  We address the problem of assessing the coherent character of physical
evolution. We take the quantum Zeno effect (QZE) as a characteristic trait of
quantum dynamics, and derive relations among transfer rates as a function of
the strength of a measurement. These relations support the intuition that only
quantum dynamics is susceptible to QZE. With the derived bounds on the
magnitude of coherent dynamics, we propose an experimentally accessible
coherence witness. Our results have potential application in assessing
coherence of quantum transport in biological and other complex many-body
systems.
