ascendancy

Etymology

ascend + -ancy or ascendant + -cy. The use in ecology is due to Robert Ulanowicz.

noun

1. Supremacy; dominant control; the quality of being in the ascendant.
   Spurs ended the half in the ascendancy and Van der Vaart was again inches away from giving them the lead when he met Bale's cross but his header flew wide. January 15, 2011, Phil McNulty, “Tottenham 0 - 0 Man Utd”, in BBC
   The Tory hard right is in the ascendancy, and a fascist street movement – led by convicted fraudster Tommy Robinson – represents a growing threat. 2018-07-18, Owen Jones, “The hard right can only be defeated from the left, not from the centre”, in The Guardian
2. (historical, Ireland, sometimes capitalized) A class of Protestant landowners and professionals that dominated political and social life in Ireland up to the early 20th century
   [W. B. Yeats] belonged not to the ascendancy class but to the protestant bourgeoisie. 1975, Terry Eagleton, New Left Review
3. (ecology) A quantitative attribute of an ecosystem, defined as a function of the ecosystem's trophic network, and intended to indicate its ability to prevail against disturbance by virtue of its combined organization and size.
   Ascendency was found to be a useful indicator for the health assessment of marine benthic ecosystems over space and time. 2009, Sven Erik Jørgensen, editor, Ecosystem Ecology, Academic Press, page 63