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.

Tuesday, October 5, 2010

Black Toad

Deep Springs Valley is about nine miles long and five miles long, and sits cradled by the White and Inyo Mountains. The valley has no drainage outlet, and hasn’t since the Pleistocene. It is a lonely place; a little-used state highway crosses the western side of the valley, and Deep Springs College (26 students [!] and a handful of faculty and staff) sits at the northern end of the valley, but that’s it for human inhabitants.  Deep Springs Valley also is home to the endemic black toad (Bufo exsul), which occupies four springs at the southern end of the valley, above the dry alkaline bed of Deep Springs Lake. The specific name, exsul, means “exile,” which is so wonderfully appropriate. For when you sit near one of the springs at night and look out on the dark rim of the valley, or up at the huge vault of heaven, and see or hear no sign of people, and think about how far away the nearest other toads are – then you understand the meaning of what it means to be exiled, like Napoleon on St. Helena.  
Black toads don’t look all that much like traditional toads, a la the eastern American toad. They are smaller (a big one measures about two inches, snout to vent), with a narrower head, and they have few warts. They also are beautifully colored – adults are mostly jet-black above, flecked with creamy yellow, and have a thin dorsal stripe of the same color. They were easy for me to find along the margin of a ditch draining one of the springs, and I counted over 100 in 30 minutes of searching. But I found few black toads at two of the other springs where they are known to occur. My inability to find many toads at the two springs could have been due to a poor search image, or to searching in the wrong place, but I wonder.  Perhaps succession and habitat loss is having a negative effect on the population – much of their breeding habitat is choked with emergent vegetation, which wasn’t the case thirty years ago – and there always is the specter of chytrid fungus. Whatever the case, I worry. For when you are exiled, there may be nowhere else to go.
Black toad, Deep Springs Valley

Black toad habitat; Deep Springs Valley in background

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