As an ecologist, Mara Alexander spends some of her workdays with a shovel in hand, uprooting specimens of Texas wild rice, an endangered species, and replanting the long aquatic grass in deeper water.

The drought is threatening the existence of Zizania texana, or Texas wild rice, as the dry spell drops water levels in the grass' sole habitat in the San Marcos River.

“Texas wild rice relies on flowing water, and it really needs water that's at least a foot of depth, though a meter is better,” said Alexander, who has worked with the rice at the San Marcos National Fish Hatchery and Technology Center for four years. “So right now, because the flows are low and water depth is decreasing greatly, we find many stands of Texas wild rice in zero to 5 inches of water, and that's not enough.”

In 2006, Alexander said, a Texas Parks and Wildlife study found that about 4,000 square meters of Texas wild rice existed, all of it swaying in the waters of a 2-mile stretch on the San Marcos River near Interstate 35.

More recent data is still being compiled, she said, but she suspects the number will have dropped quite a bit.

“We're trying to move struggling patches before we start to see them die,” Alexander said, “but we do see some yellowing of the leaves. The plants are stressed and drying out.”

When replanting the grass in deeper water, Alexander must be careful because if the water is more than a foot or 2 deep then, when river water levels rise again, the plant will be too far under water to absorb adequate sunlight.

This balancing act exposes the finesse necessary to preserving a species on the brink. And that's why Alexander is just one of many scientists with organizations at the local, state and federal level studying the rice, hoping to ensure its survival in the face of human development and use of its habitat.

Her studies, when she is not replanting the rice, focus on the plant's life history and seed production, with the aim of understanding what the rice needs to survive and thrive.

“The ultimate goal is to take Texas wild rice off the endangered species list,” she said. “And the more you know about the biology of these species, the more you know about the requirements they need to survive.”

This is a difficult goal, Alexander says, but the U.S. Fish and Wildlife Service plans to issue a recovery plan for the rice in the next few years that will, among other things, specify the amount of rice that would need to exist before it could be removed from the list.

But in the meantime, Alexander is just trying to keep the species going.

“It's a very beautiful grass,” she said. “If you were to see it flowing under water, in good conditions, you would know. It floats along the surface in green ripples.”