1. CHAPTER 53 COMMUNITY ECOLOGY Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section C1: Disturbance and Community Structure 1.Most communities are in a state of nonequilibrium owing to disturbances 2. Humans are the most widespread agents of disturbance

2. Disturbances affect community structure and stability. Stability is the ability of a community to persist in the face of disturbance. Introduction Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

3. Disturbances are events like fire, weather, or human activities that can alter communities. Some are routine. 1. Most communities are in a state of nonequilibrium owing to disturbances Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 53.16

4. Marine communities are subject to disturbance by tropical storms. Fig. 53.17 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

5. Fig. 53.17 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

6. We usually think that disturbances have a negative impact on communities, but in many cases they are necessary for community development and survival. Fig. 53.18 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

7. Human activities cause more disturbance than natural events and usually reduce species diversity in communities. 2. Humans are the most widespread agents of disturbance Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings