A self sustaining ecosystem must have the complete set of both Biotic or living factors and Abiotic or non-living factors.
For the Biotic factors, the producers must always be the most in number and population as compared to that of consumers and decomposers. In addition, primary consumers or herbivores must be bigger in population compared to secondary and tertiary consumers in order to maintain great survival for the ecosystem. The Abiotic factors include light intensity for the photosynthetic process of plants, the right temperature which will have an effect on the enzyme action of organisms, the water availability, Oxygen content, salinity or salt concentration and acidity. If all these factors are proven to be the exact right amount, then an ideal self-sustaining ecosystem will prosper.