Restoration Success





Restoration Decisions: (and theory)


reference sites

Case Studies


State of the Science

success criteria
floristic quality


Created by:

Abby Rokosch
Jessen Book
Siobhan Fennessy


Evaluation and monitoring of wetland restoration projects in order to determine project success has been evaluated in many different ways. The ability to restore a wetland depends on many factors (Kusler and Kentula, 1990; Thayer, 1992; Richardson, 1994; Mitsch and Wilson, 1996 in Kentula, 2000):

  • Type of wetland
  • Region of country
  • Ecological functions of interest
  • Degree of degradation
  • Surrounding land use
  • Ability to establish or maintain proper hydrology
  • Financial feasibility

Historically, "successful" restoration projects have been evaluated primarily by the establishment of certain wetland attributes such as vegetation cover and the abundance of animal species, it is necessary to move beyond this tradition and focus not only on wetland attributes, but on ecosystem function (Kentula, 2000; Zedler, 2000).

Much like the term "wetland," different authors define success in different ways.

1) Kentula (2000) postulates that success can be positioned in three different ways:

  • Compliance success: is determined by evaluating compliance with the terms of an agreement, e.g. a contract or permit
  • Functional success: is determined by evaluating whether the ecological functions of the system have been restored
  • Landscape success: is a measure of how restoration (or management, in general) has contributed to the ecological integrity of the region or landscape and to achievement of goals such as the maintenance of biodiversity

2) Mitsch et al. (1998) define success as the establishment of a biologically viable and temporally sustainable wetland ecosystem.

3) Ewel (1987) takes the definition further, by establishing a list of five criteria that must be upheld by the restored/mitigated wetland in order to consider it a success:

  • the reconstructed community must be sustainable,
  • the community must be resistant to invasive species,
  • restored communities need to be as productive as undamaged communities,
  • the community should not lose more nutrients than an undamaged reference,
  • plant populations must be viable enough to support community wide interactions.

4) Cairns (2000) defines functional success by emphasizing goals that restore the functions perceived by society as ecosystem services. Some of his recommendations include the following goals:

  • to see that the machinery of nature has sufficient energy to deliver necessary ecosystem services
  • to avoid poisoning or impairing the machinery of nature by altering both the structure and function of natural systems by means of intoxicants
  • to devise a better balance in meeting short-term and long-term needs of human society

Essentially, all definitions of success are dependent upon the likeness of the restored wetland (both in terms of structure and function) to comparable reference sites. However, many would still argue that no restored wetland will ever be as successful as the original, therefore some minor relaxations in criteria must be considered (Zedler, 1996). Nevertheless, without using standardized criteria, wetland success will continue to go unassessed, which in turn may lead to continued mistakes and failures.

Having thus defined success, the next step becomes working towards the realization of these goals. Specifically, restoration engineers must:

1.Use pre-existing ecological theory to maximize their potential for success; and
2.Periodically (re)evaluate their own success via certain guidelines.