Thomas J. Givnish

 

Henry Allan Gleason Professor of Botany and Environmental Studies

Ph.D. (1976) Princeton University • 315 Birge Hall • 608-262-5718 • givnish@wisc.edu

Plant ecology and evolution; adaptive radiation and molecular systematics;
phylogeography; physiological ecology; landscape dynamics

Adaptive radiation - the rise of a diversity of ecological roles within a lineage - is a major research focus. My students and I use variation in DNA sequences to derive phylogenies for lineages of ecologically divergent species, and then use these family trees to reconstruct patterns of morphological evolution, ecological diversification, and geographic speciation.


Current and recent projects include studies of the pattern and tempo of adaptive divergence in the Hawaiian lobeliads, the largely South American families Bromeliaceae and Rapateaceae, and the North American mariposas (Calochortus) and lilies (Lilium). Emily Sessa recently studied phylogeny and adaptive radiation in photosynthetic physiology among the woodferns (Dryopteris) of North America. Stephanie Lyon investigated the phylogeny, biogeography, and adaptive radiation of the helmet orchids (Corybas) in Australia, New Guinea, Borneo, and other parts of the southwest Pacific.


My colleagues and I are currently reconstructing the backbone phylogeny of the orchids – the largest family of flowering plants – and using it to identify drivers of their extraordinary diversity.


Rebecca Montgomery and I continue to investigate the ecology and evolution of photosynthetic light adaptations in the Hawaiian lobeliads, using field studies, physiological measurements, and common-garden experiments to re-examine several classic ecological questions in a phylogenetic context and test whether the lobeliads have, in fact, undergone an adaptive radiation.

Adaptation and speciation on islands are recurring themes of my research, and I am eager to recruit students interested in testing my recent model for the evolution of woodiness in island plants, or studying the adaptation of different Eucalyptus species to different portions of the steep rainfall gradient in Victoria, Australia.


 

Photographs:  TOP - Brocchinia hechtioides (Bromeliaceae), one of two carnivorous species in the genus with the greatest diversity of nutrient-capture mechanisms in all flowering plants; Trematolobelia kauaiensis (Lobeliaceae) growing in boggy subalpine openings on Kaua`i, representing one of the most sun-adapted lineages of the Hawaiian lobeliads; Platanthera ciliaris (Orchidaceae), pollinated by day-flying hawkmoths in a group marked by exceptional pollinator diversity; and Calochortus pulchellus (Liliaceae), a serpentine endemic limited to Mt. Diablo, and member of a genus characterized by repeated, parallel adaptive radiations in floral syndrome (fairy lantern in this case) and serpentine tolerance. Photograph of Platanthera ciliaris © 1996 Jeffrey R. Hapeman, reprinted with permission; photograph of Calochortus pulchellus © 2000 Robert M. Case, reprinted with permission.


© 2011 University of Wisconsin Department of Botany

Last updated: 27 November 2011