Recreationists unintentionally trample vegetation, erode soil, and disturb wildlife. Such human-related impacts present a dilemma for managers charged with the dual objectives of providing recreational opportunities and preserving natural environments. This paper presents some of the principal findings and management implications from research on visitor impacts to protected areas, termed recreation ecology research. This field of study seeks to identify the type and extent of resource impacts and to evaluate relationships between use-related, environmental, and managerial factors. The capabilities and managerial utility of recreation impact monitoring are also described.