Maintaining natural populatons. In nature, plant and animal populations regulate themselves. However, when human impacts reduce numbers of species, the entire system is affected. For example, the removal of a predator such as a wolf causes an unnatural abundance of smaller, plant-eating animals. Plant life is affected, and eventually food supplies are reduced to the point that animals may die.
Publications are available at park visitor centers which cover a broad range of wildlife topics.
Be especially cautious if your encounter wildlife with young.