Final answer:
Managers and staff specialists often rely on their expertise as their main source of power, especially when other forms of authority are unavailable.
Step-by-step explanation:
Managers and staff specialists, who may lack other sources of power, typically have to depend on their expertise as their primary source of power. This expertise is the extensive knowledge or skill in a particular area, and it imparts the ability to influence decisions, guide public policy, and contribute to an organization's success.
The dependence on expertise arises from the fact that formal authority, charismatic authority, and traditional authority might not be available. Expertise can be a more tenuous type of power as it must constantly be proven and is subject to the acceptance of others. Nonetheless, it is crucial for staff specialists and managers to cultivate and maintain as they navigate organizational environments.