Where does community collide?

In ecology a community is the set of populations of different species that live together and interact in a shared place: predators and prey, competitors, plants and their pollinators, all bound into one assemblage whose structure ecologists describe by which species are present and how abundant each is. Ricklefs's 2008 Disintegration of the Ecological Community examined how far such an assemblage behaves as an integrated unit rather than a loose overlap of species with independent ranges. The referent is a biological grouping of interacting populations at one site, counted by species and abundance, not a human group bound by belonging, a dense cluster in a graph, or an infection caught outside a hospital.[1]

Unit

One local assemblage of interacting species populations, described by which species occur and how abundant each is

Recovery means

After disturbance the assemblage may re-form through ecological succession, though not always back to the same species mix

Measured by

Surveyed by sampling a site and recording species richness, composition, and relative abundance across the assemblage

In sociology a community is a set of people bound together by shared social ties, a common place, or a felt identity, from a village to a circle of friends to a dispersed group who feel they belong together. Tönnies's 1887 Gemeinschaft und Gesellschaft drew the founding contrast between community, built on personal bonds and belonging, and society, built on impersonal exchange, and Wellman's 1979 The Community Question tested whether such close ties survive in a modern city by mapping the intimate networks of one Toronto district. The referent is a human group defined by belonging and relationship, studied by who is tied to whom, not an assemblage of species, a cluster in a graph, or the population outside an institution.[2][3]

Unit

One human group whose members share ties, a place, or a feeling of belonging

Recovery means

Not applicable

Measured by

Studied through surveys, ethnography, and network mapping of who is tied to whom and how strongly people feel they belong

In network science a community is a subset of nodes in a graph that are more densely connected to each other than to the rest of the network: a tight-knit cluster picked out by the pattern of links alone. Girvan and Newman's 2002 Community Structure in Social and Biological Networks introduced a way to uncover such groups by progressively removing the edges that bridge them, and later work scored the result with a quantity called modularity. The referent is a structural cluster in an abstract graph, defined purely by connection density, not a group of people who feel they belong, an assemblage of species, or an infection caught outside a hospital.[4]

Unit

One cluster of nodes more densely linked within itself than to the rest of the graph

Recovery means

Not applicable

Measured by

Detected by community-detection algorithms and scored by modularity, the gap between within-group and between-group link density

A specialized, non-geographically bound group of people organized around their shared admiration for a brand, held together by a felt connection to one another and not only to the product. Muniz and O'Guinn's 2001 Brand Community identified three markers that make such a group a real community: a shared consciousness of kind, in which members feel they belong together and differ from outsiders; shared rituals and traditions; and a sense of moral responsibility to help fellow members. Schau, Muniz, and Arnould's 2009 How Brand Community Practices Create Value later catalogued the everyday practices through which members build and sustain it. The referent is a consumer collective centred on a commercial brand, not a residential population, an assemblage of species, or a group of workers learning a craft.[5][6]

Unit

One brand's community of admirers, its members and their bonds

Recovery means

Not applicable

Measured by

Assessed through membership, participation in rituals and practices, and survey markers of shared consciousness and mutual obligation

A group of people who share a concern or a craft and deepen it by interacting regularly, learning from one another as they do the work. Wenger's 2000 Communities of Practice and Social Learning Systems described such a community as a joint enterprise held together by mutual engagement and a shared repertoire of tools, stories, and ways of doing things, and treated it as the basic unit through which practical knowledge is built and passed on. The referent is a learning collective defined by a common practice, whether a team of engineers or a guild of restorers, not a brand's admirers, a residential population, or an assemblage of species.[7]

Unit

A group and the practice they build and share

Recovery means

Not applicable

Measured by

Assessed through participation, mutual engagement, and the shared repertoire and knowledge the group develops