Also see web site on Mt. St. Helens for before and after pictures, maps and text information.

This video, produced by NOVA, covers both the geologic and biological ascpects of the 1980 eruption.

Concepts:

• Biological succession is the gradual replacement of communities by other communities over time.
• Primary succession is succession where there has been no previous life. The lava flows at Mt. St. Helens would qualify.
• Secondary succession occurs in areas where life previously existed. At Mt. St. Helens lakes and burned areas qualify.
• Pioneer organisms are the organisms that first invade a distutrbed or new area. Fungi, lichens, and bacteria on the lava flows. Primitive plants and insects are examples in secondary succession.

In your journal make note of the variety of examples of primary and secondary succession.
Primary: Pumice fields
Secondary: Clearwater creek

How many pioneer species could you indentify? What were some of them? fireweed, wind blown seeds and insects (maybe 1000 species). Predators come first following dead insects blown in.

What living things had survived? pocket gopher - their mounds catch windborn seed. Many fish.

What are some of the trapping methds employed by researchers? golf ball trap

What is one of the most important legumes in this succession? lupine

Describe some micro-environments: Nutrient pumps of disolved minerals; shadows of logs over pools of water - cool water.

What are some unique species of Mt. St. Helens? Tailed frog has an inverted cloaca. The tadpole has a sucker-type mouth for feeeding and locomotion.