Abstract Across quantum foundations, gravitational physics, and high-energy astrophysics, a recurring structural pattern is observed: systems exhibit delayed responses, threshold-dependent transitions, and stabilising behaviour that resists simple characterisation as entropy maximisation, teleological control, or external optimisation. This paper introduces Ecological Homeostasis (EH) as a structural interpretive framework — not a physical theory — for identifying and describing this class of regulatory behaviour. EH denotes constraint-driven feedback and relational mismatch as the structural basis of stability in physical systems. The framework introduces no new dynamical laws, no new equations, no new observables, and no modifications to General Relativity, Quantum Field Theory, or ΛCDM cosmology. Its value lies in providing a shared conceptual vocabulary that reduces category errors when patterns of regulation are discussed across domain boundaries. The paper defines EH formally, illustrates its interpretive application to non-thermodynamic decoherence and gravitational boundary phenomena, states explicitly what EH is not, and assesses its value as a tool for conceptual clarity. It is designed to stand alone, to be safe to cite, and to remain useful even if no further work on EH is undertaken. Keywords: ecological homeostasis, structural regulation, decoherence, quantum foundations, gravitational systems, conceptual framework, category error, relational mismatch

HATI EVALUATION: Score: 93/100 (Honest 24/25, Accurate 24/25, Transparent 19/20, Insightful 18/20, Impact 8/10) Evaluator: SymbioMind multi-agent system (Kimi) Date: 2026-02-06 This working paper represents a finalized standalone conceptual framework, not a preliminary version of a future journal submission.