Association of State Wetland Managers - Protecting the Nation's Wetlands.

The Compleat Wetlander: Why Is Wetland Restoration Failing?

“Many wetland recovery programs have failed by trying to re-create the original ecosystems. Recent successes have focused on one or two limited goals and have let nature take it from there.”

–John Carey

An article in the December Issue of Scientific American by John Carey “Architects of the Swamp” has been receiving a lot of attention among wetland professionals.  A number of people I’ve talked to over the last couple months have read it or heard about it.  Carey interviewed several prominent wetland restoration experts including Joy Zedler, Robin Lewis, and John Teal and found that wetland restoration – both voluntary and for mitigation – has a less than satisfactory success rate.  In fact the take away conclusions of the article were:

  • Wetlands across the U.S. and the world continue to disappear at a rapid rate.
  • Projects to revive wetlands have largely failed and wasted millions of dollars, primarily because they have attempted to fully engineer all aspects of an ecosystem to their original conditions.
  • Instead scientists should attempt to achieve one or two benefits, such as boosting fish populations or improving water quality, leaving the rest alone.
  • A growing number of restorations built on that principle are succeeding in Delaware Bay, in coastal Louisiana and around the globe.

A study published in 2012 by David Moreno- Mateos and others examined 621 wetland sites, some over a century old, and found in general that they failed to provide the same level of function (environmental benefits) as existing natural wetlands.    The authors stated:

“Our analysis suggests that even a century after restoration efforts, these parameters remained on average 26% and 23% (respectively) lower in restored or created wetlands than in reference wetlands. Our results also indicate that ecosystem size and the environmental setting significantly affect the rate of recovery. Recovery may be more likely and more rapid if more than 100 contiguous hectares of habitat are restored. In warm climates, and in settings linked to riverine or tidal flows, recovery can also proceed more rapidly. In general, however, once disturbed, wetlands either recover very slowly or move towards alternative states that differ from reference conditions. Thus, current restoration practice and wetland mitigation policies will maintain and likely accelerate the global loss of wetland ecosystem functions.”

In an editorial published in November 2013 in Ecological Engineer, When will ecologists learn engineering and engineers learn ecology? Editor in Chief Bill Mitsch issued a mid-term grade for some of the most important wetland restoration efforts underway in the United States and abroad.  Of the six case studies evaluated, the Louisiana Delta received a D-, and the Everglades faired only marginally better with a D+.  On the bright side, the Delaware Bay Salt Marshes and the Mesopotamian Marshlands received an A- and an A respectively.  The two other restoration projects reviewed were the Indian Ocean Mangroves with a C and the Mississippi/Ohio/Missouri watershed with an incomplete.

Over the past few weeks, I’ve been calling and talking to wetland restoration experts with decades of experience asking them about the conclusions of these reports.  Their comments have been interesting. There seems to be consensus that the necessary understanding of wetlands and associated ecological systems exists.  The ability to restore these systems exists. However, individuals have identified one or more of the following barriers.

  1. Access to the information about how to implement successful restoration is limited.  It’s dispersed among journal articles that are expensive to access, or in written documents available through government agencies, in books, on the web, in the grey literature or in someone’s head.
  2. There is no framework for ensuring the necessary training occurs.  Universities and colleges provide limited opportunities for training.  There are no certification programs specific to ensuring a wetland restoration professional has training in ecological restoration and design.
  3. Best Management Practices are not identified or are wrong.
  4. Many wetland permitters at the federal, state and local level do not receive adequate training in reviewing proposed wetland restoration/mitigation projects to identify problems during the permit review process.
  5. A good wetland restoration plan must be followed correctly. Mistakes are made in implementing restoration construction plans.
  6. Wetland programs, both regulatory and voluntary, lack strong wetland construction, compliance and enforcement policies.

The good news is that we can collectively address these issues, and that doing so has the potential to significantly reduce the costs of restoring these systems while providing significant benefits to people and the environment.

In the coming months the Association of State Wetland Managers looks forward to working with partners to begin to address these and other issues that may be identified as the dialogue continues.  If you would like to join us please e-mail me at  There is much to be done.

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