An artificial ecosystem meets all the criteria of a natural ecosystem but is made and controlled by humans. It is created to mimic a natural ecosystem but often is less complex and with a very low genetic diversity. Orchards, farmlands, a garden and man-made reservoirs are some examples of artificial ecosystems.
A natural ecosystem consists of a diverse species of plants and animals that significantly interact with the nonliving things that are also present in the system. It is naturally sustainable and does not require the intervention of humans to survive. A forest and a pond are both examples of a natural ecosystem. An artificial ecosystem, however, cannot thrive productively without human supervision.
Humans need to tend to each component of an artificial ecosystem to make it a sustainable environment. A paddy field requires fertilizers and a consistent supply of water in order to grow crops. When the crops are harvested, it leaves the farm an open system that depends on external sources in order for new plants and organic matter to develop and thrive. A garden needs to be tended by pulling out weeds and eliminating parasites through chemical or organic fertilizers. Small rodents, insects and birds can also survive in the garden and provide biodiversity, but humans drive away most of these animals to maintain the equilibrium of the garden.