Cascades Frog
Rana cascadae
![[Cascades Frog]](/images/65ds.jpg)
©Ray Bruun
Description
Distribution Range
General range map taken from CWHR.
Museum records taken from following institutions: CAS Herps, MVZ Herps.
There are historically several groups of Cascades Frogs that seem to have been isolated from each other. The main groups are primarily located in the Cascade range of Oregon and Washington and do not enter California. Two populations are in California (Stebbins 2003 Map 53) and at least historically, both of these populations extended into Shasta County.
One population is associated with the Lassen area and is generally referred to as the Lassen population. In Shasta County, this population is found in the south eastern portion of the county.
The other population inhabits the Klamath and Siskiyou region of northwestern California and is often referred to as the Trinity Alps population. Historically this population enters the northern part of Shasta County.
Typical Elevation
We do not yet have enough records from distinct localities to calculate typical elevation. We need 15 more distinct localities.
Additional Information
Notes
The Lassen population and the Trinity Alps population may actually be genetically distinct taxon. For now, they are treated as the same taxon.
The Lassen population is on the brink of extinction, having lost roughly 99% of its former range. During extensive surveys from 1993 to 2007 (Fellers, Pope, Stead, Koo and Welsh, Jr. 2008), the species was only found at six localities with a report of a single specimen at a seventh locality. The populations where they were found were numerically small, many of them had no signs of recent reproduction.
Only two of those localities occur within Shasta County, one of which may have already gone extinct. The other is known to me have had the frog as recently as 2010 (see Record 347.)
The Trinity Alps population appears to be a much healthier population, though it too has suffered significant declines (about 50%) from its historic range. I do not know the current status of that population within Shasta County. Three museum records from 2003 exist (CAS 227212, 227980, 227984) but I am unaware of the current status at that locale.
Cause of Decline
The cause of decline is probably due to multiple factors. Understanding the cause of decline is important if recovery of the species is to occur. Recovery programs will ultimately fail if the cause of original decline is not identified and corrected.
Introduction of sport fish in alpine lakes is clearly one factor. The following excerpts from a backpacking guide demonstrate the issue:
Fishing is generally good in the Trinity Alps. Sometimes it's even terrific! Almost all of the lakes have been stocked with trout at some time, and some are still stocked regularly. The only lakes without trout are a few that are just too remote and too small, and some high lakes that are so shallow that they just freeze solid in the winter, killing the fish. Most of the trout in the lakes are eastern brooks because this species can reproduce without running water.
(Linkhart and White 2004 pg 28)
As the above paragraph suggests, we planted a predatory fish in alpine lakes where the fish were not native. Furthermore, we had to use a species from the east coast because most of these lakes simply could not support the species of trout that are native to the west coast. What is the net impact? From the same book:
Found lake sits at the head of the basin ... You will want to climb down to Tapie Lake if you want to fish, as multitudes of frogs live in the lakes of the upper basin, but no fish.
(Linkhart and White 2004 pg 120)
Alpine frogs evolved without the presense of predatory fish species. Addition of these fish to the habitat of these frogs is a major factor in their decline. For their recovery, we need to significantly reduce the number of alpine lakes where fish are planted and when possible, remove fish from alpine lakes in order to allow the frogs to recover. This is not popular with the fishing lobby, but considering the fact that we are talking about the survival of a species that should be plentiful and is quickly disappearing, I think the fishing lobby needs a serious reality check. When choosing between the survival of a species and a recreational hobby, the survival of a species must take precedence. Perhaps the following compromise would work:
Continue stocking sport fish in man made lakes and reservoirs. Continue stocking sport fish in natural lakes that meet all of the following criteria:
- Easy access by vehicle
- Trout are currently reproducing on their own
- Trout removal would be difficult
Stop stocking sport fish in any natural body of water that does not have easy access by car and remove all take limits (size and quantity) in those bodies of water. Remove fish from bodies of water where it is practical to do so, starting with bodies of water that either currently have Cascades Frogs or are close to populations of Cascades Frogs.
Drought also probably played a role. There was a multi year drought at the end of the 70s. These frogs will breed in temporary pools that do not support planted trout, but during a long drought, that option is largely taken from them leaving lakes and streams that support trout as the only option for breeding.
Another possible factor in the decline is the Chytrid fungus. More info to come. The fungus may have wiped out large numbers of the frog just before the drought prevented reproduction in temporary pools that lacked trout. A perfect storm, so to speak.
It is possible that the Cascades Frog will eventually develop a natural defense to this disease over time. However, that will be difficult for the species to do if their numbers are kept low and gene flow between populations is hindered due to trout. We really need to remove the pressure on the species caused by the introduced sport fish and may need to help with artificial gene flow (ie transplant egg masses or tadpoles, of course performed by qualified biologists) between remnant populations that use to have continuos range between them. Chytrid fungus may always be a part of the population, but localities that are extremely low in population density can be periodically treated for the disease allowing their numbers to increase to sustainable levels.
Airborne pollutants, largely from agriculture, are also likely playing a role in their decline (reference needed). This is a more difficult problem to overcome. If we stop using pesticides for farming, our production yield will decrease and the cost of food will go up. Especially during economic hard times, this is a problem. While I am willing to give a species priority over a hobby, it is more difficult to give a species priority over hungry people. Perhaps more efficient delivery methods that result in less airborne particles could be developed, or pesticides that pose less of a colaterol damage could be developed. Alternative methods of agricultural pest control could also be developed. More research needs to done on pesticides and their impact on our amphibian populations.
Images
Unless otherwise noted, all images are of wild specimens in Shasta County.
Please be kind, do not hotlink images and do not use images without permission of the copyright owner.
![[Cascades Frog]](/images/10sm.jpg)
![[Cascades Frog]](/images/146sm.jpg)
©Michael A. Peters
Lassen Population Specimen. Notice the prominent dorsolateral fold compared to the American Bullfrog and Foothill Yellow-legged Frog. This frog was located about two hops from the slow moving stream. When startled, it jumped to the bottom of the stream where it remained motionless. Shasta County, CA
![[Cascades Frog]](/images/65sm.jpg)
Habitat Shots
Unless otherwise noted, these habitat shots are from within Shasta County where this species is known to occur.
![[Cascades Frog habitat]](/images/144sm.jpg)
©Michael A. Peters
Cascades Frogs often like to utilize slow moving streams through meadows. Shasta County, CA
![[Cascades Frog habitat]](/images/145sm.jpg)
©Michael A. Peters
The meadow in the background of this photograph probably had over 90% of its surface covered by at least a half inch of water, and it had not recently rained. Shasta County, CA
Species of Special Concern
This species is listed as a Species of Special Concern by the State of California Department of Fish & Game.
If you come across this species, please note that it may be a violation of state law to collect it or even touch it. Federal laws may also apply.
If you can, please do the following:
- Accurately record the location where the animal was found. The best way to do this is with a GPS device.
- Photograph the specimen. Take as many photographs as you can without causing too much stress to the animal.
- Take note of the habitat and its condition. Photographs are good for this, but do not always tell the entire story.
- Take note on any possible threats to the population. For example, if it is one of our threatened native frog species, is there an American Bullfrog population in the immediate vicinity? Are you aware of an American Bullfrog population in a nearby aquatic system? What about erosion? Introduced trout?
- Report the sighting to the California Natural Diversity Database.
It takes a little effort to file a report, but your report may help the necessary agencies protect that population. It is difficult for them to protect populations they do not know about or populations they think are extirpated. Even species of special concern that are currently doing well in Shasta County should be reported. When population declines happen, they tend to happen very fast. Reports of specific localities where a species is known to have occured may help researchers determine survey sites if our population of one of these species does crash.
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