What is a sustainable ecosystem?
A sustainable ecosystem is a long lived and self sufficient one
If an ecosystem is able to maintain its full functions and properties even though it is harvested, it is called a sustainable ecosystem. Optimum level of harvesting, adoptability to changing conditions (such as global carbondioxide buildup), self regulation capability are some factors that can be listed to increase sustainability of an ecosystem.
According to Smith and Smith (2009), "sustainable use can also be constrained indirectly as a consequence of negative impacts on ecosystem services that arise from resource management, extraction, or use. A prime example is waste (unused or unwanted materials). Dealing with domestic, industrial, and agricultural waste is a growing environmental issue with implications for ecosystems and human health. Wastes and by-products of production often contaminate the environment (air, water, and soil) with harmful substances, which can limit or disrupt the ability of ecosystems to provide essential resources and services."
Smith, T. M. and Smith, R. L. (2009) Elements of Ecology. (Seventh Edition). Pearson International Edition. Benjamin Cummins. Pearson Education, Inc. San Francisco, CA. USA.