There are Islands in the Desert: A Look at Ash Meadows National Wildlife Refuge

There are islands in the desert. One might argue that islands are supposed to be surrounded by water, and water is in short supply in the driest corner of North America's Basin and Range province. But islands can take many forms, and in this region there are extremely high mountains and deep fault valleys that cross so many life zones that the "island" can be defined as an isolated ecosystem atop a high mountain. There are relict forests in the Mojave Desert of fir trees that survived the end of the ice ages in their cool mountain redoubts, for instance. On our way to Ash Meadows National Wildlife Refuge, we could see a mountain island rising out the Amargosa River plain. Eagle Mountain is an isolated fault block that rises above the blowing dust of the afternoon.

Desert surrounds Ash Meadows, an unlikely oasis in western Nevada

There are of course islands of civilization that persist in the desert, maintained by the importation of energy and supplies. These outposts actually make the exploration of this desert possible, one of the most isolated regions in the lower forty-eight states. In the end though, it is water that makes the islands. In this case an "island" of water surrounded by barren desert. It is the largest island of endemic species in the lower 48 states.

Endemic species are those that occur nowhere else on the planet. The boundaries of endemism are usually the shorelines of islands, because new species arise from isolation. Hawai'i is the absolute leader in endemic species in the United States, being one of the most remote islands on the planet. There are literally thousands of endemic plants and animals on the islands that are found nowhere else in the world. The Galapagos Islands are another famous example of numerous endemic species. There are lots of endemic species within the boundaries of the lower 48 states, but there are relatively few found in any specific area. There are simply too many pathways for species to spread out over a wide region.

One such island is the oasis of Ash Meadows in western Nevada. Within the 37 square miles of the National Wildlife Refuge are (or were) nearly three dozen endemic species of plants and animals, species found nowhere else on the planet. They exist in this one isolated location because of the geology, which has funneled the groundwater of a vast region into a series of three or four dozen springs that emit tens of thousands of gallons per minute. Water in the desert is life. Lots of water in one spot of the desert is almost miraculous, and that is the situation at Ash Meadows.

The creek that flows from Crystal Spring. An ADA accessible boardwalk provides access

The unique lifeforms found here include four living species of fish (along with one extinct species), eleven species of snails, three aquatic bugs, two species of bee, one extinct mammal (the Ash Meadows Montane Vole), and nine plant species.

"Ash" Meadows seems a particularly apt description of the region in winter

The desert that surrounds Ash Meadows is every bit as much a barrier to species travel as the open seas that surround Hawaii or the Galapagos. The meadows are only a few miles from Death Valley, the hottest place on the planet. So how did these water species come to be here in these springs and pools? Much of the explanation lies with the Pleistocene Ice Ages. A dozen or more times in the last 1.8 million years, the climate cooled and glaciers developed in the Sierra Nevada mountains off to the west. Meltwater from the glaciers filled the intermontane valleys of the Great Basin, forming a series of huge lakes and connecting rivers. These precious tendrils of water allowed fish and other aquatic species to invade the former deserts, but as each ice age stage ended, the dry conditions returned, and a few survivor species found safe harbor in isolated springs and pools like those found at Ash Meadows.

Devil's Hole, home of the extremely endangered Devil's Hole Pupfish. The pool in the cavern opening is their only home.

The refuge at Ash Meadows includes a single pool of water called Devil's Hole that contains the rarest fish species on the planet, the Devil's Hole Pupfish. The pool is an outlier of Death Valley National Park. Two other species of pupfish are found at Ash Meadows, the Ash Meadows Amargosa and the Warm Springs Pupfish. The Ash Meadows Speckled Dace is also found here. The Ash Meadows Killifish was driven to extinction in the 1950s as a result of spring alteration and agricultural development.

King's Spring can also be visited by an ADA accessible boardwalk.

It is remarkable that Ash Meadows ever came to be a protected ecosystem because water in the desert attracts another species, one capable of altering the landscape and erasing from existence the other species that have survived in isolation for tens of thousands of years. The water at Ash Meadows caught the attention of desert travelers more than a century ago, and the water was used to irrigate alfalfa fields and other crops. Many of the springs were put into piping systems and numerous invasive species arrived to compete with the native ones. It's hard to believe, but as recently as the 1980s, a proposal to build casinos, strip malls, and 30,000 houses almost became a reality.

If you have visited Ash Meadows in the past, you will find some major changes. A marvelous new visitor center opened only a few months ago. There was plenty of excellent information about the geology and biology of the refuge, but I was especially impressed with the paleontology exhibits. Entire walls are devoted to a creative diorama of the fossil species found in the region, including the ancient billion year old animals as well as the various waves of Homo sapiens throughout time.

Western Kingbird at Point of Rocks in Ash Meadows

Death Valley National Park is one of the greatest national parks in our country, and if you visit, you will find more than enough to keep you busy for many days. But if you find you have a day to spare, drive on over to Ash Meadows. Closed roads (flood damage) convinced us to pay a visit in February.

To wrap up, have a look at an Ash Meadows Amargosa Pupfish defending its territory at Longstreet Spring. These are fascinating creatures, and true survivors. In our next post we'll drive through a mountain range. Not over, but through...

This is a highly abridged version of a blog I did on Ash Meadows last year. I've included pictures of our latest trip.

How Did Fish Get into the Desert of the Basin and Range Province?

Source: "Pleistocene Lakes and Rivers of Mojave" by Philip Stoffer (14 January 2004). Changing Climates and Ancient Lakes (.html). Desert Landforms and Surface Processes in the Mojave National Preserve and Vicinity. USGS, US Department of the Interior. Retrieved on 2009-09-12. - http://pubs.usgs.gov/of/2004/1007/images/glaciallakes.gif.

Following a pair of posts that mention fish in the desert (here and here), I received a comment asking where the connections were that allowed fish to make the journey from the Colorado River system into areas as isolated at the Owens Valley and Death Valley. Courtesy of Philip Stoffer of the U.S. Geological Survey, here is the map. The drainage through Danby, Cadiz, and Bristol Lakes is the probably route of numerous fish species during the ice ages. From there, they were able to move through Soda and Silver Lakes into the Death Valley-Owens River system.

It is an unexpectedly diverse group of fish. According to this report, there were 56 species and 75 subspecies of fish living in the Basin and Range/Mojave Desert provinces. Ten of these historically known species/subspecies are extinct. Another 75 are listed, are candidates for federal listing, or are species of concern. 9 out of 10 of the subspecies are endemic, meaning they are found nowhere else in the world. The fish include the highly endangered Devils Hole Pupfish, the popular Lahontan cutthroat trout, as well as a variety of dace, chubs and suckers.

The story of why they are endangered is easy to summarize. They need water to survive, and so do humans. It is the choices that humans make that will determine the future of this fascinating group of fish. The Owens pupfish (Cyprinodon radiosus) would be extinct today but for the intervention of a Fish and Wildlife officer who carried the worlds entire population (800 individuals) out of a drying pond in two buckets, and established the fish in six other localities (four of these remain). The Devils Hole Pupfish in Death Valley National Park exist today because of a Supreme Court decision halting the drilling of groundwater near the only pool in which they exist.

A Death Valley Pupfish, found in Salt Creek on the floor of Death Valley.

 

 

Strangers in a Strange Land: Salt and the end of all things

In February and March I made a series of trips to the Mojave Desert and Death Valley, and since then I have been conducting a blog journey through the basic principles of geology as exposed in this extraordinary desert environment (Strangers in a Strange Land). In the last post we were looking up at the Black Mountains and the strange Turtleback faults, but today we are looking down, down as far as we can look on the North American continent. We have reached Badwater and the salt pan of Death Valley.

The end of all things? Strange topic I suppose, but I have been watching Frozen Planet on the Discovery Channel over the last few weeks, and it has had an emotional impact. Not so much the cute animals and the little dramas of survival against their predators and so on. That gets to be manipulative after a while and loses impact with me. It was more watching the Emperor Penguins, and their struggle to survive as the last year-round non-flying vertebrate life form on the continent of Antarctica (Oh, except for this...).

Antarctica was once a lush forested continent. It once teemed with life, with dinosaurs that wandered through the trees and swamps, along with birds, amphibians, and later on, marsupial mammals. Antarctica was in fact the bridge by which ancient marsupials reached Australia for the first time, where they thrived.

But life in Antarctica was doomed. As long as the continent was still connected to the other southern continents, warm ocean currents kept the landmass temperate enough to hold back the formation of glaciers. But sometime in the early Cenozoic era, around 50 million years or so, the last connections to the other continents were severed. Antarctica was isolated, not just by water, but by cold ocean currents that surrounded the continent. The glaciers grew larger and larger, turning into ice sheets thousands of feet thick. As more and more land disappeared, animal and plant species disappeared, unable to adapt to the new frigid conditions.The thread of life frayed to the point of snapping.


Source: http://en.wikipedia.org/wiki/File:Kaiserpinguine_mit_Jungen.jpg

Except for those penguins. Somehow, they have continued to survive, adapting their reproductive habits to the seasonal patterns, standing their ground through the harsh winters, standing for months on end with an egg, and later a chick between their legs. The parents don't eat for months at a time, trading parental duties while their mates chase fish many miles away. They stand, literally, at the edge of survival in the harshest land imaginable on this planet.

What do these musings have to do with Death Valley? The "end of all things" can be interpreted any number of ways, and here, the extremes run the opposite direction. Death Valley is the product of the disruption of the Earth's crust, a disruption so complete that no river drainages in the province will ever reach the sea. Death Valley is the sump, the low place to which all waters flow, on the surface and underground. It is the end of rivers. And Death Valley is, like Antarctica, a place where animal and plant life face insurmountable challenges. Out on the salt flats life ends.

Death Valley was a pleasant environment once upon a time. During the Ice Ages, which dominated much of the last two million years (equaling about half the time that the Death Valley graben has existed), the valley collected glacial meltwater, and thus was a freshwater lake. The surrounding mountains were still semi-arid, but forests of juniper and other trees extended to the shores of the lakes, along with extensive grasslands. A diverse ecosystem thrived; mammoths, mastodons, horses, camels, antelope grazed here, and were hunted by carnivores like sabertooth cats, American lions, and wolves. At some point in time, a connection was made with the Colorado River drainage or some other river system now lost to us. So there were fish in the lakes.

No one could mistake Mono Lake for a verdant paradise, but forests come almost to the shoreline.

But things changed. Around 11,000 or 12,000 years ago the latest stage of the ice ages, the Tioga, ended. The rivers shrank to a trickle and gave out. The vast lake in Death Valley, over 100 miles long, and 600 feet deep, evaporated bit by bit, and with each dry season the salt content climbed. Finally, the last of the water left, and a vast salt flat was created. The desert baked in the summer sun.

Some animals migrated elsewhere, and but most went extinct. Bighorn sheep and coyotes are the largest animals still found anywhere in the region, but you won't find them here on the salt pan. It is one of the most sterile environments on the planet (the biologists will have to let me know if bacteria can thrive in a pure salt environment like this). And what of the fish?

Nope, no fish here anymore...

As pointed out before, Death Valley was the sump where all the regional water collected. It still is. The surface water is wildly inconsistent, but springs tap into underground reservoirs, and they flow on a year-round basis, and have been doing so since the last of the freshwater lakes dried up. A precious few species of fish took refuge in these springs and survive to the present day. In Death Valley the survivors are the pupfish (Cyprinodon). Like their penguin counterparts in the southern hemisphere, they survive in some of the harshest climates in the world. Some of the Death Valley species persist in water that reaches 100 degrees, and salinity that is three times that of seawater.

They're also hard to photograph...

The most endangered species is the Devils Hole Pupfish. The entire population occupies a single cavern opening in Ash Meadows just east of Death Valley. The population has hardly ever exceeded 300 individuals, but it sometimes dips to only two or three dozen. As if the 92 degree water and the precarious food supply (a ledge of algae covered rock) isn't enough, they sometimes have to put up with the bizarre effects of distant earthquakes (check out this video). But through it all the pupfish have found a way to adapt survive.

That's the entire population of Devils Hole Pupfish down there....

Death Valley is the hottest and one of the driest places on the planet. And the climate is warming. What changes are in store? It is hard to know. But I have a feeling that the rare years when the Amargosa River flows all the way to the valley floor will become all the rarer.

It will not be so often that we can see a six-inch deep lake on the floor of Death Valley, and imagine how it once was...

The Last Animal Anyone Expects to Find: The Rarest Creature in Death Valley

Looking over the blasted barren rocks of Death Valley National Park, one is struck by the apparent lack of life. A region that averages less than two inches of rain in a year, with summer temperatures regularly topping 120 degrees, is just not going to have a lot of moisture left over to support life. and yet life persists, and sometimes in incredible ways. Hundreds of species are found in the region, including dozens of endemic and endangered species.

What is the last kind of animal you would ever expect to find in a place like Death Valley? Here's a candidate: in an outlying part of the park, just over the border in the state of Nevada, there is a barren hillside of carbonate rock (limestone), that has been twisted upwards and fractured. Strolling towards the base of the hill, one notices a cavern opening surrounded by reinforced fencing. It's a deep cave, more than 900 feet, but surprisingly, it is filled with groundwater at a constant temperature of 92 degrees.

Looking through the fence, one can see the small pool of water at the bottom of the narrow cleft. The monitoring equipment is a clue that something extraordinary lives here. It's a fish! And not just any fish, it is probably the rarest fish in the world, the Devil's Hole Pupfish. The species has lived in this little bit of water for the last 20,000 years, when it was isolated here by the drying of the glacial meltwater lakes that punctuated the Death Valley region. Through droughts, climate change, cooling, and in the last few years, interference by human beings, the little community of a few hundred individuals has grown, reproduced and died in this opening.

A few decades ago, as many as 600 fish lived here, but by 2004 the population had crashed to just over two dozen individuals. The population had recovered by 2007 to 126 fish, but their continued existence will always be tenuous. They would have been extinct in the late 1970's had the Supreme Court of the United States not stepped in. It was an early major test of the Endangered Species Act. As can be seen below, major efforts have been expended to monitor the health of the population.

It is not really possible to see the individual fish at Devils Hole, but a much larger and more stable population of a related species can be seen a few short miles away at Ash Meadows. The pool below is Crystal Spring, which produces 2,600 gallons per minute of 87 degree water. The Ash Meadows Pupfish lives in the pond and nearby stream, and is far easier to see, as we did today.

My picture of the Ash Meadows fish didn't come out, so I am slipping a picture of the Salt Creek pupfish from a previous trip. The Salt Creek fish live in the bottom of Death Valley not too far from Furnace Creek Resort.
Four species of pupfish live in various parts of Death Valley, with some living in the hottest and saltiest water of any fish species on the planet. Others live in fresh water. They are all descended from a single species of pupfish that lived in the glacial meltwater lakes of the ice ages. An example of real resilience in the face of difficult conditions!

I Don't Believe in Evolution Either...

I'm off to Death Valley for what promises to be a wet and wild weekend in drought-stricken California. The storm door is open across the state, and I am sincerely hoping that the rain and snow can ease the dry conditions. That remains to be seen, of course. I just don't know why the storms seem to be always coming on the Presidential Birthday weekend when I take the students on our long field trip.

In addition to a presidential birthday, it also happens to the be the 200th birthday of Charles Darwin. When I am making my way across the desert in the next few days, I will have a few opportunities to meditate on the intellectual advances that he and Alfred Wallace introduced to the world of science.

Like the Ethical Paleontologist, I would like to state here in no uncertain terms that I DO NOT BELIEVE IN EVOLUTION. Of course, I also don't believe in gravity, and I most certainly do not believe in atoms. What I DO believe, especially in the subject area of higher beings, is actually not your business, and is not germane to a discussion about evolution. If you would like a serious discussion about such issues, you are free to contact me in other ways.

Of course, despite my professed non-beliefs listed above, the world continues to behave EXACTLY AS IF evolution, or gravity, or atoms exist. My continued existence is in fact possible only because each of these phenomena do exist, and science has provided a framework for understanding each of them. In the case of evolution, my continued existence is actually threatened as I continue to fight off an infection that has proved resistant to antibiotics (don't worry, it's not that serious yet).

Death Valley National Park is a place to witness a few incredible examples of evolutionary change in action, both in the past and in the present day. The park contains something like seven vertical miles of sedimentary deposits that preserve one of the most complete fossil records of the development of life from over a billion years ago to the end of Paleozoic time to be found anywhere. The first picture above is a trilobite that same or crawled in the Cambrian coastline around 520 million years ago. Thousands of species evolved over millions of years before they went extinct around 250 million years ago.

The innocuous-looking fish in the second photo are cyprinodon pupfish, one of the most unlikely living creatures to be found in the driest place in North America. Sorry for the photo quality; they aren't easy to photograph. The pupfish are the ancestors of a species that lived in the Colorado River system and in fresh-water lakes that filled these desert valleys during the Pleistocene Ice Ages. As the ice ages ended, the lakes dried up, and doubtless many species and individual fish perished, but in a few watercourses and springs a few of the pupfish survived. In the last few tens of thousands of years, some of the fish populations thrived in freshwater springs, but others were trapped in increasingly salty ponds and creeks (like Salt Creek on the floor of Death Valley). The fish adapted to the conditions, eventually forming at least four or five species, and perhaps a dozen subspecies. No other fish is known to survive in water as salty as one of the species, and one of the species is known to survive in 100 degree conditions. No other fish is that hardy. Others survive in freezing conditions.

The most familiar species is the Devils Hole Pupfish. The entire species lives in a single water-filled cavern opening in the Ash Meadows area east of the main park. In that one hole, they have survived for thousands of years. Their population crashed a few years ago, down to a few dozen, but they may be recovering (several have been taken to other refugia to preserve the species in case of disaster).

They are luckier than the Tecopa Pupfish. The entire species was wiped out in an afternoon when bulldozers destroyed the springs they lived in to build a hot springs spa in the 1940's. What a shame to lose out due to human interence after so many thousands of years.

Happy birthday, Mr. Darwin! You enriched our understanding our world in many ways!