The state has 24 federally endangered species and 12 classified as threatened, according to figures cited by conservation experts. Last month, the administration determined that destroying places where protected species breed, feed or shelter would no longer trigger federal penalties. An internal memo also outlined plans to interpret the law as prohibiting only the intentional killing of endangered animals, rather than conduct such as harassing, harming or capturing them.

The legal consequences of the changes are being contested: nearly two dozen state attorneys general have sued over some of them. Elizabeth Forsyth, a senior attorney with Earthjustice’s biodiversity defense program, said the administration’s approach would reduce habitat protections and give industry more power over decisions affecting at-risk species.

Three examples illustrate what is at stake in Illinois:

The rusty patched bumble bee, once common across 28 states and parts of Canada, has declined by nearly 90% in the past 30 years and now occupies about 0.1% of its historic range. It was listed as federally endangered in 2017. The bee spends roughly half the year in soil, making it hard to detect before construction or other development disturbs its habitat.

Libby Shafer, an urban ecologist and Northwestern University doctoral candidate who previously searched for the bee across Illinois, Indiana and Wisconsin as a federal biological technician, said she saw just one during a three-month effort. She warned that removing habitat protections would be bad news for the species.

Piping plovers, small shorebirds that nest on beaches, also depend on vulnerable shoreline habitat. A pair known as Monty and Rose drew attention after nesting at Montrose Beach in Chicago from 2019 to 2021—the first such nesting on the city’s beaches since at least 1948. Great Lakes populations have recovered from a low of about a dozen breeding pairs in the 1990s, but researchers say the birds still face competition with people for beaches used for recreation and development.

Freshwater mussels account for half of Illinois’ federally endangered wildlife, according to the source material. The state once had about 80 recorded mussel species; by around 1970, that number had fallen to 59. Pollution, degraded habitat and invasive species threaten the animals, while decades of industrial agriculture have altered waterways and river connections across Illinois and the Midwest.

Kentaro Inoue, a research biologist at Shedd Aquarium, said the consequences of the federal changes remain uncertain. Protecting endangered mussels, he said, requires protecting the river systems they rely on—not only the animals themselves.