자료유형  

 학위논문

Control Number  

0015494000

International Standard Book Number  

9781687938305

Dewey Decimal Classification Number  

910

Main Entry-Personal Name  

Barrett, Kevin D.

Publication, Distribution, etc. (Imprint  

[Sl] : The University of Wisconsin - Madison, 2019

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2019

Physical Description  

155 p

General Note  

Source: Dissertations Abstracts International, Volume: 81-04, Section: A.

General Note  

Advisor: Hotchkiss, Sara C.

Dissertation Note  

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2019.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Tropical montane peatlands in Hawai軻i are important repositories of biodiversity and water resources, and paleoenvironmenal archives preserved in Hawaiian peatland deposits are a rare cache of past terrestrial environments and climate in the middle of the North Pacific. I researched the distribution and ecology of testate amoebae, single-celled protists that produce their own shells ("tests") and Cladocera (water fleas) in montane peatlands on Kohala and on windward Mauna Loa on Hawai軻i Island to 1) describe the spatial distribution of testate amoebae diversity in relation to Hawaiian peatland envirnmental gradients, 2) develop a new approach for peatland paleoecology that integrates testate amoebae (TA) and Cladocera data as proxies for peatland water-table depth, and 3) produce new paleorecords of peatland paleohydrology based on subfossil TA and Cladocera in Hawaiian peat cores. I analyzed correlations between peatland environmental gradients and testate amoebae by using taxonomic and functional trait approaches. TA are sensitive to biotic and abiotic peatland variations in Hawai軻i, including composition of peatland surface vegetation, soil bulk density, water table depth, and pH. Sphagnum palustre L. in Kohala generates vertical and chemical gradients on the peatland surface that resemble peatland environmental gradients in temperate and boreal regions. TA taxonomic diversity was greatest in habitats dominated by emergent rushes in the genus Juncus L. and lowest in Sphagnum hummocks. Peatland hydrology, measured as water-table depth, was the dominant environmental control on TA distribution in Kohala. Transfer functions relating species assemblage data to water-table depth performed well under leave-one-site-out cross-validation (RMSEP = 9.75 cm, r2 = 0.62). A peat core spanning the last 300 years shows that peatland water tables dropped from 1700 to 1850 CE, then rose to a near-surface level between 1900 and 1930 CE, a period characterized by anomalously high rainfall in Hawai軻i. A 4000-yr peat record had evidence of abrupt peatland drying and a shift to an oxidizing state from 2.7 to 1.6 thousand years ago (ka) that interrupted two periods of high and stable water tables, from 3.3 to 2.7 ka and 1.6 to 1.2 ka. The period of drying overlaps with a period of increased aridity inferred from paleorecords on Oahu, Maui, and Moloka軻i (from 2.2 to 1.5 ka) and occurred during a period of increased El Nino acitivity. These results provide evidence for a centuries-long period of increased aridity in Hawai軻i and point to the occurrence of statewide drought, likely associated with El Nino-like conditions in the North Pacific, between 2.2 and 1.5 ka.

Subject Added Entry-Topical Term  

Ecology

Subject Added Entry-Topical Term  

Geography

Added Entry-Corporate Name  

The University of Wisconsin - Madison Botany

Host Item Entry  

Dissertations Abstracts International. 81-04A.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:568746