June 15, 2011

Out in the Field Again, Finally!

It has been a long winter here in the Sierra Nevada. This "spring" was one of the coldest and wettest on record, and as a consequence the higher portions of the mountains are still blanketed in snow. But now that the melt has finally begun in earnest, my field season is fast approaching. Last week I hiked into the Golden Trout Wilderness to have a look at a particularly important population of the southern mountain yellow-legged frog (Rana muscosa). This population is the furthest south R. muscosa population left in the Sierra Nevada. Populations historically occurred as far south as Breckenridge Mountain in Kern County, and included large populations in the montane and subalpine meadows along the South Fork Kern River and Golden Trout Creek. As far as we know, those are all gone now, and this population that I visited is the last hold-out in this southern portion of the historic range. 

The fact that this population is still extant is remarkable. Most of the meadows in the Golden Trout Wilderness have been badly degraded by intensive sheep and cattle grazing in the late 1800s and early 1900s that resulted in channel incision and lowered water tables. As a consequence, many of the ponds and other amphibian habitats disappeared. In addition, California golden trout (that were native to much of the South Fork Kern River watershed) were moved into the few naturally fishless lakes and streams that existed in the area, further reducing habitat for R. muscosa. And then probably sometime in the 1970s or 1980s, the amphibian chytrid fungus (Batrachochytrium dendrobatidis) swept across the region, further decimating R. muscosa populations. 

Despite all of these changes, this population of frogs somehow hung on. But for how much longer into the future they will remain is an open question. This R. muscosa population is centered on a single small breeding habitat, an abandoned stream channel filled with sedges and fed by seepage from the adjacent stream. When the stream someday moves back into this channel (as it inevitably will), the only breeding site will be gone and so too will be the frogs. As such, it is imperative that frogs from this population be used to reestablish populations in suitable habitats elsewhere in the vicinity. Based on the low success rate of developing new mountain yellow-legged frog populations, this won't be an easy task. But without such an effort, the range of R. muscosa will continue to contract until this once abundant species is all but gone from its former haunts.

Back to The Mountain Yellow-legged Frog Site.


  1. Hi Roland, Glad to hear you're out and about again. This question came up in the HST forum:

    "I am curious where this location is, and how far south. I live fairly close to Breckinridge Mt. that he mentions in his report, but it looks more like an area like Casa Vieja Meadows, Golden Trout Creek, or Mulkey Creek, which are further north and west."

    Comment as you see fit, please,


  2. The site is located in the headwaters of the South Fork Kern River near Ramshaw Meadows.

  3. Hello Roland:

    I am a first time poster. If frog restoration is done here, I hope the golden trout population is not eradicated in the South Fork Kern. I am familiar firsthand with the general area, and as you probably know, much work has been done through the years to keep the native golden trout in this area free from non-native species. Here is a link that details some of these efforts. http://www.californiagoldentrout.org/
    I know you said that is not the actual stream channel, and I don't even know for sure that it is the South Fork you are talking about, but I thought I would bring the subject up. I am the HST poster that Russ mentioned in his previous post.


    Richard Long

  4. Hi Richard. Historically, mountain yellow-legged frogs actually seem to have coexisted with golden trout throughout the South Fork Kern River, probably because they bred in fishless off-channel pools like the one I described in my original post. So, restoration of frogs in this area would not require removal of trout from the SF Kern. One of the options we are currently exploring is reintroducing frogs back in to some of the headwater lakes in the Golden Trout Creek drainage, lakes that have recently been allowed to return to their original fishless condition (Rocky Basin Lakes, Chicken Spring Lake).

  5. Stop trying to kill Sierra fishing.

  6. What will "kill Sierra fishing" is ignoring resource issues related to the introduction of non-native trout. I would argue that the focus on the "fish-frog" issue during the last decade has improved the overall quality of fishing in the Sierra Nevada by forcing the CA Dept. of Fish and Game to finally take these fisheries seriously and manage them more carefully.