Making a Difference: Butterfly Ecologist

Dr. Alfonso Alonso

Dr. Alfonso Alonso examines a monarch as part of his efforts to understand its ecology.

Imagine millions of butterflies swirling through the air like autumn leaves, clinging in tightly packed masses to tree trunks and branches, and covering low-lying forest vegetation like a luxurious, moving carpet. According to butterfly ecologist Alfonso Alonso, this is quite a sight to see.

For many winters Alonso would climb up to the few remote sites in central Mexico where anywhere from 23 million to over 170 million monarch butterflies spend the winter depending on the site. His interest in monarchs came from a desire to help preserve their habitat and the butterflies themselves. His work helped him earn a Ph.D. in zoology from the University of Florida.

Monarchs are famous for their long-distance migration. The butterflies that eventually find their way to Mexico come from as far away as the northeastern United States and southern Canada. Some of them travel up to 4,828 km before reaching central Mexico.

Wintering Habitat at Risk
Unfortunately, the habitat that the monarchs travel long distances to reach is increasingly threatened by illegal logging and other human activities. Logging reduced the size of the wintering region by approximately 44 percent between 1971 to 1999. Mexico has set aside several of the known butterfly sites as sanctuaries, but even these are endangered by people who cut down fir trees for fuel or money.

Alonso’s work and the work of other ecologists after him has helped Mexican conservationists better understand and protect monarch butterflies. Especially important is Alonso’s discovery that the monarchs depend on bushlike vegetation, called understory vegetation, that grows beneath the fir trees.

Keeping Warm
Alonso’s research showed that when the temperature falls below freezing, as it often does in the mountains where the monarchs winter, understory vegetation can mean the difference between life and death for some monarchs. These conditions are life threatening to the monarchs because low temperatures (–1°C to 4°C, or 30°F to 40°F) limit their movement. In fact, the butterflies are not able to fly at such low temperatures. They can only crawl. At even colder temperatures (–7°C to –1°C, or 20°F to 30°F), monarchs resting on the forest floor may freeze to death. But if the forest has understory vegetation, the monarchs can slowly climb the vegetation until they are at least 10 cm above the ground, where it is warmer. This tiny difference in elevation can provide a microclimate that is warm enough to ensure the monarchs’ survival.

monarch butterflies

At their over wintering sites in Mexico, millions of monarchs cover trees and bushes in a fluttering carpet of orange and black.

The importance of understory vegetation was not known before Alonso did his research. Now, thanks to his work, Mexican conservationists will better protect the understory vegetation. And the Mexican government has passed a new decree that protects monarchs in areas the butterflies are known to use.

The Need for Conservation
Although the monarchs continue to enjoy the forests where they overwinter, those forests are still threatened. There is little forest left in this area, and the need for wood increases each year. Alonso hopes his efforts will help protect the monarch both now and in the future.

Now that he has completed his Ph.D., Alonso is devoting himself to preserving monarchs and other organisms. He works as assistant director for conservation and development for the Smithsonian Institution’s Monitoring and Assessment of Biodiversity (MAB) program. He is developing several new projects in collaboration with others including a forest conservation project in Madagascar, and conservation projects in Panama and Mexico that combine cultural values with natural values to preserve threatened areas.

If you are interested in learning more about monarchs, including their spectacular migration, visit the website for Monarch Watch. Monarch Watch is an organization based at the University of Kansas that is dedicated to educating people about the monarch and promoting its conservation.

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