From Indian deserts to Joshua tree: A journey into a fragile ecosystem

I have visited deserts in India, one of them being the Rann of Kutch, which is home to the rare wild ass. It has an ecosystem of its own. The vast expanse of the Rann is mostly barren, with wild asses moving around in groups. There are a few bushes and scattered patches of water bodies. I have travelled across the Rann not once, but half a dozen times.

Another desert I have visited is near Jaisalmer in Rajasthan. It is a vast, barren, sandy landscape where tourists come during winter to experience the desert—riding camels and taking jeep rides in heavy vehicles capable of navigating the sand dunes. I found very little vegetation here, almost none at all.

Now, while staying in Los Angeles, we planned a trip to Joshua Tree National Park, and I found it remarkably different from the deserts I had seen in India.

The Joshua trees are wild, twisted plants, with thick trunks and green clumps of leaves at their tops. Their crooked arms reach out in all directions, almost as if they are dancing. Amid these trees, each separated from the next by several metres, wild bushes grow everywhere.

It took us more than two hours to reach the park by car. When we left Los Angeles at around 9 in the morning, the temperature was around 25 degrees Celsius. But as we approached the gates of the national park past 11 a.m., we realised that the heat was far more intense than what we had experienced during summer in Ahmedabad. The temperature had reached 40 degrees. As our car entered the park and we drove deeper inside for another hour, it climbed to nearly 44 degrees.

Yet, despite the scorching heat, at several places we decided to get out of the car to look at the interesting rock formations. The rocks appeared to have been sculpted by the harsh forces of nature, their edges softened over thousands or perhaps millions of years until they became almost semi-round. Some formations looked so delicately balanced that they seemed as if someone had carefully placed one rock on top of another.

What struck me, unlike my experiences in the Indian deserts, was the amount of information provided to visitors. At several locations, explanatory boards described how old the rock formations might be, how they were formed over thousands of years, how the Joshua trees survived in such an extreme environment, and why these remarkable trees are found in this particular region.

From these explanatory boards, I learned that the national park holds immense ecological significance because it protects a major ecosystem transition zone where two distinct North American deserts meet, creating an important habitat for wildlife.

The park covers more than 800,000 acres. One part lies within the Mojave Desert, where Joshua trees dominate the landscape, surrounding what are known as massive monzogranite rock outcrops. The other part belongs to the Colorado Desert, which contains the remarkable Cholla Cactus Garden.

The relationship between the Joshua tree and the Yucca moth is particularly fascinating. The Joshua tree is pollinated exclusively by the Yucca moth. In return, the moth lays its eggs in the flowers, and its larvae feed on a portion of the developing seeds. The relationship is so closely intertwined that without the moth, the Joshua tree cannot reproduce sexually; without the Joshua tree, the moth cannot survive.

Despite the severe drought conditions, the park also contains oases—natural springs created by fault lines. These springs support lush groves of vegetation and create microclimates that are critical for birds, amphibians and mammals living in the desert.

The park also provides a protected refuge for threatened species, including the desert tortoise and desert bighorn sheep, as well as more than 250 species of resident and migratory birds.

Impact of Climate Change 

But the Joshua tree faces a serious threat from climate change.

Researchers say that Joshua trees are extremely sensitive to rising temperatures, prolonged drought and changes in winter rainfall. The park therefore serves as an important outdoor laboratory for studying the effects of climate change on desert vegetation and for tracking how species respond to environmental stress.

Climate change poses an existential threat to the Joshua tree within its namesake park. Although mature trees may appear resilient in the short term, changing climate patterns can disrupt every stage of their life cycle.

Predictive ecological models, including studies associated with UC Riverside and the National Park Service, indicate that under high-emissions scenarios, as much as 90–99 percent of suitable Joshua tree habitat in the park could be lost by 2100. Even under moderate warming scenarios, the habitat could shrink by around 80 percent.

Mature trees can store water and endure prolonged dry spells, but young seedlings are far more vulnerable. In the warmer, lower-elevation areas of the park, scientists have observed virtually no seedling survival. This raises a disturbing possibility: as older trees die, there may be no younger trees to replace them.

Fire is another growing threat. Historically, fires were relatively rare in this sparse desert environment. Today, however, warmer conditions combined with invasive non-native grasses such as red brome create continuous fuel across the desert floor.

Joshua trees are poorly adapted to high-severity wildfires. Large numbers of trees across the Mojave Desert have been destroyed in major fires in recent years.

The human history of Joshua Tree National Park stretches back at least 10,000 years. It includes prehistoric hunting cultures, Indigenous trade networks and, later, miners, ranchers and homesteaders who arrived during the 19th and 20th centuries.

The park area was once home to two particularly lucrative gold mines—the Desert Queen Mine and the Lost Horse Mine. These mines generated millions of dollars in wealth for their owners and left behind heavily scarred hillsides, abandoned mine shafts, stamp mills used to process ore and structures reminiscent of ghost towns. Many of these remnants still stand today, preserved within the park.

As non-Indigenous settlers moved westward in the late 19th century, cattle ranchers began driving herds into the high-desert valleys, where seasonal grasses grew after the winter rains.

Ranchers built small dams and modified natural rock depressions to trap rainwater for their livestock. But overgrazing eventually depleted the fragile desert ecosystem, and most cattle operations had disappeared by the middle of the 20th century.

The Cholla Cactus Garden

Deep inside the park, we moved towards the Colorado Desert area and came across another remarkable landscape—the Cholla Cactus Garden.

The garden is dominated almost entirely by one species: the teddy bear cholla cactus. These cacti are concentrated here because the local conditions are particularly favourable for them to thrive and multiply.

What fascinated me was the way they reproduce. They can grow from detached stems that take root in the ground and develop into new plants. These detached stems are often too heavy for the wind to carry very far. As a result, new plants tend to grow close to the parent plants, gradually creating a dense colony—the remarkable landscape known as the "garden."

The history of protecting this extraordinary landscape is also interesting.

During the 1920s and 1930s, cactus poaching, urban expansion and other forms of desert vandalism were increasingly threatening the region. Minerva Hamilton Hoyt, a California socialite and passionate lover of plants, led an intensive campaign to protect the desert's unique flora and fauna.

Her efforts eventually helped persuade President Franklin D. Roosevelt to establish Joshua Tree National Monument in 1936. Nearly six decades later, in 1994, the area was officially designated Joshua Tree National Park.

Standing there in the intense heat, surrounded by twisted Joshua trees, strange rock formations and vast stretches of desert vegetation, I found myself thinking about the three deserts I had experienced.