New Advances in Fern Ecology
Arcand, Naomi N. .
Flagship of the Understory: Population Structure of Hapu`u, the Hawaiian Tree Fern ( Cibotium chamissoi ) within Intact and Degraded Forests on O`ahu, Hawai`i.
THE endemic species of Hawaiian tree fern, known locally as hapu`u, is considered a keystone species in Hawaiian forest communities. Yet this charismatic component of the understory may be in decline on O`ahu. Hypothesized causes for the restricted range include predation by feral pigs, encroachment of invasive vegetation, historical over-harvesting, and an episodic two-spotted leafhopper infestation in the early 1990ís. I examined the distribution, population structure, and restoration importance of C. chamissoi in forest communities within a range of native to degraded forest ecosystems on the island of O`ahu. Hapu`u is commonly found at the transitional elevation range where degraded forests of lower elevation overlap with areas of intact native forest in both the Wai`anae and Ko`olau mountain ranges. In addition to assessing individual C. chamissoi morphological attributes, I also measured plant community diversity, percent native cover, canopy density, slope, elevation, and soil nutrients at each research site. To gauge the effects of ungulate predation, plots were paired inside and outside of fenced ungulate exclosures in the Wai`anae Mountain range. Plots were also located singly in unfenced locations across the Ko`olau Mountains. Multiple components analysis and ANOVA results indicate feral ungulates are responsible for severely limiting C. chamissoi sporeling recruitment. Trends in population structure are also analyzed and compared between the Wai`anae and Ko`olau Mountains. Implications for tropical forest understory restoration will be discussed.
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1 - University of Hawai`i at Manoa, Geography, Saunders 441, 2424 Maile Way, Honolulu, Hawaii, 96816, USA
Hapu`u tree fern
intact and disturbed tropical island forest
Presentation Type: Symposium or Colloquium Presentation
Date: Monday, July 31st, 2006
Time: 10:30 AM