Name:
Understanding Amphibian Decline
Using similar methods as you used during our first POGIL activity, take the time to read
through and really understand the causes of amphibian decline and the parts of this world
that this decline is the worst.
Module 1: Why are they Declining?
FACTOR
PROCESS(ES)
Habitat destruction,
alteration and
Fragmentation
Roads, introduced species, or other factors separate remaining populations of amphibians from each other.
Introduced Species
Non-native species prey on or compete with native amphibians.
Over-Exploitation
Amphibians are removed from the wild and sold internationally as food, as pets, or for medicinal and biological
supply markets
Climate Change
Amphibians are extremely sensitive to small changes in temperature and moisture. Changes in global weather
patterns (e.g. El Niño events or global warming) can alter breeding behavior, affect reproductive success, decrease
immune functions and increase amphibian sensitivity to chemical contaminants.
UV-B Radiation
Levels of UV-B radiation in the atmosphere have risen significantly over the past few decades. Researchers have
found that UV-B radiation can kill amphibians directly, cause sublethal effects such as slowed growth rates and
immune dysfunction, and work synergistically with contaminants, pathogens and climate change.
Chemical Contaminants
Chemical stressors (e.g., pesticides, heavy metals, acidification and nitrogen based fertilizers) can have lethal,
sublethal, direct or indirect effects on amphibians. These effects may include death, decreased growth rates,
developmental and behavioral abnormalities, decreased reproductive success, weakened immune systems and/or
hermaphroditism.
Disease
New diseases (such as chytridiomycosis) or higher susceptibility to existing diseases leads to deaths of adults and
larvae.
Deformities
There has been a recent and widespread increase of deformities (or malformations) in natural populations of
amphibians; this is now perceived as a major environmental problem.
Synergisms
Multiple factors can act together to cause mortality or sublethal effects.
1. What is the name of one of the diseases that is currently affecting amphibian populations?
2. Which of the factors impacts amphibians because it causes problems with their reproduction, impacts their
immune system and causes an increase in their sensitivity to chemicals?
3. Based on the ways it’s used in the text box above, give your best guess definition for synergistic or synergism.
4. After reading through the different impacts, explain why synergism or synergistic is a good term to use to
describe the factors impacting amphibian decline.
Module 2: Where are they Declining?
Figure 1
Figure 2
Figure 3
1. What information is being shown to you in Figure 1?
2. What information is being shown to you in Figure 2?
3. What information is being shown to you in Figure 3?
4. What parts of the globe have the most species of amphibians?
5. What parts of the globe have the least number of amphibians?
4. What continent has the highest variety of amphibian species existing on it?
5. Looking at Figure 2, how would you describe the distribution of threatened species? (i.e. where do you find the
most species that are facing extinction)
6. Compare Figure 2 and Figure 3. What pattern do you notice between these two maps? (there is something try to
figure it out)
7. Why do you think deforestation could add to the increase in numbers of amphibians dying? Think beyond they
are losing their habitat. What else could lack of habitat cause?