Even though Carolinian Canada is quite small compared with other Canadian vegetation zones, making up only 1% of Canada's total land area, it boasts a greater number of both flora and fauna species than any other ecosystem in Canada. It is estimated that some 2,200 species of herbaceous plants are found here, including 64 species of ferns, at least 110 species of grasses, and over 130 different sedge species. There are 70 species of trees alone.  Click here for a list of Representative Carolinian Species

Numerous species of reptiles and amphibians make their home primarily or entirely in this southern portion of Ontario, including the Eastern Spiny Softshell Turtle, the Eastern Fox Snake, the Hognose Snake, the Queen Snake, and Fowler's Toad. Close to 400 bird species have been recorded representing over half of the species in all of Canada. Several butterflies, such as the Karner Blue and the Frosted Elfin are restricted to this region. As well several mammals such as the Badger, the Gray fox, and the Virginia Opossum are primarily restricted to the Carolinian forest.

Ontario's Carolinian zone is the province's most threatened ecological region. Over 125 species in Carolinian Canada are considered vulnerable, species of special concern, threatened or endangered by either the federal or provincial government. Over 400 species in Carolinian Canada are considered rare by the Natural Heritage Information Centre.

The Carolinian zone habitats and ecosystems include forests, tallgrass prairies and savannas, wetlands, streams, shorelines and other aquatic habitats. Fifty-eight of these ecosystem types is considered rare. Each of these ecosystems have a distinctive set of species.