Historically, the Meramec Highlands IBA contained upland oak and mixed-hardwood forest and woodland and bottomland forest (Nigh and Schroeder 2002). Today upland second-growth and bottomland forest remain amidst a rapidly urbanizing landscape on the edge of the St. Louis metropolitan Area. Sixteen percent of the IBA is publicly-owned conservation land, including the Missouri Department of Natural Resource's (MDNR) Castlewood State Park (SP) (1,803 acres, 730 ha), and the Missouri Department of Conservation's (MDC) Forest 44 Conservation Area (CA) (988 acres, 400 ha), Rockwoods Range (1,433 acres, 580 ha), and Rockwoods Reservation (1,892 acres, 766 ha).

The Meramec Highlands IBA represents a complex of forest habitat for breeding forest birds, such as Red-shouldered Hawk, Prothonotary Warbler, in addition to confirmed nesting for Cerulean Warbler at Castlewood SP (as many as 15 simultaneous pairs of Cerulean Warblers have been confirmed by J. P. Malone). Henslow’s Sparrows have also been sighted in low prairie openings at Castlewood SP.

The Meramec Highlands IBA exists amidst a forest landscape becoming rapidly fragmented by suburban sprawl of St. Louis metropolitan area. The IBA contains much public land for local urban dwellers to observe forest interior birds. Protection of additional forest land through acquisition would likely be cost prohibitive in this urbanizing landscape.