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The purpose of this guide is to provide a general overview of theamphibian decline issue. In particular, it highlights the geographicextent, severity, causes, and consequences of the problem. As well, itidentifies actions that can be taken toward problem resolution. Whilethis guide assumes the reader has a basic knowledge of amphibiansand conservation issues, it is intended for use by a wide variety ofstakeholders — government agencies, non-governmentalorganizations, academic institutions, private industry, and fundingfoundations. It will be especially useful to those intending to workwithin the United States.

This guide is meant to serve as a springboard for additional effortstoward amphibian conservation. There is an urgent need to translatethe information presented here into products for specific audiences —to effectively reach such groups as policy makers, resource managers,and children.

The guide is designed in three units: 1) a narrative overview of theissue; 2) a series of brief facts on amphibians, amphibian declines, andproblem resolutions; and 3) a listing of resources for furtherinformation. The narrative overview provides the basis fordeveloping an oral presentation on the subject. The facts in brief andlist of resources can be photocopied and distributed as stand alone“fact sheets.”

The reader’s challenge is to identify the means by which he or shecan personally work to conserve amphibians sooner rather than later.

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TADD - Federal Taskforce on Amphibian Declines and DeformitiesPARC - Partners in Amphibian and Reptile ConservationDAPTF - Declining Amphibian Populations Task ForceACA - Amphibian Conservation Alliance

This guide is released as a joint publicationof the Federal Taskforce on AmphibianDeclines and Deformities (TADD), Partnersin Amphibian and Reptile Conservation(PARC), the Declining AmphibianPopulations Task Force (DAPTF), and theAmphibian Conservation Alliance (ACA).

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The clearance process for this guide included a review of the text bymembers of the TADD, PARC, DAPTF, and ACA.

Photos ©Jamie K. Reaser or Antonio Salas may not be reused in anyformat without the express written consent of Jamie K. Reaser orAntonio Salas.

On the cover from top to bottom: Rhacophorus sp., (treefrogs fromTaiwan), in amplexus (©Jamie K. Reaser); Plethodon cylindraceous (slimy

salamander)(©Jamie K. Reaser); Bufo sp. (toad) (Donna Foulke).

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Columbia spotted frog (Rana luteiventris)

TTTTTable of Contentsable of Contentsable of Contentsable of Contentsable of ContentsExecutive Summary .............................................................................. 6

Overview ............................................................................................... 8

Amphibians: Facts In Brief ................................................................. 14

Resolution: Declining Amphibian Populations................................. 24

Opportunities For Problem Resolution.............................................. 25

Resources ............................................................................................ 28

Text References .................................................................................. 31

Treefrog from South America (Hyla granosa)

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ultraviolet radiation? Could this be a signthat global warming is in progress? Arediseases newly emerging or beingtransported further and faster from theirpoints of origin? Although many suchquestions have yet to be answered, several“culprits” have been clearly identified:

• climate change• habitat loss and fragmentation• introduced species (especially fish

and bullfrogs in the western U.S.)• contaminants (especially biocides)• ultraviolet radiation (UV-B)• acid precipitation• disease• unsustainable harvest and trade

Why Care?Amphibians provide many services to

ecosystems and their inhabitants:• pest/disease control• indication of environmental quality• pharmaceuticals (for example,

painkillers)• subjects for a wide variety of

research programs (even in outerspace!)

ExecutivExecutivExecutivExecutivExecutive Summarye Summarye Summarye Summarye SummaryAmphibian Declines

Amphibians, a class of vertebrates thatincludes frogs, salamanders, andcaecilians, are amazing. As a group, theyhave been on this planet long before andever since the dinosaurs. Variousamphibian species have adapted to live inwetlands, forests, deserts, savannas,agricultural landscapes, and cities. Yet allof a sudden, many amphibian populationsare declining around the world.

Ranges of many specieshave been dramatically

reduced and speciesextinctions haveoccurred rapidly,even in “protected”areas.

Concern for theapparent worldwide

decline in amphibianpopulations was initially

voiced by the internationalcommunity in 1989 at the First WorldCongress of Herpetology, held in England.At this meeting, participantspresented scientific papers andexchanged personal accounts ofamphibian declines anddisappearances. Based on theinformation presented at this andsubsequent meetings, amphibianresearchers concluded that thenumber and geographic extent ofthe reports indicated that thesituation should be approached asa potential environmental crisis.

In the decade that hasfollowed, amphibian declines haveindeed come to be regarded as anecological emergency in progress.What is wrong with our planet?Could the thinning of theatmosphere’s protective ozonelayer be increasing exposure to

Gray treefrog (Hyla versicolor)

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• food (protein that is especiallyimportant in many developingcountries)

• inspiration for religion, folklore,and the arts

What To Do?The most evident threat to amphibians

is habitat loss. Any effort to save nativehabitat will help all wildlife. Luckily, someamphibians will benefit from even thesmallest efforts to save wetlands and forestremnants. Promoting a sustainable trade inamphibians and curbing the use of toxicchemicals, as well as greenhouse andozone depleting gases, will provide furtherassistance. These efforts will increase thelong-term productivity of forests andwetlands for human uses as well.

To help amphibians, we need topromote:

• enforced protection of ecosystems,especially forests and wetlands

• strict regulation of toxic chemicals,invasive alien species, andgreenhouse and ozone-depletinggases

• inventory and monitoring ofamphibian populations

• education on the ecological andcultural significance of amphibians

• sustainable use of amphibians andtheir habitats

• training of herpetologists (scientistswho study amphibians)

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2) an international working groupshould be established to determine theextent of the problem using scientificallydefensible information. (See DAPTF page13).

In the decade that has followed, theamphibian decline issue has indeed cometo be regarded as an ecological emergencyin progress. Population declines involvinga large percentage of the amphibiancommunity continue to be documented.Ranges of many species have been dra-matically reduced and species extinctionshave occurred rapidly in some “protected”areas. Furthermore, amphibian popula-tions of multiple species around the worldare experiencing a surge in bizarre andperplexing abnormalities.

OvOvOvOvOverererererviewviewviewviewviewThe Problem

• In the early 1900s a team of biologists surveyed amphibians along a transectrunning through the Sierra Nevada mountains, including Yosemite NationalPark. In the 1990s, biologists Charles Drost and Gary Fellers, then with theNational Park Service, resurveyed the same line. Five of the seven frog and toadspecies had suffered severe declines. The foothill yellow-legged frog (Rana boylii)had completely disappeared from the area. The mountain yellow-legged frog(R. muscosa), once the most abundant species, consisted of only a few remainingpopulations.

• The golden toad (Bufo periglenes) of Costa Rica, so named because of the male’sbright orange color, never failed to show up for its annual spring breeding orgyfrom the early 1970s through 1987. Dr. Martha Crump, then at the University ofFlorida, and her colleagues counted more than 1500 individual adult goldentoads and a few tadpoles in 1987. In 1988 only 11 adults were found. A singleadult male was last observed in 1989. Despite intensive searches, no goldentoads have been seen since. The species is now believed extinct.

• In Australia, just north of Brisbane, a small frog was discovered in 1972. Thegastric brooding frog (Rheobatrachus silus), so named because it swallowed

and brooded its young in its stomach, was an immediate wonder toscience. It was also a potential boon for physiologists interested in

finding cures for ulcers and possibly other gastric disorders inhumans. The frog has not been seen since 1981. There is littleclue as to what caused its presumed extinction. It was found inrelatively undisturbed tropical forest, far from routine humanactivity. The loss is of worldwide significance.

History Concern for the

apparent worldwidedecline in amphibian

populations was initially brought to theattention of the international communityin 1989 at the First World Congress ofHerpetology, held in England. At thatmeeting, participants presented scientificpapers and exchanged personal accountsof amphibian declines and disappearances.Based on the infor-mation exchanged atthis and subsequent meetings, amphibianresearchers reached two major conclusions:

1) the number and the geographicextent of the informal reports indicate thatthe situation should be communicated andapproached as a potential environmentalcrisis; and

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The Causes of Decline What is wrong with our planet? Could

the thinning of the atmosphere’sprotective ozone layer be increasingexposure to ultraviolet radiation? Couldthis be a sign that global warming is inprogress? Are diseases newly emerging orbeing transported further and faster?While many such questions have yet to befully answered, a few “culprits” have beenclearly identified:

Habitats: Clearedand Drained

The most evidentthreat to amphibians isthe loss of forest andwetland habitats. Largeherds of buffalo oncecreated systems ofwallows throughout theGreat Plains, providingextensive surface water for amphibians.Beaver, the master wetlands engineers,once used their dam-building skills tocreate and maintain massive, complexwetland systems throughout much of theUnited States. Due to over-hunting and“pest control,” buffalo and beaver are nowgone from many regions, particularly theAmerican West, and their former lands rundry.

Each year more forestland is clearedand additional wetlands are drained.Increasingly, the conversion is permanent;urban and suburban developments replacehabitat with concrete and well-maintainedlawns. The high levels of consumerism inthe United States result in a seeminglyinsatiable hunger for land and water.Technological advances enable

exploitation that is more rapid andextensive than at any time in history.Given the rapid rate and extensive scale ofchange, many amphibian species areunlikely to adapt and survive.

Trading Away Our FutureSome amphibians travel far from their

native range. Increasing internationaldemands result in the trade of amphibiansas pets, food, medicine, research subjects,

souvenirs, and evenaphrodisiacs. While ithas been welldemonstrated thatseveral amphibianspecies can besuccessfully raised incaptivity, data on theU.S. import and exportof amphibians suggestthat many species areharvested from the wild

by the hundreds to thousands annually.Because the population size and naturalhistory of most amphibians are so poorlyknown, it is currently impossible toaccurately determine their sustainablelevels of use. For most regions of theworld, the regulation and enforcement ofthe amphibian trade is weak or non-existent. Furthermore, large numbers ofamphibians die under inhumaneconditions when they are transported.

PoisonedBecause of their porous skin,

amphibians may be particularly susceptibleto chemical contamination. Wetlands arethe repository for everything that runsdownstream or washes downhill. Thechemicals that drain off of roads can createa complex, toxic cocktail that includes suchingredients as gasoline, oil, and ice-melting agents. The rapid increases inhuman population size and consumerspending mean that more food must beproduced for local use and export. The“modernization” of agriculture intensifieschemical use. Large amounts of variousfertilizers and pesticides are added to theenvironment. These chemicals often areapplied directly to amphibian habitats.However, they may also be transported by

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air or water and carried long distances,impacting amphibians far from theoriginal point of contamination. Severalof the chemicals used in the United States,known to be toxic to wildlife and threatenhuman health, have been banned for useby other countries.

Game OverThere is increasing evidence from

around the world that where non-nativepredators such as fish,crayfish, and bullfrogsare introduced,amphibians oftendecline. These“invasive alienspecies” have beenintroduced outsidetheir native ranges forcommercial andrecreational purposes,as food for otherspecies, and as biological control agentsfor pests, many of which are also non-native species. A great diversity of theseanimals also have entered our watersthrough the hands of bored pet ownerswho release their captive pets, thepurposeful stocking of warm waters byaquarists, the dumping of bait buckets, andas escapees from aquaculture facilities.Many of these invasives consumeamphibians (adults, young, and eggs), andalso compete with amphibians for insectprey. Invasive species can carry diseasesand parasites, potentially spreading themto native amphibians.

Atmospheric ChangesAs our atmosphere’s protective ozone

layer is depleted, damaging ultravioletradiation (UV-B) from the sun reaches theearth in greater quantities. Ultravioletradiation is, in part, what causes sunburnin people, and it can harm amphibians aswell. UV-B damages DNA, a cell’s sourceof genetic information. As a result, thecells mutate or die. Some species ofamphibians create a product calledphotolyase that repairs this damage intime to save themselves, but many otherscannot produce the chemical.

Since the early 1970s climatologistshave projected a rapid increase in globaltemperatures. Changing weather patternsthat result in drier conditions, alter thetiming of the seasons, or lead to extremelyhot and cold temperatures could threatenamphibians. If the current projections areaccurate, global warming will have such animpact on many regions of the world.There is now evidence that the goldentoad (Bufo periglenes) and several other

species of frogs atMonteverde Cloud ForestReserve in Costa Ricadisappeared, at least inpart, due to a shift inclimate; the region is nowwarmer and drier thanwhen the frogs thrived. Inthe United Kingdom globalwarming seems to becausing several species offrogs and newts to breed

weeks earlier than they did twenty yearsago. The newts used to breed after thefrogs, but now breed earlier and devourfrog eggs and tadpoles.

Sick and DyingAt several sites around the world where

biologists have found multiple species ofdead and dying amphibians, abnormaltadpoles, and/or dead egg masses, diseaseseems to be one of the culprits. Whenanimals are stressed, their immune systemsweaken, making them especiallysusceptible to infection by a wide variety ofviruses, bacteria, and fungi. In most casesin which diseases impact amphibians, theoriginating stressors themselves areunknown. There is little information onthe biology of most disease-causingorganisms. In the search for the causes ofamphibian declines, researchers continueto discover new amphibian diseases. Wherethey came from, by what means theyattack, and how they are moved from onesite to another have yet to be determined.

Implications For Society and theEnvironment

Amphibians warrant substantialconservation attention. To some theyprovide inspiration and natural services.

Bullfrog (Rana catesbeiana)

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For others, they have become a profitablesource of commercialization. Amphibiansare considered valuable indicators ofenvironmental quality, and concern thatamphibian declines serve as a warning ofthreats to human health has invoked theattention of the public, research biologists,and policy makers.

Amphibians are not protected by fur,feathers, or scales. Chemicals andradiation readily penetrate their skin.Thus, they unwittingly sample what we addto the environment. Their populationdynamics may therefore provide a reliablegauge of environmental quality. When thepopulation size is large and young animalsare regularly added to the population, theenvironment is likely in good health.However, when the number of individualamphibians decreases dramatically andyoung animals are not produced or dieprematurely, biologists are inspired toinvestigate whether a decline inenvironmental health is responsible.

Because amphibians occupy both waterand land habitats on all continents exceptAntarctica, they can provide us withgeographically comparative information.The spatial extent of an amphibianpopulation decline provides valuableinsights as to the causative factors. Forexample, climate change would beexpected to have a broad impact onwildlife populations, while a chemical spillmight have very localized repercussions.By monitoring the dynamics of amphibianpopulations, we can identify and prioritizeour responses to regions and habitats thatseem to be declining in environmentalquality.

Amphibians arethe most diversegroup of terrestrialvertebrates. Theapproximately4,800 speciescurrently describedby science employmany different lifehistory patterns. Forexample, somespecies are only

aquatic, while others are only terrestrial.Some species spend the majority of theirlives underground, and some speciesprimarily are found high in the canopy oftrees. Many species have aquatic larvalforms that metamorphose into terrestrialadults, but some produce young that aretiny replicas of their parents. This greatdiversity provides yet another tool forevaluating environmental quality and foridentifying factors that threaten ecologicalsystems. For example, if the amphibiansthat are dying in a given area are mostlyaquatic species, aquatic breeding species,and aquatic larval forms of terrestrialspecies, we would suspect that the factor(s)contributing to the decline in the amphib-ian community will be found in the fresh-water systems. If the only species im-pacted are aquatic species that breed or

have larval developmentin the spring, we mightfurther suspect that thethreats have a specifictime component.

Amphibians have veryimportant functions in thefood chains of bothaquatic and terrestrialsystems. Amphibiansconsume aquatic©

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vegetation, as well as invertebrates andother vertebrates. In the absence of fish,amphibians are usually the top predatorsin freshwater systems. However,amphibians are also prey to numerouspredators, including snakes, fish, birds,mammals, spiders, and even each other.Consequently, amphibians influence thepopulation dynamics of other organisms,as well as the cycling of nutrients and theflow of energy.

In some developing countriesamphibians are an important source of theanimal protein consumed by local people.Frogs are exploited as delicacies andaphrodisiacs in Europe, Asia, the UnitedStates, and many other countries.Amphibians, in finding novel ways to wardof predators and disease, have becomeliving “chemical factories.” Thecompounds they produce have inspiredthe development of some painkillers andantibiotics. Furthermore, amphibianproducts have had critical roles inadvancing the treatment of wounds,certain cancers, such as small cell lungcancer, and gastrointestinal problems.Even the treatment of mental healthdisorders such as schizophrenia maybenefit from compounds specific toamphibians.

Because many hunting poisons,ceremonial hallucinogens, and traditionaldrugs are amphibian products, and thecalls of frogs often coincide with life-giving

rains, amphibians are totems of luck fornumerous native cultures. Frogs are modelsystems for laboratory research andinstruction, as well as field studies thathelp explain the complexity of biologicalsystems. Amphibians appeal to the humanspirit, and provide inspiration for religion,folklore, and the arts, as well as corporatemarketing campaigns. Due to theiraesthetic appeal, amphibians have becomeincreasingly popular in the pet trade.

The amphibian decline “crises”demand that the status of amphibianpopulations be assessed rapidly and thatwhere declines are apparent, mechanismsbe identified, habitats managed, andrecovery programs established. This ismuch more easily stated thanaccomplished. Studies critical tounderstanding the population dynamics ofamphibians are a challenge to supportfinancially; scientific funding is usuallyprovided for three-year cycles, but long-term research and monitoring oftenrequire ten or more years to complete.And, time is not on the side of theamphibians: human population andresource consumption continue toincrease, rapidly changing the landscapein which amphibians have been evolvingfor roughly 350 million years.

The ChargeWhile the world’s amphibian

community has already sufferedpermanent losses, hope exists, at least forsome species. At a few sites thatexperienced rapid declines, amphibianpopulations have rebounded or been re-established by colonizing individuals.Maintenance andrecovery ofenvironmentalhealth, and therestoration offragmentedlandscapes, willenable manyamphibian speciesto persist. Withthe properguidance,conservation

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Wandering garter snake (Thamnophiselegans vagrans) eating a Columbia spottedfrog (Rana luteiventris)

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The Players:Searching For and Implementing the Solutions

Declining AmphibianPopulations Task Force (DAPTF)

An international investigatory team, theDeclining Amphibian Populations TaskForce operates under the umbrella of theWorld Conservation Union’s SpeciesSurvival Commission. Formed in 1990,DAPTF employs a scientific approach toamphibian conservation; thousands ofscientists volunteer their expertise to theprogram. The primary objectives of theDAPTF are to determine the geography,extent, and causes of declines anddisappearances of amphibians.

Working groups coordinate theprogram’s efforts across geographicregions and examine potential causes ofamphibian declines, including toxins,UV-B radiation, and disease. DAPTFproduces “Froglog,” a newsletter primarilyfocused on working group updates andsummaries of recent research findings.DAPTF supports research on amphibiandeclines through its “Seed Grant”program.

Partners in Amphibian andReptile Conservation (PARC)

Partners in Amphibian and ReptileConservation (PARC) was established in1998 to facilitate communication andcooperation amongst governmentagencies, industry, academic institutions,funding institutions, hobbyists and thepublic. PARC is not a funding organiza-tion; rather, it is a network of individualsand organizations committed to workingcooperatively to conserve amphibians,reptiles, and their habitats. Five workinggroups coordinate PARC activities:

research, monitoring, management,education, and international policy.

Taskforce on AmphibianDeclines and Deformities (TADD)

Formed in 1998, TADD is the UnitedStates’ federal interagency response to thephenomena of amphibian declines andabnormalities. TADD’s mission is topromote and coordinate federal agencyactivities for elucidating the causes of theseproblems and implementing the solutions.Four working groups (international,science, conservation, and education)coordinate taskforce activities.

Amphibian ConservationAlliance (ACA)

ACA is a nonprofit, science-driveneducation and advocacy organizationestablished in 1997. ACA promotes theconservation and restoration of amphibianspecies and populations by supportingscientific research efforts related toamphibian conservation and restoration,and by facilitating the establishment andmaintenance of an effective publicconstituency. ACA produces a newsletterentitled “Ribbetting News.”

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organizations, societies of naturalists, andregional agencies can successfully establishlocal amphibian inventory and monitoringprograms. Concerned citizens can joinforces to restore private lands and tosupport government policies that protect

and restore critical habitats.Environmental education programs can bedeveloped to bring to light the manyimportant roles that amphibians play invarious societal and ecological contextsaround the world.

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Natural History• Three groups.

Amphibians consist ofthree major groups ofanimals: frogs(including toads andtreefrogs), salamanders(including newts), andcaecilians (little-known,worm-like creatures ofthe tropics).

• Numbers.Approximately 4,800amphibian species havebeen described byscience. The rate of species loss isimmeasurable; we don’t know howmany amphibian species have comeand gone without recognition.

• “Dual lives.” The term amphibianis derived from Greek words (ambiand bios) that combine to meandual life. Many amphibian specieshave an aquatic larval (tadpole)form that metamorphoses into aterrestrial adult form.

• Long-term residents. Amphibiansevolved during the Devonian Era,and have survived approximately350 millions years of climatic,geologic, and biological changes.

• Adaptable. Amphibians have themost diverse life histories of anyterrestrial vertebrate. They haveadapted to thrive not only in themost stable and resource richenvironments, such as rainforests,but also in those most variable andhostile, including deserts wherewater may be limited to temporarypools of rain.

• Abundant. In some wetland andforest ecosystems, amphibians arethe dominant vertebrate group interms of total number of

individuals and/or biomass(weight).

• Permeable skin. Amphibianstransport water and air primarilythrough their skin rather thanstomach and lungs. One group ofsalamanders (Plethodontidae) lackslungs altogether. Regardless of lifehistory pattern, amphibians remainobligated to moisture throughouttheir lives.

• “Cold-blooded.” An amphibian’sbody temperature is stronglyinfluenced by the temperature ofits surrounding environment. Inorder to keep from becoming toohot or cold, an amphibian mustchange its body position, location,or employ a number of interestingphysiological adaptations; forexample, the wood frog, Ranasylvatica, produces a type of “anti-freeze.”

• Big families. Most species of frogswhich breed in ponds and otherwetlands lay egg masses consistingof hundreds to thousands of eggs.In one instance, a single femalebullfrog (Rana catesbeieana) laid47,840 eggs in one gelantinousmass! Such big families are

Horned frog (Ceratophrys sp.)

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Amphibians: FAmphibians: FAmphibians: FAmphibians: FAmphibians: Facts In Briefacts In Briefacts In Briefacts In Briefacts In Brief

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necessary to increase the likelihoodthat at least a few of the offspringwill survive to adulthood.

• Little Families. Amphibians thatprimarily reproduce on land and intrees (water-filled cavities,epiphytes, etc.) tend to have smallclutch sizes; some lay as few as ahalf-dozen eggs. In some of thesespecies, parents guard their nestsand young in order to better thechances of survival.

• Long life potential. Although themajority of amphibians will liveonly a few years, individuals ofmany species have the potential tolive for one or more decades.

Major North AmericanMajor North AmericanMajor North AmericanMajor North AmericanMajor North AmericanAmphibian GroupsAmphibian GroupsAmphibian GroupsAmphibian GroupsAmphibian GroupsA. Completely aquaticA. Completely aquaticA. Completely aquaticA. Completely aquaticA. Completely aquatic

1. Salamanders (for example,hellbender, mudpuppy, siren,amphiuma, neotenic1

ambystomatid salamanders).2. Frogs (for example, African

clawed frog; introduced)

B. Lentic (still water) breeding/B. Lentic (still water) breeding/B. Lentic (still water) breeding/B. Lentic (still water) breeding/B. Lentic (still water) breeding/semi-terrestrial adultssemi-terrestrial adultssemi-terrestrial adultssemi-terrestrial adultssemi-terrestrial adults

1. Salamanders (for example,ambystomatid salamanders,newts2)

2. Frogs (for example, spottedfrogs, wood frogs, treefrogs,toads)

C. Lotic (running water) breeding/C. Lotic (running water) breeding/C. Lotic (running water) breeding/C. Lotic (running water) breeding/C. Lotic (running water) breeding/semi-terrestrial adultssemi-terrestrial adultssemi-terrestrial adultssemi-terrestrial adultssemi-terrestrial adults

1. Salamanders (for example, redand spring salamanders)

2. Frogs (for example, foothillyellow-legged frog, tailed frog)

D. Completely terrestrialD. Completely terrestrialD. Completely terrestrialD. Completely terrestrialD. Completely terrestrial1. Salamanders (for example, red-

backed salamander, slendersalamanders)

1Animals reach sexual maturity but retain the larval form.2The eastern red-spotted newt (Notophthalmus viridescens) has an aquatic larval form that metamorphoses into a terrestrialsubadult form (red eft). When the newt reaches sexual maturity (3-7 years) it makes a few more changes (morphologicaland physiological) and returns to the water for the rest of its life.

Pacific treefrog (Hyla regilla)

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Two-lined salamander (Eurycea bislineata)

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RolesBiologicalCritical roles in providingNature’s services.

• Consumers. As larvae, manyamphibians graze on plant matterand debris. As adults, mostamphibians prey upon smallinvertebrates, such as insects, andother vertebrates. The giant toad(Bufo marinus) will opportunisticallyconsume dog food and garbage.One species of tropical frog isknown to eat fruit.

• Prey. Amphibians provide animportant prey base for birds,mammals, fish, reptiles, insects,and spiders. Amphibians will evenconsume each other. Some speciesof bats and snakes consume onlyamphibians.

• Efficient. One study indicates thatamphibians can be remarkablyefficient at converting food forgrowth and energy. The red-backed salamander (Plethodoncinereus) has an efficiency rate of95%, compared to 1-5% forhumans.

SocietalImportant sources of inspiration,players in health care andinternational economies.

• Chemical factories. Huntingpoisons, ceremonial hallucinogens,and medical drugs have beenderived from amphibians. Manypainkillers and antibiotics weredeveloped from amphibianproducts. Amphibians arecurrently employed in searches forcures to several major diseases.

• Pest/disease control. Amphibiansconsume large quantities of insects.By preying upon mosquitoes,amphibians may have critical rolesin the control of diseases, such asmalaria, especially in tropicalcountries.

• International trade. Amphibiansare used throughout the world byculinary, biological supply, and petmarkets.

• Charismatic. Amphibians provideinspiration for religion, folklore,the arts, and corporate marketingcampaigns. Amphibians are totemsof luck for numerous nativecultures.

Status• Species extinctions. Within the

last two decades, entire amphibianspecies have mysteriouslydisappeared, most notably inAustralia and Central America.Recent disappearances in theUnited States include the extinctLas Vegas Valley leopard frog3 andthe extirpated Tarahumara frog.4

• Range reductions. Due todocumented rarity and severereductions in range size, manyspecies in the United States arenow protected, or have beendeclared warranted for protection,under the federal EndangeredSpecies Act.

• Increased recognition of rarity.Advanced molecular techniques arerevealing that several broad-ranging species are actuallycomplexes of multiple, similar-looking species. This means thatmany species are rarer and morevulnerable than previously thought.

3The Las Vegas Valley Leopard frog (Rana fisheri) was likely always a rare species.4The Tarahumara frog (Rana tarahumarae) is still abundant in parts of Mexico.


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• Stability. Amphibian populationdynamics typically fluctuate and areoften characterized as “boom andbust.” For this reason, long-term(more than a decade) monitoringprograms are required todetermine whether amphibianpopulations are stable. Suchmonitoring programs exist at onlya few sites in the world.

• Range confusion. Someamphibian species are relocated asgame species or as a prey base forgame species. This practicethreatens native amphibians byintroducing predators, competitors,and disease. Furthermore, itcomplicates our ability to assess thestatus of native amphibianpopulations.

Patterns Of Decline• Natural wetland loss. In both

urban and rural areas, amphibian

rangereductionscorrelatewith theloss anddegradationof natural wetlands.

• Even protected areas. Many of therecent, rapid population declines(and even some extinctions) haveoccurred in protected parks andwilderness areas.

• Species introductions. Through-out the world, amphibians arebeing lost at locations where gamespecies (for example, fish and alienamphibians) have been introduced.

• Ultimate factors. Variouspathogens (bacteria, fungi, fungal-like algae, and viruses) are oftenthe ultimate causes of amphibianmortality. The specific stressfactors that made these amphibianssusceptible to disease are largelyunknown.

List of U.S. fList of U.S. fList of U.S. fList of U.S. fList of U.S. federederederederederally endangally endangally endangally endangally endangererererered anded anded anded anded andthrthrthrthrthreatened amphibians*eatened amphibians*eatened amphibians*eatened amphibians*eatened amphibians*

EndangeredEndangeredEndangeredEndangeredEndangered ThreatenedThreatenedThreatenedThreatenedThreatened

SalamandersSalamandersSalamandersSalamandersSalamandersBarton Springs (Eurycea sosorum) Cheat Mountain (Plethodon nettingi)Desert slender (Batrachoseps aridus) Red Hills (Phaeognathus hubrichti)Santa Cruz long-toed San Marcos (Eurycea nana)

(Ambystoma macrodactylum croceum) Flatwoods (Ambystoma cingulatum)Shenandoah (Plethodon shenandoah)Sonoran tiger (Ambystoma tigrinum stebbinsi)Texas blind (Typhlomolge rathbuni)California tiger (Ambystoma californiense5)

FrogsFrogsFrogsFrogsFrogsArroyo toad Puerto Rican crested toad (Bufo microscaphus californicus6) (Peltophryne lemur)Houston toad (Bufo houstonensis) Guajon (Eleutherodactylus cooki)Wyoming toad (Bufo hemiophrys baxteri) California red-legged (Rana auroraGolden coqui (Eleutherodactylus jasperi) draytonii)

*Most of these species have geographically restricted ranges.Additional species await federal listing and numerous species andsubspecies are on state endangered species lists.

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Treefrogs from SouthAmerica (Hyla brevifrons)

5Santa Barbara Co. pop.6May soon be reclassified as a distinct species, Bufo californicus

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Causative Factors: State OfKnowledgeHabitat Loss

• Permanent wetlands. In the twocenturies from 1780-1980, thelower 48 states lost an average of54% of the estimated original 221million acres of wetlands. Somestates have been profoundlyimpacted; for example Iowa haslost approximately 95% of itswetlands. Small wetlands (< 0.2 ha)are being lost particularly fast.Furthermore, wetlands serve asdeposition sites for numerouschemical, metal, and nutrientpollutants.

• Ephemeral wetlands. Thetemporary, small rain-filled vernalpools that many amphibiansdepend on for breeding are ofteneliminated for road grading,mosquito control, and “tidiness.”

• Forestry. The practices of tree anddeadfall removal make habitatsunsuitable for many amphibians byincreasing ground temperatures,reducing moisture, and eliminatingrefuge sites.

Habitat Fragmentation• Roads. Many amphibians must

travel long distances to and frombreeding sites. Mortality due toautomobile traffic can alterpopulation dynamics and causesignificant losses of both breedingadults and dispersing juveniles.

• Drains/culverts. In urbanenvironments, amphibians can betrapped in roadside drains,culverts, and other open systemswhere they are drowned, starved,or swept into inappropriate habitat.

• Curbs. Roadside curbs can act asbarriers to dispersal, trappingamphibians in traffic-prone areas.

• Chemistry. Because amphibianshave limited chemical tolerances,even small patches of pollutants orextreme pH can preventamphibians from dispersing widely.

Introduced Species• Deadly game. Amphibians can be

eliminated when predacious gamefish, crayfish, and bullfrogs areintroduced to aquatic habitats. Fishintroduced as bait and for mosquitocontrol have also been shown toprey upon amphibian eggs andlarvae.

• Variable susceptibility.Amphibians inhabiting the

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Treefrog from Taiwan (Rhacophorus sp.)


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historically fishless aquatic systemsof the western U.S. and highelevations nationwide areparticularly vulnerable tointroduced species. Theseamphibians may not have had theopportunity to evolve adequatechemical and behavioral defensemechanisms.

• Disease transmission. Manypathogens carried by introducedfish have the potential to infectamphibians, particularly ifamphibians are under stress.

• Increased isolation. There isincreasing evidence that someamphibians can chemically detectthe presence of fish. Amphibiansthat avoid water inhabited byintroduced fish becomeincreasingly isolated in marginal,fragmented habitats.

Climate Change• Species extinctions. There is now

scientific evidence suggesting thatthe golden toad (Bufo periglenes)and severalother species offrogs atMonteverdeCloud ForestReserve inCosta Ricadisappeared, atleast in part,due to a shift inclimate. Theregion is nowwarmer anddrier than whenthe frogsthrived.

• Breeding time.In the UnitedKingdom five

species of amphibians bredsignificantly earlier in 1990-1994than they did in 1978-1982. All ofthe shifts in the timing of breedingcorrelated with changes in climateover the same period; winter andspring average temperatures aresteadily increasing.

Ultraviolet Radiation (UV-B)• Species-specific mortality.

Laboratory and field experimentshave demonstrated that specieswith low levels of DNA repairenzymes such as photolyase haveembryos that are particularlysusceptible to mortality via UV-Bradiation.

••••• Developmental abnormalities.Laboratory research and fieldstudies have revealed that thelarvae of some species ofamphibians may suffer abnormaldevelopment (for example,skeletal, eye and skin deformities)when exposed to typical and/orincreased levels of UV-B radiation.

White’s treefrog (Litoria caerulea)

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••••• Damage. UV-Bradiation can causeretinal damage in theeyes of adultamphibians.

• Geographic variation.UV-B radiation isgreatest at higherelevations and towardthe polar regions.Deterioration of theozone layer willincrease the amount ofUV-B reaching theEarth’s surface.

• Buffers. Vegetationand cover objects, such as logs, canreduce the amount of UV-Breaching terrestrial amphibians.Some amphibians are behaviorallyadapted to place their eggs in lowUV-B microhabitats.

• Synergisms. UV-B can increaseamphibians’ susceptibility todiseases such as the pathogenicfungal-like algae Saprolengia. LowpH can exacerbate the negativeimpacts of UV-B radiation.

Contaminants• Deadly cocktails. Laboratory

studies demonstrate that, tovarying degrees, amphibians aresusceptible to compounds such asbiocides, heavy metals, andpetroleum products that oftencontaminate aquatic systems.

• Aerial spraying. Numerouschemicals, particularly those usedin the agricultural industry, aredispersed from aircraft. Thispractice provides significantopportunity for the biocides to becarried by air currents and tocontaminate non-target areas,including wetlands.

• Endocrine connection. Laboratorystudies have shown that certainsynthetic chemicals, includingmany biocides, can mimic orinterfere with the action ofnaturally occurring hormones.Because of the critical role thathormones play in development, thenegative impacts can bedevastating. Research is currentlyunderway to evaluate the role ofthese “estrogen disrupters” in theamphibian decline scenario.

• Prey-base. Many aquatic insectsare susceptible to biocides.Amphibians are thus further at riskvia a reduced and/or contaminatedfood supply.

• Synergisms. Low pH and UV-Bcan increase the toxicity of somecontaminants. Stress due tocontaminant toxicity likelyincreases amphibian susceptibilityto disease.

Acidic Precipitation and Soil• Limited tolerance. pHs below 4-5

can be lethal to the embryos andtadpoles of some amphibianspecies.

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Great Basin spadefoot (Spea intermontanus)


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• Influence on dispersal. Ithas been demonstrated in thefield that the presence of lowpH substrates can limit thedistribution of terrestrial andaquatic amphibians.

• Prey base. Low pH can causehigh mortality of terrestrialand aquatic invertebratefauna, amphibians’ criticalprey base.

• Synergisms. Laboratory andfield studies have revealedthat low pH can exacerbatethe negative impacts of heavymetals, biocides, and UV-B onamphibians. Amphibians stressedby low pH may also be highlysusceptible to disease.

Disease• Ultimate factors. Pathogens

(bacteria, fungi, viruses, andfungal-like algae) are often theultimate causes of amphibianmortality. The stress factors thatmade these amphibians susceptibleto disease are typically unknown.

• Transmission. Many pathogenscarried by introduced fish have thepotential to infect amphibians,particularly if amphibians arealready under stress. Disease mayalso be spread by people, and byanimals such as livestock, whenthey unwittingly transport aquaticdebris and organisms from onewetland to another, and even acrossinternational borders.

Trade• Culinary. Large frogs are

particularly susceptible to theinternational trade in frog legs.

This trade has been implicated as afactor contributing to the decline ofthe California red-legged frog(Rana aurora draytonii), theintroduction of the predaciousbullfrog to many parts of the world,and a surge in mosquitopopulations where native frogspopulations have been decimated.

• Aphrodisiacs/medicinal. Manycultures, particularly in Asia, regardcertain amphibians as havingaphrodisiac and/or homeopathicqualities. The United Statesexports native amphibians to meetthese demands.

• Pet trade. Due to their charismaand small size, amphibians arebecoming increasingly popular inthe pet trade. Although someindividuals are captive-bred, mostspecies are still primarily collectedfrom wild populations.

• Biological supply. Mostamphibians used as model systemsfor basic anatomy lessons andbiological research are stillcollected from wild populations.

American toad (Bufo americanus)

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AmphibianAbnormalitiesStatus

• Widespread. Amphibianabnormalities have beenreported in more than50% of the United States,as well as in countriessuch as Canada, Peru,England, Germany,Japan, India, andAustralia. At least thirty-three amphibian specieshave been involved.

• Novel? Abnormalities inamphibians, such as extra(“supernumerary”) or missinglimbs and/or digits, missing and/ordamaged eyes, and incorrectlypositioned appendages, are notnew phenomena, and have beenreported in the literature for morethan two centuries. While someaccounts report seemingly isolatedincidences involving only a fewindividuals, others documentproblems impacting numerousanimals of multiple species.

• Trendiness. Although thefrequency of abnormal amphibianaccounts has increased in the lastfew years, it should be noted thatpublished reports of amphibianabnormalities have fluctuated innumber since the early 1700s.

• Lack of comparative data.Unfortunately, long-term studies ofamphibian population dynamicsare rare and most museumcollections are not sufficient todetermine the “normal levels” ofmalformations. Based on a fewrecent field studies, some biologistsconsider malformations found ingreater than 1% of the sampledpopulation to be indicative of aproblem.

• Something out of the ordinary. Allcaveats aside, there are a growingnumber of multi-year studies ofamphibians that indicate malfor-mations may be unusual and recentin parts of the U.S. and Canada.

Causative Factors• Multiple hypotheses. A wide

variety of factors have beenimplicated as causative agents ofamphibian abnormalities, includingparasite infestation, toxincontamination (for example,biocides, heavy metals,acidification), predation, UV-Bradiation, radioactive salts, ground-level ozone, excessive heating ofeggs, cosmic rays, andreformulated gasoline. Of these,only the parasite, toxin, UV-B, andpredation hypotheses havesupportive evidence.

• Parasites. Encysted trematodeshave been isolated from Pacifictreefrogs (Hyla regilla) withsupernumerary limbs. When thesetrematodes are introduced toPacific treefrog tadpoles in thelaboratory, a significant percentageof the tadpoles develop limbabnormalities. Furthermore, theAfrican clawed frog (Xenopus laevis)can be induced to develop such

Pacific treefrog (Hyla regilla) with extra set of legs

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abnormalities when a resin ball(meant to mimic an encystedtrematode) is inserted in atadpole’s region of limb buddevelopment.

• Toxins. Many toxins havemutagenic effects on amphibianswhen administered in thelaboratory. In Canada, a highincidence of abnormalities hasbeen found in three species of frogsfrom agricultural sites exposed totoxins.

• Predation. Injury due to failedpredation attempts and/or livestocktrampling has been observed inColumbia spotted frogs (Ranaluteiventris), western toads (Bufoboreas), and Pacific treefrogs (Hylaregilla), resulting in completely and/or partially missing limbs. Insalamanders, such injuries can leadto the development of extra limbs/digits if errors occur duringregeneration.

• UV-B. In laboratory and fieldexperiments, UV-B radiation caninduceskeletal, eye,and skindeformities indevelopinglarvae.

Implications• Part of the

declinescenario? At alocal scale,abnormalitiesmay contrib-ute to thedecline ofpopulations,but they areunlikely to

explain the disappearance ofspecies worldwide. Nonetheless,the issue of amphibian abnormali-ties is rightly poised within thediscussion of amphibian declinesfor the following reasons:

(1) Abnormalities have thepotential to result in high levels ofamphibian mortality;

(2) Unraveling of the amphibianabnormality phenomena will likelyassist us in understandingamphibian population dynamics,and thus strengthen our ability totease apart human-inducedproblems and the mechanisms bywhich they operate;

(3) The issue of amphibianabnormalities is drawing theattention of the public andgovernment officials to amphibiansin general; and

(4) Abnormalities have been shownto impact some threatened andendangered species of decliningamphibians.

Southern toad (Bufo terrestris)

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RRRRResolution: Desolution: Desolution: Desolution: Desolution: Declining Amphibian Peclining Amphibian Peclining Amphibian Peclining Amphibian Peclining Amphibian PopulationsopulationsopulationsopulationsopulationsThis resolution was drafted by participants of a 28-29 May 1998 workshop on amphibian declinessponsored by the National Science Foundation, Washington, DC.

Whereas, there is compelling evidence that over the last 15 years there have beenunusual and substantial declines in abundance and numbers of populations ofvarious species of amphibians in globally distributed geographic regions, and

Whereas, many of the declines are in protected areas or other places not affected byobvious degradation of habitats, and

Whereas, these factors are symptomatic of a general decline in environmental quality,and

Whereas, even where amphibian populations persist, there are factors that may placethem at risk, and

Whereas, some patterns of amphibian population decline appear to be linked bycausative factors, and

Whereas, declines can occur on multiple scales, in different phases of amphibian lifecycles, and can impact species with differing ecology and behavior, and

Whereas, there is no obvious single common cause of these declines, andWhereas, amphibian declines, including species extinctions can be caused by

multiple environmental factors, including habitat loss and alteration, globalchange, pathogens, parasites, various chemicals, ultraviolet radiation, invasivespecies, and stochastic events, and

Whereas, these factors may act alone, sequentially, or synergistically to impactamphibian populations, and

Whereas, to understand, mitigate, and preempt the impacts of these factors, acomprehensive, interdisciplinary research program must be undertaken, and

Whereas, this research program must be conducted in several regions around theglobe, both in areas of known declines, and in areas where declines have notbeen documented, and

Whereas, this research must examine issues ranging from environmental quality oflandscapes to the condition of individual animals,

NOW BE IT THEREFORE RESOLVED, the signatories hereto call for theestablishment of an interdisciplinary and collaborative research program, whichwill specify and quantify the direct and indirect factors affecting amphibianpopulation dynamics, and

Be it further resolved, that this program will include basic research and monitoringthat will test hypotheses of causative factors and examine patterns of changethrough historical records, field-based correlative data, and controlled, multi-factorial experiments, and

Be it further resolved, that interdisciplinary, incident response teams should beassembled in “hot spots” of amphibian decline to identify causative factors tofacilitate the mitigation of these sudden declines, and

Be it further resolved that the signatories hereto call upon both public and privateagencies and institutions, to promote and support research, policies andconservation measures that will ameliorate losses and declines of amphibianpopulations, and

Be it further resolved that this broad-based approach to the study of amphibianpopulation dynamics will serve as a model for study of the global biodiversitycrisis.


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Appropriations• Interdisciplinary. Allocate funds

for cooperative, interdisciplinarystudies that seek to investigatemultiple factors and unravel thecomplex mechanistic processesleading to amphibian declines.

• Regional surveys. Supportregional surveys of amphibianpopulation status and associatedenvironmental factors, especially inareas for which comparativehistorical data are available.

• Long-term. Support monitoringprograms that measure amphibianpopulation dynamics andassociated environmental factorsfor multiple years (preferably adecade or longer).

• Multiple scale. Although a smallpercentage of amphibian declineresearch is necessarily conductedwith large budgets, extensiveprogress can be made if numerouslow to moderately funded grantsbecome available.

Regulatory• Habitat protection. Promote,

implement, and enforce policiesthat protect and restore aquatic andwoodland ecosystems. Evaluate theeffectiveness of wetland mitigationpolicies for amphibianconservation.

• Biocide testing. Develop andimplement programs that 1) testcommercial biocide formulas,rather than just active ingredients;2) test biocide formulas under“natural” conditions; 3) requireevaluation of native amphibian

OpporOpporOpporOpporOpportunities Ftunities Ftunities Ftunities Ftunities For Por Por Por Por PrrrrroblemoblemoblemoblemoblemRRRRResolutionesolutionesolutionesolutionesolution

species of varying life histories; and4) identify models of susceptibilityacross species and life historystages.

• Biocide regulation. Assess effectivepolicies and procedures ofcountries (for example, Australia)that are banning biocides becauseof their negative impacts onamphibians. Re-evaluate U.S.policies on biocide exportation incases where biocides are alreadyknown to have a negative impacton wildlife.

• Species introductions. Develop,implement, and enforce policiesthat are extremely cautious withrespect to fish and amphibianintroductions, have austerepenalties for unauthorizedintroductions, and requirerestoration of impacted ecosystems.

• International trade. Assess U.S.importation and exportation ofamphibians by region and species.Evaluate impact of harvest onpopulations within regions oforigin. Develop, implement, andenforce harvest policies that sustainnative populations of amphibiansand require their humanetreatment.

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• National Environmental PolicyAct (NEPA). Utilize the NEPAprocess to analyze federal impactson amphibian populations.

Research• Strategic planning. Develop and

implement a strategic investigatoryapproach to diagnosing the causesand consequences of amphibiandeclines.

• Rapid assessment. Design a rapidassessment approach and designateregional rapid assessmentcoordinators for evaluatingdramatic amphibian die-offs inprogress.

• Standardization. Utilize and reporton a standard sampling/research

protocols in order to make findingscomparable.

• Stressors. Develop and implementresearch programs that examinethe most likely stress agents.

Monitoring• Standardization. In order to make

findings comparable, utilizepreviously published standardsampling protocols and specifythem in reports (see referencesection for standard techniqueguides).

• Historical comparisons. Identifyand prioritize sites for which thereare good historical data; accountsshould be verifiable and sitespecific.

• Long-term. Design and implementmonitoring programs that can becarried out and are comparableacross multiple years, preferably adecade or longer.

• Multi-variable. Design andimplement comprehensiveprograms that collect adequatedata on multiple species of varyinglife histories, as well as factorswhich might threaten them.

Management• A lands perspective. Develop and

implement a program formanaging amphibian populationson federal lands, and incooperation with private and statelandowners.

• Adaptive. Develop and implementstrategies using current knowledgeof biological patterns andprocesses. Re-evaluate andimprove management strategies asnew information becomes available.

Is INTERNATIONAL in scope;COOPERATIVE acrossdisciplines and geographicregions; IDENTIFIESinformation needs (localities,biological understanding) andPRIORITIZES them;INVESTIGATES both processand pattern in habitats,individual animals, andpopulations; utilizesMULTIPLE APPROACHES (forexample, diagnostic and casestudy); INTEGRATES top-downand bottom-up studies (i.e.,landscape to molecular); andPROVIDES GUIDELINES forinventorying, monitoring, andmanagement.

AN EFFEAN EFFEAN EFFEAN EFFEAN EFFECCCCCTIVETIVETIVETIVETIVERESEARRESEARRESEARRESEARRESEARCHCHCHCHCHSSSSSTRATRATRATRATRATTTTTEEEEEGGGGGYYYYY:::::


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• Risky business. Develop andimplement a strategy for assessingthe risk of anthropogenic activitiesto amphibians of varying lifehistories and life stages.Incorporate this strategy intoenvironmental impact assessments.

• Getting into the game. Assess theimpact of game management onamphibian species and identifyopportunities for enhancingamphibian management via gamemanagement programs, such asthose employed for native trout.

Communication• Say it like it is. Express the grand

challenge of conservingpopulations, species, andecosystems in an environmentwhere stress factors actsynergistically and systemicdisruptions can have cascadingimpacts. This serves toappropriately illustrate theinterconnectedness of biologicalsystems.

• Case studies. Develop andpromote a story approach toexplain the complex scenario ofamphibian declines.

• So what? Stress the consequencesof amphibian loss and what thepattern of amphibian loss maysignify, particularly for human well-being.

• Poster larvae. Develop a strategy/campaign for using the amphibiandecline issue as a means to drawattention to and explain the causesand consequence of the generalbiodiversity crises. Illustrate thatthese animals have been around forapproximately 350 million yearsand thus have evolved greatcapacities for survival, yet are nowdeclining rapidly.

• Stakeholder analyses. Identifyspecifically what information, inwhat form, and on what timelinepolicy makers, educators, etc., needin updates from the scientificcommunity. Develop a strategy forbringing science into the service ofsociety in a timely and effectivemanner.

• Not by science alone. Emphasizethat science in and of itself cannotsolve the amphibian decline crises.It will be solved by placing scientificfindings in the extended hands ofpeople who have the capacity tomake change happen.

Training• Needs assessment. Determine the

necessary skills and knowledgerequired to conduct basic researchon, manage, and monitoramphibians. Evaluate theknowledge and skill base of field-based personnel charged with thesetasks.

• Expand target audience.Encourage the participation ofbiologists from other field-basedscience and management practices.In addition, evaluate the potentialof utilizing a volunteer naturalistworkforce for specific tasks andprojects.

• Transfer tools. Develop andimplement training courses thatfulfill the needs of the targetaudience in a timely manner.

• Ongoing support. Evaluate theutility of existing materials,including booklets, fact sheets,reports, videos. Develop anddisseminate materials andmechanisms such as topical shortcourses or advisory networks to thetarget audience.

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PublicationsFroglog. Newsletter of the Declining Amphibian PopulationsTask Force (DAPTF). Write to John W. Wilkinson, Department of Biology, TheOpen University, Walton Hall, Milton Keynes, MK7 6AA, UnitedKingdom or find on the World Wide Web at:http://www.open.ac.uk/OU/Academic/biology/J_Baker/JBtxt.htm

Ribbetting News. Write Amphibian Conservation Alliance (ACA), 563 Main Street,Oakland, CA 94609-1568, or call (510) 653-6006. This quarterly newsletter is free to all

ACA members and donors.

Web sitesAmphibia Webhttp://www.amphibiaweb.org

ACA (Amphibian Conservation Alliance)http://www.frogs.org

CARCN (Canadian Amphibian and Reptile Conservation Network)http://www.cciw.ca/ecowatch/dapcan

DAPTF (Declining Amphibian Populations Task Force)http://www.open.ac.uk/OU/Academic/biology/J_Baker/JBtxt.htm

FrogWebhttp://www.frogweb.gov/

The Froggy Pagehttp://frog.simplenet.com/froggy/

NAAMP (North American Amphibian Monitoring Program)http://www.im.nbs.gov/amphibs.html

NARCAM (North American Reporting Center for Amphibian Malformations)http://www.npwrc.usgs.gov/narcam

PARC (Partners in Amphibian and Reptile Conservation)http://www.parcplace.org

TADD (Taskforce on Amphibian Declines and Deformities)http://www.frogweb.gov

Recommended ReadingAmphibian Declines

Green, D. M. (ed.) 1997. Amphibians in Decline: Canadian Studies of a GlobalProblem. Society for the Study of Amphibians and Reptiles, HerpetologicalConservation, Number One.

RRRRResouresouresouresouresourcescescescesces

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Lannoo, M. L. (ed.) 1998. Status and Conservation of Midwestern Amphibians.University of Iowa Press, Iowa City.

Phillips, K. 1994. Tracking the Vanishing Frogs: an Ecological Mystery. St. Martin’sPress, New York.

Souder, W. 2000. A plague of frogs: the horrifying true story. Hyperion Press,New York.

Survey TechniquesFellers, G. M. and K. L. Freel. 1995. A standard protocol for surveying aquatic

amphibians. Technical Report NPS/WRUC/NRTR-95-01.Heyer, W. R., M. A. Donnelly, R. W. McDiarmid, L. C. Hayek, and M. S. Foster. 1994.

Measuring and Monitoring Biological Diversity: Standard Methods forAmphibians. Smithsonian Institution Press, Washington, DC.

Olson, D. H., W. P. Leonard, and R. B. Bury. 1997. Sampling Amphibians in LenticHabitats. Society for Northwestern Vertebrate Biology, Olympia, Washington.

Natural HistoryBadger, D. 1995. Frogs. Voyageur Press, Stillwater, Minnesotta.Bishop, S. C. and E. D. Brodie. 1994. Handbook of Salamanders of the UnitedStates, of Canada, and of Lower California. Comstock Publishing Associates, Ithaca,

New York.Petranka, J. W. 1998. Salamanders of the United States and Canada. Smithsonian

Institution Press, Washington, D.C.Stebbins, R. C. and N. W. Cohen. 1995. A Natural History of Amphibians. Princeton

University Press, Princeton, New Jersey.Wright, A. H. and A. A. Wright. 1995. Handbook of Frogs and Toads of The United

States and Canada. Comstock Publishing Associates, Ithaca, New York.

General BiologyDuellman, W. E. and L. Trueb. 1994. Biology of Amphibians. Johns Hopkins

University Press, Baltimore, Maryland.

Use of AmphibiansGrenard, S. 1994. Medical Herpetology. Reptile & Amphibian Magazine, Pottsville,

PA.Neil, W. T. 1974. Reptiles and Amphibians in the Service of Man. The Bobbs-Merrill

Company, Inc., New York.

Field GuidesBehler, J. L. and F. W. King. 1979. The Audubon Society Field Guide to North

American Reptiles and Amphibians. Alfred A. Knopf, Inc., New York.Conant, R. and J. T. Collins. 1998 (3rd expanded edition). Reptiles and Amphibians

of Eastern/Central North America. Houghton Mifflin, New York.National Audubon Society. 1998. North American Reptiles and Amphibians.

Chanticleer Press, Inc., New York.Smith, H. M. 1978. A Field Guide to Identification: Amphibians of North America.

Golden Press, New York.Stebbins, R.C. 1985. Western Amphibians and Reptiles. Houghton Mifflin, New

York.Zim, H. S. and H. M. Smith. 1987. Reptiles and Amphibians. Golden Press, New

York.

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Contacts

DAPTFDr. James HankenMuseum of Comparative ZoologyHarvard University26 Oxford StreetCambridge, MA 02138Tel. (617) [email protected]

Dr. Michael J. LannooDirector, U.S. Office DAPTFBall State UniversityMuncie Center for Medical EducationRoom 209 Maria BinghamMuncie, IN [email protected]

TADDMr. Dan JamesUS DOI/USGS/BRD12201 Sunrise Valley DriveMS 301Reston, VA [email protected]

Audio Tapes

Sounds of North American Frogs by Charles BogertSmithsonian FolkwaysCenter for Smithsonian Folklife and Cultural Studies955 L’Enfant PlazaSuite 7300, MRC 953Smithsonian InstitutionWashington, DC 20560

Frog and Toad Calls of the Pacific Northwest by Carlos DavidsonFrog and Toad Calls of the Rocky Mountains by Carlos Davidson

Library of Natural SoundsCornell Lab of Ornithology159 Sapsucker Woods RoadIthaca, NY [email protected]

PARCDr. J. Whitfield GibbonsSavannah River Ecology LabDrawer EAiken, SC [email protected]

NAAMPMr. Sam DroegePatuxent Wildlife Research Center12100 Beech Forest DriveLaurel, MD [email protected]

ACAMr. Paul S. Speck, Jr.PresidentAmphibian Conservation Alliance563 Martin StreetOakland, CA 94609-1568Tel. (510) 653-6006Fax: (510) [email protected]

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Blaustein, A.R., J. M. Kiesecker, D. P. Chivers, and R. G. Anthony, 1997. AmbientUV-B radiation causes deformities in amphibian embryos. Proceedings of theNational Academy of Sciences of the USA 94: 13735-13737.

Green, D. M. (ed.) 1997. Amphibians in Decline: Canadian Studies of a GlobalProblem. Society for the Study of Amphibians and Reptiles, HerpetologicalConservation, Number One.

Grenard, S. 1994. Medical Herpetology. Reptile & Amphibian Magazine, Pottsville,PA.

Johnson, P. T. J., K. B. Lunde, E. G. Ritchie, and A. E. Launer. 1999. The effect oftrematode infection on amphibian limb development and survivorship. Science284:802-804.

Pounds, J. A., M. P. Fogden, and J. H. Campbell. 1999. Biological response to climatechange on a tropical mountain. Nature 398:611-615.

Reaser, J. K. 1996. The elucidation of amphibian declines: are amphibianpopulations disappearing? Amphibian and Reptile Conservation 1:4-9.

Reaser, J. K. and P. T. Johnson. 1997. Amphibian abnormalities: a review. Froglog24:2-4.

Scott, N. J., Jr. and R. A. Siegel. 1992. The management of amphibian and reptilepopulations: specific priorities and methodological and theoretical constraints.In D. R. McCullough and R. H. Barrett, eds., Wildlife 20001: Populations.Elsevier Applied Science Pub. Ltd., Essex, England.

Stebbins, R. C. and N. W. Cohen. 1995. A Natural History of Amphibians. PrincetonUniversity Press, Princeton, NJ.

Sections of Facts in Brief were inspired by “An outline of issues associated withamphibian declines” by S. Droege; the dialogue of participants of the National ScienceFoundation’s “Amphibian Population Dynamics: Is the Threat Increasing forAmphibians?” workshop, 28-29 May 1998, Washington, D.C.; and the “Mechanisms ofDevelopmental Disruption in Amphibians” workshop, 5-7 November 1998, San Diego,CA.

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CitationReaser, J. K. 2000. Amphibian declines: an issue overview.Federal Taskforce on Amphibian Declines and Deformities,Washington, DC.

This guide was written by:

Jamie K. ReaserBiodiversity and Foreign Affairs OfficerU.S. Department of StateOES/ETC, Room 4333Washington, D.C. 20520

AcknowledgementsThe information reported in this booklet could not havebeen conveyed without the dedication and contribution ofcountless researchers who have spent many years afield andin the laboratory, searching for solutions to the amphibiandecline and abnormality problems. This text particularlybenefited from the constructive input of Andrew Blaustein,Jim Collins, Sam Droege, Whit Gibbons, Tim Halliday,James Hanken, W. Ron Heyer, Joe Mitchell, Paul Speck,Peter Stangel, David Wake, and David Wilcove, as well asnumerous members of the Federal Task Force onAmphibian Declines and Deformities. Their feedback andpatience are sincerely appreciated.

Although this booklet has been written by a single author, much of theinformation presented reflects the consensus points of individualparticipants of several amphibian decline and abnormality meetings.In addition, members of several organizations have contributedvaluable comments. The views expressed here do not necessarilyreflect policies of the U.S. Department of State.

By Jamie K. ReaserFinal edition edited by Lisa ZollyDesign by Donna Foulke

“The Silence of the Frogs” by Susan Rea Katz. ©Susan Rea Katzand 5 A.M. Used with permission of the author. Reprinted in OfFrogs and Toads, edited by Jill Carpenter (Ione Press, 1998).

Request for additional copies:U.S. Government Printing OfficeSuperintendent of DocumentsP.O. Box 371954Pittsburgh, PA 15250-7954phone: (202) 512-1800fax: (202) 512-2250shop online at http://www.access.gpo.gov/su_docs/sale.html

This document is also available online as a PDF at:http://www.frogweb.gov/tadd/publications.html

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It’s too much for a child to know: while we sithere on the back porch, talking,the last glass frog on earth could be singingsomewhere in the cloud forest,lime-green jewel in the night, our own griefentangled in its vanishing cadenza.

-- from “The Silence of the Frogs” by Susan Rea Katz

printed on recycled paper

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