BROOKFIELD — The legacy of environmental pioneer Rachel Carson and the dramatic recovery of the bald eagle were the focus of the final program in the Warren-Trumbull County Public Library’s Backyard Conservation Series on Saturday at the Brookfield branch of the library.

The program, presented in partnership with the Trumbull County Soil and Water Conservation District, explored the lasting environmental impact of Carson’s work and how her warnings about pesticide use helped lead to one of the most successful wildlife recoveries in American history.

Carson (1907-1964), an American marine biologist and conservationist, helped launch the modern environmental movement through her groundbreaking 1962 book “Silent Spring.” Her earlier “sea trilogy” of books, published between 1941 and 1955, had already brought the wonders of the ocean to a wide audience, but “Silent Spring” shifted her focus to conservation and the dangers of synthetic pesticides.

The book warned that humanity was attempting to control nature with “terrible weapons” that could ultimately harm the entire ecosystem. One of Carson’s most widely quoted observations — “In nature nothing exists alone” — underscored the interconnectedness of living systems.

At the time, Carson’s warnings sparked fierce opposition from chemical companies, but the book galvanized public awareness about environmental issues and led to major policy changes.

Among the most significant was the nationwide ban on the pesticide DDT in 1972 and the later creation of the U.S. Environmental Protection Agency. Carson was posthumously awarded the Presidential Medal of Freedom in 1980 by Jimmy Carter.

Saturday’s presentation was led by Amy Reeher, district administrator and watershed coordinator for the conservation district. Reeher discussed how Carson’s research revealed the devastating impact of DDT on birds of prey, particularly the bald eagle, which is the national bird of the United States.

DDT, a pesticide widely used after World War II, entered waterways and accumulated in fish. Because eagles sit at the top of the food chain, they consumed increasingly concentrated amounts of the chemical — a process known as bioaccumulation.

The chemical interfered with calcium metabolism, causing female eagles to lay eggs with shells so thin they often broke under the weight of the incubating parents. By the 1960s and 1970s, widespread reproductive failure pushed bald eagle populations close to extinction in many regions of the United States.

Ohio’s population fell to just four known nesting pairs in 1979.

Following the federal ban on DDT and protections provided by the Endangered Species Act of 1973, bald eagle numbers began a slow but steady recovery. Intensive monitoring by the Ohio Department of Natural Resources in the 1980s also helped boost survival rates.

Today, the comeback is dramatic. Ohio now has more than 900 active bald eagle nests. While nesting has increased across the state, the highest concentrations remain along the Lake Erie shoreline. The bald eagle was removed from the federal endangered species list in 2007, and populations continue to grow as water quality improves and habitat protection expands.

Reeher also discussed modern alternatives to broad-spectrum pesticides like DDT. One option is the use of larvicides, specialized insecticides designed to kill mosquito larvae in standing water before they develop into biting adults.

These treatments can be applied to water sources such as birdbaths, gutters or containers and are often used by pest management professionals using trucks, aircraft or drones. Some larvicides rely on naturally occurring bacteria that are toxic to mosquito larvae, while others prevent insects from maturing or create a thin film on the water’s surface that suffocates larvae.

Because they target mosquitoes at their breeding source, larvicides are often considered safer and more precise than widespread spraying for adult insects.

Reeher noted that while DDT has been banned in the United States for decades, it is still used in some parts of the world where malaria remains a major public health threat.

The presentation also highlighted the role of local conservation efforts. The Trumbull Soil and Water Conservation District, formed in the late 1940s, is a political subdivision of the state that provides technical assistance and educational programs focused on natural resource management.

The district works in partnership with local governments, the U.S. Department of Agriculture Natural Resources Conservation Service and the Ohio Department of Agriculture to help residents address issues such as erosion, water management, land use planning and habitat conservation.

Reeher said her passion for conservation stems from her upbringing.

“Growing up in a family with hunters, fishermen and farmers who cared about animals and their habitats, it was a natural fit to change my career path to a conservation focus,” she said.

Today, she continues that work through watershed partnerships, aquatic habitat management and public education programs designed to help residents understand how everyday choices can affect the natural world.

Carson’s message, Reeher said, remains just as relevant today.