Tag Archives: Big Bend Ranch State Park

Places: Big Bend Ranch State Park’s Arroyo Mexicano

Big Bend Ranch State Park covers 311,000 acres of the Chihuahuan Desert.

Big Bend Ranch State Park: The Other Side of Nowhere

Big Bend Ranch State Park hugs the Mexican border and sprawls over 311,000 acres of the Chihuahuan Desert in West Texas. State park staff affectionately call it “The Other Side of Nowhere.” To the casual visitor, the park appears to be all rugged mountains, deep canyons, and miles and miles of rough roads designed to destroy your vehicle and shake the fillings loose from your teeth.

But those rugged mountains and deep canyons hold treasures if you’re a naturalist. The rough roads? They’re just a necessary evil if you want to experience the park.

Groves of cottonwood and ash trees line the bottom of Charro Canyon.

Cottonwood, Ash, and Oak Trees Line the Bottom of Chorro Canyon

I spend two days with Blaine Hall and Roy Morey exploring sites for a Native Plant Society of Texas field trip. Blaine aka “Big Foot” wears one shoe 3 sizes larger than normal to accommodate the brace and bandages that stabilize an ankle broken during a hike two weeks ago. Recently retired from his position as the interpretive ranger for Big Bend Ranch State Park, Blaine chatters away, teasing Roy and me, and pointing out geologic features as he skillfully guides the truck up rock-covered slopes, across ridges of limestone, and down sandy washes. He pulls over frequently so that we can enjoy the view.

Roy is quiet, not letting Blaine’s teasing phase him. Roy is a plant person. After retirement, he moved to Terlingua and began compiling photographs of the plants of Big Bend National Park. His hobby became a full-time pursuit, ultimately resulting in Little Big Bend: Common, Uncommon, and Rare Plants of Big Bend National Park. Once he completed that book, Roy shifted west and began working on a companion volume that will describe the plants of Big Bend Ranch State Park.

“I need to get up there someday,” says Roy, looking up at the sheer cliffs of a mountain. I’m surprised. Between Roy and Blaine, I would have sworn that they’ve walked every inch of the park’s 311,000 acres.

Today, we’re looking for unusual plants, so we head for Arroyo Mexicano, a box canyon that ends at Mexicano Falls. Canyons often harbor botanical treasures such as groves of cottonwood and ash trees and tiny plants that cling to the rock walls. Canyon walls protect plants from the harsh sun and fierce winds of the desert and often have seeps and springs that provide extra moisture. “One of the only mountain laurels in the park is up Arroyo Mexicano,” says Roy. “I hope it’s still alive.” It was.

An ammonite impression in limestone.

A Dinner-Plate Sized Ammonite Fossil in the Limestone

“Want to see an ammonite?” Blaine asks as we drive down Fresno Canyon. The creek has eroded deeply into the rock, exposing the flat-lying, flaggy Cretaceous limestone of the Boquillas Formation and the nobby, white limestone of the Buda Formation.

We pile out of the truck to admire the dinner plate-sized ammonite lying exposed on an upturned piece of Boquillas limestone. The thick limestones and this ammonite fossil are evidence of a time when a shallow sea covered part of Texas. You won’t see ammonites swimming around today. The last of them went extinct when a giant meteorite struck the earth about 66 million years ago. The short and long-term effects of the meteorite impact—wildfires, tsunamis, and clouds of debris that blackened the skies and blocked the sun for years—killed about ¾ of Earth’s plants and animals.

A Mexican Buckeye Provides Nectar for Pollinators

Mexican Buckeye Tree on the Edge of the Arroyo

We eventually arrive at the mouth of Arroyo Mexicano, shoulder our packs, and trudge our way up the canyon. I’d like to say that we hiked briskly, but I have to admit that I’m a trudger in soft sand. Fairly quickly, we see pools of water and a shallow stream meandering its way across the sand bottom. Groves of cottonwoods, their new leaves a beautiful, fresh spring green, provide shade along the way.

Occasionally a spot of pink reveals the location of a Mexican buckeye tree. These early-blooming shrubby trees are an important source of nectar for bees and butterflies. A Mournful Duskywing flits between flowers, ignored by a nectaring Grey Hairstreak. I search unsuccessfully for a Henry’s Elfin—a small brown and silver butterfly that uses Mexican buckeyes as a host plant. Henry’s Elfins are more common in the eastern United States, so seeing one in West Texas is pretty special. Roy and Blaine have moved on, so I quit looking for butterflies and hurry to catch up.

Huge velvet ash trees with their gnarly roots exposed.

Velvet Ash Trees in the Arroyo

As we move up the canyon, we walk under large velvet ash (Fraxinus velutina) trees. I am fascinated by the texture of the bark and the thick, gnarly roots wrapped around giant boulders. Of course, the exposed roots are also a warning sign. This canyon carries water—often with enough force to roll boulders and wash away enough sediment to expose the roots of trees. I check out the sky (gray clouds gathering) and look for high ground. The vertical walls of the canyon look back. I’m doomed.

Conglomerate boulder made of smaller, rounded, igneous rocks.

Volkswagen-sized Conglomerate Boulder in the Arroyo

In places, we skirt boulders the size of Volkswagon Beetles or larger. I envy Blaine his ability to read these rocks. “See,” he says, “this rock is made up of older rocks that have been cemented together to form a conglomerate.” This particular conglomerate is just a baby rock if you can wrap your mind around geologic time.

All of the “clasts” or smaller rocks that make up the conglomerate are volcanic in origin which means they were deposited about 27 million years ago. Over time, they broke away from their parent rock, were tumbled and smoothed, and came to rest in one place long enough for the white matrix rock to cement them all together again. The conglomerate eventually broke up, and Volkswagon-sized boulders tumbled down the slope, coming to rest in the stream bed.

Fern-covered walls and plunge pool of Mexicano Falls

Mexicano Falls at the End of the Arroyo

After about 3.5 hours of walking and stopping to admire rocks, plants, and scenic views we reach the end of the canyon. At this time of year, Mexicano Falls is more of a drip than a fall. Maidenhair ferns, yellow-flowered columbines, and thick carpets of moss fill the cracks where water seeps from the rocks. The plunge pool is thick with green algae.

Blaine points to a gap in the canyon rim where water funnels through to create a waterfall during the summer rainy season. I’d love to be there to see the waterfall, but then I remember those exposed roots and the flood debris wrapped three to four feet high up the trunks of the trees that we were walking through earlier. Flash floods are real and dangerous in this canyon.

The tiny, yellow, fringed monkeyflower hangs from the wet walls of the canyon.

Fringed Monkeyflower Hangs from the Wet Walls of the Canyon

While Blaine and I photograph the ferns and columbines, Roy walks the face, scouring the seeps for fringed monkeyflower (Mimulus dentilobus). “Found it!” he calls. Fringed monkeyflower is a rare plant in Texas, found only in places where water drips from the West Texas mountains. I’m surprised by how tiny it is. The bright yellow flower with its fringed petals and red spots in its throat rises above a mat of small leaves hugging the wet rock face. We’re lucky to find these in bloom. It’s only March and according to the field guides, fringed monkeyflower blooms from June to August.

Blaine and Roy fix a flat tire.

Flat Tire

The wind begins to blow, and the clouds build, getting thicker and grayer. We decide to return to the truck before a storm drenches us. The hike back takes about 2.5 hours. We quickly pack up and drive off, but Blaine stops almost immediately. He walks around the truck and discovers a flat tire. “That’s two this week,” he mutters. Razor-sharp rocks can slice through the sidewalls of a tire and mesquite thorns pierce treads easily. We unload all the gear to access the spare, and Blaine and Roy begin the laborious task of changing the tire. Fortunately, nothing goes wrong and within 30 minutes we’re back on the road. We eliminate a couple of side trips and head straight back to the park headquarters at Sauceda. Driving any further than necessary without a spare is foolish.

The flatirons of the Solitario provide a perfect backdrop for a patch of Big Bend Bluebonnets.

Big Bend Bluebonnets and the Solitario

Since Blaine and Roy have the flat-tire situation in control (and they’re a bit annoyed with my photographic documentation of the event), I wander off a few feet to photograph a patch of Big Bend bluebonnets with the flatirons of the Solitario in the background. The Solitario is a massive igneous dome created when molten rock pushed up the flat-lying rocks above it creating a circular feature 10 miles in diameter. The dome attracts geologists, botanists, and naturalists from around the world and is probably the most famous feature in Big Bend Ranch State Park.

I love going to the Solitario, but this opportunity to explore Arroyo Mexicano with Blaine and Roy was as close to perfect as a day could be.

Posted in Chihuahuan Desert, Geology, Plants, Texas Also tagged , , |

Chihuahuan Desert Ferns

Cheilanthes fern, Fort Davis National Historic Site, TexasNormally, I’m outside every day in September enjoying the cooler temperatures, brilliant sunshine, and abundant life inspired by the afternoon thunderstorms of the monsoon season.

But not last week.

Rain (torrential at times), heavy cloud cover, and temperatures in the low 50s kept me huddled in the house muttering about the imminent arrival of the next Ice Age. As I stared morosely out the window, watching the rain drip from the roof, I began to wonder: What happens to the butterflies, bees, and bugs when the temperatures go from warm and dry to cool and wet in a single day?

Thinking this was the perfect subject for a blog (I’m sure you’ve all been dying to know), I donned my rain jacket, grabbed my camera gear, and wandered through the mist to the Fort Davis National Historic Site. Although chiefly known for the 19th century fort buildings, they also have a wonderful nature trail that loops from the fort site, up the ridge that separates the Fort from Davis Mountains State Park, and back down again. Here, I was sure I would find my sleeping bugs.

I probably would have, too, if I hadn’t gotten distracted. Every place I peered and poked for insects, I was confronted by ferns. Beautiful, lush, green ferns. The magic of desert rain.

Dancing Bommeria, a Chihuahuan Desert fern, growing near Fort Davis, Texas.Most people don’t hot-foot it to the desert to look for ferns. But perhaps they should. According to botanists Sharon Yarborough and Mike Powell, there are 64 different types of ferns that grow in the Trans-Pecos region of Texas.

Ferns can grow in the desert because they’re experts at finding little microhabitats that are just a tinier bit wetter than the surrounding landscape. Look for them growing from cracks in the rock, under the shelter of a tree, or peeking out from beneath a boulder. Depending on when you look, though, you may not be overly impressed. In fact, during most of the year, desert ferns are brown, crispy, and look—well—dead.

Chihuahuan Desert ferns dehydrate during the warm, dry months and wait for rain.But fear not! Playing dead is just one of the many adaptations that ferns have for surviving in the desert. And what an adaptation it is. Your average plant can drop to about 75% moisture content before it begins to wilt and beg for water.  Creosote, one of our common desert shrubs, can lose about half its moisture before it begins to look a bit peaked.

But the ferns. Oh, the ferns. They are the masters of dehydration. During the dry season, some species can desiccate to less than 6%—or as dry as many seeds—but begin to green up, unfurl, and grow within an hour after a refreshing rainfall. When it dries up again, so do the ferns.

But ferns don’t give up their moisture easily. They may be able to survive as a brittle frond, but life is better when you’re green and photosynthesizing. So to stay green as long as possible, the ferns (and many other desert plants) have ways to reduce moisture loss.

Small Leaves

Small Leaves

Waxy Coating

Waxy Coating

Protective Hairs

Protective Hairs

Thickened Leaf Margins

Thickened Leaf Margins

Small is better. Most desert ferns are much smaller then their rainforest cousins. Remember that during the process of photosynthesis the plant takes in carbon dioxide and releases oxygen and water as a waste product. The smaller the leaf, the less water is released.

Be waxy. Most water is lost (transpired) from special cells on the leaf called stomata. These open and close to absorb and release gases (carbon dioxide, oxygen, and water). But other parts of the leaf surface and stem can lose water through simple evaporation. To help protect from this “incidental” water loss, many of the ferns have a cuticle of waxy deposits on the leave surface that make them thicker and seal in the water.

Get hairy. Have you noticed how many ferns are grey and fuzzy? If you look closely, you’ll notice that the color is due to a dense coating of hair. These light-colored hairs serve a couple of purposes. First they reflect light making the leaf surface temperature cooler and they efficiently trap rain, dew, and other forms of moisture to raise the humidity around the leaf surface. Keeping the air surface immediately around the leaf cooler and more humid reduces the evaporative demand from the atmosphere.

Thick leaf margins. The last defense against moisture loss is the ability of the leaflets to roll, thus protecting the surface and the spores. Many fern leaflets have thickened margins that enhance the ability of the leaf to roll.

Not all ferns found in the desert have these adaptations for dry conditions, though. Others simply seek places where there is enough moisture. Delicate maidenhair ferns, for example, can be found on many shaded rock faces with perennial seep springs. You can find these beautiful ferns at the bottom of Modesta Canyon at the Chihuahuan Desert Nature Center or in the grotto at Ojito Adentro, Big Bend Ranch State Park.

Water Clover (Marsileaceae) is a Chihuahuan Desert fern that grows in puddles during the rainy season.But my favorite fern is the water clover. This aquatic fern survives the dry season as a packet of spores (sporocarp) in the mud of ephemeral pools. When the rainy season arrives and the pools fill with water, the gelatinous interior of the sporocarp swells, rises to the water surface and splits, releasing the male and female spores. Once they do what males and females do, the newly fertilized embryo sinks to the bottom of the pool, takes root and begins to grow, eventually spreading its four leaflets across the surface of the pool to begin the cycle of life again.

It’s starting to rain. Time to go look for ferns!

Posted in Chihuahuan Desert, Plants Also tagged , , , |