Technical Report #179.
February 2012. Benitez, D.M., R. Loh, T. Tunison, N.G. Zimmer, J.
Makaike, R. Mattos and M. Casali. The distribution of invasive
plant species of concern in the Kīlauea and Mauna Loa strip areas of
Hawai'i Volcanoes National Park, 2000-2010.
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Alien plant surveys conducted between 2000 and 2010 in Hawai'i Volcanoes
Park quantified the distribution of 134 alien plant species over 87,908
ha between sea level and 4,169 m elevation. Searches were conducted by
foot, vehicle and helicopter and incorporated past survey and control
data. Mapping identified 33 widespread species distributed broadly
across the park and 101 locally distributed species with fewer, more
discrete populations. Sixteen species were incipient invaders not
previously known from the park, and an additional 15 new species were
identified in a separate survey by Pratt et al. Relatively high
concentrations of invasive species were found along roadsides and
trails, particularly in the Kīlauea summit area, `Āinahou, the Mauna Loa
rock quarry and Highway 11, where heavy visitation, high traffic, and
importation of road building materials likely facilitated introduction
and spread of species from outside areas. A geodatabase documenting the
distribution of these species was generated, and survey data were
compared to previous studies (Fosberg 1966; Tunison et. al. 1992) to
evaluate changes in distribution and serve as a baseline for monitoring.
Relative to the last parkwide mapping of localized species completed in
1992, eight species managed to control populations were found to have
increased in abundance, while 30 apparently became less abundant.
Thirteen managed species could not be relocated and may be extirpated.
Key management recommendations based on survey results include expanding
control to 13 additional species identified during this study, quickly
eradicating all newly discovered species before they spread,
intensifying monitoring in high risk areas, and expanding pre-emptive
measures such as sanitation, public education, and prevention of
deliberate plant introductions to the park.
Abstract, introduction, methods, results, discussion, management