Nature Notes: Where the Great Plains Meet the Mountains: the Native Grasslands of West Texas

The West Texas grasslands are a sight to see. In autumn, the golden expanse of the Marfa Plain or the Diablo Plateau shines beneath a brilliant blue sky, to dazzling effect. The grasslands are also a foundation – central to the region’s ranching industry and to native wildlife. And, in much of the Trans-Pecos, 2016 was an outstanding year for grasslands.

In 2011, Texas witnessed an unprecedented drought. The hardiest of plants – lechuguilla, prickly pear – withered and died in desert lowlands. West Texas became a tinderbox, and the Rock House Fire burned 300,000 acres of the Marfa Plain and Davis Mountains.

But in 2016, monsoon rains transformed the landscape – particularly the Trans-Pecos grasslands.

Dr. A Michael Powell is a distinguished professor emeritus at Sul Ross State University. One of the region’s leading botanists, he’s the author of Grasses of the Trans-Pecos and Adjacent Areas.

“It was dry, extremely dry, until about mid-summer,” Powell said, “and then it started raining, with spottier rains, and they sort of kept up, and it was apparently just what grasses needed. This is an exceptional year for grasses. It’s the best I’ve seen since I’ve been in this country myself, which is over 50 years.”

Our region is a threshold, a crossroads. Here, the Great Plains – which awed early settlers as an “ocean of grass” – reach an arid limit. The grassy sea has broken against desert and spilled over into mountain basins.

From Texas to Arizona and northern Mexico, the Chihuahuan Desert’s high valleys have historically sustained rich grasslands. They’re often referred to as desert or semi-desert grasslands.

Powell makes a different distinction. At elevations between 4,000 and 5,200 feet, the mix of grasses is similar to those found on Nebraska or Kansas plains. These grasslands are an extension of the Great Plains into the mountains, Powell said.

“The concentration of species is approximately the same – speaking of grasses now – as in the mid-grass prairie in the Great Plains country,” he said. “Most of the species that are characteristic of that also comprise the grasslands say, on the Marfa Plateau – those great, beautiful grasslands, that are still magnificent, as a matter of fact.”

Muhlenbergia – muhly grasses – are the most widely represented in terms of species numbers. But the dominant native grasses are of the genus Bouteloua – the gramas.

“The nutritional aspect of these grasslands is based mainly on blue grama and sideoats grama,” Powell said, “and to an only slightly lesser extent, black grama. In most of the alluvial fill, the more or less flat, fairly deep soil alluvial basins of the mountains, is where we have blue grama and sideoats grama.”

These Trans-Pecos grasslands are similar those that once blanketed the Midland-Odessa area, and sustained the Llano Estacado’s vast bison herds.

Powell said there is a second type of Trans-Pecos grassland – a true desert grassland. Below the high plateaus, at elevations of 3,500 to 4,000 feet, the mix of grasses changes. The dominant grass is chino grama.

West Texas grasslands were transformed by the Anglo settlement. Beginning in the 1880s, in the first rush of settlement, ranges were heavily stocked with cattle. As grasses were denuded, soils eroded away. Plants adapted to rocky soils – mesquite, creosote, prickly pear – spread into former grasslands.

Cattle producers recognized the problem as early as 1900. They sought drought-resistant grasses to revegetate. Grasses native to Africa and Asia – buffelgrass, Lehmann’s lovegrass and King Ranch bluestem – were introduced in the Southwest.

They did stabilize soils. But in some places, they’ve largely displaced natives.

“Let’s take a trip from Alpine to Odessa-Midland,” Powell said. “Once we get out of the mountains toward Fort Stockton and then past Fort Stockton on some of those roads that lead to Midland-Odessa, one can see a band of this King Ranch bluestem about 6 feet wide from the pavement – and then it’s replaced by Lehmann’s lovegrass for the rest of the way and out in the pasture. And these are introduced species. That’s how they spread.”

Non-natives are spreading in the Trans-Pecos. There’s no easy way to slow their progress. And the effects of climate change may accelerate the “desertification” of grasslands. But the Trans-Pecos still contains some of the country’s most intact native grasslands. In a year like 2016, they shine with their ancient glory.

Nature Notes is underwritten by the Dixon Water Foundation and is produced by Marfa Public Radio in cooperation with the Sibley Nature Center. This episode was written by Andrew Stuart.

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