Controlling Weeds in Natural Areas in Hawai`i: a Manager's Perspective

Managers of most natural areas in Hawai`i have a simple mandate: to know, restore, protect, and maintain native ecological communities and natural processes. Applying this to management of normative plants requires skillful evaluation of ecological principles and consideration of manpower and financial limits. Professional opinions, lay public demands, and even administrative preference must be considered. Hawai`i Volcanoes National Park integrates most of these considerations in order to delineate priority categories for alien plant control work. The Park prioritization guide is a useful model for other lands, even those with more complicated land use mandates. Normative species that are disruptive (because they replace native species and communities) and those that are benign (because they do not dominate) are distinguished, and disruptive species are categorized according to distribution. Localized species are prioritized and placed on a control schedule, whereas widely distributed species are targeted for control only in designated areas, called Special Ecological Areas. Funding and staffing levels are inadequate for parkwide control of widely distributed disruptive plant species. MANDATES AND OBJECTIVES In Hawai`i, the National Park Service manages Haleakala and Hawai`i Volcanoes National Parks, as well as smaller historical parks and sites on Hawai`i Island, Maui, Moloka`i, and O`ahu. The Service operates under a land management mandate to maintain native plant and animal communities and the natural processes that shape them, and to minimize unnatural disturbances. "Native" is defined as endemic or indigenous. Species introduced by Polynesian settlers prior to the arrival of Europeans in the late 1770s are usually not disruptive of native communities or have cultural values. "Natural" is defined as unaffected to a great degree by humans, in the past or present, including subsequent restoration (removal of aliens and/or replacement or some encouragement of natives.) The