Soils are naturally occurring loose rock particles and organic surface matter changed through physical, chemical, and biotic processes with the ability to support plant life. Soils are the basis of an ecosystem and sustain the living systems above and below the ground surface. Soils regulate water flow and perform vital functions, such as filtering, immobilization, and detoxification. In addition to storing and cycling nutrients, soils support organisms that decompose, release nutrients, create pores, and stabilize soils. Natural and cultural resources are affected by soil properties. The National Park Service Inventory and Monitoring Program conducts soil inventories in cooperation with the National Cooperative Soil Survey, the Natural Resources Conservation Service and other federal agencies. In order to track changes in ecosystem condition, Networks within the NPS Inventory and Monitoring program monitor soil stability, structure and/or chemistry.