Species differ in their environmental requirements and tolerances and can serve as sensitive indicators of environmental health. Within North Cascades National Park Service Complex some 300 species of mammals and birds have been documented. At least 8,000 species of arthropods occur within the park complex.
Many wildlife species are charismatic and have high public visibility.
These species assemblages were selected for long-term monitoring because they represent a highly diverse group of taxa. Coupled with their varied biological and ecological activities, their diversity provides an extremely fine-grained reflection of the environmental conditions within the park, both natural and disturbed. Of primary importance to monitoring wildlife populations is understanding how these animals respond to natural processes. A baseline knowledge of natural variability enables a monitoring program to distinguish between this natural variability and human-induced disturbance effects. Wildlife are under massive, escalating, and accelerating assaults from multiple human agents and activities.