Protecting the monarch butterfly requires international action

The monarch butterflies that are now returning to southern U.S. states to lay their eggs are completing one of the world's longest and most incredible insect migrations. Late last summer these same butterflies flew thousands of miles to central Mexico, where they converged by the millions in the forest highlands of the Monarch Butterfly Biosphere Reserve. The sight of so many orange- and black-winged butterflies filling the sky and weighing down the branches of the trees in the reserve is so spectacular that in 2008, the United Nations Educational, Scientific and Cultural Organization (UNESCO) declared the Monarch Butterfly Biosphere Reserve a World Heritage Site. Yet this exceptional natural phenomenon is at risk of disappearing - over the past two decades the monarch population that overwinters in the area has plummeted by 90%. While degradation of the monarch's overwintering forest habitat has been a historic threat to the species, in recent years there has been marked improvement. Today scientists point to factors north of the border as the primary threat to the monarchs -specifically the skyrocketing use of glyphosate herbicides that is wiping out the milkweed plants where butterflies lay their eggs so their larva can feed. That's why NRDC has joined groups from Mexico and Canada to ask the UNESCO to declare the World Heritage Site "in danger" and urge the US and Canada to do their part in protecting the monarch butterfly.

Protecting monarch habitat in Mexico

While local residents in central Mexico have always known that millions of monarchs descend on the area every fall, the overwintering sites were "discovered," by international scientists in the mid-1970s. The "discovery" and subsequent visibility it brought the site helped spur efforts in Mexico to protect the temperate oyamel and pine forests that provide the perfect microclimate necessary to shelter the butterflies during the winter.

The monarch overwintering sites first came under official protection through a government decree in 1980. However, specific conservation areas were not identified and extractive activities continued to be allowed except during the overwintering season. So in 1986, protections were strengthened by identifying five sanctuaries and prohibiting extractive activities within their core zones. Ultimately this arrangement also failed to go far enough to stem forest degradation. In the period between 1971 and 1999, 44% of high-quality forest habitat for monarchs was degraded by illegal logging.

To further enhance protections the current Monarch Butterfly Biosphere Reserve was established in 2000, following years of dialogue between local communities and ejidos (communal lands) and the conservation sector. The 56,259 hectare reserve succeeded in uniting all five sanctuaries and consists of three core zones surrounded by buffer zones. In total there are over 90 owners, including indigenous communities, ejidos, small private owners, and the government. To make this complex conservation solution work, a fund was also established to help foster forest protection and restoration. Communities and landowners receive economic incentives to protect and conserve their land.

The good news is that in recent years, these efforts have started to pay off. The results of a ten year monitoring effort showed that while pockets of illegal logging remain, since 2009 there has been a significant reduction in deforestation. Experts point to better enforcement, collaboration with communities on conservation and restoration efforts, and support for alternative income generation as keys to this success. The progress seen in Mexico is in large part due to efforts by local groups and communities to protect and restore habitat. Groups like Danaidas, Conservación y Desarrollo Sustentable and WWF Mexico work with ejidos and communities to establish native species nurseries used in reforestation projects. Other organizations work to promote alternative income generation activities for communities and promote sustainable resource management. Efforts like these help protect the forest and conserve natural resources. They are good for the butterflies and also good for local populations because they maintain critical watersheds and prevent erosion.

Time to protect breeding habitat in United States and Canada

But alone these efforts cannot save the monarch migration phenomenon. For that to happen it is necessary for the United States and Canada to also step up and start protecting the monarch's breeding habitat and the milkweed plants that provide the only source of nourishment for monarch caterpillars. The expansion of industrial agriculture and glyphosate resistant crops in the past two decades has resulted in a dramatic increase in the use of glyphosate which eliminates plants like milkweed. In turn this has contributed to a dramatic decline in monarch numbers. This past overwintering season an estimated 56.6 million butterflies arrived in the reserve. This is down from a long-term annual average of 350 million and astonishingly low in comparison to the approximately one billion that arrived in the mid-1990s. Such low numbers put the population at greater risk from other threats. For example, in 2002 inclement weather killed more butterflies than currently make up the entire population.

World heritage at risk

When the UNESCO designated the Monarch Butterfly Biosphere Reserve as a World Heritage Site in 2008, it noted that "due to its migratory nature, the maintenance of the overwintering phenomenon also requires attention to the conservation of the monarch butterfly by those countries through which it travel during its life cycle."

That's why NRDC has joined Mexican and Canadian groups ** in sending a report and petition to the UNESCO's World Heritage Committee to update them on the threats to the monarch migration, in particular the use of glyphosate. We're encouraging the Committee to consider including the site on the "List of World Heritage in Danger," to help draw critical attention to the urgent need to address threats to the monarchs in their breeding habitat. Last year President Obama, Mexican president Peña Nieto and Canadian Prime Minister Stephen Harper agreed to work together to help save the monarch butterfly, but a year later little progress has been made. This week, conservation leaders from each of the three countries come together again in San Diego to discuss the international wildlife issues affecting North America and are scheduled to discuss the monarch migration.

Mexican poet and environmentalist, Homero Aridjis, who like other local residents of central Mexico grew up waiting for the monarchs' arrival each fall (and who would later help call for legal protections for the sanctuaries and the World Heritage designation ), recently wrote that the "discovery" of the monarch overwintering grounds by Canadian and American scientists forty years ago was "mutual enlightenment for people at both ends of the fabulous 3,000-mile-long migration of the monarch butterfly."

We now need another moment of mutual enlightenment - the realization that to preserve the world heritage phenomenon that is the monarch migration requires conservation efforts at both ends of this spectacular journey.

** The petition to the UNESCO was filed by NRDC, Mexican organizations Grupo de los Cien, Alternare A.C., Danaidas Conservación y Desarrollo Sustentable A.C., Telar Social México, and CostaSalvaje, and the David Suzuki Foundation in Canada.

About the Authors

Carolina Herrera

Latin America Advocate, International program

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