In North America, concepts of Historical Range of Variability are being employed in land-management planning for properties of private organizations and multiple government agencies. The National Park Service, U.S. Fish & Wildlife Service, Bureau of Land Management, U.S. Forest Service, and The Nature Conservancy all include elements of historical ecology in their planning processes. Similar approaches are part of land management and conservation in Europe and Australia. Each of these user groups must struggle with the added complication of rapid climate change, rapid land-use change, and...