Common Pool Resource
From the Wikipedia at http://en.wikipedia.org/wiki/Common_Property_Resource
"The terms common-pool resource (CPR), alternatively termed a common property resource, is a particular type of good, and a natural or human-made resource system, whose size or characteristics of which makes it costly, but not impossible, to exclude potential beneficiaries from obtaining benefits from its use. Unlike pure public goods, common pool resources face problems of congestion or overuse, because it is subtractable.
The term "common property regime" refers to a particular social arrangement regulating the preservation, maintenance, and consumption of a common-pool resource. The use of the term "common property resource" to designate a type of good has been criticised, as common-pool resources are not necessarily governed by common property regimes."
"These resources are non-excludable, but they are rivalrous. The solution to the problems associated with common-pool resources is not necessarily private property, though. “If exclusion costs are comparatively high, common ownership solutions may be preferable.” The possibility of co-existence of different governance regimes is particularly important for common-pool re-sources because many CPRs incorporate characteristics of private and public goods. In some instances, this is known as the “comedy of the commons.” The “comedy of the commons” is the opposite of the “tragedy of the commons” – the notion that users of commonly held property such as forests, fisheries, and most notably air, work together to ensure that overexploitation does not occur." (http://cyberlaw.stanford.edu/system/files/From+Wifi+to+Wikis+and+Open+Source.pdf)
"A common-pool resource (CPR) is defined as any resource in which exclusion is difficult and consumption of resource units is rival. Examples of CPRs include groundwater basins, fisheries, forests, grazing ranges, and irrigation systems in which property rights--or the ability to uphold such rights--do not allow for privatization." (http://dlc.dlib.indiana.edu/archive/00003301/)
"Common-pool Resources (CPRs) are natural or human-made resources where one person's use subtracts from another's use and where it is often necessary, but difficult and costly, to exclude other users outside the group from using the resource.. The majority of the CPR research to date has been in the areas of fisheries, forests, grazing systems, wildlife, water resources, irrigation systems, agriculture, land tenure and use, social organization, theory (social dilemmas, game theory, experimental economics, etc.), and global commons (climate change, air pollution, transboundary disputes, etc.), but CPR's can also include the broadcast spectrum. Issues
Whenever a group of people depend on a resource that everybody uses but nobody owns, and where one person's use effects another person's ability to use the resource, either the population fails to provide the resource, overconsumes and/or fails to replenish it, or they construct an institution for undertaking and managing collective action. The common pool resource (CPR) can be a fishery, a grazing ground, the Internet, the electromagnetic spectrum, a park, the air, scientific knowledge. The institution can be a body of informal norms that are disseminated by word of mouth, enforced by gossip or religious stricture, and passed from one generation to another, or a body of formal written laws that are enforced by state agencies, or a marketplace that treats the resource as private property, or a mixture of these forms. In the real world of fishing grounds and wireless competition, CPR institutions that succeed are those that survive, and those that fail sometimes cause the resource to disappear (e.g., salmon in the Pacific Northwest)." (http://www.cooperationcommons.com/node/361)
- There is no such thing as a common property resource – there are only natural resources controlled and managed as common property, or as state property, or as private property. Or, and this is where confusion persists in the literature, there are resources over which no property rights have been recognized. The latter situation is one of open access (res nullius). 
Source: BROMLEY, D.W.: Environment and Economy: Property Rights and Public Policy. Oxford (Basil Blackwell). 1991
On the Difference between Common Pool Resources and Common Property Regimes
"Scholars in the neo-Hardinian tendency have carried on many important empirical studies of common property systems across the planet as well as have made a number of important distinctions in the study of common property. This is not the place to assess their empirical studies (cf. the extensive bibliography on Private and Common Property Rights in (Ostrom 2000: 352-379) and the Digital Library on the Commons mentioned above), but their most important theoretical distinctions are worth reviewing, since some can be useful to the anti-capitalist commonist movement.
Of course, the primary one is between common property and open access regimes, since the confusion between them is the basis of Hardin's deduction of the tragedy of the common. Common property regimes are "where the members of a clearly demarcated group have a legal right to exclude nonmembers of that group from using a resource. Open access regimes (res nullius)-including the classic cases of the open seas and the atmosphere-have long been considered in legal doctrine as involving no limits on who is authorized to use a resource" (Ostrom 2000: 335-336). On the basis of this distinction, common property and open access regimes are mutually exclusive and anyone who had as their political ideal the creation of an open access regime would not be a supporter of the commons.
The second important distinction is between a common-pool resource (which is a thing or stuff) and a common property regime (which is a set of social relations). A common-pool resource is such that (a) "it is costly to exclude individuals from using the good either through physical barriers or legal instruments and (b) the benefits consumed by one individual subtract from the benefits available to others" (Ostrom 2000: 337). Because of its two defining characteristics, a common-pool resource is subject to problems of congestion, overuse and potential destruction. Access to, withdrawal from, management and ownership of such a resource can be in the form of a common property regime, but it need not be. "Examples exist of both successful and unsuccessful efforts to govern and manage common-pool resources by governments, communal groups, cooperatives, voluntary associations, and private individuals or firms" (Ostrom 2000: 338). Much of the work of the neo-Hardinians has been to study what attributes of common-pool resources that "are conducive to the use of communal proprietorship or ownership" and what attributes of common-pool resources that "are conducive to individual rights to withdrawal, management, exclusion and alienation" (Ostrom 2000: 332).
The neo-Hardinians, however, seem to be less interested in the fact that not all common property regimes involve common-pool resources. On the contrary, when we examine the history of common property regimes, we must conclude that many have been based on non-common-pool resources. For example, money income, personal belongings, literary texts, and even children have been communalized. Thus the 15th century Taborites' first act of forming their community was to dump all their personal belongings in large open chests and begin their communal relations on an even footing (Federici 2004: 54). On the basis of the history of common property regimes it is difficult to decide what types of goods are "conducive" to private property and what kinds of goods are "conducive" to common property.
The third important distinction is between common-pool resources (e.g., a fishery, a river) and public goods (e.g., knowledge of a physical law, living in a just and peaceful society). They share one characteristic, i.e., it is difficult to exclude people living within the scope of these resources or goods from their enjoyment. But they also differ in another characteristic, for a common-pool resource like a fishery is reduced when something of value like a particular fish is withdrawn from it while a public good like knowledge of the Second Law of Thermodynamics is not diminished when still another person uses it to construct a new engine." (http://www.globaljusticecenter.org/papers/caffentzis.htm)
Common Pool as a specific proprety regime, according to Elinor Ostrom
"Ostrom claims that common-pool resources are associated with property rights, where a property right is an enforceable authority to undertake particular actions in a specific domain. These property rights are the following.
First, access is the right to enter and receive non-subtractive benefits from the use of the good in the common pool.
Second, withdrawal is the right to remove resources from the common pool.
Third, management is the right to set any use procedures and transformation of the good.
Fourth, exclusion is the right to determine and select which unit can access and transfer rights of the good.
Fifth, alienation is the right to sell/lease any management, withdrawal and exclusion rights of the good. Attributes and rights of the nature of goods form the traits that identify them.
Finally, transacting units have terms of operation such as technology, endowment of capital and nature of stakeholders that reflect the degree of collection, status and organization of the unit and these determine the different incentives for seeking the bundle of traits of goods more appropriate for them to produce and distribute."
(source, Panayotis Economopoulos, The orientation of the Reaction Process)
- STEVENSON, G.G: Common Property Economics. A General Theory and Land Use Applications. Cambridge. Cambridge University Press.1991.p.58.
- Book: BERKES, F. (Ed.): Common Property Resources: Ecology and Community-Based Sustainable Development. London (Belhaven Press). 1989.
- TAYLOR, M.: The Economics and Politics of Property Rights and Common Pool Resources. Natural Resources Journal 32. 1992. p. 635.