In the Fullness of Time

This blog will focus on my fall sabbatical, and the ecology, evolution, and conservation of endangered and rare species in the Death Valley / Owens Valley area of California. Two taxa that I am particularly interested in are the Inyo Mountain salamander, and desert pupfish in the genus Cyprinodon. I plan on exploring not only the science of these species (and others), but also their beauty.

Friday, November 5, 2010

Ash Meadows

For twelve days I volunteered at Ash Meadows National Wildlife Refuge, which is situated southeast of Death Valley National Park, in the transition zone between the Mojave, Sonoran, and Great Basin deserts.  Although Ash Meadows is about the same size as Iroquois National Wildlife Refuge plus the adjacent Tonawanda and Oak Orchard Wildlife Management Areas, it supports 25 endemic taxa, including four fish, eight plants, and 13 invertebrates. Twelve of these are listed as threatened or endangered under the federal Endangered Species Act. Remarkably, the number of endemic and listed species at Ash Meadows exceeds those of any other local area in the United States.  Another comparison: Death Valley is the largest National Park in the lower 48 states, at 3,370,000 acres, which is about 146 times as large as the nearby Ash Meadows refuge. Death Valley also has a much greater range of habitat types – yet its total of endemic species is “only” about 34. Although the boundaries of  Ash Meadows National Wildlife Refuge do not include the spectacular landscapes that characterize Death Valley, the refuge’s biodiversity makes it an equally beautiful place.  
Ash Meadows from the east; green areas in middle ground mark springs.
Death Valley NP (Black Range) in distance.

Large (!) endemic Warm Springs pupfish

Water bug with unlucky Warm Springs pupfish prey

The high degree of endemism at Ash Meadows  is due primarily to its archipelago of springs and wet alkali meadows, many of which are isolated from one another, and from other similar systems in the region. All of the endemic (and listed) species are either aquatic organisms, or dependent upon relatively wet, localized terrestrial habitats. Because most of the endemic organisms occur in or near only a few springs, any damage to the springs can lead to catastrophic population declines. Three endemic organisms went extinct during the twentieth century – the Ash Meadows montane vole, the Ash Meadows killifish, and the Longstreet Spring snail – while many others remain vulnerable to exotic species, invasive plants, and decreasing spring flows. In the late 1960s and early 1970s, before the refuge was established, a company began growing water-intensive alfalfa and cotton at Ash Meadows, even though the area’s water resources and alkaline soils could not support long-term agricultural development. Many springs in the area were devastated, along with their populations of fish and invertebrates. Ash Meadows National Wildlife Refuge was established in 1984, and since then the Fish and Wildlife Service has done an excellent job of protecting and restoring many of the springs. Much work remains to be done, though, and future, large-scale groundwater withdrawals (viva Las Vegas) could severely impact the hydrology and endemic species of Ash Meadows.
King's Pool, 1969. Image courtesy US Fish and Wildlife Service.

King's Pool restored, 2010

The other day, I walked across the desert from Devil’s Hole, the only home of the Devil’s Hole pupfish and an endemic riffle beetle, to School Spring, one of several low-volume springs that support the endemic Warm Springs pupfish and Warm Springs naucorid (an aquatic insect).  The half-mile walk took me only 15 minutes, and yet for those fish and flightless insects, Devil’s Hole and School Spring might as well have been separated by a continent. The species are that isolated, and they have been so for at least ten thousand years. There is a beauty in their isolation and tenacious persistence, but also an ineffable sadness. For the pupfish and insects, the desert is an immense and inhospitable barrier, and they are irrevocably committed to their tiny habitat islands.  Despite their proximity to one another, they are just about as alone as any creatures can get in this world. And so, as I wove through the cacti and creosote scrub, and thought about the perilous existence of so many species at Ash Meadows, the desert was for me both metaphor, and habitat. 
Ash Meadows desert at sunset; appropriately named
Last Chance Range to left.

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