Endangered species, aquifer levels being affected by Stage 4 drought

Special to the Star

As extreme drought conditions in Central Texas persist, endangered species and natural wildlife are being monitored and cared for by local specialists.  

San Marcos is currently in a Stage 4 drought, which has caused significant concern regarding the San Marcos River and the organisms that call it home. The San Marcos salamander and Texas wild rice are just some of the endangered species that may be affected.

Weston Nowlin, associate professor in the Department of Biology Aquatic Station, said endangered species like the endangered riffle beetle, San Marcos salamander and Texas wild rice are of special concern. The Endangered Species Act, passed to protect and recover jeopardized species and the ecosystems they depend on, will try to protect the organisms from local extinction, he said.

“These organisms have very limited distributions and have highly concentrated areas where they only occur,” Nowlin said. “Texas wild rice is only here. It’s fundamentally important for the maintenance of biodiversity in the river.”

Knowing if the endangered species have been directly impacted by the drought is an ongoing process, Nowlin said.

“There are people collecting data to determine that and also to see how they’ve responded to low water levels as well,” Nowlin said. “That data should be out soon and will be published and presented to the general public.”

The drought system is dependent upon aquifer levels, which are determined by groundwater-well height and the amount of water flowing through the river, he said.

When those levels hit certain critical thresholds, the Edwards Aquifer and City of San Marcos officials enact conservation measures to slow the consumption of water, Nowlin said.

If the flow in the San Marcos Springs drops below 120 feet per second, construction work is forced to stop, Nowlin said. The river is currently at 117 feet per second.

As the aquifer’s water level lowers, the amount of discharge from the springs decreases, Nowlin said.

“How low can we go in river discharge before we start impacting these species?” Nowling said. “We’re seeing accelerated extinction rates, and it’s very likely related to human influence.”

The San Marcos River, Edwards Aquifer and Comal Springs have all been low, and these organisms have responded, Nowlin said.

The endangered species have not been negatively impacted by the drought and have adapted accordingly, said Dianne Wassenich, program director of the San Marcos River Foundation.

Rudy Rosen, research professor at the Meadows Center for Water and the Environment, said he thinks the drought delivers a message to Texans.

“We have to get far more serious about the ways we respond to drought, maybe not so much because the drought is getting worse, but because there are more and more people coming to Texas that are depending on a reliable water supply, so we need to do more with technology and more with conservation,” Rosen said.

Drought is a weather-driven phenomenon. However, human impact is also an aspect of climate changes, Rosen said.

Water is a limited resource, Nowlin said.

“That’s it,” Nowlin said. “That’s all we have. There’s a lot of negative impacts of drought, but I think one positive impact of it is it makes people aware of the preciousness of the resource.”