YIELD
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(2) |
| ID | ◀ 3796 ▶ |
| Object type | General information |
The output of a system, usable by other systems.
Obviously, as the system depends of its environment for its inputs, yields are generally variable with environmental conditions. Variations may be more or less cyclical in an intricated way, depending on the interrelations of the system with other ones, which may be its competitors for inputs.
Yields in ecological systems have been studied by V. VOLTERRA, A. LOTKA, H.T. ODUM and many others.
In very complex ecosystems, not perturbed by man, yields of the different species tend to vary only slightly. According to H.T. ODUM: “If the yield is not taken, the stocks and system structure develop” (1983, p.93). Of course, there are limits to this development.
ODUM moreover states: “There is an optimum removal rate that optimizes the stock to its energy input with the maximum steady drain of the yield. This is called the optimum catch” (Ibid).