The distribution of selected localized alien plant species in Hawai'i Volcanoes National Park

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.Prior to this study, the alien plant control program at Hawai'i Volcanoes National Park was hampered by the paucity and quality of alien plant distribution maps. A systematic program to map important localized alien plants was conducted 1983-1985 to determine the need and feasibility of controlling key alien plant species, establish a baseline for assessing the spread of these species, infer range expansions, locate all populations of a target species to assure thorough treatment, and assess the effectiveness of control programs. Thirty-six species were mapped, with emphasis given to localized alien plant species and those listed as target species in the 1982 Resources Management Plan (National Park Service 1982). The studies focused on Ainahou Ranch, Kilauea Crater, and the Coastal Lowlands west of the 1%9-1974 Mauna Ulu flows. The species distributions were mapped on topographic maps at 1:24,000, 1:12,000, or 1:6,000 scales, although most species are displayed in this report on smaller scale maps. In addition, species profiles are provided. These characterize importance to management, significance as a pest in native ecosystems, effective treatment methods, and history of management. There were two important findings from the distribution studies. Eleven species, previously not targeted for management, were identified from mapping efforts to be invasive and require control efforts. These are Formosan koa, slash pine, loquat, sisal, orange pittosporum, oleaster, English ivy, paperbark, blackwood acacia, kudzu, and guavasteen. The second finding is that five target species were found to be much more widespread than previously thought. These include silky oak, koa haole, fountain grass, Russian olive, and raspberry. This finding lead to an approach in which control efforts on widespread species were carried out only in intensive management units called Special Ecological Areas. Additional distribution mapping studies are recommended for widespread species.National Park Service Contract No. CA 8004 2 000

Early succession in pig-disturbed mountain parkland: Hawai'i Volcanoes National Park

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.Prior to their eradication in 1987, feral pigs (Sus scrofa) were a common source of ground disturbance in the mountain parkland ecosystem of Hawai'i Volcanoes National Park, especially in grasslands. In 1985-1986, 27, 2x5m plots were established in 9 open, grassy sites recently damaged by pigs. No pig digging occurred after the plots were initially established. The purpose of monitoring vegetation changes was to evaluate the efficacy of pig control in promoting community recovery and to detect any changes that might need further management intervention. Percent cover of plants was determined by point-intercept methods, and woody plants were counted in height classes in 1985, 1986, 1987, 1989, and 1992. The 27 plots were stratified into 5 plant communities based on a Braun-Blanquet analysis of surrounding vegetation, and successional changes were graphed. Deschampsia nubigena, a native bunchgrass, consistently increased in cover in most communities where it was originally a dominant or codominant species in surrounding vegetation. It did not increase in cover where it was initially a minor component. These trends suggest that Deschampsia will continue to increase in importance. Velvet grass (Holcus lanatus), the main competitor with Deschampsia in mid and upper elevation sites, recovered rapidly at first but generally declined from its maximum cover after 2-4 years. However, Holcus cover may be stable at upper elevation sites where it was dominant prior to disturbance. In lower and mid elevation sites, Holcus species may continue to decline in importance, while other alien grass species, e.g., sweet vernal grass (Anthoxanthum ordoratum) and beardgrass (Schizachyrium condensatum), show signs of becoming more abundant. There was some recruitment of native shrubs in the disturbed areas, especially at lower elevations. Koa (Acacia koa), a root-sprouting, clonal tree in the study area, invaded many sites. The continued expansion of koa colonies may, at least locally, be more ecologically important than competition between Deschampsia and alien grasses.National Park Service Cooperative Agreement CA 8007 2 900