The downfall and comeback of the Texas horned lizard

August 6, 2015December 11, 2015 / Rowdy / 2 Comments

Texas horned lizard. Horny toad. Horned frog. These are all common names for the same creature, Phrynosoma cornutum. Texas horned lizard is perhaps the more “correct” common name, but for some people, this lizard will always be whatever name they grew up calling it. This lizard brings on strong opinions; it seems like everyone I have met believes their name for it is the best name, and everyone seems to love the actual animal. Many people older than perhaps 25 remember playing with them as children, and have noticed that they no longer see horned lizards around.

Most people have heard that horned lizards populations have greatly declined in Texas. Texas Parks and Wildlife, The Horned Lizard Conservation Society, the Forth Worth Zoo and others have done an excellent job educating the public about the decline of the horned lizard in Texas; however, there are two problems in this situation:

Information gets diluted

Horned lizard conservation efforts are getting good press today, and now anyone who has ever read anything about horned lizards shares that in the comments sections of these stories. Some of this information is helpful and some of it is… less than helpful. It can be difficult to pick out what someone has actually learned from science and what they have picked up from something their great grandfather told their father, who told it to him. I do not mean to take anything away from the wisdom of grandfathers, but in some things conditions change over time, new information is learned, and honestly, not everyone’s grandfather is wise.

The case is not closed

While we have a better understanding of what has led to the decline in horned lizards new research is constantly being conducted. Some of the research supports what we have suspected and some of it indicates that we still have a lot to learn about such a popular animal. For example, during a seminar about horned lizards I attended we were all told that horned lizards will very rarely (nearly never) feed right at the entrance of an ant colony and we should concentrate our search efforts along ant trails instead of the colony. Since then I have had the opportunity to work with horned lizards in a professional capacity and have observed horned lizards feeding on ants at the colony enough times I am unashamed to disregard that suggestion.

So, what did happen to them?

As, I mentioned above, there is still work happening to figure that out, and while we may never know exactly all the details, we are are fairly sure that it was no one single event or thing that triggered the decline in horned lizards. Let’s take a look at some of the factors

Fire ants

Harvester ants

In the 1930s an invasive species (actually several species) of ants from South America were introduced into the United States along the coast of Alabama due to shipping traffic. It wasn’t until the 1950s that these ants first entered Texas. Since then they have steadily spread north and west covering much of the state. Fire ants are probably the most well known suspect when it comes to the demise of the horned lizard. There is just one problem with that: There are areas of southern Texas that have had fire ants for decades and did not lose their horned lizards. Certainly, fire ants have had an impact; however, it is likely our response to them that made the greater impact.

We went to great lengths in our attempts to eradicate the fire ant, and our careless use of poison likely caused a great decline in the red harvester ant. The red ant is a main (but not only) food source for the Texas horned lizard, and killing them is a sure way to remove horned lizards from an area.

Habitat fragmentation

During the same time we were killing the red harvester ant by mistake we were also destroying habitat. In the last 30 years Texas has experienced a surge of urban building. Today more than 80% of Texans live in the city, and the cities have grown, which removes horned lizard habitat. Horned lizards need open (but not too open) ground, preferably with bunch grass and low thorny shrubs to protect against predators. The short and dense turf grasses planted on most yards are not suitable.

Habitat degradation

In the city

Many homeowners love the dense turf mentioned above and will use a large number of insecticides to keep it thick. This leads back to the ant issue. This habitat degradation also has happened outside of the cities.

In the country

Cotton and wheat, while vital crops to the local economy form large monocultures that provide little shelter some of the year and no shelter after harvest and the same pesticide issues are present as well. In pasture lands, overgrazing has been identified as a problem.

Lands placed in the Conservation Reserve Program (CRP) were allowed to grow too dense, displacing horned lizards. While one would think lands removed from agricultural production would be good for horned lizards; however, it is possible to preserve it “too well.” Rachel Granberg’s work suggests that prescribed fire is needed to keep grasslands from becoming too thick.

What is the Conservation Reserve Program?
CRP is a program which will pay long term rent (10-15 years) on ecologically sensitive lands if the landowner will take it out of production and take actions to protect it, such as planting native grasses. This has greatly helped with erosion, water quality and wildlife habitat across the country

The times, they are a-changin’

After decades of decline, we may be poised to see a comeback of the Texas horned lizard in Texas. Many of the culprits I discussed above are still present, but we are as a culture moving away from large scale insecticide use in some areas, partly from education and partly from the environmental laws passed in the 1970s. We are also learning that prescribed fire is not evil, and grazing practices are becoming more refined every decade.

In some areas people are starting to see horned lizards again, but in other areas, it may take a bit of help to bring them back. Texas Parks and Wildlife started a reintroduction study last summer to investigate the viability of releasing wild-caught lizards into areas they were known to once roam. It is too early to know the results, but people are hopeful.

While the observations of lizards returning is only anecdotal at this point, between that and the possible reintroduction in other areas by TPWD, we stand a good chance of seeing horned lizards making a comeback in Texas. This recovery hinges on Texans continuing to follow good practices, and to extend them to other areas, such as xeriscaping portions of their yards.

Mexican ground squirrel

August 5, 2015August 5, 2015 / Rowdy / 1 Comment

In a park near you

The mexican ground squirrel is a rather small squirrel Texans most often see in open park areas darting through the low grass to suddenly disappear. Their burrows are often just holes in the ground without any noticeable mound around it. The ground squirrels in the above photo are grouped around one such hole.

These interesting little squirrels tend to excavate more than one entrance to their tunnels, so that a predator (or blog writer) lying in wait over one entrance may be unaware of an audience behind him.

Despite the feature photo above, mexican ground squirrels are often solitary creatures which will usually evict any other ground squirrels that attempt to share the same area. The above photo is an example of one of the more rare times that they will live in a colony setting. They spend the first part of the year eating plants, but in truth, mexican ground squirrels are omnivores; they will eat insects later in the year, and even meat if it is available.

Prairie dog, not a ground squirrel

They are often the most noticeable small mammal in parks in west central Texas; however, they are sometimes mistaken for the much larger prairie dog. The prairie dog has long been in decline in this part of the state, and many urban residents have never seen a prairie dog in person, so it is not unthinkable that there may be some confusion.

Prairie dogs are large bodied and do not have spots while mexican ground squirrels are slender and have nine rows of white spots on their back. Also, note the difference below between the burrows:

prairie dog

not a prairie dog!

Explore your Neighborhood

So, where is the best place to find nature? In your neighborhood! When we see amazing nature photos or videos we often think of those images being from out there; someplace far away and too rugged for use to actually see ourselves. Truth is that there is plenty of nature to experience in your backyard, down your street, and in your local park. Often we are moving too fast to notice or appreciate it, but I promise you, it is there.

This post is the first in a new series titled, “Explore your Neighborhood,” in which I’ll share with you a few of the great bits of nature that can be found by most urban residents.

A scalping at Fort Phantom

August 3, 2015August 4, 2015 / Rowdy / 1 Comment

Sunset at Lake Fort Phantom

In my previous posts I mentioned the three reservoirs which supply Abilene’s water, what it takes to fill them up, how that water gets to the lakes, and what happens to that water when we’re finished with it. There is one last source to talk about and that is the Clear Fork of the Brazos River, which is a tributary of the Brazos.

As you can see, the Clear Fork of the Brazos passes very close to Fort Phantom Lake, but does not fill it. Wouldn’t it be great for Abilene if it did? Apparently, over 65 years ago, someone thought so, because in 1950 construction began on a diversion dam across the Clear Fork of the Brazos near Fort Phantom Lake. This was nearly 20 years after the dam for the lake was built.

Pumps at the diversion dam “scalp” some of the water from the river and divert it into the lake. Permits dating from 1949 indicate that the City of Abilene was originally authorized to divert 30,000 acre-feet per year. That is approximately 9.7 Billion gallons of water! I reached out to Howdy Wayne Lisenbee, Assistant Director of Water Utilities for the City of Abilene and Mr. Lisenbee confirmed that the city is still permitted up to 30,000 acre-feet per year.

The diversion dam and pump station.
Aerial photography courtesy Rocky White

There are conditions that have to be met before that water is allowed to flow. First, it has to rain on the upstream watershed of the Clear Fork of the Brazos. Once the water is flowing, the city of Abilene is obligated to allow 600 acre feet of water through the dam for downstream users, and must allow some water to flow through the dam while they are pumping. Many Abilene residents show frustration when the City of Abilene does not pump water from the Brazos after a rain, but we are under legal and ethical obligations to let people downstream from us have some of the water.

How does it happen?

When the conditions mentioned earlier are met, water is impounded behind the dam shown in the lefthand side of the above photo. Eight pumps (located on the righthand side of the same photo) push the water a little over 300 yards through a pipeline into Fort Phantom Lake. Of the eight pumps, five are 1,500 horsepower and are capable of moving roughly 100 million gallons per day. the other three, while smaller, are not lightweights: they are 1,000 hp and can pump 50 million gallons of water per day! If all of these pumps were running at the same time it would be possible to fill 984 olympic sized swimming pools in a single day.

Due to permit restrictions and maintenance reasons, usually only a few pumps are utilized at any one time. If during a pumping session one pump were to break pumping could continue with the other pumps. Mr. Lisenbee stated that during the scalping in May the city used a combination of two to four large pumps and a couple of the smaller pumps to add 651 million gallons to Fort Phantom reservoir over the course of three days.

The pipeline which carries water from the Brazos to Fort Phantom Lake

Aerial view of Brazos diversion pipeline. Water flows straight up from this pipe.

What is an “acre foot?”

An acre foot is the amount of water it would take to cover an acre of land (43,560 square feet) with 12 inches of water.

Once the water reaches the end of the pipeline it flows straight up out of the large pipe shown on the right.

This water comes roaring down the into the lake:

The same type of scalping occurs on a smaller scale on the east side of the lake. In 1954 the City of Abilene acquired a permit to divert up to 3,000 acre-feet of water per year from Deadman Creek when conditions allow. In return for this use Abilene is obligated to release a certain amount of treated wastewater back into Deadman creek.

Same as it ever was

This additional water security did not come easily for the citizens of Abilene. Before the Clear Fork of the Brazos diversion dam was even completed landowners downstream began to complain and seek legal action. According to articles from the Abilene Reporter-News from the 1950s, an argument raged between Abilene and the landowners near Albany throughout the ’50s. These battles echo the new arguments over some of Abilene’s projected water projects.

As the population of the area grows and as climate change continues to alter our landscape, these arguments over water will also continue. In my final article on Abilene water I will explore what the search for new water in the past was like as compared to the searches in our near future.

instante mense

things of interest in this month

Month: August 2015