The Invariance Maintenance Condition (IMC) - Translation for Ecological Population Regulation

The Invariance Maintenance Condition (IMC) [Thomas, 2026a] identifies the class of systems that actively maintain structural invariants under perturbation at measurable cost. This paper demonstrates that self-regulating populations satisfying density-dependent demographic dynamics meet all four IMC applicability conditions by their own internal logic. We provide an explicit variable-by-variable correspondence between IMC objects and standard population ecology objects, expressed in demographic and life-history terms. The maintenance cost column carries thermodynamic grounding via trophic efficiency, making this translation the second most directly grounded in energy units after nonequilibrium thermodynamics. We derive five predictions: a precursor demographic signal in vital rates preceding abundance decline; recovery hysteresis requiring active augmentation rather than passive perturbation removal; the extinction debt phenomenon as a structural consequence of the critical regime; intervention transfer efficacy between ecologically isomorphic populations; and a destruction threshold asymmetry distinguishing reversible population depression from irreversible carrying-capacity elimination. The ecology translation contributes one structural insight that is novel to the other translations in the series: the IMC’s invariant φ must be defined as a demographic regime rather than as an abundance threshold, because abundance is a partial and lagging indicator of viability regime membership. This distinction has direct implications for conservation monitoring practice.