Here is how the information can be categorized:
What they found
- The overall numbers of butterflies in Ohio have decreased year over year for the past two decades—about 2 percent each year. When the researchers compared that rate to other long-term studies, the general decline matched the results of monitoring programs in the United Kingdom, the Netherlands and Spain.
- But the team wanted to understand why some species of butterflies were harder-hit than others, and why some actually increased their populations over the course of the study.
- There was a difference in how northern and southern Ohio butterflies were doing.
- The wild indigo dusky-wing is doing really well in Ohio because a plant it eats is used as erosion control on construction sites. It’s three times more numerous now than it was 20 years ago.
Why this matters
- Butterflies pollinate flowers, control plant populations by munching on leaves as caterpillars, and provide food for other insects, birds, amphibians and mammals. Their decline could have cascading effects on forests, prairies and even backyards across North America—vital wild habitats for an abundance of living things.
- Changes in butterflies can signal larger environmental changes.
- The solution to a worldwide insect decline won’t be simple. “If it was just one thing, we would know how to fix it,” Moreau said. “But I think of the situation as, like, death by a thousand cuts.”
- The decline of Ohio’s butterflies has been captured through statistics and recorded data rather than anecdotes, but the scientific literature abounds with anecdotes as well. One recent article from experienced researchers Daniel Janzen and Winnie Hallwachs warns that insects around the world are in the midst of a “gradual and very visible decline.”