Joshua Trees: Trapped in a Crucible of Climate Change

Southern California’s iconic Joshua trees may be an early casualty of climate change as their desert home continues to heat up.

“It’s the Joshua tree’s struggle that gives it its beauty.”

— Jeannette Walls

In a habitat as inhospitable as the Mojave Desert, the driest desert in North America where temperatures can soar above 120 degrees, plants and animals often need each other to survive. Nowhere is this natural teamwork more apparent than in Joshua Tree National Park, where the namesake Joshua trees rely on a relationship with a symbiotic moth. However, the park’s changing climate is straining this vital relationship.

A study from 2018 found that Joshua trees are being forced to move to either higher altitudes or farther north as temperatures continue to increase. This raises the logical question of how will these trees move? Trees and other plants move in groups, often with the aid of wind or animals to help disperse their seeds to new areas.

One of the early “vehicles” of seed dispersal was an animal you would never expect to find in such an inhospitable environment. Until 11,000 years ago, Shasta ground sloths lived in these deserts, feasting on the fruit of the tough Joshua tree, all the while ingesting the plant’s seeds as well. While the shaggy ground sloths moved across the southwestern deserts (probably at a similarly slow pace to their living relatives), they would drop the Joshua tree seeds in heaps of dung, some of which have been found fossilized with almost intact seeds. The bear-sized sloth probably succumbed to human hunting-induced extinction, which removed an important seed disperser for the Joshua trees.

A Shasta ground sloth skeleton on display at the La Brea Tar Pits Page Museum

Relatively intact remnants of Joshua trees found in Shasta sloth dung preserved in Gypsum Cave, Nevada.

Shasta sloth dung preserved in Gypsum Cave, Nevada!

But the Joshua trees have been able to survive the disappearance of the ground sloths thanks to another mutualistic relationship (a relationship between two species where both benefit) with the yucca moth. These moths help the trees by pollinating their flowers and the tree returns the favor by offering the moth’s offspring food and shelter in their developing seeds. Adult yucca moths are selfless, lugging (relatively) large balls of pollen from tree to tree before promptly dropping dead. Only their offspring will reap the rewards of eating through the Joshua tree seeds before returning the favor themselves as adults in a cycle that has worked for eons.

The 2018 study examined this relationship throughout the park, finding that Joshua trees were healthiest in the areas where the moths were abundant. More moths makes it easier for the trees to reproduce, but will the two species be able to maintain this relationship as the Joshua trees continue to creep closer to cooler temperatures?

Joshua trees are incredible plants, capable of reaching 40 feet in the most hostile of environments.

This is where the outlook for Joshua trees turns bleak. The study found that the yucca moth populations, in the few areas with suitable temperatures for Joshua trees, are not healthy. The relationship of these species is so tight, they may not make it through the century as climate change continues to force them apart. And the clock is already ticking down for both the yucca moth and the Joshua trees. In Joshua Tree National Park, the trees at lower altitudes are already becoming scorched and dying from the heat as trees in higher altitudes cannot successfully reproduce without the moths. Without the moths, Joshua trees are forced to asexually reproduce, creating inadequate clones that are vulnerable to pests and not able to disperse the species.

If Joshua trees were to disappear from their namesake park, something that could happen by as soon as 2100, many other animals, besides the yucca moth, would feel the loss. They provide shade from the brutal desert heat and provide habitats for insects, small mammals and birds. But some of the life that sprouts up around Joshua trees are harmful. Invasive grasses have entered the park, bringing with them a higher chance of wildfire that can decimate Joshua trees, which have never adapted to fire. As climate change continues to warm the park, the threat of wildfires will only increase.

While many visitors will mostly only see Joshua trees when they visit Joshua Tree National Park, there is an abundance of life that perseveres in this difficult environment. 57 species of mammal call this park home, including this coyote.

So is there any way to save the Joshua trees? In terms of helping the trees navigate to cooler environments within the park, people with knowledge of all the different pockets of climate around the park can try to plant the fruit of the trees in cooler areas, but this would be useless in the long run if yucca moths are not able to live there too. The complexity of interspecies relationships makes navigating climate change that much more difficult. Another, more out-of-the-box idea, would be trying to bring back the Shasta sloth to fill their ecological roles as large seed dispersal—a role that has remained empty after they left. Copious amounts of hair and other genetic material has been preserved in the hot, dry caves throughout the area to make them a somewhat logical de-extinction candidate. But at this point, that idea is more science fiction than reliable solution.

The reality is there is no easy solution to the Joshua tree’s predicament. The only thing we can do is treat the world better and try to individually reduce our emissions of green house gases that drive climate change. This phenomenon is not only sinking faraway islands and melting the ice at the poles. It is happening across the United States, even threatening an iconic Southern California symbol. It takes over a century for a Joshua tree to grow to a mangled, wind-beaten adult. In 80 years, the spiny symbol of perseverance in the inhospitable desert could be gone from its last stronghold. It simply cannot take the heat.

Above: Almost nothing is more hauntingly beautiful than gazing upon Joshua trees at sunset. Their mangled limbs make them seem like alien monsters as light fades beyond the horizon. They are the perfect subject to highlight the incredible explosion of colors in the back drop.

All photography by Jack Tamisiea.

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Sources:

https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.2439

https://www.nationalgeographic.com/environment/2018/10/joshua-trees-moths-threatened-climate-change-scientists-seek-solutions/

https://blog.nationalgeographic.org/2013/04/13/missing-sloths-modern-pollution-and-the-fate-of-the-joshua-tree/

https://www.nps.gov/articles/shasta-ground-sloth.htm

Climate Change Hits the Tetons

One of America’s iconic National Parks is feeling the heat from climate change. The results could trigger a dangerous cascade through the last (relatively) untouched pocket of wilderness in the United States.

The last rays of sunshine falling over historic Moulton Barn.

Thirteen million years ago, the land of what is now Wyoming violently shook. All the shaking resulted in a tear in the earth along the earthquake’s fault line miles below. The land west of the fault line was lifted upward as the land east of the line sunk some 20,000 feet. The result of these vicious earthquakes is the Teton Mountain Range, the picturesque backbone of Grand Teton National Park, and the sunken valley containing Jackson Hole to the east.

But the craggy pinnacles of the soaring mountain range were not only created by tremors deep in the earth. Glaciers carved the mountains into the iconic, jagged shapes we see today over tens of thousands of years as they advanced and retreated. While the massive, canyon-carving glaciers have been gone for the past 10,000 years, many smaller glaciers formed in an extended cold period that lasted from 1400-1850. Today these small glaciers demonstrate how the park’s climate is changing.

The majestic peaks of the Tetons soar high above the sunken valley at dusk one summer night.

Glaciers are a body of thick ice that slowly move as snow accumulates and compacts on mountains or near the poles. Logically, a warming climate would cause glaciers to melt. But another important factor is the rate and extent to which the Teton glaciers are shrinking. This is what researchers in the park’s Glacier Monitoring Project are trying to determine by mapping the retreat of the glaciers.

With the additional benefit of glacier data that dates back to the 1950s, the project has uncovered some startling trends as the ice continues to thaw. Overall, 25 percent of the total glacier cover has disappeared between 1967 and 2006. All seven of the park’s remaining glaciers have shrunk between the 1960s and 2010 and one glacier in particular, Teepe Glacier, lost 60 percent of its area over this period as summer temperatures continue to skyrocket. Teepe Glacier can be gone in as little as a decade as it has stopped moving, becoming a stranded snowball in a climate change-induced hell.

One of the most recognizable glaciers remaining in the National Park is the Skillet glacier on Mount Moran. Easily seen from Jackson Hole, the glacier resembles a skillet or broken guitar.

The Grand Teton glaciers may seem like a logical casualty of global warming, but that does not make their loss any less devastating. Besides their role in creating the iconic soaring peaks of the Tetons, the natural melting of the glaciers provides crucial cool water to downstream ecosystems. The park’s dozen or so native species of fish, from the mountain whitefish to the cutthroat trout, rely on the cool water from glacier melts. These fish control the insect population and provide food for a multitude of creatures, including bald eagles. Trout, in particular, bolster the park’s reputation as one of the premier trout fishing spots in the country. Once the glaciers are gone, will the park’s ecologically and economically vital native fish population disappear as well?

Climate change will not only expedite the melting of glaciers, but it will also continue to change the distribution of animal and plant species, altering the park’s ecosystems. For example, in Alaska’s Denali National Park, high-altitude Dall sheep have been forced to continuously climb higher into the mountains as their plants of choice are found only in increasingly higher altitudes due to the warming climate below. Eventually they may have nowhere else to go.

During my visit to the park, we were constantly playing “spot the moose” as the large herbivores were surprisingly cryptic. Whenever we were close to a moose it would disappear into the forest and vanish. This is one of the best shots I was able to capture of an adult female moose as it retreated into the thicket with its calf.

The Grand Teton National Park is such a crucial area to examine the effects of climate change because it constitutes a large swath of one of the last, relatively undisturbed areas of temperate wilderness in the world. Together with the nation’s first national park, Yellowstone, and a handful of protected forests and state areas, the Greater Yellowstone Ecosystem harkens back to a Western landscape nearly untouched by man. The ecosystems containing the world-famous natural phenomenons, like Yellowstone’s geysers and hot springs that helped it achieve the distinction as the world’s first national park, flow seamlessly into the ecosystems surrounding the iconic Tetons to the south. Together this connected web of wilderness encompasses some 20 million acres of habitat for iconic species, from bison to grizzly bears.

America’s national mammal, the hulking bison, in Grand Teton National Park.

Grand Teton National Park, in particular, is located in the rugged heart of this undisturbed wilderness and acts as an ark for animal species that once inhabited most of the western United States. The park contains 18 species of carnivore, 7 hoofed mammals, 5 amphibian species, 300 birds and 900 species of flowers that splatter the alpine meadows with color each spring. The full reach of the Greater Yellowstone Ecosystem even stretches farther than the three states (Idaho, Montana and Wyoming) that it officially spans. The Swainson’s hawk that resides here in the summer travels all the way down to South America each winter.

An American crow, one of the 300 or so bird species that fly through the park at some point each year, lets out a vocal “CaaW!-CaaW!-CaaW!”.

Grand Teton National Park is also the summer destination of one of the continent’s last great mammal migrations. As the snow begins to retreat north at the beginning of spring, hundreds, even thousands, of pronghorn antelopes begin the 100 mile-plus journey north from their wintering grounds in the Upper Green River Valley in central Wyoming to Jackson Hole.

What was that? One of my favorite pictures that I’ve taken is of this pair of alert pronghorn antelopes trying to figure out where a sound came from.

With large organs to aid air intake and padded feet, pronghorn antelopes are the second fastest land animal on the planet, capable of reaching speeds of 60 miles per hour. These incredible speeds easily outpace any living predator in North America. The only creature that could ever keep up with the pronghorn was a prehistoric North American cheetah that pursued ancient pronghorns here millions of years ago. The pronghorns outlasted the cheetah and have been traversing this migration path for some 6,000 years. However, their migration is becoming more strenuous as several areas along their route are claimed for large-scale energy development. Large swaths of protected wilderness are vital to help pronghorns continue their incredible migration for thousands of years to come.

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In such a complex collection of ecosystems that comprise the Grand Teton National Park, one species disappearing could have unforeseen consequences throughout the environment. For example, in nearby Yellowstone, the removal of wolves through decades of hunting interestingly led to the near disappearance of the park’s beavers.

So what was the connection between wolves and beavers? With the wolves eradicated, the population of elk skyrocketed. The unnaturally large population of elk heavily browsed young willow plants, which served as the beaver’s lifeline during the winter months. The return of wolves to the park in 1995 helped dent the large elk population and disperse them throughout the park, saving the willows from over-browsing and resulting in larger beaver populations. Moreover, the more robust beaver population caused improved hydrology of the streams where they lived. Their dams store water and help remove some of the seasonal runoff into the streams.

A herd of elk saunters across the plains in Grand Teton National Park.

The Grand Teton National Park is an incredible habitat for dozens of species which represent the last vestiges of a bygone era before the west was settled. Huge herds of bison roam the plains, nonchalantly crossing a highway, indifferent to the automobiles and pavement beneath them. Their incredibly brawny frames illustrate the defiance of the natural world as they lumber across the road. It is one of the last places where you need to worry about both the mother grizzly and the territorial bull moose.

Kings of the Road: Weighing up to 2,000 pounds and standing over 6-feet tall at the shoulder, the American bison is the largest mammal in North America and more than capable of doing its fair share of damage to any vehicle. Yellowstone National Park is the only place where bison have continuously lived since prehistoric times as the great creature was almost hunted to extinction in the 19th century.

But physical signs of man’s quest to conquer nature still are evident here, none more iconic than the Moulton Barn. The wooden barn is perhaps the most picturesque barn in the world with the jagged peaks of the Tetons as its backdrop. It has come to symbolize the inclusion of humans in the western landscape, a trend that began when settlers rushed to grab any parcel of land they could over a century ago.

Today, the signs of man’s relationship with nature are becoming more and more evident as the glaciers in the Tetons continue to melt. This will cause ripples in the park’s ecosystems, already complex and fragile. Each species plays a major role for the rest of the ecosystem, as the wolves in Yellowstone illustrate. As the climate continues to warm, whole ecosystems can vanish in one of the world’s last great wildernesses.

A Uinta ground squirrel hanging out by the Moulton Barn in Grand Teton National Park.

All photographs by Jack Tamisiea.

Sources:

https://www.yellowstonepark.com/things-to-do/wolf-reintroduction-changes-ecosystem

https://www.conservationinstitute.org/10-fastest-animals-on-earth/

https://snowbrains.com/nasa-how-the-teton-mountain-range-wy-was-created/

https://www.nps.gov/yell/learn/nature/greater-yellowstone-ecosystem.htm

https://northamerica.wcs.org/wild-places/yellowstone-and-northern-rockies/pronghorn-field-program/pronghorn-migration-path.aspx

https://www.nps.gov/im/gryn/climate.htm

https://www.nps.gov/grte/learn/nature/animals.htm

https://www.gtnpf.org/wolves/

https://www.nationalgeographic.com/science/earth/surface-of-the-earth/yellowstone-tetons/

https://www.nps.gov/grte/learn/nature/glaciermonitoring.htm

https://www.nps.gov/grte/learn/nature/upload/pope-parks-climate-change.pdf

https://www.nps.gov/grte/learn/nature/fish.htm

Flying-Foxes Struggling in the Heat of the Moment

Climate Change is Throwing Queensland’s Flying Foxes Straight Into the Fire

Brisbane’s black flying-foxes shortly after sunset

As someone who is new to the continent of Australia, I was taken aback one night when I witnessed the procession of flying-foxes parading over the Brisbane River. The colony of bats initially appeared to be just another flock of birds meandering across the blue-tinted dusk sky, soaring as they bobbed in between one another. However, as the specks of black approached my balcony, I noticed their leathery wings beating against the cool night air.

Flying-foxes, of the Pteropus genus, are one of the largest species of bats in the world, with some species growing as long as 1.5 meters from wing tip to wing tip. They inhabit the tropics and subtropics of Asia, Australia and parts of Africa, also going by the moniker of fruit bats. Unlike some other species of bats, they must use sight to make up for their lack of echolocation. As a result, their wide-eyes have become their trademark and have helped them take on cultural significance with many indigenous groups of people. Their teeth have even been used as currency for some odd reason. 

I have never been to an area where flying-foxes are found, which is why their appearance over Brisbane was so exciting to me, although the locals may barely take notice of such a sighting. Unfortunately, thanks to recent climate events, the existence of one species of flying-fox in northern Queensland may become much more rare. 

During a heatwave in the northern Australian city of Cairns in November 2018, hundreds of flying-foxes were dropping out of the sky due to record temperatures. Over 4,000 spectacled flying-foxes were seared when temperatures soared to 42.6 C (108.7 F).

Flying-foxes at Lone Pine Koala Sanctuary

What makes this tragic extreme weather event even more dismal is that spectacled flying-foxes, named after the light patches of fur surrounding their huge eyes, were struggling well before this grueling heat wave. The Australian government lists the species as endangered, having experienced a 78 percent population drop-off between the years 1985 and 2000 due to habitat loss and paralysis caused by the Australian paralysis tick, among other factors. The environmental stress caused by extreme weather events like the recent heatwave is fast becoming this species’ greatest threat. 

Although spectacled flying-foxes have not dealt with a heatwave of this magnitude in recent memory, other species of flying-foxes have been similarly decimated in the not too distant past. In 2004, a heatwave even warmer than the 2018 one killed between 5,000 and 7,000 Grey-headed flying-foxes. Most of these bats were less than 4 months of age, wreaking havoc on the whole population. 

Cyclones are another extreme weather event that threatens the existence of flying-foxes, destroying the trees that offer the bats the fruit that sustains them. Their fancy for fruit has also led them into conflict with the humans that run fruit orchards. The spectacled flying-foxes are often culled because of their reputations as fruit thieves. And what flying animal isn’t exempt from electrocution from power lines?

The larger theme is the threat of extreme weather events on flying-foxes because they have the ability to drastically diminish the size of a bat population within a matters of days. These events are even more detrimental when they involve an endangered species like the spectacled flying-fox. Our changing climate is continuing to cook up these extreme weather events, and species like the spectacled flying-fox are paying the price. 

According to Dr. Sean Maxwell, of the University of Queensland’s School of Earth and Environmental Sciences, extreme weather events are becoming more frequent and more intense, spelling doom for not only spectacled flying-foxes, but also hundreds of other species. A recent study he conducted on the responses of different species after extreme weather events found 31 different cases of local species’ extinction after such extreme weather events throughout the world. 

Although climate change is a long-term trend, it is easy to recognize the immediate effects in weather around the world as the world warms. Because of the swift intensity of events like a cyclone or a heatwave, wildlife populations are ill-equipped to survive it, as the thousands of dead flying-foxes in northern Queensland demonstrate. All it took was one heatwave to eliminate almost a third of the population of spectacled flying-foxes. What will happen to these bats, and countless other species around the world, when the storms and heatwaves keep coming, each one stronger than the last?

Sources: 

https://www.uq.edu.au/news/article/2018/12/wildlife-struggle-cope-extreme-weather

http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=185

https://www.theguardian.com/environment/2018/nov/30/queensland-flying-fox-species-decimated-by-record-heatwave