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Hamline University Graduate School St. Paul, Minnesota Frogs as Bio-indicators Joan Chadde, MI Technological University Tony P. Murphy, Hamline University Kristin Schuster, Houghton Middle School Hamline University Graduate School St. Paul, Minnesota What are we being told by: Amphibian (frog and toad) malformities Amphibian populations locally and globally But first…… Vs. Frogs have: cold blood smooth or slimy skin strong, long legs and webbed hind feet two bulging eyes Toads have: cold blood warty and dry skin stubby bodies with short hind legs parotid glands behind eyes lay eggs in clusters lay eggs in long chains a group of frogs is called an ARMY of frogs a group of toads is called a KNOT of toads Anuran Diversity Frogs and Toads 14 species in MN, 13 species in MI 92 species in USA 3,300 species in the world MN Frogs and Toads Why We Care 1. Anurans are a part of the planet’s bio-diversity. 2. Anurans interact in interesting ways with each other and the environment, i.e. both prey and predators Why We Care 3. Anurans 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--amphibious 2) 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 Malformed Amphibians External Malformations • • • • • extra or missing limbs branching limbs spikes or protuberances missing eyes abnormal webbing Internal Malformations • reproductive • digestive • urinary Malformed Frog Pictures Dr. David Hoppe, University of Minnesota-Morris Dr. David Hoppe, University of Minnesota-Morris Dr. David Hoppe, University of Minnesota-Morris Dr. David Hoppe, University of Minnesota-Morris 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 Dr. Stanley K. Sessions, Hartwick College Possible Chemical Contaminants • • • • agrochemicals heavy metals acid rain chlorofluorocarbons (CFCs) Types of Agrochemicals • herbicides Maneb-fungicide • pesticides propylthiourea • fertilizers Dr. 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 Where have all the frogs gone? Global Anuran Decline • • • a concern during the past decade frog declines widespread and welldocumented 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