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Topic: Decline in frog populations


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In the News (Fri 23 Feb 18)

  
  Decline in frog populations - Biocrawler
In many instances, these declines are attributable to adverse human influences acting locally, habitat degradation as a result of deforestation or draining of wetlands, urban encroachment, and pollution.
His research indicated that frogs sheltered from the infiltration of parasites developed normally, while those that were exposed developed deformities.
The mountain yellow-legged frog which typically inhabits the Sierra Nevada lakes have seen a decline in numbers due to stocking of non-native fish (trout) for recreational fishing.
www.biocrawler.com /encyclopedia/Decline_in_frog_populations   (0 words)

  
  Decline in amphibian populations - Wikipedia, the free encyclopedia
Dramatic declines in amphibian populations, including population crashes and mass localized extinction, have been noted since the 1980s from locations all over the world, and amphibian declines are thus perceived as one of the most critical threats to global biodiversity.
Small populations that survive within such fragments are often susceptible to inbreeding, genetic drift, or extinction due to small fluctuations in the environment.
Frogs infected by this disease generally show skin lesions and hyperkeratosis, and it is believed that death occurs because the fungus makes it impossible for the amphibian to respire across the skin.
en.wikipedia.org /wiki/Decline_in_frog_populations   (2097 words)

  
 THE FROG DECLINE IN AUSTRALIA - PUBLISHED IN 1996.
Frog declines appeared to start in Australia in the late 1970's and continued through the 1980's and are still continuing.
The declines may be either as a result of the compounds themselves or the compounds weakening the frogs so that they become vulnerable to other environmental threats such as disease.
Frog declines are continuing and are likely to remain a problem for some time yet.
www.smuggled.com /frodec1.htm   (4496 words)

  
 Informat.io on Frog
Frog populations have declined dramatically since the 1950s, with more than one third of species believed to be threatened with extinction and more than 120 species suspected to have become extinct since the 1980s.
Frogs are used as a food source; frog legs are a delicacy in China, France, and in many parts of the American South, especially Louisiana.
Frogs are used in cloning research and other branches of embryology because frogs are among the closest living relatives of man to lack egg shells characteristic of most other vertebrates, and therefore facilitate observations of early development.
www.informat.io /?title=Frog   (5134 words)

  
 frog
The rapid worldwide decline in frog populations is now a well recognized phenomena which has attracted research efforts from scientists all over the planet in a concerted effort to understand the causes for this alarming occurrence.
Our data indicates that whole body metabolism of acid-exposed frogs for ten days, is not different from the metabolism of frogs exposed to pH 7.0 during the entire experimental period, in spite of the large differences in their survival (see abstract SICB 1998).
In contrast, frogs exposed to pH 6.0 have the same total number of WBC/spleen as controls (frogs exposed to pH 7.0), the same percent WBC as controls and the same percent viable WBC (Journal of Herpetology 2002).
science.widener.edu /~vatnick/frog.html   (0 words)

  
 Frogs Australia Network - Frog Declines
The reasons behind the sudden decline in frog numbers over recent years are still being investigated.
The effects of human activities upon frogs and frog habitats are well documented and include disruption and destruction to natural habitats, the introduction of non-native species, and the use of herbicides and pesticides.
While the reasons for many local losses of frogs can be put down to specific causes such as these, the decline and disapperance of frogs in Australia and other continents from relativelty undisturbed habitats indicates that direct human activities are not solely responsible for all declines.
www.frogsaustralia.net.au /conservation/frog-declines.cfm   (784 words)

  
 Troubled Times: Frog Populations
On October 15, 1996 ZetaTalk stated that Frog Populations with their vulnerable DNA would be affected worldwide, the cause puzzling.
But the decline in frog numbers could be a warning of a much more serious ecological problem.
Frog populations worldwide have been declining for the past 20 years, some to the point of extinction.
www.zetatalk.com /theword/tworx122.htm   (0 words)

  
 Disappering Frogs Activity
In 1992, Gary Fellers and Charles Drost surveyed the frogs and toads in the mountains of California's Yosemite National Park.
Researchers determine the size of a frog population by listening to the frogs calling.
If the frogs and toads at our park have a problem, there may not be a solution we can use to help them.
www.nps.gov /archive/indu/education/westbeach/disappearingfrogs.htm   (511 words)

  
 Frogs | Environmental Encyclopedia
For example, in the leopard frog, the relatively long intestine of the vegetarian tadpole is reorganized to form the short intestine of the carnivorous adult frog because nutrients are more difficult to extract from plant sources.
Consequently physiologists have used frogs for the study of muscle contraction and the circulation of blood which is easily seen in the webbing between the toes of a frog.
Frog anatomical defects are regarded as a warning sign for potential problems in humans exposed to the same chemicals, since retinoic acid regulates human limb development as well.
www.bookrags.com /research/frogs-enve-01   (1831 words)

  
 Dramatic decline of California native frog linked to introduced trout in mountain lakes
Vredenburg began his study in 1996 in the Sixty Lake Basin, a bare, rocky landscape between 10,000 and 11,500 feet in elevation that is a two-day hike from the nearest roadhead.
He spent several years, from June until the snows came in October, documenting the fish and frog populations at the more than 60 lakes in the basin, and noticed a trend first established by UC Santa Barbara researcher Roland Knapp in an earlier survey of Sierra lakes.
The fungus, which is threatening frog populations around the world, attacks the mouthparts of tadpoles as well as adults, and can kill adult frogs.
www.eurekalert.org /pub_releases/2004-05/uoc--ddo051204.php   (0 words)

  
 Where have all the frogs gone
Frogs examined during a middle-school science outing in Minnesota are found to have astonishingly high rates of physical deformities.
In the United States and its territories, major declines of frog populations have been noted in California, in the Rocky Mountains, in Puerto Rico, and in areas of the Southwest.
Scientists who have studied amphibian declines and deformities agree that the deformities are unlikely to have caused the extensive, well-documented declines of many amphibian species worldwide.
www.frogsvilleusa.com /frogs   (0 words)

  
 Fungus infection: Origin of the amphibian chytrid fungus
dendrobatidis is common in African frogs from Ghana, Kenya, South Africa, and Western Africa (12,15) and declines in frog populations are poorly documented in Africa (7,16).
A frog of a related species, X. tropicalis, died in captivity from chytridiomycosis, it was suspected of having contracted the fungus from X. laevis (27).
The establishment of feral populations of X. laevis in Ascension Island, the United Kingdom, the United States, and Chile in 1944, 1962, the 1960s, and 1985 (37), respectively, show that transmission could have become ongoing if these feral populations were infected.
www.racyja.pl /chytrid_fungus.html   (0 words)

  
 The Frog And Tadpole Study Group of NSW inc.
Global frog declines are related to changes in global climate and widespread atmospheric pollution.
Unfortunateley, frog populations that have been decimated cannot be restored and many species have disappeared for ever.
Frogs are sensitive creatures and their demise is a salient warning to mankind that the Earth has finite resources.
www.fats.org.au /frogs/decline.html   (601 words)

  
 Utah Division of Wildlife Resources   (Site not responding. Last check: )
The frogs are found in western North America, as far north as Alaska and as far south as Utah and Nevada.
The Columbia spotted frog is closely associated with the marshy edges of ponds, lakes, slow-moving cool water streams and springs.
Chorus frogs are commonly heard and resemble the sound made when you repeatedly drag your thumb down the teeth of a comb.
www.wildlife.utah.gov /news/04-04/frogs.html   (420 words)

  
 Frog Summary
Frogs are said to croak incessantly before it rains, or to announce or bring rain by croaking.
Frogs range in size from 10 mm (Psyllophryne didactyla of Brazil and Eleutherodactylus iberia of Cuba) to 300 mm (Goliath frog, Conraua goliath, of Cameroon).
Frogs tend to be very different in some ways, but alike in others and it all depends on the species.
www.bookrags.com /Frog   (8207 words)

  
 Nearctica - Environment - Water Pollution - Amphibian Declines
Populations are in decline and some frog populations are showing remarkable abnormalities.
The exact causes of these declining populations and deformations is not entirely known, although a large number of hypotheses have been suggested.
Frog abnormalities, however, seem to be clearly linked to water pollutants, such as pesticides.
www.nearctica.com /environ/water/mfrog.htm   (371 words)

  
 Origin of Amphibian Chytrid Fungus | CDC EID
Chytridiomycosis was proposed as the cause of death in frog populations in the rain forests of Australia and Panama and was associated with the decline of frog populations in Ecuador, Venezuela, New Zealand, and Spain (3–6).
Evidence for a countrywide decline in frog populations in South Africa is lacking (7), and local declines of several species have been ascribed to two main threats, habitat destruction and pollution (8).
Infected frogs were found in 5 of the 9 provinces in South Africa, including the Western Cape (5 of 171), Northern Cape (2 of 22), Free State (6 of 141), Kwazulu-Natal (3 of 152), and Eastern Cape (1 of 137), as well as in Swaziland (2 of 42).
www.cdc.gov /ncidod/EID/vol10no12/03-0804.htm   (3358 words)

  
 [No title]   (Site not responding. Last check: )
Frogs and toads have survived on this planet for over two hundred million years and have done so by being sensitive to the environment.
One frog captured that day had only one hind leg, while another had two feet on one leg and a bony protrusion from the spine." Thus began an intensive investigation of the frogs, which is still ongoing in conjunction with scientists from the Minnesota Pollution Control Agency.
It's clear that not just frogs and toads are negatively influenced by the presence of pesticides in their environment; the common symptom of hindquarter abnormalities and fetal deformities is certainly no coincidence.
www.psln.com /egehrman/frogs.htm   (1240 words)

  
 Blanchard's Cricket Frog - WDNR
Cricket frogs are mostly diurnal (active during the day) in spring and fall, but also nocturnal (active after dark) in May through July when males call night and day to attract mates.
The tremendous flooding of 1993 which resulted in the flushing of several key rivers twice during cricket frog breeding is suspected to be the cause for the most recent declines.
While no cricket frog management plan has been developed, the DNR encourages citizens to reduce the use of environmental contaminants that get into the water supply, and discourages the destruction of the wetlands so critical to the survival of Blanchard's cricket frogs and other Wisconsin wildlife.
www.dnr.state.wi.us /org/land/er/factsheets/herps/Crifrg.htm   (0 words)

  
 Frog, Lizard Extinctions Caused by Climate, Not Fungus, Study Suggests
The massive decline of frog populations in particular has been widely linked to a fungus known as BD, which can wipe out a species in months.
But the new study found slow, steady declines of both lizards and frogs in pristine, protected rain forests that are free of the BD fungus, researchers say.
Populations in the lowlands of Central America were thought to be free of risk," said Steven M. Whitfield of Florida International University, the lead author of the study.
news.nationalgeographic.com /news/2007/04/070417-frogs-lizards.html   (0 words)

  
 Origin of the amphibian chytrid fungus Emerging Infectious Diseases - Find Articles
The sudden appearance of chytridiomycosis, the cause of amphibian deaths and population declines in several continents, suggests that its etiologic agent, the amphibian chytrid Batrachochytrium dendrobatidis, was introduced into the affected regions.
Chytridiomycosis was proposed as the cause of death in frog populations in the rain forests of Australia and Panama and was associated with the decline of frog populations in Ecuador, Venezuela, New Zealand, and Spain (3-6).
B. dendrobatidis is common in African frogs from Ghana, Kenya, South Africa, and Western Africa (12,15) and declines in frog populations are poorly documented in Africa (7,16).
www.findarticles.com /p/articles/mi_m0GVK/is_12_10/ai_n8592189   (785 words)

  
 Ecology of Infectious Diseases: Frog VS. Trout
The large lake in the foreground is a frog population source and the three lakes in the background are trout removal lakes now colonized by large frog populations.
The trout are causing the disappearance of the mountain yellow-legged frog.
For example, frog and toad populations have declined dramatically in the past several years, many in high-altitude places in the United States, Puerto Rico, Costa Rica, Panama, Colombia and Australia.
www.nsf.gov /news/special_reports/ecoinf/vs.jsp   (0 words)

  
 FrogsVilleUSA - Froggy Bloggy
Both are amphibians, but frogs generally spend most of their lives in or near water.
The frogs, which measure less than half an inch, are threatened in their natural habitat in the rainforests of South America....
frog population has dwindled and the eastern tiger salamander is...
www.frogsvilleusa.com /froggy-blog   (0 words)

  
 Burke's Backyard Archives 1999 - Frog Sounds
In the last decade or so, there's been a serious decline in frog populations all over the world, and in Australia alone eight species have become extinct in the last 25 years.
Frogs are having a hard time at the moment, and there are a few things we can do to give them a helping hand.
Frogs eat insects, they also have very thin skin which absorbs chemicals from the air and water.
www.burkesbackyard.com.au /1999/archives/25?p=2004   (388 words)

  
 Lost Frogs
It was entitled: "Frog Hunters Told to Hang Up Their Jam Jar", and was a call from England's Wildlife Trust, a conservation organization, to stop the collection of "frog spawn" by schoolchildren.
Frogs and toads have survived on this planet for over two hundred million years and have done so by being sensitive to the environment.
It's clear that not just frogs and toads are negatively influenced by the presence of pesticides in their environment; the common symptom of hindquarter abnormalities and fetal deformities is certainly no coincidence.
www.sonomacountyfreepress.com /reaction/lost_frogs.html   (1250 words)

  
 Troubled Times: Deformed Frogs
The first major sign that frogs were feeling it was the sudden disappearance of the golden toad in 1989.
Acid rain is known to increase the acidity in soil, which in turn affects the population mix of bacteria and fungi living underground.
These are the kinds of theories that biologists will bring to the table Thursday in an effort to solve the mystery of the declining frog populations and to generate new research funding.
www.zetatalk.com /theword/tword23o.htm   (0 words)

  
 PANNA: Atrazine: Possible Cause of Global Decline in Frogs?
For the last decade, scientists have documented a worldwide collapse in frog populations, and some believe that as many as 20 species are now extinct.
While the declines are well documented, the cause is a mystery; suggested culprits have included global climate change, habitat destruction, toxics, predation from introduced species and diseases.
Though this document is supposed to consider all the major ecological impacts, developmental impacts on frogs like those shown by Hayes' paper are not considered in their risk assessment model.
www.panna.org /resources/panups/panup_20020510.dv.html   (0 words)

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