Linked from
The 13 pages that link to Ionic conductivity, each with the reason it gives.
ElectrolyteRelated: It measures the charge-carrying process that defines electrolyte conduction.
Point defectRelated: Charged point defects can migrate and carry current through ionic crystals.
Hydration shellRelated: Hydrated ion size and mobility help determine transport through water.
Schottky defectRelated: Vacancies provide sites through which ions can migrate in an ionic crystal.