A flagship species is a species from the plant or animal kingdom that is used to represent a certain environmental issue or cause. There are a number of types of issues that can be represented by a flagship species. For example, the polar bear has been used as a species to raise awareness about what global warming is doing to the planet. There have been photographs and videos taken of polar bears standing atop melting chunks of floating ice. The purpose of these photos is to try and get people to understand that the human impact on the earth has led to global warming which creates a vast array of problems, including creating habitat problems for animals that live in glacial regions.
Very often a flagship species will be chosen because of its attractiveness or because it has unique features. In many cases, other species are overlooked because, for one reason or another, they are not seen as being sensational or do not seem to have the kind of appeal that will garner the the same sort of interest as a of large groups of whales. Although a vast number of species may stand to benefit or at least gain protection from a certain effort on the part of an organization, it is the flagship species of that organization that will be used to draw supporters.
Sometimes young members of the species are also used to garner sympathy for a certain cause. In the polar bear example, there is a video of a mother polar bear swimming away from her baby in search of food; the baby is left standing on the small, floating ice block, seemingly abandoned and alone. Because it is known that most people have an emotional response for young animals, using a baby polar bear to get the message out about global warming can be a very effective marketing strategy.
Sometimes a flagship species will be used as the representative of an environmental disaster. For example, a photograph of a brown pelican drenched in oil soared through the media and via online news sources and quickly became the face of the environmental disaster in the Gulf of Mexico that was a result of the BP oil spill. Not only was this one of the first available pictures of an animal drenched in oil, but the brown pelican served as the perfect flagship species for this event because it also happens to be the state bird of Louisiana.