Edge Effects, resource utilisation and community psychology

Paper to be given at III European Conference on Community Psychology; September 2000; Bergen, Norway.

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Mark Burton, Manchester Learning Disability Partnership
Carolyn Kagan, Manchester Metropolitan University


The concept of the 'edge effect' is offered as an organising concept in community psychology. The origins of the concept in environmental ecology will be explored. The application of the concept to problem contexts in community psychology is explored, with a particular focus on resource utilisation.


The edge effect
Application to community psychology
Strategies for increasing edge
Creation and maximisation of edge
Stewardship of the edge


Community psychologists typically work with complex social contexts. These might be called communities, groups, cultures, organisations, or something else. Often it is necessary to engage simultaneously with more than one of these entities. In these circumstances it is important that resources are focused effectively, if the community psychology practice is going to add any value to what might happen anyway in these settings. To do this organising concepts are crucial. Community Psychology does have its share of organising concepts, for example:
· Person-in-context
· Psychological sense of community
· Social Support
· Power and empowerment
· Prevention
· Social system
... but are we alone in finding community psychology conceptually rather impoverished? What concepts there are seem to be rather general, catch all ideas, with little to define their appropriate scope of application in description, explanation, or action. Perhaps the problem is psychology itself - the rejection of much of the apparatus of individual psychology leaves community psychology rather bereft of theoretical content. Elsewhere we have argued for the use of concepts from non psychological spheres such as social movement theory, and the analysis of ideological struggle (Burton, 2000; Burton and Kagan, 1996; Kagan and Burton, 1995, Lewis, Kagan and Burton, 1995). Here we want to suggest the usefulness of a concept that relates to the use of resources in community contexts and in the practice of community psychology.
This is the 'edge effect', a concept from the field of ecology. As Levine and Perkins note (1997: 111-2)

"Ecology" is a fundamental metaphor or analogy in community psychology, embodying both the structure of a scientific paradigm and a specific set of values.

They go on,

We assume that there are enough similarities between the problems that concern community psychologists and those studied by biological ecologists that we may use the concepts to illuminate problems of interest to us

In the same spirit, we will use this specific ecological concept because it seems to fit reasonably well with both observations that we have made and problems that we have encountered.

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The edge effect

Ecologists define distinct biological communities, characterised by a set of populations living in a particular area or habitat. Such a community will be organised: it has characteristics in addition to its component individuals and populations, and these elements interact in an organised way, for example through metabolic flows and transformations (e.g. Odum, 1971: 14). Examples of such communities include forests, grasslands, or ponds.
The transition or edge between two or more communities is known as the 'ecotone'. Examples are the transition area between forest and grassland, or the tidal area of a river estuary. The ecotone may have a considerable size, but will not be larger than the adjoining communities.
The ecotonal community will contain many of the organisms found in each of the overlapping communities, and in addition may contain organisms that are characteristic of, or even restricted to the ecotone. Often both the number of species, and the population density of some, are greater than in the 'pure' communities. Furthermore, the junction between communities often acts as a kind of net or sieve for resources such as humus and seeds - they accumulate at the boundary. This enrichment in terms of variety and density at the join between communities is known as the 'edge effect'. One of the most important general types is the forest edge, which is characterised, for example by many of the fruit and nut species that have been selected for human cultivation.
Human settlements and methods of food production, particularly traditional methods, create or increase the extent of edge. In applied ecology - for example in the design of sustainable settlements and cultivation systems, the edge effect has sometimes employed. Examples of ecologically designed and traditional patterns that utilise the edge effect include:-
· alley cropping, where trees are combined with agricultural crops to provide protection and through pruning a source of mulch;
· chinampas, a system of canals and banks in parallel allowing fish production, the fertilisation of land crops with waterweed and silt, the moderation of temperature, and irrigation;
· integrated fish and livestock systems, e.g. the Chinese carp / duck system;
· town planning initiatives such as garden suburbs and 'city/country fingers'.
(see Alexander et al., 1977; Altieri et al., 1987; Mollison, 1988, 1991). All of these models increase the edge between communities through strategies such as placement, overlapping, tessellation (the use of wavy or convoluted boundaries to increase the extent of the edge), and the use of narrow strips.

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Application to community psychology

Just as it is possible, through the design of sustainable systems of ecological development, to increase the relative contribution of the 'edge' to each adjoining community, so it is possible to create a larger edge effect in organisational and community development and thereby maximise its benefit to the system as a whole.
We need to be clear that we are using 'edge' here as a metaphor. An edge effect in a natural ecological system isn't necessarily the same thing as an edge effect in a human community system - the mechanisms, the transactions, and the mediations will be different. At any rate we remain agnostic about the existence or not of some superordinate systemic principles that underlie both the ecological edge effect and the analogous phenomenon in community and organisational development.
Here, however, is our application of the idea. Quite often community psychological projects involve working across boundaries. Examples from our work include initiatives spanning the one or more of the following boundaries;
· University and marginal housing estates,
· Health and social welfare services,
· Governmental and non-governmental organisations,
· Schools and business,
· Families and social welfare bureaucracies,
· The criminal justice system and alienated young people.
We have used the notion of the 'edge effect' to describe the phenomenon of enrichment in some of these alliances and confrontations. When edge is actually created we notice an increase in energy, excitement and commitment.
What characterises all of these contexts (whether edge is significantly created or not) is the problem of spanning social entities with greatly differing modes of operation, power structures, cultures, physical environments, and ideologies. Not only is it necessary to know something about how to navigate in at least two contexts, but the need to do so increases the demand on resources, of both the participating sectors, and the community psychologists themselves.
We can identify three types of strategies for working across such boundaries:

Figure 1: Three strategies for working across community or organisational boundaries.

Strategy Method Results Schematic example
Working within boundaries Development and change targeted at each community separately. Energy inefficient and unlikely to lead to co-ordinated change in the common domain. no edge
Working at the interface Attempts to bridge communities. Energy intensive: some likelihood of co-ordinated change, but effort is on the margins of each community area of concern, so sustain ability is questionable. bridged edge
Maximising the 'edge: Using natural resources - getting people from different communities to work together and utilise the expertise of each. Energy efficient and high likelihood of leading to sustainable and co-ordinated change. edge

These are of course 'ideal types': in reality almost any piece of work will involve some elements of each strategy. However, the comparison among these abstracted strategies is illuminative. It suggests that in working to increase the edge and working with the edge, a project will be most likely to maximise the amount and variety of resources available to it. It is also more likely to preserve the best features of adjoining systems and to enhance the likelihood that developments will be sustainable ones.

Strategies for increasing edge

How might a productive inter-community edge be increased? We suggest the following strategies, which divide into strategies for creating and maximising edge, and strategies for the careful stewardship of the edge.

Creation and maximisation of edge:

The following strategies have in common the maximisation of points of contact between distinct communities and organisations.
Location and co-location of projects, teams, events (e.g. a worker funded by a social welfare organisation to recruit volunteers is located in a community education centre).
Formation of inter-organisations with membership from more than one sector (e.g. an inter-generational initiative has a steering group drawing from education, local government, community, and local business organisations).
Creation of new settings (temporary or long-standing) that bring elements together - (e.g. community festivals that bring diverse sections of a community together - members of the public have fun in each others' company, while those who set up the event learn to work together).
Conduct of activity in other locations, that is in territory associated with another sector (e.g. a health promotion programme operates in a shopping centre rather than from a clinic base).
Creation of multiple points of contact (tessellation) (e.g. a University department sends students to work on a variety of community projects in a particular community, and invites community members to hear students presenting their projects. Meanwhile staff members establish a mentoring programme to strengthen community leadership skills with community activists, and join demonstrations against local government policy).

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Stewardship of the edge

Whilst the 'edge' is usually enriched by the adjoining communities, with bad stewardship it can become barren and impoverished, supporting little of environmental benefit. Working at the 'edge' therefore has responsibilities to preserve the very best of all adjoining communities and this may present further challenges for a project in the future. The following strategies are possible ways of protecting and supporting the edge community.
Recognise 'edge species' and encourage them. (e.g. a community activist develops skills and credibility in mediating between her ethnic minority community and the police. She is careful to maintain her profile in her base community, continuing to live and socialise there, and she shares her skills with members of what started her support group).
Encourage fairness in resource exploitation (e.g. a group of mental health service survivors are paid as consultants to a project on service planning).
Pool resources between sectors (e.g. a local government department provides office accommodation for a community initiated project on isolated older people).
Respect the uniqueness of each community, or else the edge can become a site of unproductive conflict.


The concept of the edge effect has been offered as an analogy from biological ecology and ecologically based design. It appears to have a relevance to community psychology for understanding and acting in problem contexts that involve more than one distinct community, organisation, or other social entity. Different ways of focusing resources in cross boundary contexts were reviewed, with strategies of creating and maximising edge advocated. Finally, it was noted that edge settings will not deliver benefits in some automatic way, but will require both safeguarding and developing through effective and responsible stewardship.

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Alexander, C., Ishikawa, and Siverstein, M. (1977) A Pattern Language: Towns, buildings, construction. New York: Oxford University Press.
Altieri, M.A., Norgaard, R.B., Hecht, S.B., Farrell, J.G. and Liebman, M. (1987) Agroecology: The scientific basis of alternative agriculture. Boulder, Colorado: Westview Press, and London: Intermediate Technology Publications.
Burton, M. (2000) Service development and social change: the Role of Social Movements. In C Kagan (Ed.) Collective Action and Social Change: Report of the National Community Psychology Conference, January 1999. Manchester: IOD Research Group.
Burton, M. and Kagan, C. (1996) Rethinking empowerment: shared action against powerlessness In I Parker and R Spears (Eds.) Psychology and Society: Radical theory and practice. London: Pluto Press.
Carolyn Kagan and Mark Burton (1995) Paradigm Change in Action: the role of social movements. Manchester: IOD Research Group (IOD Occasional Papers 3/95) , ISBN 1-900139-10-3.
Levine, M. and Perkins, D.V. (1997) Principles of Community Psychology. New York: Oxford University Press.
Mollison, B. (1991) Introduction to Permaculture. Tyalgum, NSW: Tagari .
Mollison., B. (1988) Permaculture: A designer's manual. Tyalgum, NSW Australia: Tagari.
Odum, E.P. (1971) Fundamentals of Ecology. Philadelphia: Saunders College Publishing.
Lewis, S., Kagan, C and Burton, M (1995) Families, Work and Empowerment: Coalitions for social change. Manchester: IOD Research Group (IOD Occasional Papers: 5/95) ISBN 1-900139-20-1

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