|Crystal Spring at Ash Meadows|
During the Pleistocene ice ages during the last two million years, the climate in this dry desert was often cooler and wetter. Rain and snow fell on the high mountain ranges to the north and east and soaked into the ground. Over the millennia the groundwater flowed slowly to the southwest, along river valleys and even through fissures right through mountain ranges. Bedrock ridges and gouge-filled fault lines forced the "fossil water" to the surface as a series of 30 or so seeps and springs. The amount of water flowing here is tremendous; some of the springs have flows measured in thousands of gallons per minute. For example, Crystal Springs in the pictures above and below has a flow of 2,800 gallons per minute. The presence of so much water in the desert makes Ash Meadows an island, but in this case it is an island of water in a landscape of dryness. It is one of the few oases left in the American desert, and has the highest concentration of endemic species in a small area anywhere on the continent.
|The proposed Calvada Lakes development from the 1980s|
Water in the desert can also attract invasive species which can do great damage to the fragile ecosystem. Mosquito Fish, which are an important species in other settings, can upset the life balance in the pools and springs. So can abandoned aquarium fish. But the worst invasive species of all, Homo sapiens, nearly destroyed the entire complex.
It happened first when farmers began to manipulate the springs into irrigation systems. They piped the water flows and started pumping groundwater so intensely that the water table started to drop, threatening the species that lived in the ponds. Lawsuits ensued and one eventually reached the Supreme Court. In 1976, the court ruled that pumping had to be limited to the extent that water tables would not drop. The farming corporation sold the properties to a land developer, which led to an even greater threat to Ash Meadows.
The real estate development is in retrospect nearly unbelievable: more than 30,000 homes, along with shopping centers, casinos, theatres, and industrial parks. An instant city in the midst of barren desert. Even today, I can't imagine 50,000 people or more simply deciding to move out to the middle of nowhere. "But Las Vegas!" is an obvious response, but other desert town developments have faltered and disappeared when people realized how truly miserable the summer temperatures could be (and that's not to mention the winter winds and dust storms). Calvada Lakes would have been a disaster on so many levels.
|Devil's Hole Pupfish|
The entire race of the Devil's Hole Pupfish lives in the shallow cavern opening on the side of a limestone hill. The water is constantly warm, almost 90 degrees, is oxygen poor, and the food supply for the fish is extremely limited. But somehow the fish have survived, and have diverged from their relatives who live in pools just a few miles away. They are thought to have been isolated for a minimum of 20,000 years, but some studies suggest as much as 60,000 years (an outlier study takes a different position, suggesting only a few centuries of isolation).
Access to the cave opening is for obvious reasons highly restricted. There is a caged platform from which the pool can be viewed from about 80 feet away. It's clearly hard to see the individual fish, but my camera has a great zoom lens. I'm not sure why they were there, but the white tiles in the pool allowed me to catch some video of the rarest fish in the world (below).
|The cavern opening where the entire population of Devil's Hole Pupfish lives|