The tropical savanna-forest boundary is commonly characterized by an abrupt transition in vegetation structure and in tree species composition. It has been hypothesized that differences in architecture between savanna and forest trees have an important role in determining the contrasting structural differences between savanna and forest ecosystems. Because of the importance the vegetation structure in determining the ecosystem properties of these systems, I performed a comparative study of tree architecture to examine differences in plant structure of savanna and forest species. To eliminate the potential bias from phylogenetic relatedness, I used congeneric species pairs containing trees of both habitat types that occur sympatrically in savannas of the Brazilian cerrado habitat at IBGE Ecological Reserve (RECOR). I found that relative to savanna species, forest species have larger crown volumes with more apical meristems and greater height for a given stem diameter. Other traits that influence patterns of light interception also differed, with savanna species exhibiting more convoluted leaf blades and shorter petioles. There was evidence that allometry and other traits are convergent in savanna and forest tree species across lineages, providing strong support for adaptive functions of these traits. Furthermore, the larger canopies of forest species imply that they play a role in reduced light in the understory and the exclusion of grasses, which potentially facilitates further expansion of forest tree species in the absence of fire.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-07222009-141233 |
| Date | 30 November 2009 |
| Creators | Lau, On Lee Annie |
| Contributors | Dr. Qiu-Yun (Jenny) Xiang, Dr. John S. King, Dr. Robert R. Dunn, Dr. William A Hoffmann |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-07222009-141233/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dis sertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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