Hammerhead worms and 3 other invasive species to watch out for in Austin

The first invasive species in Texas came courtesy of the Spanish explorers, who released pigs into the wild in the 16th century, creating an issue that now costs the state economy hundreds of millions of dollars per year. Numbering in the millions in Texas alone, feral pigs can be found in every county. They carry a range of bacterial, viral and parasitic diseases that can be devastating to livestock.

According to the Texas Invasive Species Institute, the state has upwards of 800 aquatic and terrestrial invasive species, and experts predict the number will grow in coming years.

Here are four species currently causing havoc in backyards:

Hammerhead worms (Bipalium kewense)

A native of Vietnam, the hammerhead worm has been in Texas at least since it was first spotted in Beaumont in the 1980s. The worms’ head shape makes them easily distinguishable from standard earthworms, and the Invasive Species Institute urges the public to report their presence. They tend to pop up after heavy rain.

After reporting the worms, the institute recommends eradicating them with a combination of orange essence and salt or vinegar, applying the lethal mixture directly on them and placing them in a zip-close bag to ensure they do not crawl away or reproduce after treatment. Because the worms are hermaphroditic, they are able to reproduce by growing a new head if not properly disposed of.

Continued removal of these invasive flatworms is considered necessary to protect populations of earthworms, which are common prey of the hammerhead.

Zebra mussels (Dreissena polymorpha)

The striped mollusks first infested a Texas lake, Texoma, in 2009. Native to the Black and Caspian seas in Eurasia, the species has taken less than two decades to infiltrate more than 30 lakes across Texas, including Travis, Austin and Lady Bird. They face no natural predators, and they spread when either larvae or adult mussels attach themselves to surfaces such as dive gear and boats. According to the Texas Parks and Wildlife Department, they are almost impossible to eradicate, though Lake Waco was cleared of the mussels in 2021.

The mussels can cause extensive damage to modern infrastructure by clogging pipes, as happened in 2019 when tap water across Central and South Austin had a distinctly fishy smell.  They also destroy algae that native species need for food, and they attach to and incapacitate native mussels.

Red imported fire ants (Solenopsis invicta)

These tiny pests have set up mounds in the U.S. since the 1930s, when they were accidentally introduced from South America. Since the 1950s, the ants have infested more than two-thirds of Texas. While their stings are uncomfortable and can produce skin welts, they are not dangerous to most people, though about 1% of the population can have a lethal allergic reaction after being stung. All native insects, birds, mammals and amphibians are susceptible to attack and oftentimes death. The fire ants also threaten and outcompete native ants.

More: Fire ant season is here, Austin: What you can do to fight them

Sacred bamboo (Nandina domestica)

Native to India, China and Japan, the sacred bamboo was initially brought to the U.S. during the 19th century and has been commonly used in landscaping due to its evergreen and ornamental appearance. The plant colonizes new areas through underground root sprouts and by animal-dispersed seeds, competing with native plant species for space and water.

Sacred bamboo can be found along Barton Creek, having washed down from landscaping projects over the years. The plant produces berries from April to September, and they are toxic to cats and some grazing animals.

What is an invasive species?

Invasive species are defined as those that are nonnative to the ecosystem and whose introduction “causes or is likely to cause economic, environmental, or human harm.”

Ashe junipers were recently targeted by members of the Texas Legislature, arguing that they are a nonnative species as a path to remove them. Experts clarified that Ashe junipers are as Texan as anything else in the state, with misinformation about their native status going back to the 1930s.

More: Learn to spot plant invaders with citizen science program

How can spread of invasive species be prevented?

The Invaders of Texas Program is a network of local citizen scientist teams that seek out and report outbreaks of environmentally and economically harmful invasive species. The program is coordinated by the Lady Bird Johnson Wildflower Center.

Keep Austin Beautiful has an Adopt-A-Creek program in which people commit to taking care of a quarter-mile segment for a minimum of two years. During that time, volunteers host events on topics such as invasive species removal, seed collection, and native tree or grass plantings.

This article originally appeared on Austin American-Statesman: Hammerhead worms and 3 other invasive species to watch for in Austin