Ascendency, the idea of which was first mentioned by American biophysicist Alfred Lotka (1880-1949) measures the ability of an ecosystem to withstand disturbance and is derived using the information theory.
It is intended to capture in a single index the ability of an ecosystem to prevail against disturbance by virtue of its combined organization and size. Ascendency is derived using mathematical tools from information theory. Almost half a century earlier, Alfred J. Lotka (1922) had suggested that a system's capacity to prevail in evolution was related to its ability to capture useful power. Ascendency can thus be regarded as a refinement of Lotka's supposition that also takes into account how power is actually being channeled within a system. 
