Fire, insects, disease, harvesting, and precommercial thinning all create mosaics on Northern Rocky Mountain landscapes. These mosaics are important for faunal habitat. Consequently, changes such as created openings or an increase in heavily stocked areas affect the water, cover, and food of forest habitats. The 'no action' alternative in ecosystem management of low elevation ponderosa pine/Douglas-fir (Pinus ponderosa/Pseudotsuga menziesii) forests needs the same careful consideration as other alternatives because the consequences may be detrimental to some wildlife habitats. Suitable management should provide habitat heterogeneity necessary for a diversity of wildlife. A database of helpful information for managers in discussed.