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Seed bank dynamics and germination ecology of fountain grass (Pennisetum setaceum)
|M.S.Q111.H3_4033_r.pdf||Version for non-UH users. Copying/Printing is not permitted||3.53 MB||Adobe PDF||View/Open|
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|Title:||Seed bank dynamics and germination ecology of fountain grass (Pennisetum setaceum)|
|Authors:||Nonner, Edith D.|
|Keywords:||Fountain grass -- Hawaii|
Soil seed banks -- Hawaii
|Abstract:||In Hawaii, fountain grass (Pennisetum setaceum) is an aggressive, fire prone invader that out-competes native flora and forms monotypic stands with large amounts of dead mass that fuels fires. Wildfires eliminate native dry forest species and contribute to further spread of alien grasses, creating a grass/fire cycle. The presence of a fountain grass seed bank can increase the possibility of the reestablishment of this alien grass. Meanwhile, restoration efforts can benefit from the presence of native seeds in the seed bank. The goals of this study were: 1. to test the basic germination requirements of P. setaceum 2. to determine the seed bank composition in a degraded dry forest site, 3. to test the effectiveness of prescribed fire and large-scale aerial herbicide treatment in removing/suppressing fountain grass seed banks. Laboratory germination trials showed that P. setaceum does not require light for germination and seedlings can emerge from at least 5 cm soil depths. However, awns on the dispersal unit imply fountain grass may form predominantly surface layer seed banks. The soil seed bank at the study site is dominated by non-native species. Of the 23 species germinated from the seed bank, 3 native species and 20 alien species emerged; 3 of the alien species are grasses, 14 are herbaceous weeds, and 3 are woody species. Pennisetum setaceum forms a patchy seed bank with a maximum density of2040 seeds/m2.Field and lab tests show that fire and heat, respectively, are effective in killing fountain grass seeds. However, the heterogeneity of lava fields on which fountain grass occurs may provide refugia for seeds during fire events. While not statistically significant, some trends are evident in the data. The P. setaceum seed bank is reduced after the passage of fire, and input of seeds into the seed bank is suppressed by herbicide treatment. The sampling methodology employed is not robust enough to show differences in the seed bank after treatment. Smaller sub plots within the research site may be more appropriate to show treatment effects. Given the paucity of native species present in the seed bank, native seed augmentation will be necessary for restoration .|
|Description:||Thesis (M.S.)--University of Hawaii at Manoa, 2005.|
Includes bibliographical references (leaves 56-61).
x, 61 leaves, bound ill. 29 cm
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|Appears in Collections:||M.S. - Botany|
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