San Jacinto Battleground State Historic Site Marsh Restoration and Boardwalk Interpretive Trail Guide
Habitats of the Upper Texas Coast
The native prairie, tidal marsh and bottomland forests of San Jacinto Battleground are some of the last remaining examples of these habitats in the area. Two hundred years ago, the coastal plain was dominated by these habitats, but the alteration of natural forces, such as fire, introduction of exotic species, such as Chinese tallow, and manipulation of the land for communities, businesses and industries, has drastically altered the landscape.
At the 1200-acre State Historic Site, it is our goal to restore the landscape to a condition much like it was at the time of the 1836 battle. In so doing, we are preserving an example of the vanishing coastal ecosystem for wildlife and for visitors of this and future generations. San Jacinto is one of the few places within an hour's drive of Houston where visitors can see such a diversity of native habitats and wildlife.
About the Trail:
The fully accessible interpretive trail starts at the parking lot on the north side of the San Jacinto Monument. The prairie portion of the trail is surfaced with asphalt and extends 700 feet to the edge of the marsh. Along the way there is a rest area under the canopy of several large oak trees. At the marsh, a boardwalk trail 510 feet in length allows visitors to experience the tidal marsh first hand, crossing both dense marsh vegetation and the open water of the tidal channel.
Native coastal tall grass prairie, dominated as it historically was by little bluestem, big bluestem, Indian grass and switch grass, has become quite rare. Less than 1% of the original coastal prairie remains. Many species of wildlife which depend on the grasslands have been extirpated from the area, including the Attwater prairie chicken, black-tailed jackrabbit, Texas horned lizard, American bison, and numerous songbirds. Factors which have destroyed the native prairie include suppression of natural fire, invasion of exotic species, especially Chinese tallow (a tree), and of course conversion for agriculture and development.
At the time of the 1836 battle, most of the battlefield was open prairie. Bands of trees lined the bluffs overlooking the marsh and the creeks and gullies that emptied into the marsh, and a few small "islands" of trees dotted the landscape. Otherwise the battle was fought in grass "as tall as a horse's belly." The trail will take you through a grass land closely resembling that prairie. In the absence of periodic fire, this prairie is maintained by mowing, which discourages Chinese tallow and other woody plants, and helps return nutrients to the soil. Individual prairie areas are mowed each spring and/or each winter. This gives native grasses all summer and fall to mature, flower and produce seed.
As you approach the boardwalk portion of the trail, you will cross the transition from uplands to wetlands. On the right you might notice a small patch of bunched grass that is different from both the grass of the open marsh and the grass of the prairie. This is marsh hay cord grass, which dominates a unique habitat called high marsh. High marsh is occasionally inundated by saltwater, but not daily as is the low marsh. Most of the marsh at San Jacinto may have been high marsh before subsidence lowered the land in the mid-20th century.
The tall grass that dominates the tidal marsh is smooth cord grass, specially adapted to the daily cycle of the tides. At one time, many thousands of acres of cord grass marshes lined the coves, flats, channels and floodplains of the Galveston Bay system. These tidal marshes are extremely important for wildlife, and play a role in the life cycle of most commercially important seafood species, including shrimp, crabs, spotted weakfish, red drum and flounder. Many species of shorebirds, wading birds, and resident and migratory waterfowl also depend on the marshes. Other wildlife you might see in the marsh at San Jacinto includes the river otter, diamondback terrapin, and nutria (an exotic rodent resembling a beaver). Keep an eye out for the cottonmouth or water moccasin, a poisonous snake which is a common predator at San Jacinto.
Tidal marshes are also important for absorbing pollutants and moderating floodwaters. Impacts to tidal wetlands are now regulated by the federal Clean Water Act. The marsh at San Jacinto was completely converted to open water in the late-1900's by subsidence (which was caused by pumping tremendous volume of water out of the ground for industry). It was restored in the 1990's by pumping clean sand and sediment into the marsh from the adjacent San Jacinto River (Houston Ship Channel). The project to restore all of the tidal wetlands at San Jacinto is ongoing.
As the coastal rivers meander back and forth in their shallow valleys, they leave behind terraces and floodplains dominated by marshes, swamps and hardwood forests. These riparian forests dissect the coastal prairies, add tremendously to the diversity of the ecosystem, and provide homes and critical foraging habitat to many species of resident and migratory wildlife. The forests, like the marshes and prairies, have been reduced to a small fraction of their original area by logging and clearing, and few examples remain in this area. In the east end of the San Jacinto Site there is a small remnant forest, with some mature trees three feet in diameter. The forest that is visible across the marsh from the trail is a younger forest, having sprung up on soils deposited by dredging throughout most of the 20th century. This forest is diverse, having been planted from seeds which floated down from upstream forests during floods. As you can see though, the trees have formed a dense canopy that provides most of the biological benefits of a more mature forest.
The construction of this interpretive trail was made possible by a Coastal Management Program grant through the Texas General Land Office, along with grants from the U.S. Fish and Wildlife Service, Galveston Bay Estuary Program (NOAA) and the National Fish and Wildlife Foundation. Partners include the Texas Department of Transportation, Telephone Pioneers of Texas, Environmental Institute of Houston, and Harris County Adult Probation Office. Future plans call for securing additional grant funding that will allow the trail to be extended another 500 feet into the forest beyond.