South Texas Habitats

PRIMARY ECOREGIONS

Based on the information from the Texas Parks and Wildlife website, there are two primary habitats or ecoregions in South Texas, Tamaulipan Thornscrub and Gulf Prairie and Marsh

Tamaulipan Thornscrub - Brush Country

The Texas Parks and Wildlife Department describes the South Texas Brush Country as plains of thorny shrubs and trees and scattered patches of palms and subtropical woodlands in the Rio Grande Valley. The plains were once covered with open grasslands and a scattering of trees, and the valley woodlands were once more extensive. Today, the primary vegetation consists of thorny brush such as mesquite, acacia, and prickly pear mixed with areas of grassland. The average annual rainfall of 20 to 32 inches increases from west to east. Average monthly rainfall is lowest during winter, and highest during spring (May or June) and fall (September). Summer temperatures are high, with very high evaporation rates. Soils of the region are alkaline to slightly acidic clays and clay loams. The deeper soils support taller brush, such as mesquite and spiny hackberry, whereas short, dense brush characterizes the shallow caliche soils. Although many land changes have occurred in this region, the Brush Country remains rich in wildlife and a haven for many rare species of plants and animals. It is home for semi-tropical species that occur in Mexico, grassland species that range northward, and desert species commonly found in the Trans-Pecos. Livestock grazing and crop production are the principal agricultural land uses.

This region owes its diversity to converging elements of the Chihuahuan Desert to the west, the Tamaulipan thornscrub and subtropical woodlands along the Rio Grande and the coastal grasslands to the east. The region is cut by arroyos and streams and is blanketed with low-growing mostly thorny vegetation. Where conditions allow, a dense understory of small trees and shrubs will develop. The distinctive woody vegetation gives rise to the name “brush country”.

Gulf Prairie and Marsh

With a landscape that is dominated by the world's 6th largest hypersaline lagoon and the world's longest barrier island, the Gulf Prairie and Marsh region provide a rich environment for tens of thousands or migrating shorebirds and songbirds each spring and fall.

SECONDARY HABITATS

The Texas Ecosystem Analytical Mapper, TEAM, delivers the Ecological Mapping Systems of Texas (EMS) data to Texas citizens in an easy to use format. The TEAM application is an interactive mapping tool that assists users in understanding the Texas Landscape and integrates EMS data with land management and resource planning of all types.

  • Brackish Tidal Flat - This type is largely unvegetated because it is inundated frequently and for extended periods by tidal fluctuations.
    CAMERON COUNTY - Bay Access Mudflats

  • Deciduous Shrubland - A discontinuous canopy of shrubs and small trees characterize this type, and soils range from clayey to loamy. Species such as mesquite, blackbrush, huisache, granjeno, sugar hackberry, pricklypear, and whitebrush are common components.
    STARR COUNTY - Falcon State Park

  • Evergreen Shrubland - Relatively dense, tall, and diverse shrublands with species such as blackbrush, mesquite, granjeno, guajillo, guayacan, whitebrush, lotebush, amargosa, brasil, and/or colima.

  • Floodplain Deciduous Shrubland - A variety of trees such as sugar hackberry, mesquite, cedar elm, Mexican ash, anacua, huisache, and black willow may be important within this type. Shrubs and small trees such as mesquite, huisache, Texas persimmon, brasil, granjeno, and colima are common components.
    HIDALGO COUNTY - Santa Ana NWR, Bentsen-Rio Grande State Park, STARR COUNTY - Salineño Wildlife Preserve

  • Freshwater Marsh - Wetland species such as cattails, American bulrush, sedges, and spike rushes are common components of this rare type. Some areas may be salty and contain specie such as sea ox-eye daisy and wolfberry, and shrubs such as black willow, retama, huisache, and buttonbush may be present.
    CAMERON COUNTY - Resaca de la Palma; HIDALGO COUNTY - Estero Llano Grande State Park, Old Hidalgo Pumphouse

  • Loma - These grasslands occur over both slightly saline and non-saline soils. Important herbaceous species may include shoregrass, gulf cordgrass, big sacaton, saltwort, buffelgrass, and seepweed. Shrubs such as mesquite, Spanish dagger, screwbean mesquite, Lindheimer pricklypear and huisachillo may also be components

  • Mixed Forest - Anacua, Mexican ash, huisache, and Texas ebony may be components of this broadly-defined type. Other deciduous species may include sugar hackberry, cedar elm, pecan, black willow, and tepeguaje. Shrubs and small trees such as mesquite, whitebrush, brasil, granjeno, and colima are common components.

  • Open Water: Fresh - This includes reservoirs, rivers, canals, and ponds.

  • Open Water: Gulf - This includes open water areas in bays and in the Gulf of Mexico where salinities are greater than 25 ppt.
    CAMERON COUNTY - South Padre Island locations

  • Palm Grove - This type is restricted to fewer than five sites along the Rio Grande in far South Texas. Mexican sabal palm is a conspicuous component, and species such as sugar hackberry, Texas ebony, anacua, Mexican ash, cedar elm, and tepeguaje are common components.
    CAMERON COUNTY - Sabal Palm Sanctuary

  • Riparian Deciduous Forest - This type is mainly deciduous floodplain terrace forest in a variety of successional and disturbance states with high diversity of shrub species, including brasil, colima, and granjeno. An overstory of sugar hackberry, cedar elm, huisache, and/or mesquite may be present. Texas ebony and anacua may also be present in the canopy.

  • Riparian Evergreen Forest - Ebony and anacua together with species such as sugar hackberry, cedar elm, mesquite, huisache, anacua, granjeno, brasil, retama, and colima are common.

  • Saline Aquatic Submerged - This system includes seagrass beds occurring along the SouthTexas Coast Dominants may include individual species or may be more diverse including multiples species of Seagrass. Halodule wrightii, which occupy thousands of acres of the Laguna Madre, and Thalassia testudinum.
    CAMERON COUNTY - South Padre Island locations

  • Salty Deciduous Shrubland - This type may be over more or less salty soils, and often contains mesquite as the overstory dominant except on the saltiest sites. A variety of shrubs and succulents may be present, including species such as blackbrush, amargosa, lotebush, palo verde, four-wing saltbush, and saladillo.
    STARR COUNTY - Falcon State Park, Salineño Wildlife Preserve

  • Salty Marsh - This includes a variety of tidal-influenced marsh types that may vary from year to year based primarily on storm events and precipitation, and across small areas due to small variations in elevation. Important species may include marshhay cordgrass, Gulf cordgrass, saltgrass, and seashore paspalum. CAMERON COUNTY - South Padre Island locations

  • Texas Saline Coastal Prairie - Gulf cordgrass may form nearly pure stands or may form mosaics with marshhay cordgrass or saltgrass and shrubs such as baccharis, Chinese tallow, huisache, mesquite, or shrubby sumpweed may also occur. Sea ox-eye daisy and saltwort are commonly encountered forbs.

  • Woody Marsh - Regularly flooded shrublands or low woodlands with black mangrove and salt tolerant species such as smooth cordgrass, saltgrass, sea ox-eye daisy, saltwort, and Carolina wolfberry.
    CAMERON COUNTY - South Padre Island locations