Systems that focus only on a single component such as vegetation or hydrology are generally easier to develop and tailor to specific objectives than those that address multiple components; for many applications, they may be very appropriate. However, from an ecosystem planning and management point of view, those classification systems that address multiple factors such as soil, hydrology, landform, vegetation, etc. will often provide a better understanding of the ultimate processes that need to be addressed by the project.
Most of the classification systems reviewed within EMRIS can be considered to be multi-component at some scale. The National Marine Sanctuary Resources Classification System is an example of a system that combines physical and biological factors with human values.