Answers to Analyzing Data 24.1 Questions
1. The edge effect of increased wind disturbance penetrates 400 m into the forest; thus, for a tree not to experience increased wind disturbance it must be more than 400 m from the edge.
2. The total area of the forest is 800 m ? 800 m = 640,000 m2. Since we assume that the tree mortality effect penetrates 300 m on each side of the forest, the only region that does not experience a rise in tree mortality is a 200- ? 200-m section in the center of the forest. This central section has an area of 40,000 m2. Thus, the area experiencing a rise in tree mortality is 640,000 m2 - 40,000 m2 = 600,000 m2, or 93.75% of the forest's total area.
3. The edge effects shown in the graph include changes to the abiotic conditions (such as increased wind disturbance and increased air temperature) and changes to aspects of the biotic environment (such as invasion of disturbance-adapted beetles and plants). By changing both abiotic and biotic components of the environment, other aspects of the environment not shown in the graph are likely to change as well. We would expect, for example, that the changing abiotic conditions could cause the abundance of some species originally present to decline, while others might increase. As we have seen throughout the textbook, such changes in abundance could lead to further changes in species interactions, community structure, and ecosystem processes (such as nutrient cycling).