Carrying capacity
Definition of Carrying capacity:
The maximum population size or level of use that a given habitat, ecosystem or resource can sustain without lasting deterioration of its condition or functioning.
This is the common definition for Carrying capacity, other definitions can be discussed in the article
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There is no single carrying capacity of a coastal area. Its practical determination depends on the activity or population considered and on the criterion used to define its limit. For example, the carrying capacity of a beach for recreation can be defined according to available space, ecological disturbance, visitor perception of crowding or the capacity of supporting infrastructure. These limits need not coincide. Carrying capacities are also not necessarily fixed, but can change through management interventions, technological development, environmental change and changes in societal preferences[1].
Carrying capacity is closely related to sustainable use. The Brundtland report Our Common Future defines sustainable development as "development that meets present needs without compromising the ability of future generations to meet their own needs"[2]. For renewable resources, sustainable use requires that exploitation remains compatible with the capacity of the resource and its supporting ecosystem for renewal. Carrying capacity thus expresses constraints within which use can remain sustainable.
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Types of carrying capacity
Several types of carrying capacity are commonly distinguished:[1]
- Physical carrying capacity refers to constraints imposed by available space or infrastructure, for example the number of berths that can be accommodated in a marina.
- Ecological carrying capacity refers to the level of human pressure that an ecosystem can sustain without significant or persistent impairment of its structure and functioning. The concept is used, for example, in aquaculture and in managing recreational pressure on sensitive habitats. In fisheries, ecological carrying capacity is generally not used directly as a management limit. Instead, management commonly refers to maximum sustainable yield (MSY): the largest long-term average catch that can be taken from a fish stock without impairing its capacity for renewal. In the European Union, MSY is a central objective of the Common Fisheries Policy and provides an important biological basis for setting Total Allowable Catches (TACs), which are subsequently allocated among Member States as national quotas.
- Social carrying capacity refers to limits determined by people's acceptance of perceived changes in natural, environmental or recreational values.
- Economic carrying capacity refers to the level of development or use beyond which existing economic activities or economic values are impaired in the long term.
Composite concepts such as tourism or recreational carrying capacity combine several of these constraints.
Carrying capacity in coastal management
Carrying capacity assessment can support coastal management by identifying the processes or resources that constrain a particular activity and by defining indicators for monitoring whether relevant limits are being approached. Some constraints, such as available area, freshwater supply or wastewater-treatment capacity, can be quantified relatively directly. Ecological and especially social limits are often more difficult to determine because defining the boundary between acceptable and unacceptable change may require weighing different gains and losses.
Carrying capacity analysis should therefore not generally be regarded as a procedure for determining a single objective maximum number of users or activities. For complex coastal systems, determining principal limiting factors and establishing acceptable conditions or threshold values may require a decision-making process in which major stakeholders are equitably represented.
This links carrying capacity with sustainability indicators, which translate broad sustainability objectives into measurable variables and trends. Carrying-capacity assessment focuses particularly on indicators and thresholds that show when population, use or pressure approaches limits considered acceptable for a particular system or activity. Relevant indicators should therefore be monitored and management adapted when limiting conditions are approached.
Related articles
- Integrated Coastal Zone Management (ICZM)
- Sustainability indicators
- Resilience and resistance
- The Tragedy of the Commons
- Multifunctionality and Valuation in coastal zones: concepts, approaches, tools and case studies
- Carrying capacity and development of the Wadden Sea
References
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