Transcript Gibbs

AMPHIBIAN AND REPTILE
CONSERVATION
Yosemite
Monteverde
.
Global Amphibian Assessment
The first-ever comprehensive assessment of the conservation
status of the world's 5,918 known species of frogs, toads,
salamanders, and caecilians
Extinct (or extinct in the wild)
Critically Endangered
Endangered
Data Deficient
Vulnerable
Not Threatened
Least Concern
Exam III
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Last day of class…Thurs, Dec. 9
Read Ch 8, 9, 10, and 11 from Gibbs et al.
(short chapters)
Read Ch. 14 from Vitt and Caldwell
Be familiar with invited lecture (Thomas) and
“Demography” and “Conservation” overview
lecture by Gibbs
Know your NYS “herp regs”
Global Amphibian Assessment
Key Findings
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Nearly one-third (32%) of the world’s amphibian species are
threatened, representing 1,856 species
(vs. 12% of birds and 23% of mammals)
As many as 168 amphibian species may already be extinct
43% of species are declining in population, vs. < 1 % increasing
Highest numbers of threatened species are in Latin American
countries such as Colombia (208), Mexico (191), and Ecuador
(163)
Reptiles in Decline
The Global Decline of Reptiles,
Déjà Vu Amphibians
BioScience 2000*
*http://www.uga.edu/srelherp/staff/Winne%
20-%20gibbons%20et%20al%202000.pdf
by
J. Whitfield Gibbons, David E. Scott, Travis J.
Ryan, Kurt A. Buhlmann, Tracey D. Tuberville, Brian S.
Metts, Judith L. Greene, Tony Mills, Yale Leiden, Sean
Poppy, and Chris Winne
HABITAT LOSS IS THE GREATEST
THREAT
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Most anurans and many salamanders breed in
wetlands.
Many reptiles also highly dependent
Loss of wetlands = loss of amphibians and
reptiles
Lower 48 states lost an average of 54% of the
estimated original 221 million acres of wetlands
from 1780s to the 1980s
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Iowa, for example, lost approximately 95% of its
wetlands.
Extinct!
Vegas Valley Leopard frog (Rana fisheri)
Declines in habitat quality…
Losses of Temporary Wetlands Especially
important
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Many eliminated by:
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Grading,
Mosquito control,
Human tidiness
Extremely vulnerable
Largely unprotected
Created by John Rozum, NEMO National Coordinator
Source: Megan Griffiths
Introduced Species
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Predation of alien species
on native species
Competition for resources
Introduction of pathogens by non-native species
Hybridization
Decline of the Mountain Yellow-legged Frog
Rana mucosa
Impact of stocked fish on yellow-legged
frog
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Knapp et al. 2001
Ecological Monographs
Reptiles and
amphibians can be
invaders, too…
Over-harvesting of reptiles
Sea turtles for food
 Freshwater turtles for food
 Iguanids for food
 Anything intriguing for the
pet trade
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Rattlesnake Round-up
Last Saturday in January
at the new RattleSnake Grounds
US 84 Whigham, Georgia
9:00 am to 5:00pm
Arts and Crafts - Food Booths
RATTLESNAKE EXIHIBITS
Over 123 tons of Western Diamondback
Rattlesnakes turned in to date
Don't forget to try some deep-fried
Western Diamondback Rattlesnake
meat …and The Gun, Knife and Coin
show that will be offered as well
Gopher tortoises in Florida
http://www.empireoftheturtle.com/Florida/gopherus_polyphemus.htm
Asian turtle “crisis”
Over-collecting and amphibians
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People collect amphibians for
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food
medicines
bait,
pets
even for teaching biology.
In some parts of the world collecting alone appears to
cause declines.
India, for example, has banned frog exports because of
pest increases in rice paddies
Real 3½" to 4" frogs
preserved in anise
scented liquid.
Three frogs per jar
A sure thing for all
game fish.
Eating Frogs to Extinction, IAN G.WARKENTIN et al., Conservation Biology
Dried newts in Lhasa market
NYS law protecting reptiles and
amphibians…know these!
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Regulation: Chapter 1 – Fish and Wildlife
http://www.dec.ny.gov/regs/2494.html
 Part 3: Reptiles and Amphibians
 * Section 3.1: Diamondback Terrapins
 * Section 3.2: Native Turtles
 * Section 3.3: Native Snakes
 * Section 3.4: Native Lizards
 * Section 3.5: Native Frogs
 * Section 3.6: Native Salamanders
Parasites and disease: Emerging
pathogens: Chytridiomycosis
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Frogs may be suffocating because of the
fungal growth
In reaction to chytrid infections, they lay
down extra layers of keratin in their skin.
Another possibility is that the fungus is
releasing a toxin.
Latest news: ionic balance
Carcass of an Australian amphibian (Myxophyes
fasciolatus) that died from cutaneous chytridiomycosis.
This individual died in a mass mortality event in a
captive collection.
Chytrid Fungi
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Chytrid fungi is at least a proximate cause of
current die-offs in Central and North America
New chytrids moving in waves around world
Direct cause? Stress-induced? New pathogen?
Spread by Xenopus?
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In the 1930s, discovered that
a female Xenopus would ovulate
if injected with the urine from
a pregnant woman
Hormone chorionic gonadotropin was the active
ingredient.
In the 1940s and 50s, the only available pregnancy test
Many hospitals kept Xenopus but many releases:
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California, Chile, England etc.
Future? Probiotics? Adaptation?
Contaminants
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Consider Atrazine, a common weed killer
More than 60 million pounds applied last year in
the United States alone.
Used to control weeds on about two-thirds of all
U.S. corn and sorghum acreage - improves corn
yield by slightly more than 4%
Contaminants - Atrazine
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Collects in frog breeding ponds
Atrazine ups production of the enzyme
aromatase, which
converts androgen
hormones to estrogen
hormones
April 16 issue of
Proceedings of the National
Academy of Sciences
Tyrone Hayes with
Colorado river toad (Bufo
alvarius). Peg Skorpinski
photo.
Abnormal gonads in a male
Xenopus frog, the result of
exposure to the herbicide atrazine.
The frog has become a
hermaphrodite, that is, it has both
male (testes) and female (ovaries)
sex organs
Deformities
see: http://www.hartwick.edu/biology/def_frogs/index.html
Parasites and deformities
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5% natural background rate
At least 41 species representing 35 genera and 21
families of trematodes have amphibian
larvae as intermediate hosts
Also use snails as hosts
Trematode larvae burrow into
amphibian tissues to form
cysts and affect limb
development
Trematodes? Natural or unnatural?
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Trematode densities are heavily influenced by water
quality
Snail hosts benefit from wetland eutrophication
Increased N concentrations
can boost populations
Please join!
..and participate
Happy Holidays!