20. Communities and Ecosystems

What is the reason that moderate levels of disturbance foster the highest diversity in a community?

Which of the following should lead to an increase in a community's diversity?

Which of the following statements most accurately describes ecological succession?

Listed below are 4 stages of ecological succession in Glacier Bay, Alaska. However, they are in the wrong order. Select the answer option that puts these events in the correct chronological order.

I. The area is invaded by alder trees, which grow up to 9 meters tall.

II. Small flowers (dryas) begin to dominate the plant community.

III. Over hundreds of years, large trees such as spruce & hemlock become the dominant vegetation.

IV. Glacier ice melts, exposing bare rock with no living organisms. Mosses & liverworts colonize this area.