Sunday, April 3, 2016

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.

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