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Agrochemical Contamination in Belize's Maya Mountains a Risk to Amphibians and Humans

 
By Melissa Normann*

Frog in the brush, MesoamericaCovering the most rugged and remote terrain in Belize, the Maya Mountains Massif is one of the largest, most biodiverse and pristine wilderness areas remaining in Central America.

Totaling over 1.25 million acres, the Massif encompasses 14 protected areas that boast a diverse mosaic of tropical rainforests and upland pine savannas. The Massif is linked to the coral reefs of the Mesoamerican Barrier Reef via the Maya Mountains Marine Corridor -- an area of private and protected lands sloping down through lowland pine savannas into coastal mangroves and offshore cayes.

The Maya Mountains watershed is an important source of drinking water for much of Belize's population and provides critical habitat to endangered species such as the jaguar (Panthera onca), ocelot (Felis pardalis), Baird's tapir (Tapirus bairdii), and the scarlet macaw (Ara macao).

Not much is known about the Maya Mountains ecosystems. For example, during the Global Amphibian Assessment, a comprehensive survey of the conservation status of the world's 5,743 known species of frogs, toads, salamanders, and caecilians, biologists realized that very little data existed about the distribution or status of amphibians in Belize, and there were no data available about the status of the nation's amphibian species of concern, which are those included on the IUCN's Red List.

To help fill this knowledge gap and design sound amphibian conservation strategies, Paul Walker, executive director of the Belizean NGO Wildtracks, is launching an ambitious project to assess the viability of and threats to amphibians in the Maya Mountains.

With support from the Critical Ecosystem Partnership Fund, Wildtracks is conducting a series of amphibian assessments in the region, training local NGOs to design and conduct amphibian monitoring plans, and bringing together key stakeholders to develop a participatory National Amphibian Conservation Action Plan for Belize.

Together with protected area managers and students from the University of Belize, Walker is conducting amphibian viability and threat assessments throughout the expansive Maya Mountain Massif. The team has already identified 18 hotspots within the region by superimposing a map of the presumed distribution of amphibians with a map of the areas thought to face the greatest threats. The eventual goal is to gather representative samples from across the entire ecosystem.

To inform future conservation actions, the project is conducting an amphibian viability assessment that looks at the distribution and abundance of species, habitat condition, and presence or absence of disease -- namely the deadly cutaneous chytridiomycosis, or "chytrid" disease caused by the Batrachochytrium dendrobatidis fungus. The presence of this fungus has been linked to regional and global disappearances of entire amphibian populations. Walker's team has discovered the presence of the fungus at all sampling sites, but the amphibians are showing no significant signs of disease.

In contrast to many researchers investigating chytrid, Walker includes the presence of the disease in his viability assessment. But rather than viewing chytrid as a threat to amphibians, he instead views the causes of chytrid as a threat to the species. Current knowledge suggests that the presence of the fungus may be caused by stresses on amphibian immune systems from pollution and climate change.

Following the work of Gunther Köhler, a herpetologist in El Salvador, Walker believes pollution may well be the culprit in the Maya Mountains. He explains, "We designed our project to determine whether the Maya Mountains are contaminated, and if so, is it at levels that can cause significant health issues for amphibians and even humans?"

Unfortunately, Walker has determined that the answer to both these questions appears to be a resounding "yes." Agrochemicals applied to Belize's coastal citrus and banana farms are being carried upward and raining down into the mountains through the effects of orographic precipitation. Walker has identified the presence of an herbicide called glyphosate in the mountains at a concentration more than 50 times higher than Europe's legal limit for drinking water. Glyphosate is an herbicide applied to the grasses underneath citrus trees.

Walker and his team are awaiting results to learn if the chemical fungicides and nematicides that are sprayed by planes over Belize's banana farms are also present in the Maya Mountains. The World Wildlife Fund has identified the presence of these chemicals in the tissues of coral reef fish at alarming levels, and Walker believes that tests will reveal the same chemicals in the mountains, potentially at higher levels.

Walker emphasizes, "If there is a mixture of several chemicals at significant levels, we don't know how the chemicals will compound each other and what the impact will be at the ecosystem level, much less at the amphibian level. It's quite likely that the ecosystem itself is becoming quite toxic."

To learn more, Wildtracks hopes to identify which of 30+ chemicals used by the banana and citrus farms are present in the mountains, at which concentrations, and at which sites. With continued funding, Walker hopes to gather samples over significant periods of time, and across a variety of altitudinal, wind and temperature gradients to learn more about how chemicals are being transported from the coast into the mountains, and at what concentration.

To increase the capacity of local stakeholders to collect data, Wildtracks has conducted four three-day training workshops for the staff of NGOs that are in charge of co-managing Belize's protected areas, representatives from the Forest Department, and University of Belize students. Participants receive training in amphibian ecology, techniques to assess and monitor amphibians, and to identify and safely handle the animals. Participants also learn how to identify disease in the amphibians, and how to record, store, and analyze data. Walker believes this is one the most rewarding aspects his work. "We've watched participants advance from having no information about amphibians, to being able to run their own assessment after three days," he says. "It is quite rewarding to see such a massive step taken in such a short amount of time."

Mario Muschamp, who works for the Toledo Institute for Development and the Environment (TIDE) as the manager of Payne's Creek National Park remarks, "The training made me realize the importance of keeping track of our amphibian species -- they are the true indicators of the health of our ecosystems. I gained the skills to start monitoring amphibians in Payne's Creek and in our private lands. We are already setting up transects." Data collected from protected areas throughout the Maya Mountains will be incorporated into a shared database and will set the foundation for long-term monitoring efforts and the creation of a national monitoring protocol.

Wildtracks is also organizing a series of strategy development workshops that will bring together protected area managers, students, key members of the agricultural and development sectors, and representatives from the Ministry of Health, the Forest Department, the Department of the Environment, and the Department of Agriculture. The goal of the workshops is to identify and establish strategies to reduce threats to amphibians and the Maya Mountain ecosystems and identify who will implement the strategies that are being developed as part of the National Amphibian Conservation Action Plan for Belize.

Protected area managers will lead efforts to monitor and collect data on amphibians, and the agricultural sector will be a major player in identifying and implementing solutions to reduce chemicals in the Maya Mountains. Possible strategies on the table include enrolling in an appropriate sustainable agriculture certification program and the use of beneficial microorganisms as an alternative to chemical pesticides and to inoculate compost material, such as citrus pulp, to promote healthy soils. Walker emphasizes, "We all have to work together and recognize that this is a human health issue as well as an amphibian issue and look at ways that we can work together to solve this problem." The first workshop was held in November 2008.

Because all of the countries in Central America host a high level of agricultural production, Walker believes that the presence and impact of chemical pollution in protected areas throughout the region should be investigated. Research in Panama has shown the presence of chytrid fungus and significant amphibian decline within pristine protected areas, and researchers in Costa Rica have found significant chemical transportation from plantations on the Caribbean Coast westward across the country.

He concludes, "We may well be looking at a far larger system of contamination than just localized drift from the coastal plain of Belize into the Maya Mountains. The implications could be far wider."

* This article was originally published in Eco-Exchange, published by the Rainforest Alliance with CEPF support.
 
 
 
 
 
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