tag:blogger.com,1999:blog-4956022410481522512012-01-27T06:38:04.575-08:00Thoughts about the management of the mountain yellow-legged frog and its anuran kin, aquatic ecosystems, endangered species, and wildlife in general in our human-dominated world.Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.comBlogger961100tag:blogger.com,1999:blog-495602241048152251.post-29508910865773632342012-01-24T08:00:00.000-08:002012-01-27T06:38:04.587-08:00

On February 2, the California Fish and Game Commission will take up the issue of whether the mountain yellow-legged frog (Rana muscosa, Rana sierrae) should be listed as Threatened or Endangered under the California Endangered Species Act (ESA). This action was prompted by a listing petition [PDF] submitted by the Center for Biological Diversity in January 2010. Neither species currently has

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com5tag:blogger.com,1999:blog-495602241048152251.post-64774983325588787682011-12-13T07:24:00.000-08:002012-01-02T19:24:56.846-08:00

For years, the California Department of Fish and Game (CDFG) has used a 1981 Beech King Air airplane to stock backcountry lakes. This aircraft has been specially modified to conduct these stocking operations and is apparently the only aircraft in the state capable of carrying out this task. The Sacramento Bee recently reported that in an effort to cut state spending, California Governor Jerry

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-16600294944123375882011-11-28T12:53:00.001-08:002011-11-28T13:57:36.376-08:00

The amphibian chytrid fungus (Batrachochytrium dendrobatidis: Bd) is the cause of the most spectacular loss of vertebrate biodiversity in recorded history. To date, at least 200 species have been driven extinct and hundreds more have suffered major declines. Even amphibians within the world's best protected ecosystems have been hard-hit, including California's mountain yellow-legged frog (Rana

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-53980369898546948242011-11-07T08:52:00.000-08:002011-11-07T08:52:21.497-08:00

One of the most puzzling aspects about the impact of the amphibian chytrid fungus (Batrachochytrium dendrobatidis: Bd) on amphibian populations is the diversity of disease outcomes. In some landscapes, the arrival of Bd causes the complete extirpation of all populations, but in others it has little or no negative effect on amphibians. There are lots of reasons for these different disease outcomes

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-31872693001938988622011-10-18T08:10:00.000-07:002011-11-07T06:21:10.298-08:00

This summer we focused much of our research effort on resurveying known mountain yellow-legged frog populations in Sequoia and Kings Canyon National Parks. We first surveyed these areas for amphibians and fish 11-14 years ago and found mountain yellow-legged frogs to be pretty common. Since then, on multiple occasions we've resurveyed the subset of sites that had contained mountain yellow-legged

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-29645267197032188922011-09-26T06:00:00.000-07:002011-09-26T06:00:04.947-07:00

Well, the field season is over for another year. I've been doing amphibian-related field work in the High Sierra for almost 20 years now, and I can't remember a summer as weird as this one was. In mid-July, high elevation lakes were still frozen solid. Summer finally arrived at the beginning of August, but in early September I found myself in a backcountry snow storm. As I hiked through a

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-88373999899516929382011-07-18T06:00:00.000-07:002011-07-18T06:00:15.915-07:00

One of the greatest things about my job as a field biologist is the chance to see amazing things happen in the natural world. I see fascinating stuff every day while out in the mountains, but some happenings are truly memorable. In the past, that has included seeing bears swimming in Sierran lakes, Clark's Nutcrackers eating tadpoles of the mountain yellow-legged frog, water shrews diving for

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-51998976169989679002011-06-15T07:06:00.000-07:002011-06-15T15:02:44.158-07:00

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

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-18861869099382200682011-05-23T08:44:00.000-07:002011-05-23T08:44:22.011-07:00

The Los Angeles Zoo is reporting that their technique of holding frogs at cold temperatures over the winter followed by a gradual warm-up in the spring  resulted in another batch of egg masses being laid in March. These egg masses subsequently hatched into hundreds of tadpoles that will be released into the wilds of southern California later this summer. For more information, check out this story

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-58525479313881227772011-05-10T07:07:00.000-07:002011-05-10T07:07:20.906-07:00

During the last decade, Karen Lips and colleagues have documented the spread of the amphibian chytrid fungus (Batrachochytrium dendrobatidis: "Bd") southward through Costa Rica and Panama, and its devastating impacts on amphibian populations. However, it has remained unclear whether Bd was also the cause of declines in areas north of the region studied by Lips et al., including Mexico, Guatemala,

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-88362968048916761562011-04-25T06:00:00.000-07:002011-04-25T06:00:17.061-07:00

Chytridiomycosis is the disease of amphibians caused by the fungal pathogen, Batrachochytrium dendrobatidis. Given the severe impacts of this disease on the world's amphibian biodiversity, there is a lot of interest in mitigating these impacts to the extent possible. I wrote about some of those efforts in a previous post. Doug Woodhams and colleagues have just published a paper that reviews the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-31417718166633823122011-04-18T09:24:00.000-07:002011-04-18T09:24:37.719-07:00

On April 14, biologists from the USGS and the San Diego Zoo released another batch of Rana muscosa egg masses that were laid in captivity. This effort is part of an effort to breed this endangered species in captivity and reintroduce the progeny into the wild in southern California. For more information, check out this link. This reintroduction effort was begun last year and I'm curious to hear

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-40461226708919920992011-04-11T06:00:00.000-07:002011-04-18T09:11:05.808-07:00

The rhetorical and legislative battles waged in Washington, DC in recent weeks over the federal budget suggest that some major changes in science funding may be underway. It is my belief that those possible changes could have real implications for the science of ecology. For years, politicians of all persuasions have spoken of the need for federal funding of science, and this largess has resulted

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-84523103830682961422011-03-30T19:22:00.000-07:002011-03-30T19:22:34.524-07:00

As I’ve mentioned in previous posts, the state Endangered Species Act (ESA) listing process for the mountain yellow-legged frog is underway, with a Status Review document due to the California Fish and Game Commission this October. In addition, the U.S. Fish and Wildlife Service (USFWS) recently sent a letter to state and federal agencies stating their intention to begin the “final rule” process

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-44470648326864703572011-03-14T09:32:00.000-07:002011-03-14T09:32:40.492-07:00

Pesticides have long been hypothesized to be drivers of amphibian declines in the Sierra Nevada. In the early 1970s, Lawrence Cory and colleagues published a study showing that DDT residues could be detected in mountain yellow-legged frogs throughout the Sierra Nevada, and they suggested that this was the result of DDT applications in the Central Valley. Since then, a myriad studies have detected

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-64832602519803676012011-02-08T08:12:00.000-08:002011-02-13T14:41:54.089-08:00

I've studied mountain yellow-legged frogs for the last 15 years, all in the High Sierra, the last stronghold of these beasts. As a consequence of my experiences, when I think of mountain yellow-legged frog habitat in the Sierra Nevada I think of lake basins in the alpine and subalpine zones. But scientists who came before me, including Joseph Grinnell and Richard Zweifel, would have had a very

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-52115186055431066032011-01-25T07:21:00.000-08:002011-01-25T07:21:54.609-08:00

Researchers and managers from California and Nevada held their annual Amphibian Populations Task Force meeting January 6-7, 2011, this time in Yosemite Valley. With more than 100 attendees, the meeting once again provided a great opportunity to hear about the status of myriad frog conservation projects and catch up with colleagues. For me, the most insightful talk was that by Adam Backlin, the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-83071033744340603572010-12-20T11:06:00.000-08:002010-12-20T11:06:35.620-08:00

Non-scientists are often understandably frustrated by the conflicting results commonly reported in the media on any one of a myriad of science-related topics. It seems that hardly a day goes by that we don't hear another story about how a previous study showed one thing but the newest study now refutes those results. With all of this conflicting information I can understand when some people throw

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-23113012553327276842010-12-14T08:39:00.000-08:002010-12-14T08:39:54.497-08:00

I've spent a large portion of the last 10 years describing the spread of the amphibian chytrid fungus (Batrachochytrium dendrobatidis - "Bd") across the Sierra Nevada. Given the hundreds of frog population extinctions that have resulted from the arrival of Bd it is sometimes easy to forget about the other side of this story - that there is also evidence of frog recovery following Bd-caused

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-55636669456280736712010-11-29T08:40:00.000-08:002010-11-29T08:42:24.783-08:00

Last week the U.S. Environmental Protection Agency announced that it would ban the use of endosulfan. Endosulfan is an organochlorine pesticide that was developed in the 1950s. Although it is an effective compound against many crop pests it comes with serious health risks to humans and wildlife, including acute neurotoxicity and endocrine disruption. As a consequence endosulfan is banned in

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-8730075330091721052010-11-22T06:00:00.000-08:002010-11-22T06:00:07.126-08:00

Despite having spent the last couple of decades hiking around the Sierra Nevada to conduct my research I'd never seen a river otter nor heard much about their presence in the mountains.That all changed a few years ago when a colleague observed a family of five otters swimming across a lake in northwestern Yosemite National Park. The following winter he observed otter tracks along a stream while

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-69277924139689876412010-11-08T09:27:00.000-08:002010-11-08T20:26:06.229-08:00

When species are listed under the Endangered Species Act, potential impacts to those species justifiably receive greater scrutiny. In our crowded world an issue that federal and state agencies frequently have to contend with is direct impacts from human visitation on habitat for a sensitive species. One of the key challenges in making such decisions is to balance the need for species protection

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-45585039151618194772010-11-01T09:25:00.000-07:002010-11-01T09:26:20.507-07:00

In late September California governor Arnold Schwarzenegger signed A.B. 2376 into law. This bill was supported by numerous fishing groups, including California Trout, Trout Unlimited, and The Sportfishing Conservancy, and was motivated by the recently-released Treanor Report that suggested changes to how the California Department of Fish and Game (DFG) and the California Fish and Game Commission

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-34621188652241508082010-10-25T06:00:00.000-07:002010-10-25T06:00:08.711-07:00

For the last couple of years our research group has conducted several field experiments aimed at understanding the extent to which we can change the outcome of outbreaks of the amphibian chytrid fungus (Batrachochytrium dendrobatidis - "Bd") from frog population extinction to persistence. This summer and last we treated frogs at die-off sites with anti-fungal drugs, something I never in my

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-89617643241568826802010-10-18T06:00:00.000-07:002010-10-18T06:00:07.044-07:00

This summer I returned again to one of the Sierra's most remote lake basins to resurvey the amphibian populations there. This basin holds a special place in my heart due to its spectacular beauty, isolation, and at one time, an incredible Sierra Nevada yellow-legged frog population. The first time I visited this basin was in 1997 when my assistants and I conducted our initial surveys of its frogs

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-10577785440761117902010-10-11T20:18:00.000-07:002010-10-11T20:18:57.853-07:00

It has been months since I've added any posts. My only excuse is that I've been in the mountains almost continuously since mid-June conducting research. I've been impressed at the number of people who emailed me during my absence from the blogosphere to make sure I hadn't abandoned my practice of regular posts related to the mountain yellow-legged frog. Rest assured that I have not. Now that my

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-63161189311102251922010-05-18T16:50:00.000-07:002010-05-18T16:51:13.458-07:00

The southern mountain yellow-legged frog (Rana muscosa) inhabits lakes, ponds, and streams in the southern Sierra Nevada and southern California. The southern California Distinct Population Segment (DPS) was listed as "endangered" under the federal Endangered Species Act in 2002. This DPS currently contains fewer than 200 adult frogs and these remaining populations are at extreme risk of

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com3tag:blogger.com,1999:blog-495602241048152251.post-52298900866502150812010-05-10T17:28:00.000-07:002010-05-18T15:44:52.664-07:00

Two papers by our research group were published today in the journal, Proceedings of the National Academy of Sciences (PNAS). Both papers are open access and can be downloaded from the PNAS web site (Vredenburg et al. paper; Briggs et al. paper). These papers represent more than a decade of research by our group on the role of the amphibian chytrid fungus (Batrachochytrium dendrobatidis - Bd) in

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-70182183473357658362010-04-20T12:43:00.000-07:002010-04-20T12:44:21.600-07:00

As opening day for trout fishing season approaches, stories in the local papers often dwell on impending issues that might affect the number of fish stocked and stocking locations. Last year the stories focused primarily on issues surrounding the court order that mandated that the California Department of Fish and Game (DFG) prepare an environmental impact report detailing the effects of its fish

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-3633486340280544042010-03-08T07:56:00.000-08:002010-03-08T08:18:48.893-08:00

The media was abuzz this week with frog and fish-related stories. First came the news that the California Fish and Game Commission voted 3-2 to support the listing of the California tiger salamander as "threatened" under the California Endangered Species Act (Santa Rosa Press-Democrat story). Because this species is already federally-listed I don't think this will change the existing management

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-24862603580439862022010-03-01T18:32:00.000-08:002010-03-08T08:18:29.807-08:00

In my last post I mentioned that in addition to the fish stocking lawsuits recently filed by the Center for Biological Diversity and the Owens Valley Committee I'd heard rumor of a third lawsuit. That rumor has now been substantiated. It was filed by Californians for Alternatives to Toxics, the Environmental Protection Information Center, Wilderness Watch, and Public Employees for Environmental

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-20861538484165328052010-02-17T09:32:00.000-08:002010-02-17T09:33:24.476-08:00

The California Department of Fish and Game (DFG) released their court-mandated fish stocking EIR-EIS on January 11, 2010. In response, at least two groups (and I've heard rumor of a third) have filed separate court petitions against the DFG. The Center for Biological Diversity petition focuses broadly on a wide variety of deficiencies in the EIR-EIS, including a flawed baseline against which

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com9tag:blogger.com,1999:blog-495602241048152251.post-7443121751584238902010-02-01T17:03:00.000-08:002010-03-08T08:17:53.800-08:00

On January 11, 2010, the California Department of Fish and Game (DFG) released their badly flawed fish stocking EIR-EIS. In response to the failure of the EIR-EIS to put into place provisions to adequately protect the imperiled mountain yellow-legged frog from impacts caused by hatchery trout, on January 25 the Center for Biological Diversity petitioned the California Fish and Game Commission ("

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-72626674981577115672010-01-25T19:31:00.001-08:002010-01-27T05:52:19.675-08:00

In my view of the world, science has a central role to play in resource management decisions. Scientific information, if obtained from well-designed studies, can serve as a foundation for such decisions, providing a description of the problem and of potential solutions. To be sure, scientific information is only part of the equation, and social, legal, and financial considerations are also

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-22672765509232314282010-01-18T16:54:00.000-08:002010-01-18T16:59:10.144-08:00

The final fish stocking EIR/EIS is now available on the California Department of Fish and Game (DFG) web site. A reading of the pertinent sections has left me, well, dejected. With this document, the DFG had an unprecedented opportunity to develop future fish stocking practices that would benefit both native species and anglers. Instead, they've done everything in their power to maintain the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-61741860660346191602010-01-11T10:58:00.000-08:002010-01-11T10:58:07.670-08:00

On November 7, 2008, Judge Marlette of the Sacramento Superior Court ordered the California Department of Fish and Game (CDFG) to prepare an Environmental Impact Report on the impacts of its fish stocking program. This document was to be submitted "no later than January 11, 2010". That would be today. Rumor has it that the document will be submitted today but no information has yet been posted on

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-72998101225943893742010-01-04T09:15:00.000-08:002010-01-04T17:40:38.455-08:00

One of the most pressing questions related to the amphibian chytrid fungus (Batrachochytrium dendrobatidis - "Bd") is where this pathogen originated from. Unfortunately, we still don't know, but a recently published paper adds an interesting wrinkle to what we do know. Until recently, the available data suggested an African origin. The "Out of Africa" hypothesis was based on the fact that the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-35789692098566417442009-12-06T11:57:00.000-08:002009-12-06T12:01:55.724-08:00

Jim Collins and Martha Crump recently published a new book entitled, "Extinction in Our Times: Global Amphibian Decline". This is a complex subject and by all accounts the authors do a great job of synthesizing this material for the scientifically-inclined as well as for more general audiences. Joe Mendelson, a scientist at the Atlanta Zoo and one of the key players in the Amphibian Ark project,

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-63882273835428516552009-11-24T07:50:00.000-08:002009-11-24T09:15:54.213-08:00

Anybody who read the California Department of Fish and Game (CDFG) draft fish stocking EIR-EIS knows that this document is badly flawed. Many of these flaws, such as an inadequate range of alternatives, are fundamental to the entire document and addressing them would require a major rewrite of the EIR-EIS. However, the court-ordered deadline for the final EIR-EIS is January 11, 2010. How is the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-87377594395162151222009-11-11T07:00:00.000-08:002009-11-24T08:00:01.375-08:00

The DFG trout stocking program currently introduces millions of fingerling, sub-catchable, and catchable trout into lakes and streams throughout California with the goal of improving existing fisheries. In addition to stocked trout, recipient habitats typically also harbor native trout populations or established non-native populations, with the latter having become established following earlier

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-3041241594390589302009-11-08T20:02:00.000-08:002009-11-08T20:16:11.878-08:00

In this post I'll focus on one of the most serious shortcomings of the EIR-EIS: the method used to evaluate the impacts of the current stocking program. In most CEQA documents the environmental impact of a new project is judged by comparing environmental conditions expected under the new project against the current environmental conditions (i.e., without the project). Applying this approach to

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-79411303766769435802009-11-02T08:26:00.000-08:002009-11-02T11:04:33.047-08:00

Last week I mentioned that in my next post I'd write about the flawed evaluation of fish stocking impacts in the California Department of Fish and Game (CDFG) draft EIR/EIS. So, here goes. The flawed evaluation derives from two sources: (1) an inadequate range of management alternatives considered, and (2) the use of the last five years of fish stocking as a baseline against which to judge

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-67372516465630853582009-10-26T09:41:00.000-07:002009-10-26T10:47:17.174-07:00

As stated in last week's blog post, the California Department of Fish and Game (CDFG) recently released their draft fish stocking EIR/EIS to the public. Comments are due on November 16. When the CDFG was ordered by the court to conduct this environmental analysis I had some hope that the CDFG would use this as an opportunity to fully evaluate their current stocking program and make changes that

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-27221341068763731582009-10-18T07:18:00.000-07:002009-10-26T09:28:20.809-07:00

My 2009 summer field season ended in late September. Now weeks later all of the research gear is put away and the data is safely in my lakes database. The summer went largely as expected, with some notable successes and some unanticipated challenges. Below I've provided a summary of what our summer objectives were and what we actually accomplished. But first a sad note....This summer I lost a

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com3tag:blogger.com,1999:blog-495602241048152251.post-82742952472525186632009-06-08T19:18:00.001-07:002009-06-08T19:21:54.226-07:00

Today is the first day of my summer field season. I'll be in the field for the majority of the next three months so my posts during this period will come at irregular intervals. I'll do my best to provide periodic updates but they won't be weekly as they are during the non-summer period.Back to The Mountain Yellow-legged Frog Site.

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-8994110566405657682009-06-01T17:59:00.000-07:002009-06-08T06:59:42.274-07:00

When it comes to the management of California's fisheries and native aquatic fauna Tom Stienstra, the writer of the Outdoors column in the San Francisco Chronicle, and I rarely think alike. In his 5/31/09 column, Tom argues that the budget crisis currently enveloping California is an opportunity to reform the Department of Fish and Game (CDFG). Although I certainly agree that the CDFG is badly

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-31674115890855232332009-05-26T07:17:00.000-07:002009-05-26T08:06:43.878-07:00

Of the Earth's amphibian-harboring continents (all but Antarctica), Asia was until recently unique in not yet having been invaded by the amphibian chytrid fungus (Bd). That now seems to be changing quickly. During the last few years ago Bd was reported from Japan, South Korea, and Indonesia, all countries around the periphery of this amphibian-rich continent. In the last few weeks Bd was reported

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-40621065620448206082009-05-18T07:00:00.000-07:002009-05-18T07:00:02.440-07:00

The number of known amphibian species worldwide has risen by approximately 20% during the the past decade thanks to intense research on this group of vertebrates. A total of 6487 amphibian species have been described to date (www.amphibiaweb.org). That is the good news.Now here comes the bad news. Based on a study published in 2004 in the journal Science, more than 40% of the world's amphibians

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-44365816816207771512009-05-04T08:14:00.000-07:002009-05-04T08:29:30.362-07:00

Much of the recent research on impacts of trout stocking has focused on aquatic ecosystems in California. However, a research program in Maine is now showing just how pervasive these impacts are. Most of Maine's naturally fishless lakes (and there were thousands of them historically) have now been stocked with numerous fish species, including brook trout, and all indications are that these

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-16287447296195059822009-04-27T07:00:00.000-07:002009-04-27T07:00:00.683-07:00

The mountain chicken, Leptodactylus fallax, is one of the world's largest frogs, with adults sometimes weighing up to one kilogram (>2 lbs). This frog was once common on some Caribbean islands but has been decimated by the amphibian chytrid fungus (Bd). In recent years the frogs were found only on the island of Montserrat, an island that until recently was free of Bd. During the last few weeks,

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-20121929206039914072009-04-21T06:46:00.000-07:002009-04-21T07:50:28.524-07:00

When it comes to impacts of introduced trout on aquatic ecosystems, the Sierra Nevada is by far the best-studied such ecosystem in the world. However, an increasing number of studies are now being conducted elsewhere and results from this research make it clear that broad impacts are a common consequence of trout introductions into montane habitats. In recent years, a research group at the Forest

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com14tag:blogger.com,1999:blog-495602241048152251.post-65826971429431581302009-04-14T07:18:00.000-07:002009-04-14T08:15:00.443-07:00

Most research on the impacts of nonnative trout on aquatic habitats in the Sierra Nevada have focused on lakes, in part because these are the habitats favored by the declining mountain yellow-legged frog. This research has shown dramatic changes to vertebrate and invertebrate species composition caused by trout predation on the larger, more conspicuous taxa. Trout also alter nutrient cycling in

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com7tag:blogger.com,1999:blog-495602241048152251.post-71934958808238318282009-04-06T09:20:00.000-07:002009-04-06T12:59:02.192-07:00

I watched the film, "Frogs: The Thin Green Line", last night. Filmmaker Allison Argo and her team did an amazing job of bringing the amphibian decline issue to a general audience. Despite how dire the situation is I was left with a feeling of hope that collectively we just might make a difference. As usual, time will tell.... The film can now be viewed online on the PBS web site.As I mentioned

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com3tag:blogger.com,1999:blog-495602241048152251.post-81722770837973765632009-03-30T08:32:00.000-07:002009-04-06T12:59:38.213-07:00

During the past year filmmaker Allison Argo and her team have been traveling around the world to film declining amphibians and find out from scientists what can being done about it. In addition to filming in Panama and the southeastern U.S., Allison's team also spent a few days with my research group while we conducted research on Sierra Nevada yellow-legged frogs in Yosemite National Park. The

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-39410308557043278272009-03-23T06:00:00.000-07:002009-03-23T06:00:00.677-07:00

Writer Jennifer Holland and photographer Joel Sartore have created a masterful story on the global amphibian decline phenomenon, just published in National Geographic magazine. The situation surrounding the mountain yellow-legged frog is described in the story, and Joel's photographs of live and dead Rana muscosa from Sixty Lake Basin bring this animal's plight into a sad focus. Check it out.Back

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-61441335091288396362009-03-16T17:19:00.000-07:002009-03-16T17:56:09.470-07:00

The ongoing severe declines of mountain yellow-legged frogs in the Sierra Nevada make it all but inevitable that these populations will eventually be listed under the federal Endangered Species Act. Such a listing will trigger the writing of recovery plans for Rana sierrae and Rana muscosa, plans that will undoubtedly call for the development of captive breeding programs. If successful such

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com8tag:blogger.com,1999:blog-495602241048152251.post-22705827519130608272009-03-10T08:11:00.000-07:002009-03-10T08:30:39.207-07:00

Research by Karen Lips and others on amphibian declines in Central America has made clear that the scope of these declines is unprecedented in modern times. In recent years dozens and perhaps hundreds of Central American amphibian species are thought to have been driven to extinction by the amphibian chytrid fungus. The following article provides a glimpse at one of those amphibians, the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-59689205451090416172009-03-03T05:59:00.000-08:002009-03-03T07:34:51.067-08:00

I remember with crystal clarity the day I realized the impact that the amphibian chytrid fungus (Batrachochytrium dendrobatidis - Bd) was having on mountain yellow-legged frogs in the Sierra Nevada. It was July 2000 and my field crew and I were surveying lakes and ponds along the Monarch Divide and Cirque Crest for amphibians and fish. I'd been as excited as a little kid to get into this area

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-67774273940830809352009-02-23T06:30:00.000-08:002009-02-23T06:30:00.645-08:00

April 28, 2009 is the first annual Save the Frogs Day. Check out www.savethefrogs.com/day for more information.The San Francisco Chronicle had a story on efforts to combat the amphibian chytrid fungus in their 2/19/2009 edition. The battle continues....Back to The Mountain Yellow-legged Frog Site.

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-69614286493840662402009-02-17T10:42:00.000-08:002009-03-04T08:40:37.560-08:00

My research on amphibian declines focuses almost exclusively on mountain yellow-legged frogs. As such, it is easy to forget the fact that the amphibian decline phenomenon has a global reach and that these declines affect a huge diversity of amphibian species. Compared to the large body of evidence showing declines in frogs and toads, evidence for salamander declines has been sparse but a new

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-22529087452244430612009-02-09T06:00:00.000-08:002009-02-09T06:00:01.934-08:00

A couple of weeks ago, I attended the annual meeting of the Amphibian Populations Task Force in Bodega Bay. The dozens of talks over two days provided an abundance of new data from a wide array of amphibians in California and Nevada. Perhaps the most relevant information for conservation of the mountain yellow-legged frog was the announcement that the captive population of southern mountain

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-78769281910658723162009-02-02T09:41:00.000-08:002009-02-02T10:36:59.014-08:00

A few years ago, Dave Graber (Chief Scientist, Pacific Southwest Region of the National Park Service) asked me a question that I've never been able to get out of my head. Dave, who studied black bears in the Sierra Nevada for many years, asked me if there was a connection between the dramatic decline of mountain yellow-legged frogs in the 1970s and the coincident increase in the number of bears

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-38866661706990634272009-01-26T06:30:00.000-08:002009-01-26T08:30:17.539-08:00

I've written a fair bit lately about controversies surrounding trout stocking and trout removal. A theme running through many of these posts is that the politics of trout management strike an emotional chord with many members of the angling community, and sometimes those emotional responses get in the way of science-based management decisions. Although I've focused my posts on this topic

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-70992934385818658122009-01-05T07:38:00.000-08:002009-01-19T12:25:06.133-08:00

Sequoia-Kings Canyon and Yosemite National Parks are both preparing draft aquatic management plans that will describe several potential scenarios designed to restore native aquatic fauna while continuing to provide abundant opportunities for recreational fishing. Both plans will likely be released to the public in the next 6-12 months. These draft plans will provide an unprecedented opportunity

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-78840207898342719242008-12-31T09:41:00.000-08:002008-12-31T09:58:29.483-08:00

Today's San Francisco Chronicle contains an editorial (page B-7) on the recent court ruling that suspended fish stocking in some California water bodies in 2009 (for background see my 11/21/08 Frog Blog post). I wrote this piece as a counterbalance to the many stories on this topic printed recently in newspapers that decried the stocking suspension as having major negative consequences for local

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-32356671351174413742008-12-29T14:21:00.000-08:002009-04-02T17:18:43.339-07:00

For thirty years I was passionate about fly fishing and carried a fly rod and a box of hand-tied flies wherever I went in wild places throughout California and the West. As a kid, fishing connected me to aquatic habitats and led me on a life-long pursuit of an endless list of ecological questions: Why did some lakes harbor a few large fish and others many small fish? What species of mayfly was

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-91092667248925806142008-12-12T06:35:00.000-08:002008-12-12T09:10:52.360-08:00

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. As a result of this work, there is now an abundance of information available on the details of how to remove nonnative trout. But how do we go about

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-52811311083954836772008-12-01T08:43:00.000-08:002008-12-01T10:21:21.602-08:00

In response to the recently-finalized interim stocking court order (see 11/21/08 post), on November 24 the California Department of Fish and Game (CDFG) released lists of California water bodies that either will or will not be stocked between now and the January 11, 2010 release of CDFGs draft fish stocking EIR/EIS. What struck me when I looked over the lists is how few waters state-wide will

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com4tag:blogger.com,1999:blog-495602241048152251.post-1439625559622110702008-11-21T08:08:00.000-08:002008-11-21T09:24:12.585-08:00

The California Department of Fish and Game (CDFG), Center for Biological Diversity, and Pacific Rivers Council have spent the last two weeks developing interim fish stocking restrictions that will be in place until the CDFG finishes their stocking EIR/EIS on January 11, 2010 (see 11/12/08 post for background). According to a press release issued by the environmental groups, an agreement on

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-50816366757950552392008-11-12T06:17:00.000-08:002008-11-12T07:22:35.619-08:00

As I discussed in my 4/18/08 post, in late 2006 the Pacific Rivers Council and Center for Biological Diversity sued the California Department of Fish and Game (CDFG) to compel the agency to complete a fish stocking Environmental Impact Report (EIR). In Spring 2007, the court agreed that an EIR was necessary and required that a draft environmental document be completed by the end of 2008.Now with

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-10974510958561602862008-10-31T07:30:00.000-07:002008-10-31T07:30:00.220-07:00

The role of climate change as a driver of amphibian declines is a controversial topic. As I described in my 3/27/2008 post, an article by Pounds et al. in Nature suggested that climate warming in South America was responsible for the emergence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) and subsequent catastrophic amphibian declines on that continent. These results have been

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-674615318651941062008-10-24T07:07:00.000-07:002008-10-24T08:20:12.484-07:00

The arrival of a new disease into a naive animal or human population usually results in strong impacts initially, but the severity of these effects often subsequently declines as the host animals develop resistance to the disease. Recent observations of amphibians persisting following die-offs caused by the amphibian chytrid fungus (Batrachochytrium dendrobatidis - "Bd") has raised speculation

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-76789408798927305192008-10-17T08:00:00.000-07:002008-10-17T09:26:09.620-07:00

I recently read a letter that stated that fish removals, far from benefiting mountain yellow-legged frogs, actually cause outbreaks of the amphibian chytrid fungus (Batrachochytrium dendrobatidis - "Bd"). The purported basis for this is essentially that fish removal causes frog populations to grow and that the resulting increased frog density boosts the likelihood of Bd outbreaks. Furthermore, by

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-14769431977103471562008-10-10T08:00:00.000-07:002008-10-10T08:00:01.412-07:00

The causes of global amphibian declines are hotly debated within the scientific community, but one of the best documented causes is the role of nonnative trout introduced into historically fishless lakes in the Sierra Nevada. (If you'd rather not take me on my word on this one, check out a 2003 review of the topic by Kats and Ferrer - Diversity and Distributions 9:99-110.) The conclusion that

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-36445641501966547462008-10-03T14:59:00.000-07:002008-10-03T16:34:10.485-07:00

Due to an extremely busy summer field season, it has been several months since I've had the luxury of a few days off. As regular readers have surely noticed, that lack of time has seriously limited my ability to continue with my usual weekly posts. But now, with fall in the air, my field season has concluded and I can once again return to a more sane schedule. So, you can look forward to weekly

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-62752413798424684862008-09-07T11:48:00.000-07:002008-09-07T12:29:25.350-07:00

In a previous post ("Frog Sex is a Strange Affair") I discussed the shenanigans that mountain yellow-legged frogs engage in during the breeding season. During a recent trip into the backcountry to survey frog populations, I was reminded of the peculiar sexual behaviors that these frogs display in the fall when frogs are obviously not breeding. With the arrival of shorter days and cooling water

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-63261345382946691942008-08-14T16:03:00.000-07:002008-10-03T18:49:20.287-07:00

I've visited a lot of mountain yellow-legged frog populations this summer during my surveys conducted throughout the Sierra Nevada, and have been amazed (as always) at the variation in frog color patterns that I've seen. Sierra Nevada yellow-legged frogs (Rana sierrae) seem to have relatively invariant color patterns, with their characteristic dorsal dark blotches and smaller cream-colored spots

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-36441823277671156682008-07-20T19:58:00.000-07:002008-07-20T20:22:59.239-07:00

During the past century, trout were introduced to thousands of naturally fishless lakes and streams throughout California's Sierra Nevada to create recreational fisheries. These introductions profoundly changed these aquatic ecosystems, often resulting in the elimination of numerous native species, including amphibians and large-bodied invertebrates. Today there is hardly a single watershed in

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-10869814315724219162008-07-07T07:30:00.000-07:002008-07-07T08:14:58.115-07:00

I've been in the field for most of the last month and given that this is frog breeding season I've seen some pretty bizarre things related to this reproductive frenzy. But first, some background on mating in frogs. To mate, a male clasps a female with his powerful front legs that he wraps around the female just behind her front legs. To strengthen that grip, the male has nuptial pads on the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-78593719891633251912008-06-21T09:39:00.000-07:002008-07-07T07:27:53.064-07:00

In this age of declines in global amphibian populations, signs of hope are often hard to come by. On my recent research trip into Yosemite National Park, I made one of those rare hopeful finds. My field crew and I were hiking through a forested low elevation portion of the Park and approached a small stream flowing through a meadow. As I neared the stream, a Sierra Nevada yellow-legged frog

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-38980141898463074212008-06-13T07:30:00.000-07:002008-06-13T07:37:55.703-07:00

I'm out in the field this week and won't be able to post anything substantive as a result. However, this photo gives you an indication of what we found on our first trip - lots of dead frogs killed by chytridiomycosis. I've seen these die-offs many times, but still get a knot in my stomach whenever I stumble across another one. More next week.Back to The Mountain Yellow-legged Frog Site.

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-39689216433768520892008-06-06T05:57:00.000-07:002008-06-06T07:42:14.850-07:00

The Endangered Species Act (ESA) was signed into law in 1973, and is responsible for bringing numerous species back from the brink of extinction. However, 35 years after its signing the ESA is increasingly showing its age. In 1973, most species endangerment was the result of local impacts that were relatively easy to identify and the resolution of which was generally straightforward. For example,

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-63835685297428459392008-05-30T07:00:00.000-07:002008-05-30T07:00:07.609-07:00

In last week's post, I wrote about the captive breeding of amphibians in general, and this week I'll focus specifically on the mountain yellow-legged frog. With the ongoing decline of this species, the topic of captive breeding seems to come up at every meeting in which population recovery efforts are discussed. Although the debate about what role captive breeding can realistically play in the

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-63098591704616333982008-05-23T06:43:00.000-07:002008-05-23T08:24:18.373-07:00

The Amphibian Ark is a conservation effort developed to implement the ex situ (i.e., captive breeding) components of the IUCN Amphibian Conservation Action Plan (ACAP). The mission of the Amphibian Ark is to "ensure long-term survival of species in nature utilizing short-term ex situ management of amphibian taxa for which adequate protection in the wild is not currently possible". Although it is

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-53300900728440491242008-05-16T07:12:00.000-07:002008-05-16T08:23:56.330-07:00

The southern mountain yellow-legged frog (Rana muscosa) has declined precipitously during the past century (check out www.mylfrog.info for details), and nowhere has this decline been more severe than in the Transverse Ranges in southern California. Mountain yellow-legged frogs are now extinct from 98% of the sites they formerly inhabited and were listed as Endangered in 2002.For the past decade,

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-32985535836074260012008-05-09T05:59:00.000-07:002008-05-09T07:09:41.356-07:00

In last week's post, I wrote about the relative lack of food for mountain yellow-legged frogs at high elevation sites, and some of the tactics they use to fill their bellies despite this scarcity. Despite this disadvantage of high elevation sites compared to lower elevation sites where food is more plentiful, the high elevation habitats also have a distinct advantage - a virtual lack of predators

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-1561268385736619802008-05-02T06:37:00.000-07:002008-05-02T07:40:05.084-07:00

In the back of our minds, I think most of us have a picture of what frog habitat looks like, perhaps a warm pond filled with lily pads and logs. Given this preconception, it comes as quite a surprise to see mountain yellow-legged frogs basking by the thousands at lakes in the Sierra Nevada that lie well above timberline, some at elevations as high as 12,000' (3,660 m). How do they survive in

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-88426422567677644282008-04-25T06:32:00.000-07:002008-04-28T16:50:05.207-07:00

Here in the eastern Sierra Nevada, signs of spring are everywhere. After a winter during which the only common birds were Mountain Chickadees and Dark-eyed Juncos, a host of birds not seen for months are now in every bush and tree. The aspen and cottonwood trees are clothed in catkins, and the trunks of Jeffrey pines smell strongly of vanilla-scented sap. With all of these reminders that summer

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-11229742726559861832008-04-18T04:51:00.000-07:002009-04-02T17:15:12.234-07:00

By the late-1990s, the California Department of Fish and Game (CDFG) was increasingly under fire for its failure to consider the impacts of its Sierra Nevada fish stocking program on native aquatic species, including the mountain yellow-legged frog. Despite an unprecedented effort by the CDFG to survey the thousands of lakes and ponds under their jurisdiction for amphibians and nonnative trout (

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-40469699011417040972008-04-11T06:27:00.000-07:002008-04-11T15:56:35.166-07:00

Following the end of World War II, the California Department of Fish and Game (CDFG) began experimenting with using airplanes to stock trout into High Sierra lakes. Following initial successes, this program was soon used to stock millions of fingerling trout into lakes in remote areas throughout the State. In the Sierra Nevada, the efficiency of aerial stocking allowed thousands of lakes to be

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-77220488957720600362008-04-04T08:53:00.000-07:002008-04-11T15:57:06.446-07:00

My posts during the next few weeks will focus on the fish stocking program of the California Department of Fish and Game. This program provides important and cherished recreational opportunities, but has also caused unintended environmental impacts, including impacts to the mountain yellow-legged frog (www.mylfrog.info).The practice of stocking fish has a long and interesting history. This

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-7986757666597546222008-03-27T06:54:00.000-07:002008-04-11T15:59:05.328-07:00

In 2006, Alan Pounds and colleagues published a paper in the journal, Nature, that claimed to show a link between global warming and the worldwide decline of amphibians. They argued that warming temperatures had allowed the emergence of chytridiomycosis, a disease caused by the amphibian chytrid fungus that has been wiping out amphibian species around the world. Despite providing only weak

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-83119844084328545522008-03-21T11:27:00.000-07:002008-04-11T16:00:11.845-07:00

The removal of trout populations from lakes and streams in California to restore mountain yellow-legged frogs (see http://www.mylfrog.info/threats/introducedfish.html) has generated a fair bit of controversy over the years. Much of the controversy stems from differences of opinion about the degree to which introduced trout are a primary cause of mountain yellow-legged frog declines, and therefore

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-65806839222179459782008-03-14T21:22:00.000-07:002008-04-11T16:01:05.472-07:00

There are a plethora of stories floating around the print media and the internet decrying the impact of mountain yellow-legged frog conservation efforts on Sierra Nevada trout fisheries. The on-the-ground realities paint a markedly different picture. In fact, one of the most remarkable outcomes of the increased research and management interest in mountain yellow-legged frogs is that backcountry

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-42526898111672258962008-03-06T06:39:00.001-08:002008-04-11T16:01:38.355-07:00

Airborne contaminants are suspected of contributing to the declines of amphibians, including the mountain yellow-legged frog in California's Sierra Nevada. Research on this important topic has been hindered by a lack of information on what contaminants are actually present and at what concentrations.The final report of the Western Airborne Contaminants Assessment Project (WACAP) was released on

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-90747714081162898062008-02-28T05:25:00.000-08:002008-04-11T16:02:04.683-07:00

The February 4, 2008 issue of High Country News featured a cover story entitled, "Unnatural Preservation", by Martin Smith and Fiona Gow. In this article, Smith and Gow ponder a question that managers and scientists increasingly face while trying to do their jobs in a warming world: "Do we rush to rescue climate-imperiled species before it's too late? Or do we let nature take its course, quietly

Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0