Balcones Canyonlands National Wildlife Refuge, established in 1992 in the Texas Hill Country northwest of Lago Vista, protects rugged Edwards Plateau canyonlands and habitat for the endangered golden-cheeked warbler and black-capped vireo. Steep limestone canyons carved by Colorado River tributaries, along with caves, sinkholes, and springs, support many native species, including creatures found only in this part of Texas. The refuge also helps safeguard the Edwards Aquifer, whose water and springs sustain nearly one million people and feed Hill Country rivers flowing to the Texas Gulf Coast. Its oak, elm, and Ashe juniper vegetation makes it especially important for the golden-cheeked warbler, which nests only in the Edwards Plateau.