Texas blackland prairies

The Texas Blackland Prairies are a temperate grassland ecoregion located in Texas that runs roughly from the Red River in North Texas to San Antonio in the south.

Setting
The Texas Blackland Prairies ecoregion covers an area of 50300 km2, consisting of a main belt of 43000 km2 and two islands of tallgrass prairie grasslands southeast of the main blackland prairie belt; both the main belt and the islands extend northeast/southwest. It is the home to many different eco-regional organisms

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 into southwestern Texas. The Central forest-grasslands transition lies to the north and northwest, and the Edwards Plateau savanna and the Tamaulipan mezquital the southwest.

The larger of the two islands is the Fayette Prairie, encompassing 17000 km2, and the smaller is the San Antonio Prairie of 7000 km2. 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 Piney Woods.

Formation
This area was shaped by frequent wildfires and Plains Bison. Large fires would frequently sweep the area, clearing shrubs and stimulating forbs and grasses. Large herds of bison also grazed on the grasses.

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 (and some groups estimate less than 0.5% to less than 0.1% remaining) and making the tallgrass the most-endangered large ecosystem in North America.