It was first applied to levels of biological organization represented by unites such as community and the biome. Just as natural ecosystems they can be thought of as including the processes of primary production, consumption, and decomposition interacting with abiotic environmental components and resulting in energy flow and nutrient cycling. Economic, social, and environmental factors must be added to this primary concept because of the human element that is so closely involved with agroecosystem creation and maintenance. Agroecosystems do not happen without human intervention in the landscape. Agroecosystems are controlled, by definition, by management of ecological processes.
All ecosystems are open, that is, they exchange biotic and abiotic elements with other ecosystems.
Because modern agroecosystems are entirely dependent on human intervention, they would not persist but for that intervention. It is for this reason that they are sometimes referred to as artificial systems as opposed to natural systems that do not require intervention to persist through space and time. Definitions of agroecosystems often include the entire support base of energy and material subsidies, seeds, and chemicals, and even a sociopolitico-economic matrix in which management decisions are made. The pattern created by this interspersion incorporates elements of the variability of structure and separation of functions among the various ecosystems. Application of this knowledge can lead to development of more sustainable agricultural ecosystems in harmony with their larger ecosystem and ecoregion.