Rewilding Wetlands: A Concise Guide
This wetland was once a drained depression in an agricultural landscape. It is now part of a provincially significant wetland and supports seven species of breeding frogs, as well as providing habitat for the endangered Blanding’s Turtle. Paul and Cathy Keddy bought this wetland, restored it, and then donated an easement with the local land trust to ensure the property is protected in perpetuity. (Photo by Cathy Keddy).
Wetlands are a vital life support system for Earth. They not only support hundreds of thousands of kinds of wild species, but they provide human services such as clean water, carbon storage, and oxygen. The world is full of opportunities to rewild landscapes by restoring wetlands. In some cases, it may be as simple and inexpensive as plugging a drainage ditch. In other cases, more elaborate and expensive methods may be necessary.
The challenge is to restore the maximum area of wetland at the lowest cost. This requires us to work with natural causal factors. It is all too easy to spend large sums of money with low benefits. Reviews of previous restoration efforts show that often the wrong kind of wetland is created—and in some remarkable cases, no new wetlands are created at all!
Vast areas of wetland around the Great Lakes are dependent upon the alternation between high water years and low water years. Dams that stabilize water levels actually reduce wetland area. Here the restoration challenge is to restore both high water years and low water years over a cycle lasting about a decade. (Photo by Tony Reznicek)
Dr. Paul Keddy has therefore written a short guide on the best methods for restoring wetlands as part of rewilding landscapes. He was a professor of ecology for over thirty years, has published over 100 scientific papers, and has worked with many wetland conservation efforts. Paul is best known for his textbook titled Wetland Ecology: Principles and Conservation published by Cambridge University Press. A new edition will be published in September 2023. Paul was aware that his comprehensive book on wetland ecology (some 500 pages and several hundred colour illustrations) was daunting for many applied ecologists and project managers who simply wanted the tools to restore wetlands. So, Paul has prepared a separate and much shorter book giving just 12 priority tools for restoring wetlands and rewilding landscapes.
Dr. Paul Keddy has studied wetlands for 50 years. The focus of his research has been finding the most important causal factors that create wetlands. This wetland, in coastal Louisiana, has a handful of causal factors: a high water table, low levels of nutrients, and low levels of salinity. (Photo by Cathy Keddy)
Books and web pages are often filled with random information on wetlands. Effective restoration requires that we focus attention on causal factors that create wetlands. Paul wrote this concise guide to focus on the most important causal factors, those that can be immediately used by wetland managers, landscape architects, and planners. (Photo by Springer Press).
This “concise guide” uses the principle of causal factors. It may not surprise you to know that flooding is the most important causal factor in creating wetlands. In nearly all cases, restoring the natural flood regime (that is, natural hydrology) is the number one priority. In some cases, this can be as simple as plugging a drainage ditch. Beavers may even provide a particularly low-cost method for accomplishing this task. In other cases, the challenge is much more expensive. Vast sums of money are being expended in the Everglades and coastal Louisiana. When large sums of money are involved, it is vital that the methods used are effective. In some cases, they are not.
Restoring the natural flooding is important, but rarely sufficient. There are other causal factors—often overlooked—that influence the composition and function of wetlands. These include nutrients, natural disturbances such as fire, grazing by herbivores, and even the amounts of coarse woody debris. Paul has lectured and written about this “causal factor approach” to wetland restoration.” Managers can make a short list of the most important causal factors that influence their landscape, and then select those factors that will achieve their objectives.
This book briefly introduces the main kinds of wetlands, and then it proceeds through the 12 causal factors. Each chapter introduces a causal factor, briefly explains its role in wetlands, and then shares several examples of these causal factors. The examples come from around the world. Each chapter concludes with some simple guidelines for immediately applying the information to wetland protection and wetland restoration.
The book is available here.
For an online lecture by Paul on the causal factor approach to wetland restoration, go here.
Dr. Paul Keddy (www.drpaulkeddy.com) was a professor of ecology for more than 30 years, writing over 100 scientific papers, and six books. His awards include a Lifetime Achievement Award from the Society of Wetland Scientists and a Meritorious Service Medal from the Governor General of Canada. He has also worked with many conservation groups. He currently lives on a dead end road within 600+ acres of protected forest and wetland that he and his late wife Cathy purchased over forty years, and then donated to a local land trust. Paul continues to write books and articles, as well as providing scientific advice.
Photo: Dr. Paul Keddy (by Susan Gibson)