Primary Succession and Ecosystem Rehabilitation (original) (raw)

The ecology of restoration: historical links, emerging issues and unexplored realms

Ecology Letters, 2005

Restoration ecology is a young academic field, but one with enough history to judge it against past and current expectations of the science's potential. The practice of ecological restoration has been identified as providing ideal experimental settings for tests of ecological theory; restoration was to be the Ôacid testÕ of our ecological understanding. Over the past decade, restoration science has gained a strong academic foothold, addressing problems faced by restoration practitioners, bringing new focus to existing ecological theory and fostering a handful of novel ecological ideas. In particular, recent advances in plant community ecology have been strongly linked with issues in ecological restoration. Evolving models of succession, assembly and state-transition are at the heart of both community ecology and ecological restoration. Recent research on seed and recruitment limitation, soil processes, and diversity-function relationships also share strong links to restoration. Further opportunities may lie ahead in the ecology of plant ontogeny, and on the effects of contingency, such as year effects and priority effects. Ecology may inform current restoration practice, but there is considerable room for greater integration between academic scientists and restoration practitioners.

Restoration as a Process of Assembly and Succession Mediated by Disturbance

Successional processes in ecosystems have long been studied in ecology, and over a century of work in this field have spawned a series of different successional theories related to how ecosystems develop over time (see Chapter 1). Although ecologists agree on some of the main drivers of changes in species composition within a community, the plethora of different habitats which occur in nature, often with differing histories and organismal composition and structure, does not allow for a unifying theory of succession applicable to all ecosystems or habitats (McIntosh 1999).

Restoration Ecolog y and the Ecosystem Perspective

Restoration Ecology, 1997

The ecosystem perspective provides a framework within which most other aspects of the ecology of restoration can be incorporated. By considering the ecosystem functions of a restoration project, the restorationist is forced to consider the placement of the project in the landscape-its boundaries, its connections or lack thereof to adjoining ecosystems, and its receipts and losses of materials and energy from its physical surroundings. These characteristics may set limits on the kind(s) of biotic communities that can be created on the site. The ecosystem perspective also gives restorationists conceptual tools for structuring and evaluating restorations. These include the mass balance approach to nutrient, pollutant, and energy budgets; subsidy/stress effects of inputs; food web architecture; feedback among ecosystem components; efficiency of nutrient transfers, primary productivity and decomposition as system-determining rates; and disturbance regimes. However, there are many uncertainties concerning these concepts, their relation to each other, and their relationships to population-and community-level phenomena. The nature of restoration projects provides a unique opportunity for research on these problems; the large spatial scale of restorations and the freedom to manipulate species, soil, water, and even the landscape could allow ecosystem-level experiments to be conducted that could not be performed otherwise.

Spontaneous Succession versus Technical Reclamation in the Restoration of Disturbed Sites

Restoration Ecology, 2008

We address the question: under which circumstances can we rely upon spontaneous succession and when are technical measures more effective in restoration programs? To answer this question, the position of a disturbed site along the productivity-stress gradient was considered. The probability of attaining a target stage by spontaneous succession decreases toward both ends of the productivity-stress gradient, whereas the acceptance of technical measures generally increases. In correspondence with that, the monetary cost of restoration increases toward the ends of the gradient. Therefore, spontaneous succession is advocated especially if environmental site conditions are not very extreme.

The Recent Double Paradigm Shift in Restoration Ecology

Restoration Ecology, 2007

The fields of ecology and ecological restoration possess an enormous potential for cross-fertilization of ideas and information. Ecology could play a major role in informing practical restoration, whereas restoration projects, often situated in quite extreme environments, provide an excellent opportunity to test ecological theories. Efforts to base restoration on more of a scientific foundation, however, have recently started gathering momentum, following the call for such a link by Tony Bradshaw in 1987. On another level, as we gather more experience and information from restoration projects, it is becoming equally clear that often neglected socioeconomic and political aspects of restoration should not be forgotten in the overall approach to restoration. The two paradigm shifts in ecological restoration, toward more scientific foundation and better inclusion of socioeconomic limits and opportunities, locate restoration firmly in the transdisciplinary arena, with all the concomitant challenges and opportunities. In this sense, ecological restoration could be compared to the medical profession, where both a sound knowledge of science and human nature are a prerequisite for success in healing.