Resilience (ecosystem)
In ecosystem theory , resilience is used to denote different terms that are intended to describe the dynamic stability properties of ecological systems. Current definitions relate, for example, to the ability of an ecosystem to maintain its basic organization in the face of ecological disturbances instead of changing to a qualitatively different system state. As a catchphrase with different theoretical definitions and interpretations on the subject of resource use, resilience has become a central stability concept in ecology , ecosystem theory and, above all, environmental research . Resilience increasingly relates to socio-ecological systems .
background
The term resilience, which comes from psychology , is often equated with the “cushioning ability” of systems against external disturbances. The term resilience was introduced to ecology in the 1970s by Crawford S. Holling . The idea of the resilience of ecological and social systems became more and more popular in the 1990s.
definition
A uniform basic understanding of the exact definition and meaning of the concept of resilience is only slowly emerging in the scientific debate (as of July 2012). The term is often used in socio-ecological approaches, which increasingly expands the original, narrower ecosystem definition by Ellenberg.
Heinz Ellenberg defines the resilience of ecosystems as follows:
" Resilience is the ability to return to the original species structure from other ecosystems after significant species shifts (e.g. from forest to herbaceous societies) through a more or less long-term succession ."
The problem with the concept of resilience from a scientific and ecological point of view is the definition of the basic state or the criteria (parameters) for whether an ecosystem that changes due to disturbances maintains its basic organizational structure or not. The resilience concept is in contrast to the dogma of the “ecological balance” that existed in the 1970s. On the other hand, resilience research today assumes dynamic systems that can develop in different directions (succession in different directions).
According to the resilience idea, which condition is considered “valuable” is based on human attribution and cannot be determined by ecological knowledge alone. Resilient ecosystem conditions can therefore not be viewed as 'good' or useful per se (see problem complex nature assessment - societal models ; see savanna example ). Resilience evaluates the observed natural conditions from an individually culturalistic instead of a strictly naturalistic perspective.
Resilience includes the concepts of sustainability related to the use of nature . Resilience approaches are mainly discussed for cultural ecosystems. This is particularly true from the point of view of the “climatic plasticity” of cultural ecosystems, which are threatened by a multitude of biotic and abiotic calamities due to climate change .
Examples
Regeneration of forests
Overexploitation of forests usually leaves behind ecologically impoverished, often stepped , karstified areas without the power to self-regenerate. One then speaks of the over- exploitation syndrome . Resilience can also be lost if the diversity of species falls below a minimum .
Resilience is particularly important in silviculture . The prevailing form of operation in the age-group forest tends to be widespread destruction in the event of any serious disturbance (biotic or abiotic calamities ), that is to say, to bare land, which corresponds to the total loss of the forest ecosystem. In the permanent forest, on the other hand, the regularly multi-layered forest structure is essentially retained even after severe calamities, without the need to replant on a bare area after the calamity. In contrast to the age group forest, it has the ability to be resilient.
Regeneration of overgrazed grasslands
Individual ecosystems, e.g. B. already heavily overgrazed savannas can be very resilient, i. That is, they endure a high number and severity of ecological disturbances (e.g. fire etc.) without changing into a different system state, which is determined by other 'slow' variables. This state therefore has a very high level of self-regeneration, in the sense that it maintains itself or adjusts itself again even with high disturbance intensities. In contrast to a non-overgrazed savannah, a heavily overgrazed savannah can therefore be more “resilient” (i.e. more resistant to disturbance in this case).
Marine ecosystems
In marine ecosystems, resilience is interesting on several spatial and taxonomic levels: Can coral reefs adapt so quickly to the rapid fluctuations in water temperature, and under what circumstances do fish stocks in different marine areas recover? Resilience issues are particularly important for the use of fish as a resource.
Fields of application
Human influences in ecosystems that are researched using resilience-theoretical approaches are, for example:
- Intensive agriculture
- Overexploitation of forests
- Marine ecosystem complexes (tropical coral reefs, seagrass forests, etc.)
- overfishing
- Garbage in marine systems
- Pollutant input into marine systems
- Eutrophication of marine and limnic systems
criticism
The theoretical approach underlying the term is that of adaptation . Against the background of global change due to economic and climate-related factors, resilience research assumes that systems have to adapt in the event of disruptions. Critics accuse her of accepting environmental changes and "making the best of it" out of an opportunistic attitude.
research
The establishment of the Stockholm Resilience Center as an independent research facility at Stockholm University in 2007 was internationally significant . The MISTRA Foundation (the Foundation for Strategic Environmental Research) is behind the center and wanted to finance it until the end of 2013. In 2015 the director of the Resilicence Center, the Swede Johan Rockström , was awarded the German Environment Prize on a pro-rata basis .
The term and topic complex resilience is occupying an increasingly larger space in social-ecological research and sustainability research.
See also
- Resilience management , an economically oriented approach to resilience
Web links
- Resilience Alliance (ecosystems)
- Transitioning towards Urban Resilience and Sustainability (TURaS) - EU city project (English)
Individual evidence
- ^ FS Brand, K. Jax: Focusing the meaning (s) of resilience: Resilience as a descriptive concept and a boundary object . In: Ecology and Society. 12 (1), 2007, p. 23.
- ↑ T. Kirchhoff, F. Brand, D. Hoheisel, V. Grimm: The one-sidedness and cultural bias of the resilience approach. In: Gaia. 19 (1), 2010, pp. 25-32.
- ↑ CS Holling: Resilience and stability of ecological systems. In: Annual Review of Ecology and Systematics. 4, 1973, pp. 1-23.
- ^ Heinz Ellenberg : Vegetation of Central Europe with the Alps. 6th edition. UTB, Ulmer, Stuttgart 2010, ISBN 978-3-8252-8104-5 , p. 110.
- ↑ Cf. on the question raised about the identity criteria of ecological units: V. Grimm: To be, or to be essentially the same: the 'self-identity of ecological units'. In: Trends in Ecology and Evolution. 13 (8), 1998, pp. 298-299.
- ^ Wilhelm Bode, Martin von Hohnhorst: Waldwende. From forest forest to natural forest. Munich 1994. (4th edition. Munich 2000, ISBN 3-406-45984-6 )
- ↑ Center background. ( Memento from July 20, 2012 in the Internet Archive ) stockholmresilience.org