Lectures on line. Feel free to use them in classes.
Five Causal Factors:
A General Framework for Wetland Science and Restoration
In this 45 minute talk Paul proposes that a small set of causal factors can unify the field of wetland ecology. The talk was given as a webinar sponsored by the Society of Wetland Scientists in December 2017. It was broadcast from Paul's home in Ontario, hosted in Wisconsin, and moderated from Florida. A question period follows. (A minor glitch with changing slides is resolved within the first couple of minutes.)
Wetlands are a vital part of the biosphere, and among the most productive ecosystems on Earth. At one time, lack of information limited our understanding of wetlands, and made restoration and conservation difficult. Now it is possible that the opposite is true: we are drowning in data on wetlands, and confused about how to best apply the huge volume of information.
This talk, given as a webinar sponsored by the Society of Wetland Scientists in December 2017, suggests a possible remedy. (A minor glitch with changing slides in Madison Wisconsin from a computer in Ottawa Ontario is resolved within the first few minutes.) Although the talk is aimed at fellow scientists and managers, it is also appropriate for novices since it focuses on general principles that can guide students.
Consider that physicists can describe most of the universe using only four forces! Without succumbing to physics envy, we could borrow from this approach, and consider causal factors as ecological forces that transcend species and geography. Causal forces might provide us with a set of general principles to organize our existing knowledge, and to guide our attempts to restore wetlands.
Dr. Keddy explores how only four causal forces may account for nearly all the variation we see in and among wetlands: hydrology, fertility, natural disturbance, and competition. These factors operate in all wetlands, be they peat bogs, mangrove swamps or freshwater marshes. The order in which we list them matters, since hydrology alone likely accounts for half the variation (ca 50 percent), with fertility and natural disturbance next (ca 15 percent). If we can explain 80 percent of the composition and function of wetlands with just three causal factors, that is actually a rather good situation to be in.
Of course, other factors influence wetlands. Near the coast, salinity needs to be added to this list. Other factors can include salinity and roads.
For further reading, Chapters 2 though 8 in Wetland Ecology provide a chapter by chapter overview of the main causal factors in wetlands.