Danielle Brigida and Ryan Richards stepped out of the tuk tuk (a three-wheeled taxi) and into Phnom Penh, the colorful, bustling capital of Cambodia. People and vehicles were rushing in all directions. Street vendors sold food, trinkets, even gasoline in old soda bottles. But there was no time for sightseeing in the dynamic city. They were en route to the countryside, to Battambang Province, to assess the results of many months of hard work: a draft of the first international guidelines for the safe and sustainable mining of guano at bat caves.
Bat guano (feces) is an outstanding natural fertilizer that has been mined worldwide for centuries. It was also exploited until the late 19th century as a prime source of saltpeter, a key component of the gunpowder of those times. Guano is still mined in North America, but only for a niche market. Yet it remains a major resource – both commercially and for subsistence farming – in much of the developing world, where mining technology often means strong backs and shovels.
But improper guano mining can be devastating to the very bats that provide this valuable commodity. Limited knowledge of bat biology, ill-defined mining and property rights at many caves and a lack of rules or enforcement frequently result in unsustainable mining practices and the loss of countless bats. And without bats, there can be no guano for the miners.
This is especially true in caves where mining disrupts bats’ roosting habitat or alters the cave’s structure or airflow within the cave. For example, miners sometimes use excavations or explosives to improve access to the guano. In addition, pesticides are often used inside the cave to kill the many insects that thrive in and around the guano. Discarded trash and other debris are also a problem. Many conservationists, recognizing that inappropriate guano mining is a major threat to bats, have for years stressed the need for science-based guidelines to minimize that risk.
Developing those guidelines, with the direct support of Bat Conservation International, became the project of the Bat Conservation Team. The team is part of an innovative training program known as Emerging Wildlife Conservation Leaders (EWCL), which is sponsored by the U.S. Fish & Wildlife Service, White Oak Conservation Center/Howard Gilman Foundation, Wildlife Conservation Network, International Fund for Animal Welfare and Defenders of Wildlife.
Every two years, EWCL selects a cohort of budding professionals and provides intensive training in conservation action and other skills, then mentors them through a two-year international wildlife conservation campaign. The young conservationists of the EWCL class of 2010 included Brigida and Richards, as well as Kate Gersh, Mathilde Iweins, Alli Sribarra and me.
Under the guidance of Dave Waldien, BCI’s Interim Executive Director, we launched our effort to make guano harvesting safer for bats. Our proposed guidelines are aimed primarily at cave managers, government agencies and guano-harvesting companies. Although our initial focus is on Cambodia and other Southeast Asian countries, our goal is to improve guano-mining practices worldwide.
The EWCL Bat Conservation Team began by studying previous scientific research on bat biology, cave ecology and guano harvesting. We found ample evidence that cave bats are highly sensitive to disturbance, which can result in declining populations. Guano extraction often introduces loud noise, bright lights and changes in air temperature when cave entrances or chambers are modified. Such things can cause mothers to drop their pups or hibernating bats to awaken and burn essential energy stores. They sometimes cause bats to abandon the cave. Harvesting can also pose threats to the miners because, without proper ventilation or respirator masks, they can be exposed to airborne diseases often found in such caves.
An international advisory committee of bat biologists provided invaluable input as we worked together on our draft guidelines. The result is an in-progress document that is envisioned as a guide rather than an inflexible code of conduct.
With support from the Columbus Zoo & Aquarium Conservation Fund of Powell, Ohio, graphic-design artist Grant Wheeler turned 10 key guidelines into illustrated posters. Although supplemental text is provided in English and Khmer, the posters are designed for easy comprehension by those who cannot read.
That is what brought Brigida and Richards to a dusty dirt road heading out of Phnom Penh. They had arrived in Cambodia after describing the guidelines at the Southeast Asian Bat Conservation Research Unit’s (SEABCRU) annual conference in Hat Yai, Thailand, where they also met researchers from around the region.
The crucial next step was field testing – actually applying the guidelines during guano harvesting. So they headed for Tarum 1 Cave in Battambang to assess the results of testing there. The site had been selected by three Cambodian graduate students and their advisor, Neil Furey of the Centre for Biodiversity Conservation at the Royal University of Phnom Penh, because it was home to the country’s largest cave-bat colony.
The ECWL representatives met with cave owners and guano harvesters to discuss the impact of the posters and to visit one of the caves. At this cave, guano is harvested twice a month by a cooperative of five farmers, who remove all the guano (100 to 200 bags of 33 pounds [15 kilograms] each) for sale as fertilizer for trees and rice crops.
The farmers proved very helpful in explaining the real-world application of the guidelines. For example, they noted that one cave already has a guardhouse (as recommended) to control access, and the cooperative records how much guano is extracted on each harvest. They also said, however, that they consider masks and gloves impractical because it’s very hot inside the cave. In addition, they wear minimal clothing in hopes of avoiding the ticks and lice from adhering to them.
They were uniformly interested in ensuring that guano remains a part of their livelihood and seemed to consider the guidelines a relevant and practical source for improving harvesting strategies.
The guidelines remain voluntary for now, but we hope they will help to encourage and inform future legislation in many countries.
In addition to the work that is being done by the Centre for Biodiversity Conservation in Cambodia, the EWCL Bat Team is also working with members of SEABCRU to expand research into guano harvesting and cave ecosystems, and build stronger connections between researchers and the communities that rely on bat guano. Projects similar to the field testing at Battambang are being planned for Thailand, the Philippines and Indonesia.
As this collaborative effort expands, the future should become brighter for both cave bats and guano miners.
CRYSTAL DIMICELI is a zookeeper with the Wildlife Conservation Society's Prospect Park Zoo in Brooklyn, New York. Ryan Richards is a doctoral fellow at the Smithsonian Institution. Danielle Brigida is Social Media Manager for the National Wildlife Federation. Kate Gersh is Associate Director of The Murie Center in Moose, Wyoming. Alli Sribarra is a Grants Administrator at Sciencenter in Ithaca, New York. Mathilde Iweins is a Natural Resources Officer with the Food and Agriculture Organization.
Here are a few key points from the draft guidelines for guano harvesting developed with BCI support and guidance by a team from Emerging Wildlife Conservation Leaders:
• Harvest guano at night when bats are not in the cave.
• Guano miners should wear masks and gloves at all times and wash thoroughly after each harvest.
• Control access to the cave through fencing or an enforceable permitting process.
• Never light fires or use kerosene lamps in a cave where bats roost.
• Do not approach or work near the bats.