Ph.D. - Botany (Ecology, Evolution and Conservation Biology)

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    Kū Ka Maile; Ethnobotany, Harvest Effects, and Recruitment of Maile (Alyxia stellata), a Hawaiian Climbing Vine
    ([Honolulu] : [University of Hawaii at Manoa], [December 2015], 2015-12) Whitehead, Amber
    Critical information needs are not being met for the conservation of culturally significant plants, with potential consequences for biodiversity, ecosystem function, and social-ecological linkages. A case study is provided for the conservation of maile (Alyxia stellata), a fragrant climbing vine in the Hawaiian Islands. Maile lei (garlands), made by stripping the bark and leaves from young stems, were traditionally used by all sectors of society. Today maile continues to be one of the most heavily wild gathered native plants in the Hawaiian Islands, and maile lei are commonly used for cultural practice, weddings, graduations, and proms. Maile have large seeds (7-14 mm in length) that are no longer being dispersed, as large native frugivores are extinct and introduced birds do not successful disperse seeds larger than 6 mm in length. In addition, maile fruit are attractive and vulnerable to predation by invasive rodents and gamebirds. The etymology and ethnobotany of the genus Alyxia was reviewed in the Hawaiian Islands and across its geographic range. In a montane mesic forest in windward Mauna Loa on Hawaiʻi Island, experimental harvest was used to assess the effects of two levels of stem harvest intensity and stem removal on survival, growth, reproduction, and yield of maile. In addition, the effects of indicators of lack of interaction with frugivores (i.e. lack of pulp removal, high densities, proximity to fruiting maile plants) were tested on seed removal and recruitment of maile using cleaned seeds, whole fruit, and planted seedlings. While native names and uses were found for Alyxia species across Southeast Asia and the Pacific, there were few similarities in nomenclature or use outside of Malesia and Polynesia. The name pulasari and medicinal uses were common in Malesia. The name maile (and variants maile, maige, mairo, meie), adornment, and perfuming uses were common in Polynesia and associated outliers, consistent with current theories of rapid two-phase colonization of eastern Polynesia after an extended pause in Samoa. The lack of additional similarities may be due to cultural isolation and independent development of language and uses, or deficiencies in methodology (i.e. the inability to access early ethnologies written in other languages). Maile is a significant cultural plant in the Hawaiian Islands, as evidenced by diversity of use and lexical differentiation. Two growth forms and ten varietal names were found for maile in the Hawaiian Islands, including three varieties that had not previously been reported in an English language text. This may be a greater number of varieties than any other native plant in the Hawaiian Islands, with the exception of ʻōhiʻa (Metrosideros polymorpha). Maile were tolerant of stem harvest over the two year term of the study. Harvest did not affect the survival of maile plants, even under exhaustive harvest treatments. Conservative harvest did not affect maile fruiting and had only weak effects of maile growth and flowering. Yields were comparable between conservative and exhaustive harvest treatments. Conservative harvest produced 50% fewer harvestable stems than exhaustive harvest, though the stems produced were 45% longer, resulting in similar lengths of harvested maile. The effects of harvest intensity differed between two similar sites and one site was consistently more productive than the other, reinforcing the importance of intimate site knowledge by gatherers. Stem removal did not affect the growth or yield of maile plants and had variable effects on flowering and fruiting. Evidence from Hawaiian oli (chants) suggests that stems were traditionally removed, and the practice of not removing stems today may be an adaptation to reductions in forest understory cover. Lack of frugivore interaction (whole fruit, high density) reduced maile survival by 55% during the first year, relative to frugivore interaction treatments (clean seed, low density). The effect of fruit pulp removal on germination was the dominant factor affecting maile survival. In combination with lack of frugivore interaction, introduced rodents and game birds reduced survival by up to an additional 85% (assuming all taken seeds were fatally depredated). Evidence from Hawaiian oli suggests that gatherers may have observed the lack of frugivore interaction with maile, and adapted their management practices to include seed scattering. Maile are tolerant of harvest, though recruitment may be threatened by lack of frugivore interaction. Adaptive management practices, such as seed scattering, can provide reciprocity between gatherers and maile populations and the reestablishment of knowledge of culturally significant plants and associated harvest practices can contribute to the restoration of resilient social-ecological systems.
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    Factors influencing algal blooms on tropical reefs with an emphasis on herbivory, nutrients, and invasive species
    (University of Hawaii at Manoa, 2003-12) Smith, Jennifer E. ; Smith, Celia ; Botany (Ecology, Evolution, & Conservation Biology)
    Algal blooms on tropical reefs have become increasingly common over the last several decades. Reduced herbivore pressure, eutrophication and the introduction of exotic species have all been posited as factors that may drive these transitions in organism dominance. Several different types of algal blooms have been identified on reefs in the Hawaiian Islands including multispecies algal assemblages, monospecific algal blooms and seasonal or ephemeral blooms. This study sought to determine the causes of these different types of algal blooms by conducting both field and laboratory experiments and quantitative field assessments. In a factorial nutrient enrichment and herbivore exclusion experiment conducted for 6 months on the island of Hawaiʻi significant changes in algal biomass, community structure, sediment accumulation and mobile microinvertebrate abundance were found. Results of this study show that benthic reef communities can change rapidly in response to changes in both top down and bottom up factors. From field assessments across the main Hawaiian Islands a total of five (Acanthophora spicifera, Hypnea musciformis, Graci/aria salicornia, Kappaphycus spp. and Avranvillea amadelpha) species of nonindigenous algae can now be considered highly successful. Detailed studies on the ecology of select nonindigenous marine algae (NIMA) have identified particular concerns and highlighted the need for management action. In summary management of these invasive species will be challenging as a result of unique ecological and physiological strategies that each NIMA possesses. The ephemeral bloom forming native alga Cladophora sericea was studied during a bloom cycle during 2001 on the island of Maui. Results of ambient and sediment pore water sampling and algal physiological parameters suggest that ground water intrusion is occurring at this site and the alga appears to be utilizing this terrestrial based nutrient source. Upwelling and internal tides can naturally deliver nutrient rich water into coral reef ecosystems. In an area where internal tidal upwelling occurs in the Florida Keys, one of the most common benthic reef algae Halimeda tuna reflected patterns associated with natural nutrient enrichment. This study provides evidence that rich and highly productive benthic algae may thrive in deep water coral reef environments in response to naturally elevated nutrient conditions.