Here are 10 of the most pesky invasive species in Greater Houston – Houston Public Media

Many invasive species threaten ecological systems and native species in Greater Houston and Texas.

In Greater Houston, we are used to people coming from all over the country and around the world for jobs and other reasons. And these newcomers can add to housing demand and add cars to the roads.

And while these are legitimate threats to the quality of life in the region, there are other fairly recent arrivals in the region that cause more life and death problems for the environment – invasive species.

Plants, animals, insects, slugs, fish, lizards, birds, molluscs and many more have arrived in our area from other parts of the world (either by accident or on purpose for some reason or another). But now they threaten the survival of native species by competing for resources and spreading disease.

In the audio above, Ashley Morgan Olvera from Texas Invasive Species Institute and Sam Houston State University talks with Craig Cohen about some of the most notable invasive species in Greater Houston and Texas.

Here are some invasive species they talked about:

chinese tallow tree
According to the Texas Invasive Species Institute, Chinese tallow trees, an invasive species, make up about 80% of the tree canopy in Greater Houston.

1. chinese tallow – About 80% of the tree canopy in Greater Houston is made up of Chinese tallow, Morgan-Olvera said. These trees are an ornamental plant brought to the United States in the 1700s. They average about 20 feet tall but can reach up to 40 to 50 feet.

The plant is able to alter the pH of the soil around it to make the soil hospitable only to it and other suet trees. This and its deep taproot (allowing it to survive well in drought conditions) is how they are able to quickly take over an area.

giant salvinia
The giant invasive salvinia plant floats on the surface of the water, depleting oxygen levels, killing fish and starving plants below of sunlight.

2. giant salvinia – These aquatic ferns grow on the surface of water, and Texas has no native species that float like it. Thus, it can coat the surface of the water, depleting it of oxygen and killing fish. It limits the penetration of sunlight, which kills other plants below.

The plant is native to South America and its Velcro-like leaves stick to objects, allowing it to be easily propagated by boaters.

Imported red fire ant
The invasive species Texans probably know best: the fire imported fire ant.

3. Imported red fire ant – This is probably the first invasive species that comes to mind for most Texans. They are native to South America and likely hitchhiked all the way to Texas in potted plants.

This particularly aggressive species is known to attack crops, lizards, birds and, of course, humans if you disturb them. The biggest ecological concern they cause is the displacement of native ants.

Nutria close-up - Wikipedia
The nutria is an important invasive species along the Gulf Coast.

4. nutria – These large, dark-colored, semi-aquatic rodents are everywhere, partly because they breed year-round. They can cause great damage to rice and sugar cane crops.

In 2019, a documentary film titled Unusually large rodents detailed the role nutria play in the environment and culture of places like Louisiana and Texas.

CONTINUED: Interview with filmmaker Quinn Costello

Black Velvet Leather Slug
Black velvet leaf slugs, native to South America, can transmit parasites to mammals and humans if the parasite reaches the digestive tract.

5. Black Velvet Leather Slug – As the name suggests, these slugs are jet black with a matte finish. They have two black eye tentacles on their heads and can grow up to 3.5 inches long. These South American natives were first found in the Gulf States in the 1960s and often hitchhike to new areas in potted plants.

If you come across one, don’t touch it. And, if you do, wash your hands thoroughly before touching your mouth. This is because these slugs can transmit parasites to mammals and humans if the parasite reaches your digestive tract. However, the disease is usually not fatal to humans, but it can be bad.

Their second biggest threat is their insatiable appetite, which makes them a threat to many types of herbs and plants.

Red bay ambrosia beetle
The invasive ambrosia beetle can be destructive to trees, transmitting a fungus causing them to wilt and die within weeks or months, a fate known as laurel wilt.

6. Red bay ambrosia beetle – This dark-colored, ball-shaped beetle is one of many wood beetles found in Greater Houston. They are quite small at 2mm long when mature, but they can have a huge impact. They transmit a fungus to trees, causing them to wilt and die within weeks or months, a fate known as laurel wilt.

The beetles threaten many types of trees, including avocado trees, negatively impacting agriculture.

They are native to Japan and Southeast Asia and are often carried when people move firewood from one location to another.

7. Japanese climbing fern – This vine-like perennial native to (you guessed it) Japan, East Asia and India, climbs over anything in its path and can reach around 90 feet in height. Its stems are green, orange or black.

The biggest concern with this invasive is that it can grow in dense layers as thick as 10 feet, choking out native plants and trees below. And its presence can intensify fires, allowing flames to climb trees.

Asian citrus psyllid
Asian citrus psyllids pose a serious threat to the citrus industry because they transmit a bacterium that causes what is known as citrus green leaf disease.

8. Asian citrus psyllid – These small, brownish insects are about an eighth of an inch long and can often be found feasting on the undersides of leaves.

The most serious problem they cause is the transmission of a bacterium that causes what is called citrus greening disease to citrus, which has caused extensive damage to the citrus industry across the country, including in the Rio Grande Valley.

The insect and disease can be found in Harris County, which is why you may have seen notices of citrus quarantines. Once a plant is infected with the disease, it must be destroyed.

Black and White Tegu Lizard
Black and white Argentine tegu lizards are an invasive species growing in Texas due to the exotic pet trade and can grow up to 50 inches long.

9. Black and White Argentinian Tegu Lizard – As its name suggests, this lizard is native to South America, first introduced to the United States via the exotic pet trade. They can grow up to 50 inches long and can reproduce very quickly. The area from Houston to the Piney Woods of eastern Texas provides good habitat for them and they feed on native species for survival.

red lionfish
The lionfish, native to the western Pacific Ocean, has taken hold in the Gulf of Mexico and threatens the health of coral reefs.

ten. red lionfish – These striking red and poisonous saltwater fish are native to the western Pacific Ocean, but have taken root in the Gulf of Mexico. Due to their venomous spines, they have no predators and so their numbers have taken off since their introduction to the Gulf, most likely through the aquarium trade.

Aggressive feeders, red lionfish can reach lengths of over 17 inches and have threatened the health of coral reefs.

Source: Ashley Morgan-Olvera and the Texas Invasive Species Institute

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