Overview

Ecological restoration is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed (SER 2004). From an ecological perspective, it is an intentional activity that reinitiates ecological processes that were interrupted when an ecosystem was impaired. From a conservation perspective, it recovers biodiversity in the face of an unprecedented, human-mediated extinction crisis. From a socioeconomic perspective, ecological restoration recovers ecosystem services from which people benefit. From a cultural perspective, ecological restoration is a way that we strengthen our communities, institutions, and interpersonal relationships by participation in a common pursuit. From a personal perspective, ecological restoration allows us to reconnect with the rest of Nature and restore ourselves as we restore impaired ecosystems. All of these perspectives on ecological restoration distill down to a simple truth: Nature sustains us; therefore, we serve our own interests when we reciprocate and sustain Nature.

While globally cumulative, ecological restoration is necessarily a local endeavor. The decision to restore represents a long-term commitment of land and resources. Ideally, that decision is reached in consensus by all who are affected. A restored ecosystem contributes to peoples' ecological and socioeconomic security and their well-being into the indefinite future. The benefits of ecological restoration are intergenerational. People develop appreciation for local ecosystems when they participate in decisions regarding restoration, and their respect for ecosystems increases if they become actively engaged in restoration activities.

Ecological restoration reinitiates ecological processes, but we cannot intervene and create desired outcomes directly. Instead, we manipulate biophysical properties of an impaired ecosystem to facilitate resumption of processes that can only be performed by living organisms. The restoration practitioner assists ecosystem recovery much as a physician assists the recovery of a patient. Patients heal themselves under the physician's supervision, care, and encouragement. Similarly, ecosystems respond to assistance provided by restoration practitioners.

Once ecological restoration project activities are completed, a successfully restored ecosystem self-organizes and becomes increasingly self-sustaining in a dynamic sense. It again becomes resilient to disturbance and can maintain itself to the same degree as would be expected of an undisturbed ecosystem of the same kind in a similar position in the local landscape. In other words, the intent is to recover an impaired ecosystem to a condition of wholeness or intactness. A "whole" ecosystem is characterized by possession of a suite of ecological attributes that are discussed in chapter 5. We use the term holistic ecological restoration to distinguish such comprehensive efforts from partial restorative actions that are limited to incremental ecosystem recovery or ecological improvement.

In spite of our ideal to recover an impaired ecosystem to a condition of total self-sustainability, the era of Earth's history when intact ecosystems were entirely self-sustainable has come to a close, for two reasons. First, human-mediated environmental impacts have become so pervasive globally, and often so severe locally, that many restored ecosystems require ongoing ecosystem management to prevent them from slipping into an impaired state once again. Second, many seemingly natural ecosystems coevolved with human inhabitants, whose traditional cultural practices have transformed them into semicultural ecosystems. Such systems degrade from disuse following abandonment and become candidates for ecological restoration. If they are restored to their semicultural state, then cultural practices that previously maintained them should be resumed to ensure their sustainability.

Ecosystems are not static. They evolve in response to natural and anthropogenic modifications in the external environment and to internal processes that govern species composition and abundance. We use evolve and evolution with respect to ecosystems here and elsewhere in this book, not in a Darwinian sense, but in a developmental sense to indicate unidirectional or cyclic ecological change through time. Ecosystem evolution, just like the evolution of species, is sometimes gradual and subtle and at other times rapid or abrupt. A record of the sequential changes in expression that an ecosystem undergoes through time is called its historic ecological trajectory. If an ecosystem is impaired, its historic trajectory is interrupted. Ecological restoration allows an ecosystem to resume its historic trajectory. This is similar to a physician assisting in the healing process, so that patients can resume their lives.

During the hiatus caused by impairment, the Earth has not stood still. External conditions and boundaries may have changed, and the internal processes of ecosystem recovery may cause ecosystem expression that was not formerly present. Therefore the outcome of ecological restoration is necessarily a contemporary expression and not a return to the past, even though many if not most species may well persist from past to future on most sites. In this way, ecological restoration connects an impaired ecosystem to its future. We restore historical ecological continuity, not historic ecosystems. Regardless of how much we try to restore to the past, it never happens. We have no choice in this matter, because we can't control outcomes of restoration without losing the quality of naturalness that we ultimately strive to recover. At best, we can only emulate the past as we restore. The reason for this is that ecosystems consist of living organisms, and life does not run backward. In many restoration projects, the future state emulates the gross structural aspects of the preimpairment ecosystem, but to believe it can ever truly return to that former state—as if time were reversible—is wishful thinking and counterproductive. We invariably restore ecosystems "to the future." Consequently, ecological restoration is in some ways a metaphor that should not be taken literally. Nonetheless, it is a...