The OPJV covers almost 60 million acres from Tulsa, Oklahoma in the north to San Antonio, Texas in the south, including all of the Edwards Plateau. Over 95% of the land is privately owned, and 85% is agricultural land. The OPJV region contains several major metropolitan areas including Tulsa and Oklahoma City in Oklahoma, and Dallas, Fort Worth, Killeen, Austin, San Antonio, and Bryan/College Station areas in Texas. These areas have seen population growth of 13 to 47% from 1990-2000.
The Oaks and Prairies Joint Venture includes the Edwards Plateau (BCR 20) in central Texas and the Oaks and Prairies (BCR 21) Ecoregion in Oklahoma and Texas. The Oaks and Prairies BCR includes the Cross Timbers, Blackland Prairies, and Post Oak Savannah.
Declining bird populations face numerous challenges in the OPJV. Fire suppression and fine fuel reduction via livestock grazing have reduced fire frequency resulting in accelerated development of shrub and tree species. The end result of this process has been a decline in habitat for savannah and grassland-associated birds. Recent estimates from Oklahoma indicate that expanding red cedar transforms about one square mile daily from shrub and grass habitats to cedar woodland. Most of the grassland habitat within the Post Oak Savannah has been converted to cotton production or planted in Bermuda grass; 98% of the Blackland Prairie has been lost, primarily to cultivation; and grassland habitat within the Cross Timbers is being planted with “improved” forages. Additionally, nearly 3 million acres of rural land in Texas and Oklahoma were converted to urban uses from 1982 to 1997.
In the map below, counties with BLACK boundaries represent our main focus for grassland bird monitoring and conservation efforts. They also represent our counties included in the Grassland Restoration Incentive Program (GRIP; see our GRIP page for more information). The counties in RED represent areas where we are working with partners to research and monitor Edwards Plateau (Green area) priority species like Golden-cheeked Warbler, Black-capped Vireo, Montezuma Quail, and many other shrubland specialists. GRAY areas represent major human population centers (large cities to smaller towns).