In a world in which natural places have become few and precious, knowledge of the composition and function of relatively unaltered natural systems is invaluable. Inventory and Monitoring programs provide a fundamental knowledge of those systems and the technical basis for "ecosystem management".
Natural resource inventorying is the process of acquiring information on park resources, including the presence, distribution, and condition of plants, animals, soils, water, air, geological features, and biotic communities. Inventories contribute to a statement of the condition of park resources, such as natural or unimpaired. Natural resource inventories have three primary uses:
- Documentation of the occurrence, location, and condition of park resources
- Identification of rare, threatened, or endangered species and ecosystems for purposes of directing management
- Development of a foundation for implementation of status and trend or monitoring programs
The ultimate intent of monitoring is to provide park managers with an understanding of the condition and trend of park resources. That is, are they "healthy and functioning normally" or not. This information allows park managers to take corrective actions to restore ecosystem health or to take precautions if resources appear to be deteriorating in condition. Just as a doctor may choose to track blood pressure or heart rate in a human patient, natural resource managers choose "vital signs" to determine the condition of resources.
The National Park Service conducts Inventory and Monitoring across the nation.