Juxtaposed among three biotic regions (Chihuahuan to the west, Edwards Plateau to the north, and Tamaulipan to the south and east), this state natural area is quite biologically diverse and provides habitat for endemic plants, fish and wildlife, including a rare salamander and several rare fish. There are large, dense stands of live oak, pecan, and sycamore trees adjacent to the river, plus semi-desert grassland vegetation on the ridges and slopes, and numerous springs and seeps teeming with mosses, ferns, herbs and vines. The area also contains unique cultural and archeological resources, including significant Lower Pecos Style rock art.

The Devils River is one of the best remaining examples of an ecologically intact river system in Texas. Its unspoiled waters tumble over limestone past rugged ridges, canyons and grassy banks. A series of springs within the state natural area's karst topography provides a substantial base of the river's flow. Three types of stream conditions characterize the river: long, deep pools; wide shallow areas; and relatively deep, turbulent rapids. The river is free of impoundments, generally inaccessible, essentially primitive and unpolluted.

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