This is a common plant of the Mojave Desert where, like many other plants, it has adapted to the water scarce ecosystem. With thick waxy coatings to its leaves to reduce loss of water through transpiration and thick roots to store water, this plant thrives in rocky slopes and mesas of the desert.
This is a low spreading plant of dry, rocky slopes in the Mojave Desert at Red Rock Canyon. It is well adapted to grow in the parched desert environment. As with other desert cacti, this plant’s leaves are spines. These thorny leaves have less surface area than broad leaves of deciduous plants. This reduces water loss to transpiration. Additionally, these spikes protect the plant from herbivores (plant-eating wildlife). Its many roots spread out to capture what little rain falls. Water is stored in the plant’s thick leaf pads which helps the plant remain viable during periods of dryness.
The Joshua tree, named by Mormon pioneers after their prophet, is the signature plant of the Mojave Desert. This is the only place in the world it is found. It is an evergreen plant that can reach a height of 40 feet and live for upwards of 200 years.
It endures the harsh, dry desert environment through several adaptations. When it rains in the desert, the upward reaching needle-like leaves direct the water to the main trunk into the soil where shallow roots absorb the water and the deeper tap roots store it.
The Joshua Tree has ways to reduce the loss of moisture from transpiration (evaporation of water from the plant). Any plant with needle-like leaves limits water loss due to a reduced surface area. The leaves also have a waxy coating that helps lessen water loss.
This resilient plant is indicative of how many desert plants survive the arid desert habitat.
In southwestern U.S. there is a region that receives less than 13 inches of rainfall annually with arid mountains and parched soils. It is the 25,000-square mile Mojave Desert. This desert has extremes in temperatures ranging from over 100 degrees in the summer to sub-freezing temperatures in the winter. The soils are arid with poor nutrients and little water.
This provides challenges to plants and animals that live there. Yet over 2,000 species of plants grow in this desert and many animals survive here including big-horn sheep, kit foxes and cottontail rabbits.
As Anne and I explored the desert within Red Rock Canyon we found hand prints imprinted in a canyon wall. These pictographs were proof that native Americans once lived here. At a nearby hotel that we stayed in present day humans live in the harsh environment with the help of modern conveniences.
As Anne and I traveled around Red Rock Canyon in Nevada, we saw immense gray carbonate mountains next to with the red sandstone hills.
At about the same time as the dinosaurs became extinct, 65 million years ago, there was a shoving match between two tectonic plates. The Pacific plate pushed under the North America plate along a fault line called the Keystone Thrust. This forced the older gray limestone carbonate layers up over the younger sandstone layers giving the area a profound contrast between the gray carbonate and the red and tan colors of the sandstone.
The Keystone Thrust is part of a series of fault lines that extend into Canada. These faults are areas where mountain ranges are born, earthquakes occur and volcanoes erupt. Geologic forces have shaped and continue to shape this area.
Millions of years of erosion have sculpted the mountains and canyon here at Red Rock. I feel miniscule compared to the eons of time that the landscape in front of me has been transformed. Will humans still be here millions of years from now? Or will we have the same fate as the trilobites and the dinosaurs?
During a recent visit to Las Vegas, my wife and I traveled a few miles west to the 196,000-acre Red Rock Canyon. Within the Mojave Desert, this area was once the ocean bottom 500 million years ago. This is before there were the current continents and at a time that the first fish appeared in the seas.
Between 180 and 190 million years ago during the time of the dinosaur, huge sand dunes formed in the southwestern deserts, lithified. Basically, the dunes became rock through this geologic process.
This resulted in Aztec Sandstone cliffs, 3,000 feet high. The red color outcroppings of these cliffs are made of iron oxide. Essentially, weathering has caused the rock containing iron to rust creating hues of red colors.
Anne and I walked down one of the trails leading to the cliffs. Upon closer view, we could see the striations of iron in the sandstone. It is hard to imagine that this was once the ocean floor.
At first glance it appeared to be dozens of tiny hummingbirds getting nectar from a large flowering bush in my neighbor’s front yard. Excited, I darted in the house to grab my camera. Once I got closer to the shrub it became apparent that these were not hummingbirds, but hummingbird moths.
These moths have plump bodies with the ability to hover over flowers just like hummingbirds do. Each moth flew from flower to flower, hovered and unfurled its long curled up proboscis to push deep into the blossom to siphon nectar.
Unlike most moths that are active in the night, the hummingbird moth flies by day and some are active at sunset. And unlike most moths that do not have any appendages to eat with, this moth depends on nectar to survive.
There are several species of hummingbird moths which are found throughout North America and many more found around the world. Two of the North American species are pictured here.