Space and scale in ecology

The practical and theoretical issues of environment and context in archaeology require a familiarity with environmental systems. These provide both the spatial and temporal frameworks, physical and biotic, within which human communities interact and that, equally so, interact with human communities.

The biosphere encompasses all of the earth's living organisms, interacting with the physical environment in an infinite number of component systems. For practical reasons, biologists commonly select only a part of the biosphere for direct study, and they may focus on vertical (hierarchical) or horizontal (spatial) interactions.

Levels of vertical organization begin with genes and cells and then range upward successively to organisms, populations, and communities. The population comprises groups of individuals of any one kind of organism, whereas the community includes all of the populations occupying a given area (Odum, 1971:4–5). Finally, the community and the nonliving environment function together in an ecosystem. Study may concentrate on an individual organism or a single population (autecology), or on a community (synecology). Such communities may be large or small, with a corresponding difference in the degree of dependence on inputs from adjacent communities. The communities, and the ecosystems they imply, range in dimension from local to subcontinental in scale.

In terms of horizontal organization, the largest terrestrial communities define the earth's key biotic landscapes.