The National Park Service recognizes that animal, human, and ecosystem health are inextricably linked and viewed holistically. A healthy ecosystem is a place where people, animals, plants, and natural processes interact in ways that support life within an historic range of variability. The living and nonliving components of the ecosystem are often connected in ways that are obscure, or are very complex and unexpected. Science (both western science and local knowledge) is essential in understanding these connections. By focusing research and monitoring on vital resources within an ecosystem, Park biologists and cooperating scientists can provide management with crucial information on current conditions and long-term trends of these vital resources. This will help ensure that the ecosystems are sustained for future generations.