Tackling the Invaders from Beyond!

By Christiana Ferris
Vea también en español

Mexico has declared war on invasive species
, and has enacted a series of measures to prove that it means business.

After four years of prodding by The Nature Conservancy and partners, Mexico’s federal government passed laws in April 2010 to control the spread of invasive species in Mexico. The new laws prohibit the import or release of exotic invasive species and call for the creation of guidelines to vanquish those invasive species that have already gained footing in the country. Mexico’s Environment Secretary, National Biodiversity Commission, the National Ecology Institute and many other partners all pushed hard for the new regulations.

And in September 2010, the National Biodiversity Commission published a national strategy addressing invasive species prevention, control and eradication in Mexico. The strategy is a joint effort by a host of government agencies, academic institutions and conservation organizations, including the Conservancy.

Now, Mexico has a list of actions to put in motion by the year 2020—such as an alert and response system, legal frameworks to control and eradicate invasive species, data-sharing mechanisms and citizen engagement initiatives—to stem the tide of invasives.

Ignacio March, the Conservancy’s science coordinator for Mexico and Northern Central America
, participated in the national advisory committee that created the invasive species strategy. spoke with him to get his perspective.

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We hear a lot of different terms bandied about. What’s the difference between invasive, exotic and non-native?


In general an invasive species is one that comes from a distant region and that causes significant damage to local ecosystems and to the local plant and animal species found there, as well as affecting the ecological services that benefit people (such as clean water or productive soil). While many ornamental plants are exotic—which means simply that they come from other regions of the world and are non-native—they are not considered invasive as long as they don’t cause any damage and they depend upon humans to survive and reproduce.

What’s so bad about invasive species? Can’t habitats and other species just adapt to them? Isn’t nature constantly evolving anyway?


Invasive species can cause the extinction of native species and they can very rapidly transform habitats that are adapted only to native species. They also can disrupt normal fire regimens and contribute to catastrophic wildfires that can affect people and their property. This ought to worry us a great deal. Plus, invasive species can rob native plants and animals (and us) of water, dramatically affect other species that we rely on for food (such as fish) and transmit and spread diseases that attack humans as well as other species.

What are some examples of risks that Mexico’s native plants and animals face from invasive species?


There are many examples. One of the species that worries us the most is the cactus moth (Cactoblastis cactorum), which originates from South America and was used both there and in Australia to control prickly pear cactus infestations. But the prickly pear cactus is a really important part of our ecosystems in northern Mexico. It’s also a national icon—on the Mexican flag—and a major ingredient in traditional cuisine. Losing the nopal would be devastating. As another example, many of the rivers, lakes and streams in Mexico have been affected by the giant reed (Arundo donax). This plant is a true water thief because it sucks up and evaporates more water than native plants. And the water hyacinth, introduced as an ornamental plant for its beautiful blossom, has invaded lakes and marshes, has smothered aquatic ecosystems and choked out native flora and fauna species.

You’ve been a big advocate for raising awareness of the problem and proposing solutions. What role has the Conservancy played in Mexico to do something about invasive species?


TNC has played a key role in elevating the importance of preventing and controlling invasives. In 2006 we organized a workshop of specialists to build the first strategies in the country to confront this threat. Afterward we presented this to the Environment Minister and his cabinet to convey just how grave the impacts of invasive species could be to Mexico’s natural capital, and also to highlight the great opportunity at hand to prevent the entry and spread of various high-impact invasive species. From that began a process coordinated by the National Commission on Biodiversity to design a national invasive species strategy. I sat on the advisory council that helped produce the strategy just published in September 2010.

Has TNC taken any concrete actions to combat invasives?


Yes, we’ve done a lot! We’ve helped design prevention strategies in protected areas in Chihuahua and northeastern Mexico. We produced a (.pdf) brochure on ornamental plants that are invasive (along with a voluntary code of conduct to avoid using invasive plants) and distributed it to local growers of ornamental plants, nursery operators, consumers and park managers in the state of Nuevo Leon. Finally, we financed an extensive program to remove giant reeds from local waterways in Cuatrociénegas, Coahuila. But there's still much to be done in the battle against invasive species.

About the Interviewee
Ignacio March is  the Science Coordinator for Mexico and Northern Central America. Among his biggest worries are climate change and invasive species.


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