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Chapter Summary
In Chapter 4, the dynamic nature of ecosystems through time, and in response to disturbance, is explored. Several aspects of change in ecosystems are examined, starting with the process of ecological succession. This is followed by a discussion of the concept of “dynamic equilibrium” and its contributing factors, with particular attention to the concepts of inertia, resilience, and stability. The importance of alien, invasive, and keystone species is studied with a focus on the impacts of invasive species in Canada. Feedback mechanisms, as major mechanisms of stability in ecosystems, are discussed. Different aspects of population growth and reproductive strategies of species are also examined, including differing life strategies such as K-strategies and r-strategies. Finally, longer-term changes such as evolution, speciation, extinction, and biodiversity are considered, with an emphasis on how global change will affect rates of species loss.
Learning Objectives
After reading this chapter, you should be able to do the following:
- Outline the nature of ecosystem change and its implications for society and environmental management
- Describe and distinguish between the processes of primary and secondary succession and identify the ways in which humans alter these processes
- Appreciate that fires, insect infestations, and major storms are often integral and natural parts of healthy ecosystem function, and discuss their roles in maintaining ecosystem structure
- Explain the impacts and management of invasive species
- List and define the main factors affecting species population growth
- Describe the nature of evolution and extinction
- Discuss some of the implications of global climate change on species distributions and abundance