Ecosystem Management: Definitions and Concepts
Definitions of Ecosystem Management
Many people and organizations have defined ecosystem management. The following examples represent a cross-section of definitions. There are two themes common to most of these definitions of ecosystem management: (1) management should maintain or improve ecosystems; and (2) ecosystems should provide a range of goods and services to current and future generations.
...regulating internal ecosystem structure and function, plus inputs and outputs, to achieve socially desirable conditions. (Agee and Johnson 1987)
...the strategy by which, in aggregate, the full array of forest values and functions is maintained at the landscape level. Coordinated management at the landscape level, including across ownerships, is an essential component. (Society of American Foresters 1993)
...a strategy or plan to manage ecosystems for all associated organisms, as opposed to a strategy or plan for managing individual species. (Forest Ecosystem Management Assessment Team, 1993)
...a resource management system designed to maintain or enhance ecosystem health and productivity while producing essential commodities and other values to meet human needs and desires within the limits of socially, biologically and economically acceptable risk. (American Forest Paper Association Forest Resources Board, 1993)
...integrating scientific knowledge of ecological relationships within a complex sociopolitical and values framework toward the general goal of protecting native ecosystem integrity over the long term. (Grumbine, 1994)
...management driven by explicit goals, executed by policies, protocols, and practices, and made adaptable by monitoring and research based on our best understanding of the ecological interactions and processes necessary to sustain ecosystem structure and function. (Christensen et al. 1996)
The term "ecosystem" was proposed by A.G. Tansley (1935) in an effort to apply systems thinking to complexity in nature. Ecosystems are hierarchical. That is, there are ecosystems within ecosystems. For example, a single decaying log on the forest floor may host an entire ecosystem; just as the watershed in which the log occurs may be considered an ecosystem. Both ecosystems depend on inputs of nutrients, water, and light; both include plants, animals, predators, prey, and detritivores that transform the inputs to produce outputs of nutrients, energy, and water. Within components of the decaying log there may be several levels of nested ecosystems. Similarly, the watershed may be a subcomponent of larger ecosystems.The rich complexity of nature can be more readily understood by approaching it in terms of a hierarchy of nested systems.
Over the course of the past century, the understanding of the nature of ecosystems has evolved. In the formative stages of the ecosystem concept, it was common to imagine that ecosystems were relatively simple, closed, fragile, and static. In the past half century research has shown that ecosystems are complex, open, robust, and dynamic. The growing realization that disturbances, both natural and anthropogenic, have played an important role in the establishment and development of forests (e.g., Oliver and Stephens 1977, White 1979, Lorimer 1980, Foster 1988, Hemstrom and Franklin 1982, Canham and Loucks 1984, Clark 1990, Whitmore and Burslem 1998, McClachlan et al. 2000) has been central to the development of the current understanding of the nature of ecosystems.
A great challenge to the implementation of ecosystem management is defining what we mean by "management." As will be discussed in the decision-making process section, management decisions within a hierarchy must be made at each level in the hierarchy. Because of the differences among levels in the hierarchy, the types of decisions that are made at each level will be considerably different. Focusing the ecosystem management debate on the merits and limitations of one particular silvicultural system (e.g., clearcutting) ignores the higher scale management decisions that are equally critical to managing multi-scale hierarchical systems. Therefore, it is important to consider carefully how we conceptualize management and the decision-making process for complex systems. First, we must think about how to manage information at different scales and how to use this information to make decisions at each level in the hierarchy. Once that has been achieved, tools to deliver and process that information can be developed or adapted from existing technology. Only then is it possible to discuss management in terms of operational details (e.g., which trees to plant or cut).