission of the author, and was originally published on Big Think.