“In the recent past, wolves were labeled a flagship species or an umbrella, indicator, or keystone species, depending on what conservation market one was trying to penetrate… A flagship species is an attraction to nearly all society's strata, but wolves are not welcomed by all factions of society. With a few rare exceptions, the rural world opposes wolves, so the animal's flagship role is restricted primarily to urbanites or to local areas. Wolves are certainly a powerful flagship species for the conservation movement, particularly that of affluent societies with strong lobbies in large cities, but a true flagship species should be able to move an entire society toward a goal.
Neither are wolves a good umbrella species (i. e., a species, usually high in the ecological pyramid, whose conservation necessarily fosters that of the rest of the chain) in that they can live well on a variety of food resources and in areas with an impoverished prey base. Wolves are not a keystone species either, in that they are not essential for the presence of many other species (e. g., herbivores flourish in areas devoid of wolves). And wolves are not necessarily indicators of good habitat quality or integrity because they are too generalist to be good indicators of the presence of a pristine trophic chain.
The above labels have been very useful in many circumstance and have contributed significantly to wolf recovery. They may still be useful in the future, but we should be aware that they are shortcuts to "sell a product" rather than good scientific grounds on which to build conservation.”

Wolves: Behavior, Ecology and Conservation (2003)