Wetlands in the Conterminous US
Wetlands are surveyed nationally on a 5-year cycle by the US Fish and Wildlife Service (USFWS). The most recent survey estimated that the continental United States has around 110 million acres of wetlands. This showed a decline in the nation’s wetland acreage, with a net loss of 62,300 acres of wetlands. The greatest losses were experienced in freshwater wetlands on the Atlantic and Gulf coastal plain of the southeast United States, including coastal Texas.
Wetlands in the Coastal Watersheds of the Conterminous US
A related study which evaluated wetland loss in coastal watersheds estimated that the coastal watershed of the US (Atlantic, Gulf of Mexico, Pacific, and Great Lakes) accounted for 41.1 million acres of wetlands in the lower 48 states. The Gulf of Mexico coastal watersheds (including the Texas coast) experienced a net loss of 257,150 acres, or 71% of the estimated wetland loss from coastal watersheds.
Wetlands in Texas
The 2010 National Resource Inventory created by USDA Natural Resources Conservation Service reviewed wetlands in all of Texas on non-federal lands (including privately owned lands, tribal and trust lands, and state and local government owned lands). This report, released in 2014, estimated almost 5.5 million acres of freshwater and tidal wetlands remained in Texas as of 2010. Approximately 43% of these wetlands occurred on forested land, 17% occurred on range land, and 18% occurred on cropland, pasture, and CRP land. This means that 78% or almost 4.3 million of all freshwater and tidal wetland in Texas are on agricultural or silvicultural lands!
Wetlands on the Texas Coast
The “Texas Coastal Wetlands: Status and Trends” USFWS report estimates that coastal Texas saw a net loss of 210,590 acres of wetlands from 1955 to 1992. By the early 1990s, 3.9 million acres of wetlands remained on the Texas coast: 567,000 acres of salt water wetlands and 3.3 million acres of freshwater wetlands. Fifty-two percent of the estimated remaining freshwater wetlands were considered farmed wetlands. In the early 1990s, agriculture was the largest land use on the Texas Coast, comprising 4.7 million acres of land. However, agriculture is no longer expanding on the Texas coast and now the greatest threat for wetland loss is from development as the Houston-Galveston region expands to accommodate population growth.
In a recent study that compared the USFWS National Wetland Inventory data developed in 1992-93 to current digital aerial photography, Jacob et al (2014) found that the 8-county Greater Houston Metropolitan Area lost around 23,000 acres of natural freshwater wetlands between 1992 and 2010 (Jacob, J.S., K. Pandian, R. Lopez, and H. Biggs. 2014. Houston Area Freshwater Wetland Loss, 1992-2010. Texas AgriLife Extension Service ERPT-002; Texas Sea Grant TAMU-SG-14-303). This study found that forested wetlands and freshwater marsh wetlands comprised the vast majority of non-tidal freshwater wetlands lost in this region. Over 70% of wetland loss appeared to be attributed to development projects.