Habitats of the Llano Estacado
Alkaline Soils
Photoessay: Scenes from a Salt Playa
In early October of 2007, many salt lakes on the Llano Estacado contained water. Much of the year had been rainy. Pastures were full of grass seeded out. The rain had brought an explosion of insect life, especially grasshoppers. As a person walked along, a dozen grasshoppers skittered away with every step.
Click on each image to see a larger version; use your browser's "Back" button to return to this page.
Every day clouds formed as the heat of the sun evaporated the water in the soil and the salt lakes. Over 100 species of wildflowers were in bloom along the roads, including the annual sunflower.
Wintering ducks were far in the future - in fact, by November, when they usually begin arriving, most of the salt playas had dried up - no rain fell after late September.
Camphor daisy bloomed strongly. If a person sniffs the leaves, it smells like medicine - and if you crush the leaves, it will clear up a stopped up nose. Beyond the camphor daisies, the pattern of run-off rain water left its trace in the salt lake basin's mud above the water line.
Alkali sacaton grass retained its vibrant green, while the pickleweed's leaves had turned brownish red. Bluestem grass waved white spires of seeds.
A young salt cedar added texture on the slope leading to the salt lake. Some salt lakes become choked with salt cedar, but this particular one has few, despite over 20 years of aggressive spreading of the species.
The closer a person comes to the water edge, the more prevalent the pickleweed becomes. Pickleweed grows closest to shore, then the alkali sacaton, and above the sacaton, other species of grasses and plants become more prevalent. This "zonation" probably reflects the level of alkalinity of the soil. Pickleweed grows in soils of 9 p.H., while alkali sacaton may not be able to exceed levels of 8.5 p.H. Every time it rains, more soil from the uplands is washed down the slopes of the basin of the salt lake. An extraordinary rain event might wash soil even further down, and cause the zonation to fluctuate, but this salt lake has retained these areas of zonation for years.
The white soil "loess" is the salty silty soil blown out of the playa. It is usually found to the north and east of salt playas. Mesquite establishes itself in the older loess, and one older salt cedar is visible on the slope as well, where rainwater collects often enough to support its growth. Some of the mesquites have died over the years - probably during periods of drought.
A closeup of the slope reveals details of the above.
One of the grasses of the slope is fall witchgrass. As the seed panicles mature, they detach and begin to soar on stronger winds like miniature parachutes, floating along a few feet above the ground, until caught by mesquites and fences. Bluestem grass and its white seed panicles poke up through the witchgrass drifts.
Some mesquite near the playa has grown to reach a height of 15 feet or more because it is able to capture some of the rainwater as it rushes down to the playa.
Grasshoppers are grazers, and in large numbers compete with other grazers, such as cattle. Go to this essay on grasshoppers and kingbirds to learn more about grasshoppers.
If a grasshopper is caught and held in a closed hand for a few minutes, it will remain on your hand when you open it up. The Sibley Nature Center staff is recording the grasshopper species of the region. After many hours of research in books, it is estimated that around 75 species of grasshoppers might live in the region. Grasshopper identification is difficult, for many species are very similar, and can only be identified by examining the adult male genitalia. As grasshoppers mature, they often change color, and there is color variation even among the adults.
Mating grasshoppers were everywhere. Some species "lek" with dozens of males surrounding a few females. Other species, when the population has grown to abnormal numbers, find mates among the "carpet" of living grasshoppers.
In some shallows of the playa, green "chara" algae filled the water - an unusual sight, but one that indicated that the water was still "sweet" enough for plants to grow (neutral p.H. (7.0 or a little above.) In the chara was a burying beetle that had drowned when it had accidently landed in the water.
A number of lady bugs were also found along the edge of the playa. When rain falls and plants grow, aphid populations explode, and so do lady bug populations. Some of the lady bugs are blown close to the shore of the playa and land on a person walking along.
As the water in the playa receded in the region with the chara, some of the chara had died and dried out. A wolf spider scooted along the chara, looking for once aerial prey that might have descended when the winds died down.
One wolf spider carried its egg sac. When disturbed it hid under a mesquite branch that had washed into the playa and later been left "high and dry."
On a fence post, a strange long-legged spider rested on the shady side of the fence post.