tailieunhanh - Insect Ecology - An Ecosystem Approach 2nd ed - Chapter 10

10 Community Dynamics COMMUNITY STRUCTURE CHANGES THROUGH TIME AS SPECIES abundances change, altering the network of interactions. Short-term (., seasonal or annual) changes in community structure represent responses to environmental changes that favor some species or affect interaction strength. | 10 Community Dynamics I. Short-Term Change in Community Structure II. Successional Change in Community Structure A. Patterns of Succession B. Factors Affecting Succession C. Models of Succession III. Paleoecology IV. Diversity versus Stability A. Components of Stability B. Stability of Community Variables V. Summary COMMUNITY STRUCTURE CHANGES THROUGH TIME AS SPECIES abundances change altering the network of interactions. Short-term . seasonal or annual changes in community structure represent responses to environmental changes that favor some species or affect interaction strength see Chapter 8 . Longer-term . successional changes in community structure often reflect relatively predictable trends during community development on newly available or disturbed sites. Finally changes in community structure over evolutionary time reflect responses to long-term trends in environmental conditions. Among the major environmental issues facing governments worldwide is the effect of anthropogenic activities . altered atmospheric or aquatic chemistry land use species redistribution on the composition of natural communities and the ecosystem services they provide to humans. How might changes in community structure affect epidemiology of human diseases How stable is community structure and how sensitive are communities and ecosystems to changes in species composition Our perception of communities as self-organizing entities or random assemblages has significant implications for our sensitivity to species loss and our approach to management of ecosystem resources. As with population dynamics study of changes in community structure requires long periods of observation. Few studies have continued over sufficiently long time periods to evaluate many of the factors presumed to affect community 283 284 10. COMMUNITY DYNAMICS structure. However paleoecological evidence and studies of community recovery following disturbance have provided useful data. Research on factors .