Monarch butterfly declared endangered amid declining numbers

Science

Last week, the monarch butterfly was officially designated as endangered by the International Union for Conservation of Nature. Scientists estimate that the species' population has dropped between 20% and 90% over the last several decades. Scott Hoffman Black, executive director of the Xerces Society for Invertebrate Conservation, joins Ali Rogin to discuss.

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  • Geoff Bennett:

    Last week, the monarch butterfly was officially designated as endangered by the International Union for Conservation of Nature. My colleague Ali Rogin has more on the significance of the move. And what accounts for the decline?

  • Ali Rogin:

    The iconic monarch butterfly can be found out across almost all of North America but today it faces threats from habitat destruction to climate change, part of why these butterflies are vulnerable is that they migrate 1000s of miles annually to California and central Mexico for the winter. When the weather warms up in the spring, they reproduce, make the journey north. Along the way they cluster in colonies to stay warm, and lay their eggs exclusively on milkweed plants.

    Over the last several decades, scientists estimate that the population has dropped between 20% and 90%. For more on what it means for our ecosystem, I am joined by Scott Hoffman Black, he's the Executive Director of the Xerces Society, a nonprofit that focuses on Invertebrate Conservation.

    Scott, thank you so much for joining us. Why is the monarch butterfly population declining so much?

    Scott Hoffman Black, Xerces Society for Invertebrate Conservation: Well, it's declining because of us. Unfortunately, the way we grow our food, the way we build our homes and have our yards, just doesn't leave much room for animals like the monarch butterfly. So habitat loss because of industrial agriculture, and because of lots of lawns, lots of pesticide use, we use a lot of pesticides, both in our food and to keep our roses perfect in our lawns, perfect. And then you overlay that also with climate change, which is one of the factors.

  • Ali Rogin:

    And we mentioned the international designation, what does that mean for monarch butterflies? And how is that different from what the U.S. Fish and Wildlife Service do?

  • Scott Hoffman Black:

    Yeah, so this is an international designation by a well — really well established international group, the International Union for Conservation of Nature. And this new report or analysis doesn't have any policy ramifications in the United States. But what it does do is put a spotlight on this animal, and how imperiled it really is and the actions we should start to take to recover it.

  • Ali Rogin:

    And experts will know that the monarch population does fluctuate somewhat from year to year. So is this — is what you're seeing now outside of that kind of standard deviation?

  • Scott Hoffman Black:

    Oh, certainly. The vast majority of scientists that have looked at the data, it's compelling data that shows that monarch has been on a decline really since the 1980s certainly since the 1990s. And in the west, we've seen over a 95% decline in monarchs that go to overwintering sites in California, and in the east, you know, somewhere between 70% and 80% decline, depending on how you look at it. So the verdict is in, this butterfly is declining across its range.

  • Ali Rogin:

    And Scott, most of us are familiar with monarchs. We know that they're beautiful patterns. In some cultures, they contain very important spiritual significance. But can you tell us about their importance to the ecosystem? Why does it matter, that their populations are declining?

  • Scott Hoffman Black:

    Well, it really matters for a widespread insect like this. Insects, like monarchs are food for so many animals, birds, among other animals. And when we used to have hundreds of millions of monarchs, and maybe down into the 10s of millions, you know, if you lose 100 million animals that used to be food, for other animals, that's going to be significant. But the monarchs also significant, because, as you mentioned, so many people know it, it's really an umbrella species. And because people really love it, people are willing to take action to protect it. And by protecting it, they're protecting bees and other butterflies as well. So this iconic species can really help way beyond just itself.

  • Ali Rogin:

    And are there other species that you would say fall under that category of, you know, hoping that the monarch butterfly will bring attention to them?

  • Scott Hoffman Black:

    Yes, you know, the monarch butterfly is kind of our charismatic species, those of us that work on insects, people don't always see the little small bees that are out there or the more diminutive butterflies. And so what we do for monarchs, which is protecting and restoring habitat, and managing pesticide use, so we're not poisoning areas, really helps this broad suite of animals that live in the same habitats as the monarch. So it's neat, we can recover this butterfly and help many other species at the same time.

  • Ali Rogin:

    You just mentioned some things that individuals can do, eliminate pesticides, but tell us more about what we can do as a society and as individuals to help monarch butterflies?

  • Scott Hoffman Black:

    Yeah, we need we need action at all levels. We need policymakers to have good, strong climate change legislation like we might be seeing coming on because climate change is a driver. But on an individual level, whether you're a gardener, a farmer, manage a park or even a National Wildlife Preserve, you can make sure that we've got milkweed in the landscape, native milkweed are the best, as you mentioned, it's the only host plant for monarchs are these native milkweeds, but also a buffet of flowers. So these butterflies, as you mentioned, migrate long distances, and they need lots of fuel.

  • Ali Rogin:

    And we could help save a population. Scott Hoffman Black, Executive Director of the Xerces Society, thank you so much for your time.

  • Scott Hoffman Black:

    Well, thank you for having me.

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