Texas Blackland Prairies


The Texas Blackland Prairies are a temperate [grasslands, savannas, and shrublands|temperate grassland] ecoregion located in Texas that runs roughly from the Red River in North Texas to San Antonio in the south. The prairie was named after its rich, dark soil. Less than 1% of the original Blackland prairie vegetation remains, scattered across Texas in parcels.

Setting

The Texas Blackland Prairies ecoregion covers an area of, consisting of a main belt of and two islands of tallgrass prairie grasslands southeast of the main Blackland Prairie belt; both the main belt and the islands extend northeast–southwest.
The main belt consists of oaklands and savannas and runs from just south of the Red River on the Texas-Oklahoma border through the Dallas–Fort Worth metropolitan area and southward to the vicinity of San Antonio, Bexar County. The central forest-grasslands transition lies to the north and northwest, and the Edwards Plateau savanna and the Tamaulipan mezquital lie to the southwest.
The larger of the two islands is the Fayette Prairie, encompassing, and the smaller is the San Antonio Prairie, with an area of. The two islands are separated from the main belt by the oak woodlands of the East Central Texas forests, which surround the islands on all sides but the northeast, where the Fayette Prairie meets the East Texas Piney Woods.
Texas counties that once supported blackland prairies include all or most of Collin, Dallas, Delta, Ellis, Hunt, Kaufman, Navarro, and Rockwall counties, as well as portions of Bastrop, Bell, Bexar, Caldwell, Denton, Falls, Fannin, Franklin, Freestone, Grayson, Guadalupe, Henderson, Hill, Hopkins, Johnson, Lamar, Limestone, McLennan, Milam, Rains, Red River, Tarrant, Titus, Travis, Van Zandt, and Williamson counties, all in the northwestern band of the region. The smaller southeastern band includes much of Grimes and Washington counties as well as portions of Austin, Colorado, Fayette, and the northwestern half of Lavaca county. Sources and maps vary on the exact boundaries of the Blackland Prairie, and some may include or exclude different portions of peripheral counties.

History

contributed to the maintenance of the prairie through controlled burns to make more land suitable for hunting bison and other game. Hunter-gatherers continually inhabited the prairie since pre-Clovis times over 15,000 years ago. In historic times, they included the Wichita, Waco, Tonkawa, and Comanche, each of whom were gradually replaced by settled agrarian society. The advent of large-scale irrigated farming and ranching in the area quickly led to widespread habitat loss.
Early Czechoslovak and German immigrants arrived in the region around 1825 to 1845 and found the rich black soil excellent for farming. By the end of the 19th century 98% of the blackland prairies were cultivated and it was the leading cotton region of the state, also producing sorghum, corn, wheat, and hay. The land was so valuable, crops were planted abruptly up to the roadsides, seldom fenced, and riparian areas were cleared right to the creek banks. Several of the larger cities in the state, such as Austin, Dallas, Fort Worth, San Antonio, Temple, and Waco, are located in the region and the agricultural activity in the area was a significant factor in their growth in the 19th century.
The U. S. Bureau of Biological Survey , led by chief field naturalist Vernon Bailey with a crew of 12 federal field agents conducted a 17-year, statewide survey of the natural history of Texas. The survey collected detailed data on the topography, land use, climate, as well as plant, bird, and mammal specimens, and extensive photographs of the landscape. However, because the natural state of the Blackland Prairie region was so altered, even at that time, that little wildlife remained and the biological survey crew spent little time there, of the total fieldwork. The human population of Texas in 1900 was less than 3,000,000, in 2001 it was over 20,000,000, in 2019 it was nearly 29,000,000. Although 98% of the land was cultivated around 1900, after 1950 a shift in land use occurred, with about 50% in cultivation and a significant increase in pasture for livestock production, tame pasture and 25% rangeland. "As a result of cultivation, overgrazing, and other imprudent land-use practices, there are few if any remnants of climax vegetation in the region."

Ecology

The Blackland Prairie was a disturbance maintained ecosystem prior to the arrival of Europeans. Fires ignited by lightning occasionally swept the area, clearing or reducing the encroachment of trees and shrubs on the prairie, while stimulating the native herbaceous prairie species of forbs and grasses which are pyrophytic, adapted and resistant to wildfires. The exact frequency of fires is unknown but estimated to have occurred at intervals of 5 to 10 years. Herds of bison, and to a lesser extent pronghorn and deer, grazed on the grasses and trampled and fertilized the soil, stimulating the growth of the tallgrass ecosystem. Bison were extirpated from the area by the 1850s.
The soil of the Blackland Prairies, from which the "blackland" gets its name, contains black or dark-gray, alkaline clay in both upland and bottomland areas. Some western areas have shallow soils over chalk, while some soils in eastern areas are slightly acidic to neutral, grayish clays and loams over mottled clay subsoils. "Black gumbo" and "black velvet" are local names for this soil. The soils have vertisols properties, shrinking and swelling with moisture content. In dry weather, deep cracks form in the clay, which can cause damage to buildings and infrastructure. Soil management problems also include water erosion, cotton root rot, soil tilth, and brush control.
The rich black 'waxland' soil of these prairies is almost proof against burrowing rodents, which penetrate the region only along some sandy stream bottoms, while the open country tempts jack rabbits, coyotes, and other plains species eastward slightly beyond their usual bounds. Few, if any, species are restricted to these prairie, however, and the effect on distribution is mainly negative."

The negative effect on distribution is evident in the Texas distribution of many wide-ranging species of both eastern and western North American fauna reaching their respective distributional limits in the region of the Texas Blackland Prairies and East Central Texas forests .

Flora

The humid subtropical climate of this ecoregion has allowed a diverse array of plants to thrive. Important prairie plants included little bluestem, yellow indiangrass, Plantago, big bluestem, tall dropseed, and a variety of wildflowers including gayfeathers, asters, Maximilian sunflower, wild indigos, Yellow Pitcher Plant and compass plant. Trees like Ashe Juniper, winged elm, cedar elm, sugarberry, green ash, live oak, Pecan, black walnut, black willow, American sycamore, honey locust, bur oak, Maple, Sassafras, American Sweetgum, Southern Magnolia and Soapberry are found in this area. Taxodium distichum and Pinus taeda '' can also be found at various points. Ferns found here include Kunth's maiden fern, Common Maidenhair Fern, Horsetails, Christmas Fern, Cinnamon Fern ,'' Spleenworts and the Bracken. Like growing shrubs like Sabal minor, Copperleaf, Buckeye, Jointfir, Snakeweed and Illinois Bundleflower.

Fauna

Mammals: Some species found in the region include Virginia opossum, nine-banded armadillo, Eastern red bat, Brazilian free-tailed bat, fulvous harvest mouse, white-footed mouse, hispid cotton rat, eastern fox squirrel, American beaver, white-tailed deer, northern raccoon, striped skunk, bobcat, gray fox, and coyotes.
The large, keystone species that once inhabited the Blackland Prairies, before the arrival of Europeans and the destruction of the tallgrass ecosystem, are now extirpated, including American bison, gray wolf, red wolf, mountain lion, black bear, and pronghorn which once ranged into the western areas, and even jaguar and ocelot that once occurred in the southern regions. Invasive species include nutria or coypu, house mouse, roof rat, and Norway rat. Feral house cats and feral pigs, are of conservation concerns and pose serious threats to native fauna.
Birds: With spring and fall migrants, wintering species, breading and summer species, well over 325 species of birds occur in the region. Various seasonal and migratory species appearing in the region include Bufflehead, Hooded Merganser, Little Blue Heron, Yellow-crowned Night Heron , Northern Harrier, Inca Dove, Yellow-billed Cuckoo, Ruby-throated Hummingbird, Scissor-tailed Flycatcher, American Pipit, Orange-crowned Warbler, Blue Grosbeak, Indigo Bunting, Painted Bunting, Harris's Sparrow, and Dickcissel.
A few of the year round resident species include wood duck, blue-winged teal, black vulture, cooper's hawk, red-shouldered hawk, American kestrel, great horned owl, barred owl, greater roadrunner, belted kingfisher, red-bellied woodpecker, hairy woodpecker, loggerhead shrike, red-winged blackbird, eastern meadowlark, eastern bluebird, tufted titmouse, Carolina wren, chipping sparrow, lark sparrow, and grasshopper sparrow.
Reptiles: Although not particularly abundant, the American alligator ranges into the Blackland Prairies. The ubiquitous red-eared slider is found throughout the region, the river cooter in the northeast, the Texas cooter in the southwest, the Mississippi map turtle in the larger rivers, and several records of the rare chicken turtle. Others include eastern snapping turtle, three-toed box turtle, ornate box turtle, Mississippi mud turtle, eastern musk turtle, spiny softshellturtle. Lizards include Green Anole, Six-lined Racerunner, Prairie Lizard, Western Slender Glass Lizard, Five-lined Skink, Broad-headed Skink, Prairie Skink, and Ground Skink.
Snakes are the most diverse group of reptiles in the region, species include the North American racer, eastern hog-nosed snake, prairie kingsnake, speckled kingsnake, coachwhip, yellow-bellied watersnake, diamond-backed watersnake, rough greensnake, western ratsnake, Graham's crayfishsnake, flat-headed snake, western ribbonsnake, and several others. Venomous species include the copperhead, cottonmouth , timber rattlesnake, and the Texas coralsnake.
Amphibians: Frogs and toads in the region include the American bullfrog, southern leopard frog, Woodhouse's toad, Hurter's spadefoot toad, Great Plains narrow-mouthed toad, Blanchard's cricket frog, Cope's gray treefrog, green treefrog, spotted chorus frog, Strecker's chorus frog, and another ten species recorded from limited areas or marginal counties of the Blackland Prairie. Salamanders include the small-mouthed salamander, central newt, and western lesser siren.
Fish: Among the many fish of the region are spotted bass, white bass, black crappie, white crappie, black bullhead, blue catfish, flathead catfish, freckled madtom, warmouth, orangespotted sundfish, longear sunfish, freshwater drum.
Just a few of the smaller species include threadfin shad, red shiner, blacktail shiner, shoal chub, ghost shiner, pugnose minnow, fathead minnow, bullhead minnow, river carpsucker, blackstripe topminnow, slough darter, bigscale logperch, and dusky darter and many others.

Conservation

Because of the soil and climate, this ecoregion is ideally suited to crop agriculture. This has led to most of the Blackland Prairie ecosystem being converted to crop production, leaving less than one percent remaining. Some groups estimate that less than 0.1% of the area is remaining. Small remnants are conserved at sites such as The Nature Conservancy's 1,400-acre Clymer Meadow Preserve near Celeste, TX.

Protected areas

The U.S. Forest Service manages the Caddo National Grassland under the multiple-use concept, balancing resource extraction, preservation, and recreation.
The State of Texas administers a number of state parks and wildlife management areas in the region, however they are mostly located around human-made lakes and riparian zones of rivers and creeks, focusing on recreation, fishing, and hunting, and not prairie conservation. Many of these areas are leased, not owned, by the state.
;Texas Blackland Prairies
;Peripheral areas