tag:blogger.com,1999:blog-4956022410481522512024-03-12T19:07:57.902-07:00Frog BlogThoughts 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.comBlogger100125tag:blogger.com,1999:blog-495602241048152251.post-38433030536382423162012-04-16T06:00:00.000-07:002012-04-16T06:00:06.539-07:00Amphibian Chytrid Fungus in The News - Again
The American bullfrog (Lithobates catesbeianus) is currently raised on farms all over the world. Many of these farm-raised frogs are exported to other countries, frequently ending up in the U.S. It is now well-documented that bullfrogs on many of these farms are infected with the amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd). So, when the bullfrogs are exported so too is the Bd.Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-86815930722179225682012-03-19T07:19:00.001-07:002012-03-19T07:22:54.883-07:00Pacific Chorus Frogs As Disease Carriers?
Last week, the journal PLoS ONE published an interesting paper by Natalie Reeder and colleagues that suggested a potential role for the Pacific chorus frog (Pseudacris regilla) as a carrier of the amphibian chytrid fungus (Batrachochytrium dendrobatidis; "Bd"). Numerous media outlets covered the paper (e.g., San Francisco Chronicle), which in essence just adds a few details to a phenomenon thatRoland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com6tag:blogger.com,1999:blog-495602241048152251.post-90666915958297884552012-02-27T06:35:00.000-08:002012-02-27T06:35:14.908-08:00A Grim Future For AmphibiansAs I mentioned in my last post, on February 2 the mountain yellow-legged frog was listed under the California Endangered Species Act. I'm in the process of researching how this listing will affect the management of the frog and its habitat. In the mean time, I thought I'd share a recent story published in Scientific American that serves as a grim reminder of the dire circumstances that amphibiansRoland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com7tag:blogger.com,1999:blog-495602241048152251.post-23853680037182714732012-02-06T09:27:00.000-08:002012-02-06T09:35:52.496-08:00Mountain Yellow-legged Frog is Listed Under California ESA
On Thursday, the California Fish and Game Commission voted unanimously to add both species of the mountain yellow-legged frog to the list of animals protected under California's Endangered Species Act (ESA). The southern mountain yellow-legged frog (Rana muscosa) was listed as "endangered" and the Sierra Nevada yellow-legged frog (Rana sierrae) was listed as "threatened". The reasons given for Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-29508910865773632342012-01-24T08:00:00.000-08:002012-01-27T06:38:04.587-08:00State Listing Decision Nears for Mountain Yellow-legged Frog
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.com6tag:blogger.com,1999:blog-495602241048152251.post-64774983325588787682011-12-13T07:24:00.000-08:002012-01-02T19:24:56.846-08:00California Budget Crisis and the Future of the Aerial Fish Stocking Program
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.com3tag:blogger.com,1999:blog-495602241048152251.post-16600294944123375882011-11-28T12:53:00.001-08:002011-11-28T13:57:36.376-08:00The Origin of the Amphibian Chytrid FungusThe 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-53980369898546948242011-11-07T08:52:00.000-08:002011-11-07T08:52:21.497-08:00Do High Elevations Provide Amphibians with a Refuge from Disease?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 outcomesRoland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-31872693001938988622011-10-18T08:10:00.000-07:002011-11-07T06:21:10.298-08:00The Amazing Disappearing FrogsThis 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-29645267197032188922011-09-26T06:00:00.000-07:002011-09-26T06:00:04.947-07:00Another Field Season......
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-88373999899516929382011-07-18T06:00:00.000-07:002011-07-18T06:00:15.915-07:00Always Something New to SeeOne 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-51998976169989679002011-06-15T07:06:00.000-07:002011-06-15T15:02:44.158-07:00Out 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 Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com6tag:blogger.com,1999:blog-495602241048152251.post-18861869099382200682011-05-23T08:44:00.000-07:002011-05-23T08:44:22.011-07:00Captive Breeding Yields Another Round of EggsThe 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 Roland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-58525479313881227772011-05-10T07:07:00.000-07:002011-05-10T07:07:20.906-07:00New Insights Into the Cause of Recent Amphibian DeclinesDuring 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-88362968048916761562011-04-25T06:00:00.000-07:002011-04-25T06:00:17.061-07:00Mitigating the Effects of Chytridiomycosis - Part 2Chytridiomycosis 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-31417718166633823122011-04-18T09:24:00.000-07:002011-04-18T09:24:37.719-07:00With Spring Come New Frog ReintroductionsOn 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-40461226708919920992011-04-11T06:00:00.000-07:002011-04-18T09:11:05.808-07:00Budget Battles and the Future of Ecological ResearchThe 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 resultedRoland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-84523103830682961422011-03-30T19:22:00.000-07:002011-03-30T19:22:34.524-07:00A Framework for Future Frog Recovery Efforts 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” processRoland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com0tag:blogger.com,1999:blog-495602241048152251.post-44470648326864703572011-03-14T09:32:00.000-07:002011-03-14T09:32:40.492-07:00The Changing View of Pesticides as a Driver of Frog DeclinesPesticides 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 detectedRoland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com1tag:blogger.com,1999:blog-495602241048152251.post-64832602519803676012011-02-08T08:12:00.000-08:002011-02-13T14:41:54.089-08:00Disappearing Frogs and Shifting BaselinesI'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-52115186055431066032011-01-25T07:21:00.000-08:002011-01-25T07:21:54.609-08:00Lessons from the Plight of Frogs in Southern CaliforniaResearchers 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-83071033744340603572010-12-20T11:06:00.000-08:002010-12-20T11:06:35.620-08:00Understanding How Science WorksNon-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 throwRoland Knapphttp://www.blogger.com/profile/04407843022354212177noreply@blogger.com2tag:blogger.com,1999:blog-495602241048152251.post-23113012553327276842010-12-14T08:39:00.000-08:002010-12-14T08:39:54.497-08:00Frog Recovery - An Emerging StoryI'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-55636669456280736712010-11-29T08:40:00.000-08:002010-11-29T08:42:24.783-08:00Pesticide Harmful to Amphibians is Banned in U.S. 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-8730075330091721052010-11-22T06:00:00.000-08:002010-11-22T06:00:07.126-08:00Otters and Trout in Sierran Lakes: Which Came First?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.com14