The Sierra Yellow Legged Frog and Dredging

As part of an ongoing effort to review those areas of the Draft SEIR classified as “Significant and Unavoidable Impact”  the Western Mining Alliance will publish a series of reviews of the issues and post them here on the web site.

This information is posted to aid you, the individual miner in thoughtfully responding to the attacks on our profession.  Armed with the facts and a reasonable voice you can accomplish much.  Remember the media, the public and the government expects us to be rabid, toothless gun toting miners that are unable to evaluate, digest and present facts. It is this perception that we must change.  Our ability to respond to, and counter the propaganda and misinformation put out by both the extreme environmental groups and the government are critical to our success.

Let’s face it, prior to the draft SEIR it’s likely that none of us ever heard of the Sierra Mountain Yellow Legged Frog, or the Foothills Yellow Legged Frog.  Only when the number of streams listed for closure to protect this frog appeared in the draft CDFG regulations did we notice there was even a frog in areas that we dredged.

It’s doubtful any of us ever willfully harmed one of these frogs, we’ve actually got better things to do when on the river than go chasing frogs.  Recovering gold being one of those better things to do.  Secondly, the existence of a mining claim by its nature limits the number of people who are mining that claim so we typically don’t have dredges lined up end to end sucking up the tadpoles.

The information on the distribution of this frog is scant but the CDFG was forced into responding to a potential lawsuit from the Center for Biological Diversity to issue regulations that were favorable to the restoration of the frog.  If you’re not familiar with the Center for Biological Diversity (CBD) then you’re unaware this is a pseudo environmental organization that is most notable for its ability to file lawsuits.  At last review they listed twenty two lawyers on their staff.  The CBD abuses a little known Federal law known as the Equal Access to Justice Act.  This act was originally designed to allow the poor citizen to be able to fight the unlimited resources of the Federal Government.  The CBD discovered this act also applies to activities that sue the government to enforce the Endangered Species Act.  Nice work if you can get it.  They simply research to find a creature that might possibly be candidates for listing, then sue the government to list it.  Where’s the profit?  Easy, if you drop so many lawsuits the government can’t respond then you are entitled to recover your attorney fees.

A brief summary of the activity most responsible for closing half the state of California to dredging from the Tucson Citizen website,

“The Tucson based Center for Biological Diversity has been waging a nation-wide war against ranchers, mines, military bases and other land uses. In a form filed with the IRS for 2008 the Center for Biological Diversity
repoprted the following salaries for its top officials:

  • Peter Galvin, Director $94,922
  • Todd Schulke Treasurer 51,500
  • Robin D. Silver Secretary 81,500
  • Kieran Suckling Exec Dir 104,313

The Center for Biological Diversity is also one of the targets in federal efforts to stop litigious environmental groups from soaking US taxpayers with a tsunami of law suits.  According to the 2008 IRS filing, the Center received $1,398,161 for its legal fees and costs from suing the government. That dropped to $ 1,173,517 in 2009 and to $ 685,981 in 2010 according to its annual reports for a toital of $3,257,659 over a 3 year period. Obviously fighting for the environment is a serious business financially.” 

The issue is not so much the CBD’s ability to accomplish this (at taxpayer expense) but rather our inability to see it coming and counter it with appropriate research and facts.  We can’t continue to play a defensive game and wait for the next shoe to drop before we react.  The purpose of the WMA is to identify these threats, provide appropriate research and provide the arguments to the legislators that will counter this extreme form of environmentalism.

Our research shows that dredging is not the proximate cause, the secondary cause and likely not even a cause of the frogs demise. The frog is facing extinction from an activity that is categorically exempt from environmental impact reviews. Fish stocking by the CDFG is likely responsible for the near extinction of the frog.  It turns out that fish eat frogs.  Who would of thought?

Quick Facts on the MYLF

The preponderance of evidence clearly shows that the cause of the Sierra Nevada Mountain Yellow Legged Frog is due to the introduction of trout.  There are no studies related to dredging or the impact of dredging on the MYLF.

  • The Sierra Nevada Mountain Yellow Legged Frog is not found in large areas that are proposed for closure under the draft dredging regulations
  • There is no data that supports closing areas to dredging would have either negative or positive impact on the ability of the frog to recover
  • Frog habitat is typically not good dredging areas
  • The primary cause of the frogs decline has been the introduction of trout

Dredging and Frog Habitat

While the results from the draft SEIR appear to provide very minimal impact from dredging, the broad application of the results based on a statewide rationale has significant local impacts.  It is inappropriate to broadly apply rules that should be specific.  Examples are closing entire watersheds to protect the frog when sampling shows there are no frogs in that watershed – or more likely the field sampling has not occurred.  The Knapp study [reference 3] provides a probabilistic model for determining high quality MYLF habitat and should be consulted by CDFG in determining specific areas for closure – these would primarily be high alpine lakes.

The proposed dredging regulations close large amounts of watersheds to dredging based on restrictions to protect the MYLF.  From a review of available literature on the MYLF it appears the likely cause of the frogs decline is the introduction of non-native trout into its habitat and dredging has no impact, or no measured impact.  Representative MYLF habitat is shown in Figure 1:

 Figure 1. provided MYLF habitat

Specific to the area of Slate Creek but generally applicable to many of the higher elevation streams a couple of pictures of the area that is proposed to be classified as “A”  due to classification as MYLF habitat.  From the above pictures to the below it would appear there is very little in common from a habitat perspective, and the above habitat is a highly unsuitable location for dredging and the below habitat is unsuitable for frogs.

Figure 2 provides a typical environment encountered in the Slate Creek watershed and is representative of most of the higher altitude dredging areas.  The canyons are extremely narrow and the bank edges in most places are near vertical and rock.

Figure 2.  Slate Creek Watershed Typical Terrain – near 5,000′

Figure 3 is from and provides the sampling locations for the MYLF in the Slate Creek drainage area.  As shown, no frogs have been found in the Slate Creek watershed or tributaries.  The sampling highlights just how little is actually known about the frog and how little sampling has been conducted.  Ironically, suction dredgers probably know more about this frog, it’s distribution and habitat but would be unwilling to volunteer any information that would result in their claim being closed.


Figure 3.  Confirmed locations of the Sierra Nevada Yellow Legged Frog

While the sampling doesn’t preclude the MYLF from being present it does show that no frogs have been found in the area.   While the frogs may exist in the area the conclusion is the habitat for most of the proposed closed area isn’t suitable for the frogs – or at least not broadly suitable or that no species counts have taken place in this area.  Further reading on the habitat of the frog provides the following taken from
(emphasis added):

Habitat Comments: The habitat of frogs of the Rana muscosa/Rana sierrae complex includes sunny river margins, meadow streams, isolated pools, and lake borders in the Sierra Nevada.  Sierran frogs are most abundant in high elevation lakes and slow-moving portions of streams.

Restoration Potential: Rana muscosa/Rana sierrae populations that have been extirpated or reduced as a result of fish introduction can recover to predisturbance levels after fish disappear, if a nearby source population of frogs exists (Knapp et al. 2001). Several agencies (National Park Service, CDFG and U.S. Forest Service) have begun and/or planned recovery efforts involving removal of introduced fishes, and a number of populations have recovered (Vredenburg 2004).

Preserve Selection & Design Considerations: Basins with a variety of deep lakes and shallow ponds may be the most appropriate reserves for this declining species (Pope and Matthews 2001).”

 It appears the frogs prefer slow moving bodies of water and ponds/lakes.  These are typically not dredging sites and certainly don’t represent high elevation mountain streams which typically have steep gradients. {Reference 3, Knapp].  Additionally, as shown in Reference 3 the occurrence of frog tadpoles is directly correlated to the water depth and is statistically shown to be found in lakes deeper than 3m (aprox 10′).
Research shows that the frog habitat is fragmented for various reasons, but appropriate habitat has been shown scientifically to not be correlated with areas that are considered good dredging locations.  It can also be inferred from the above that dredging would have beneficial impacts on frogs by:

  • Introducing into the stream small aquatic insects that would normally be under the cobbles
  • Providing aeration to the water in slower moving portions of the creek
  • Providing a fine layer of silt which acts to protect and hide the eggs (taken from and proven through scientific study by Knapp, reference 3)

The SEIR and the proposed draft regulations should take into account that dredging can actually benefit the frog.

The Real Cause of the Frogs Demise is the CDFG

The Western Mining Alliance supports the reestablishment of the frog, but the reality is dredging has no impact on this species and the banning of dredging will have no impact on the recovery of the species.  The CBD petition to list the frogs as endangered cites the introduction of non-native trout as the primary cause of the decline. The introduction of trout has dramatically reduced the frog’s numbers and it’s expected that the elimination of the trout would result in the expansion of the population.

Even the Center for Biological Diversity lawsuit acknowledges the primary cause of the frogs near extinction is the introduction of non-native trout into its habitat.  An excerpt from the CBD website provides the following information:

“it’s not surprising that the main reason for the frog’s decline is the California Department of Fish and Game’s introduction of nonnative trout to high alpine lakes. These stocked fish prey upon tadpoles and juvenile frogs, and scientists predict that the yellow-legged frog could be extinct within decades.”

Another example that clearly rules out dredging activity as a cause of the frogs decline is reported in the Fresno Daily Republican on March 1st, 1996.  The following excerpt is the summary of study of the frogs decline in Yosemite Park, an area completely free of dredging and protected. (emphasis added)

Park Service biologists have compared their findings with a 1915 study of frog and toad species in Yosemite National Park. The found that 80 years ago, the wilderness in and around Yosemite National Park was rife with the trilling, croaking songs of frogs and toads. This is no longer the case, according to the new study.

By comparing a recent survey of frog and toad species with one done in 1915, researchers were able to provide long-term data needed. For while many researchers are documenting declines of frogs and toads around the world, most focus on one or a few species with data spanning 20 years at best, leaving some to questionwhether the drops in numbers seen are simply harmless, short-term fluctuations.

National Park Service zoologists say the new study, published in the current issue of the Journal Conservation Biology, provides some of the best evidence that the declines are a long-term problem. “I was really very impressed by the [Yosemite] study,” said Dr. Martha Crump, a behavioral ecologist at Northern Arizona University in Flagstaff, suggesting that the new paper would convince the last remaining skeptics. “It’s such a large fauna declining over such a large area. That’s what makes this a really important study.” The Smithsonian’s amphibian expert Dr. Ronald Heyer, said: “It’s kind of chilling in its effect. Here we have
what we consider to be a relatively protected place, and amphibian declines are occurring even there.”

Researchers have ruled out habitat destruction as a cause of the disappearance. “You can’t find a place on earth that’s entirely pristine,” Drost said, “but by and large, this is about as pristine an area as you can find in the lower 48 United States.” Drost said the field sites still look essentially as they did in the 1915 photos.

The 1996 study conducted by Ronald. Knapp (reference 2) provides a strong linkage between the non-native trout and the decline of the frog.

 ” The introduction of non-native trout has caused widespread declines of native trout species such as golden
trout as a result of hybridization, competition, and predation. The decline of at least one amphibian species, the mountain yellow-legged frog, has been attributed largely to predation by introduced trout.

My report suggests that lakes and probably other aquatic habitats in the Sierra Nevada, including those in wilderness areas, may be so extensively modified by the introduction of non-native trout that they are unable to serve as refugia or as control areas. One species may already have disappeared (the phantom midge) and several others endemic to the Sierra Nevada have suffered dramatic population declines (e.g., golden trout, mountain yellow-legged frog). Continued decline of these species will likely result in listing under the Endangered Species Act, a step that could have far-reaching consequences for the management of aquatic ecosystems throughout the Sierra Nevada. The simplest and perhaps most effective way to reduce impacts of introduced trout is to modify current trout stocking programs to cause the die-out of some introduced trout populations.”

Knapp continued his studies of the effect of trout on the MYLF populations with a 2000 report that specifically addressed this issue, and a 2007 report (Reference 2) in which he studied the recovery of the MYLF when trout were removed.  Figure 3 provides an excerpt from his work which shows the dramatic increase in frogs after the removal of the trout.

I contacted Dr. Knapp to inquire whether any studies had been conducted on the effects of suction dredging on the MYLF and he responded that there were no studies he was aware of that looked at dredging and the impact on frogs.  [Personal Correspondence 27 March 2011].  Studies on restoration show the frog increases rapidly when the native trout are removed.

“Numerous mountain yellow-legged frog recovery projects have been conducted in the last five years, with more in the planning stages. Virtually all of these projects relied on the removal of nonnative trout and most have met with stunning success… [Knapp 12 December2008, from website]

…high quality habitat is generally characterized as lakes deeper than 3 m (10′), located at elevations below 3600 m (11800′), and surrounded by other suitable habitats including fishless lakes, ponds, marshes, and low-gradient streams (see Knapp et al. 2003 for details).”  [Knapp 12 December 2008, from website].


There is no scientific basis to close large areas of the State to suction dredging based on the possible location of the frog.  As shown in Figures 1 and 2 above the specific terrain must be evaluated as an area can contain both suitable and unsuitable habitat.  It would be sufficient to simply regulate the specific destruction of amphibian eggs or the willful destruction of the frog.   Using established probability models in existing research can help define the precise areas these frogs are likely to be found and establish protected refuges for them.  As mentioned earlier the areas where the frog tends to locate is normally not a desirable dredging location.  The high alpine ponds simply have no gold and the slow moving areas of the rivers are typically the high overburden areas which require too much effort to reach bedrock.



Internet Sources (Roland Knapp’s website)

Scientific papers referenced in preparing this response.

1.  Knapp, R. A. 1996.
Non-native trout in natural lakes of the Sierra Nevada: an analysis of their distribution and impacts on native aquatic biota. Pages 363-407 in Sierra Nevada Ecosystem Project: final report to Congress. Volume III, Chapter 8. Centers for Water and Wildland Resources, University of California, Davis (available at

2.  Knapp, R. A., D. M. Boiano,
and V. T. Vredenburg. 2007
. Removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, Rana muscosa). Biological Conservation 135:11-20.

3.  Knapp, R. A., K. R. Matthews,
H. K. Preisler, and R. Jellison. 2003
. Developing probabilistic models to predict amphibian site occupancy in a patchy landscape. Ecological Applications 13:1069-1082.

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