Hamline University Graduate School St. Paul, Minnesota .
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Transcript of Hamline University Graduate School St. Paul, Minnesota .
Scientists in MN and elsewhere had found malformed frogs in the early 1990s. Then the issue hit the national media in 1995. Why?
Students in Henderson, MN, found hundreds of malformed frogs at a site.
A Thousand Friends of Frogs was formed in the wake of this media coverage
What are we being told by:
Amphibian (frog and toad) malformities
Amphibian populations locally and globally
But first……a few questions!!
smooth or slimy skin warty and dry skin strong, long legs and stubby bodies with short
webbed hind feet hind legs two bulging eyes parotid glands behind eyes
lay eggs in clusters lay eggs in long chains
Both are considered ectothermic (often called cold blooded) because their body temperature adjusts with the outside environment.
Vs.
Frogs have: Toads have:
A group of frogs is A group of toads is called called
an ARMY of frogs a KNOT of toads
Vs.
Frogs Toads
Why We Care
1. Frogs and toads are a part of the planet’s bio-diversity.
2. Frogs and toads interact in interesting ways with each other and the environment, i.e. both prey and predators
Why We Care
3. Frogs and toads provide benefits to humans i.e. Gastric Brooding Frog of Australia might have provided answers for people suffering from gastric ulcers
(Case of the Vanishing Frogs, T. Halliday and W. R. Heyer).
4. Frogs As Bio-indicators
1) double life--amphibious2) permeable skin 3) absorb and concentrate toxins--
biomagnification
4. Frogs As Bio-indicators
Biomagnification: a process in which retained substances become more concentrated with each link in the food chain
External Malformations
• extra or missing limbs• branching limbs• spikes or protuberances• missing eyes• abnormal webbing
Causes of Malformations
• genetic origins• parasite disruption of limb formation• chemical contamination• viruses• ultraviolet radiation• physical trauma (predation, people)
Trematode (flatworm) cysts have been demonstrated to cause problems in limb bud development in tadpoles
Dr. Stanley K. Sessions, Hartwick College
Types of Agrochemicals
• herbicidesManeb-
fungicide
• pesticides propylthiourea
• fertilizersDr. Stanley K. Sessions, Hartwick College
Types of Agrochemicals
applications of the herbicide atrazine have led to egg mortality and tadpole deformities (Hazelwood 1970)
Dr. Stanley K. Sessions, Hartwick College
Correlations to Human Health Concerns
• high nitrate levels (from fertilizers) in human drinking water and frog breeding ponds are hazardous
• human birth defects result from pesticide application
• UV radiation results in blindness and skin cancer in humans and other animals; DNA damage in developing frog eggs
Where have all the frogs gone?
Global Population Decline
• a concern during the past decade• frog declines widespread and well-
documented• possible causes include habitat
destruction, increased UV radiation, and chemical contamination
Global Population Declines
•Loss of habitat from filling in wetlands to
create more farmland for crops, and to build more houses and roads
(Case of the Vanishing Frogs, T. Halliday and W. R. Heyer).
Global Population Declines
• Increasing ultraviolet radiation• Pollution by chemicals• Acid rain• Pathogens• Parasites• Introduction of non-native species
Global Population Declines
Amphibian declines occurring in locations where habitats relatively undisturbed.
Australia:
Gastric Brooding Froglast seen in wild in 1980s
Global Population Declines
Other places experiencing declines include: Puerto Rico Ecuador Venezuela Brazil U.S. Rocky Mountains Cascade Mountain Range in Washington, Oregon, and California
Malformity and Calling Surveys
Various types of surveys depending on your objectives
Malformity surveys: deal specifically with malformities in amphibians
Calling surveys: need to know the calls of anurans
terrestrial salamander monitoring
aquatic surveys
Malformity and Calling Surveys
A Thousand Friends of Frogs has two surveys—
Malformity and Calling
http://cgee.hamline.edu/frogs/students/involved.html
Malformity and Calling SurveysMalformity surveyProtocols for collecting and reporting data.
Data collected and transferred to scientists
Results on web site
http://cgee.hamline.edu/frogs/science/datasht.html
Calling survey: Minnesota Frog WatchOver 100 volunteers surveying in the state
Working with MN Dept. Natural Resources
http://cgee.hamline.edu/frogs/science/wach2000.html
Malformity and Calling SurveysNorth American Reporting Center for Amphibian Malformities (NARCAM)
http://www.npwrc.usgs.gov/narcam
Report data on the web
Malformity and Calling SurveysNorth American Amphibian
Monitoring Project (NAAMP)
http://www.im.nbs.gov/amphibs.html
Protocols for reporting data
State coordinators
Malformity and Calling Surveys
What you need to know to survey?
Depends on type of survey conducted
ID of frogs, toads and salamanders—color, shape, etc.
Calls of frogs and toads
Let’s learn a few calls!!
Bullfrog
Spring Peepers
Student Activities
Other student activities
Student Reports on Project Web Site
Student Poetry
Student Writing
Student Art