Ohio is defined by dynamic natural boundaries and distinct ecological regions, making the question of “true nativeness” complex. This geographical diversity supports a wide array of wildlife, but not all species encountered today are indigenous. Understanding the difference between common wildlife and truly native species requires looking back into the state’s natural history.
Defining True Nativeness in Ohio
To determine if an animal is truly native to Ohio, biologists rely on a historical benchmark: its presence in the region prior to significant European settlement. This period, generally before the late 18th and early 19th centuries, serves as the baseline before industrial-scale habitat alteration began. A truly native species, also called an indigenous species, naturally occurs or historically occurred in a particular ecosystem without human introduction.
Historical biogeography confirms a species’ range by examining records, fossils, and pre-settlement habitat types. This means the species evolved within Ohio’s specific environmental conditions, adapting to its unique climate and plant communities. This framework helps distinguish between species that belong to the ecosystem and those that have merely established a population after being introduced.
Keystone Native Species of Ohio’s Major Ecosystems
Ohio’s major ecosystems are sustained by native fauna adapted to specific conditions. The White-tailed Deer is a widespread native herbivore in forested regions, playing a substantial role in shaping undergrowth through browsing. The Eastern Cottontail and Fox Squirrel are common indigenous mammals that thrive in woodlands and open areas across the state.
Aquatic ecosystems, including Lake Erie and the Ohio River, are home to native fish like the Walleye, Perch, and various Bass species. The Lake Erie Water Snake is a native reptile found almost exclusively on the islands and shores of Lake Erie. In Ohio’s forests and wetlands, the Northern Cardinal and Blue Jay are recognizable native birds that contribute to seed dispersal.
Native amphibians and reptiles, such as the Eastern Box Turtle and the American Bullfrog, rely on remaining forested tracts and wetland habitats. The Great Blue Heron is a native wading bird that utilizes the state’s network of rivers and lakes for feeding. The condition of these habitats directly determines the survival of these indigenous species.
Distinguishing Native from Introduced Species
Many animals commonly seen in Ohio are not native, having been introduced accidentally or intentionally by human activity. An introduced species occurs outside its historical range. The most problematic introduced species are classified as invasive, meaning their presence causes environmental or economic harm.
One disruptive aquatic invader is the Zebra Mussel, which arrived in the Great Lakes region in the 1980s via ship ballast water. These mollusks are filter feeders that outcompete native organisms for food resources. Another example is the Round Goby, a fish from Eurasia that displaces native species by consuming their eggs and young, particularly in Lake Erie.
On land, the Emerald Ash Borer, an insect native to Asia, has caused widespread devastation by killing millions of native Ash trees. Feral Swine, a mix of domestic pigs and Eurasian wild boars, also cause extensive environmental damage through rooting. The introduction of these species demonstrates the difference between a native species that evolved with the ecosystem and a non-native one that lacks natural controls.
Recovering and Extirpated Native Fauna
Ohio’s native fauna has experienced losses, with many species being extirpated—lost from the state but still existing elsewhere. The Bison, Eastern Elk, and Gray Wolf were eliminated from Ohio by the mid-19th century due to habitat loss and unregulated hunting. The Passenger Pigeon was also driven to extinction.
The North American River Otter represents a success in native species recovery. Otters were extirpated by the early 1900s due to poor water quality and over-trapping. Reintroduction efforts between 1986 and 1993 successfully restored the population across four Ohio watersheds.
Today, species like the Black Bear and Bobcat are naturally recolonizing the state, particularly in the forested Appalachian regions. Black Bear populations are growing, and Bobcat sightings are on the rise. The Bald Eagle, whose population crashed due to pesticide poisoning in the 1970s, has also seen a strong recovery. These successes demonstrate that with improved habitat quality, native species can return to their historical ranges.