Monarch butterflies are in decline. The International Union for Conservation of Nature has designated them as endangered.

An expert explains the effect of climate change on monarchs, and what anyone with a home garden can do to help.

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TRANSCRIPT:

MELBA LARA, HOST: You’re listening to WBEZ. Monarchs are some of the most iconic and beautiful butterflies, but they’re a species in decline. Last month, the International Union for Conservation of Nature designated the migratory monarch butterfly as endangered. In this week’s climate conversation, we’re going to discuss the effect of climate change on monarchs, and what anyone with a home garden can do to help. Our guest is Andres Ortega, an ecologist with the Forest Preserve District of DuPage County. Andres, thanks for talking with us today. 

ANDRES ORTEGA: Absolutely. Thank you for having me. 

LARA: Let’s start with what changes in the monarch population have you observed over the years? 

ORTEGA: Well, I think what we’re seeing is similar to many other individuals and organizations along their range are seeing, namely a very steep, very rapid decline in the population. And it’s important to remember when you have a species like this, where you have this long term data set, you’re observing them over many years, it’s normal to have fluctuations in the population, you have some good years and some bad years. But what we’re seeing with monarchs is that the good years are not nearly as good as they used to be. And the bad years are much worse. 

LARA: Tell us about what role climate change might be playing in this decline? 

ORTEGA: Well, it is believed that climate change is one of the major drivers behind this decline in the population. So you can look at the direct impacts of climate are having on the animals themselves. It could be an increase in the severity of storms. It could be an increase in hot dry years, or even cold, wet years. All of these extreme weather patterns, which are driven by climate change, can directly harm the butterflies in the caterpillars. But what we also find is that climate change is indirectly impacting their environment. So if we have a particularly warm year, the butterflies may begin their migration earlier than what we would consider the historical average. If they do this, it may mean that they arrive in these areas before their resources are available. It could also mean that the climate is affecting the resources themselves. And that the emergence time of milkweed, or the bloom time and duration of the nectar flowers they depend on are altered from the historical average. 

LARA: So after hearing all of this, people probably want to know, what can they do to help? What can we do to support monarchs? 

ORTEGA: When we talk about things like climate change, or endangered species, we can often feel very dejected about it. But the great news with monarchs is that you can have a positive impact on the species even at the individual, homeowner or organizational level. So making sure that you have milkweed and nectar flowers available as early as early spring, and as late as late fall, even if it’s a small pot of land, even if it’s just a few flowers in your garden or something on your windowsill - that is now resources that were not previously available, and can provide a significant benefit to the species. The other thing people can do is reduce or eliminate their use of pesticides and insecticides. And the final thing you can do that provides a huge benefit is participate in citizen science projects where you can go out and observe butterflies, other pollinators, plants, and you can start contributing to that long term dataset, which is absolutely critical to managing the species. 

LARA: I’ve been speaking about monarch butterflies with Andres Ortega, an ecologist with the Forest Preserve District of DuPage County.

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