Texas Ecoregions

Places in Texas are as different as you can imagine. Southeast Texas includes the Big Thicket, an area with pine forests as well as beech and magnolia trees, bogs with pitcher plants, and sloughs with cypress trees. In some areas the forest and understory growth are nearly impenetrable. Across the state to the west is the Trans-Pecos region where you find desert and scattered mountain ranges. Depending on such things as elevation, underlying geology, rainfall, and location, a place will fall within one of several ecoregions in Texas. One of the maps provided by Texas Parks & Wildlife Department (TPWD) shows ten such ecoregions. Depending on exactly how you look at it and how much you need to either lump similar areas together or split them according to slight differences, you may see more or fewer ecoregions. The TPWD’s Texas Conservation Action Plan divides the state into 12 ecoregions. Regardless of how you slice it, Texas has a lot of places worth knowing about. We will stick with the map showing ten ecoregions and offer a description and a few photos of places within each one.

Piney Woods

This region within east Texas contains loblolly and other pines and mixed hardwood forest with such trees as oak, sweetgum, elm and ash. It is an area with sandy soil and relatively high rainfall. There are many ponds and other wetlands in parts of the Piney Woods. The area extends from the Red River in northeast Texas nearly to the Gulf Coast around Houston and Beaumont.

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Caddo Lake
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Angelina National Forest
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Big Thicket National Preserve

Gulf Prairies and Marshes

Along the edge of the Gulf of Mexico, the Texas coast includes marshland, bays, and estuaries, and further inland the land gently rises and grasslands often predominate before shading into one of the other ecoregions.  Coastal marshes may be saline (composed of salt water) to varying degrees, and many are “brackish,” meaning that it is more saline than fresh water but less saline than sea water. These marshes support an amazing diversity of bird life. Many marshes along the upper coast support strong populations of the American alligator.

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A marsh at Anahuac National Wildlife Refuge
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Pelicans in the surf at Sea Rim State Park
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American alligator at Brazoria National Wildlife Refuge

South Texas Plains

This is an area roughly southwest of San Antonio, characterized by grasslands, cacti, and many thorny shrubs or trees such as honey mequite, lotebush, and Texas paloverde. The area is also known as the Tamaulipan thornscrub, emphasizing the extent of the thorny, scrubby vegetation in many parts of the ecoregion. This area is home to the Texas tortoise and the Texas indigo snake, both of which are protected species. Near the Rio Grande, the habitat is different and includes semitropical areas including a few remnant stands of the sabal palm tree.

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In the thorn scrub
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Sabal palms at the Nature Conservancy’s Southmost Preserve
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A Texas tortoise

Edwards Plateau

This is a broad area of uplift in central Texas, extending westward to the Pecos River. The western part of the plateau is mostly grassland with scattered trees, while the eastern areas have extensive juniper (“cedar”) and oak woodlands and limestone canyons and caves. That eastern and southeastern part of the plateau is what is referred to as the “Hill Country.” It is home to a number of salamander species that may be found only in one particular cave or spring, some living out their lives in complete darkness.

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Colorado Bend State Park
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Gorman Falls, Colorado Bend State Park
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Barton Creek Greenbelt, Austin

The Cross Timbers

This is a forest, savannah, and prairie ecosystem running from north-central Texas through Oklahoma and into a small area of Kansas. It is dominated by post oak and blackjack oak but also includes prairies such as the Grand Prairie. In Texas, it is found east of the Rolling Plains and west of the Blackland Prairie. Two belts of oak woodland and savannah – the eastern and western cross timbers – are separated by open prairies.

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Western cross timbers at the LBJ National Grasslands, Wise County
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Eastern cross timbers at the Ray Roberts Lake State Park, Denton County
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Prairie, Fort Worth Nature Center & Refuge

Blackland Prairie

The Blackland Prairie is a tallgrass ecosystem running roughly north to south in Texas from the Red River to San Antonio, named for its rich, black soil. It is located to the east of the Cross Timbers and the Edwards Plateau, and west of the Post Oak Savannah. Historically, this ecoregion supported little bluestem as well as big bluestem, Indiangrass, switchgrass, side-oats grama, and other grasses. Today, this tallgrass prairie has nearly all been lost to development and agriculture, with only a few remnants preserved.

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Park Hill Prairie, Collin County
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Snow-on-the-prairie at Park Hill Prairie
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Eryngo, Park Hill Prairie

Post Oak Savannah

East of the Blackland Prairie is the Post Oak Savannah, running in a broad northeast-to-southwest band from the Red River to just below San Antonio. Here, the black soils are replaced by sandy or clay soils. Historically it was savannah grassland with clumps of trees, mostly post oak. Occasional fires kept the savannahs from being taken over by woody vegetation, and periodic grazing by bison helped maintain it as well.

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Upland clearing at Gus Engeling Wildlife Management Area (WMA)
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A pond at Gus Engeling WMA
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Bottomland near a creek, Gus Engeling WMA

The Rolling Plains

The Rolling Plains are bordered on the west by the High Plains, on the south by the Edwards Plateau, and on the east by the Cross Timbers. Much of it contains mesquite grasslands, as well as juniper, prickly pear, and other plants. The eastern part is flatter while the western part contains more canyons and mesas, before the landscape steps up onto the High Plains.

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Ranchland, Shackelford County
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Ranchland, Shackelford County
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Mesquite, Knox County

The High Plains

This is an area of relatively flat landscape, short grasses, playa lakes, and relatively sparse rainfall in the western part of the Texas panhandle. It starts at the Pecos River and extends northward as part of the Great Plains. It includes the area often referred to as the “Llano Estacado” or “Staked Plains,” based on the notion that early explorers planted stakes in the ground to navigate the flat, treeless landscape.

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Early April, grasslands near Lake Meredith
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Grassland within Palo Duro Canyon
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Palo Duro Canyon

The Trans-Pecos

This is the part of Texas that is found west of the Pecos River. Although some areas around the Pecos River could be considered a transition from the Edwards Plateau, most of it would be described as Chihuahuan Desert. Several plant species characterize this desert, such as creosote bush, lechuguilla, and ocotillo. The lower elevations are flat and gravelly, while higher areas support grasslands, and several mountain ranges are found in the Chihuahuan Desert region.

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Chihuahuan Desert within Big Bend National Park
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McKittrick Canyon, in the Guadalupe Mountains
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The Chinati Mountains, seen from the desert near Chinati Hot Springs