Transcript AMPHIBIAN AND REPTILE CONSERVATION
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
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 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
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 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
Many eliminated by: Grading, Mosquito control, Human tidiness Extremely vulnerable Largely unprotected
Created by John Rozum , NEMO National Coordinator
Source: Megan Griffiths
Introduced Species
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 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
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
People collect amphibians for 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!
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
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
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?
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: California, Chile, England etc.
Future? Probiotics? Adaptation?
Contaminants
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
Collects in frog breeding ponds Atrazine ups production of the enzyme aromatase, which converts androgen hormones to estrogen hormones
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 April 16 issue of
Proceedings of the National Academy of Sciences
Deformities
see:
http://www.hartwick.edu/biology/def_frogs/index.html
Parasites and deformities
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?
Trematode densities are heavily influenced by water quality Snail hosts benefit from wetland eutrophication Increased N concentrations can boost populations