Givnish Lab


Current Lab Members:

  1. Steve Hunter – I am interested in biodiversity in all of its manifestations, and seek to understand the historical bases for patterns of species distributions, co-occurrence, abundance, and genetic variation. Next-generation molecular systematics provides a powerful tool with which to explore the patterns and processes involved in speciation, extinction, vicariance, and dispersal. I approach these issues from the perspective of my mathematics and programming background, and am happiest when coding simulations of evolutionary processes and testing whether the outcome of a proposed model matches observed data

    For my Ph.D. dissertation, I am using a battery of methods to analyze next-generation sequence data to resolve patterns in the phylogeny, historical biogeography, morphological evolution, and species diversification of the Hawaiian lobeliads, the largest group descended from a single ancestor native to the most isolated archipelago on Earth, and one of the most striking examples of adaptive radiation among plants on islands.

  2. Evan Eifler – I am reconstructing speciation, adaptive radiation in substrate, climate, and floral form, and historical biogeography in the remarkable South African genus Geissorhiza (Iridaceae). Geissorhiza provides a unique system for studying species diversification and endangerment in fynbos vs. renosterveld, two extremely species-rich and endangered communities restricted to nutrient-poor, sandy soils vs. nutrient-rich, clay-rich soils in the winter rainfall region in the Cape Floristic Province. Some 16 species are what I term “micro-endemics”, known from only a single site, and over 70% are considered are of conservation concern.

  3. Amanda Salvi – One of the most important but least studied constraints on the evolution and productivity of land plants is the sensitivity of mesophyll capacity to leaf water potential. While declines in photosynthesis during drought partly reflect decreased stomatal conductance, the intracellular photosynthetic machinery appears to shut down increasingly at lower leaf water potentials. This tendency – what we call mesophyll sensitivity – was likely an important constraint on the evolution of land plants, driving several key traits for water use efficiency. However, almost nothing is known about mesophyll sensitivity among related species in different habitats.

    In order to better understand this fundamental constraint on plant competitive ability during moisture scarcity, I plan to compare the mesophyll sensitivities of (1) closely related species of Eucalyptus that are differentially distributed along a moisture gradient in Victoria, Australia, as part of the large Givnish-McCulloh-Smith study; and (2) a variety of plants from Oregon, USA, that differ in stringency of stomatal control (from isohydry to anisohydry). I predict that wet environments and greater degrees of isohydry will be associated with greater mesophyll sensitivity, and that the degree of sensitivity across all species will help shape optimal stomatal conductance and allocation among leaves, roots, and hydraulic conduits.

  4. Valerie Gehn – I am just entering grad school this fall, after helping conduct ecological and ecophysiological research at Cedar Creek the last two summers. I am interested in the expression and adaptation of various physiological traits in response to the increases in temperature, CO2 and O3 levels, as well as decreases in soil moisture, expected under climate change. I am also interested in the unique adaptations seen in resurrection plants.

  5. Duncan Smith – I am interested in the fundamental tradeoff that most plants experience where water is lost to the atmosphere while taking in carbon for photosynthesis. Avoiding or tolerating water stress is key to plant survival and plants employ a variety of anatomical and physiological strategies to address this. The genus Eucalyptus has adapted and diversified to hundreds of species that dominate a wide range of habitats with varying water availability in Australia and elsewhere. I am studying adaptation and physiological plasticity in response to moisture availability, based on intensive studies of photosynthetic, hydraulic, and allocational traits in ten Eucalyptus species that dominate different rainfall bands along a steep rainfall gradient in Victoria, Australia, studying seedlings and saplings grown in four large common gardens planted along that gradient. I am the lead field researcher in this massive project, conducted in collaboration with Tom Givnish, Kate McCulloh, Mike Adams, and Tom Buckley.

Recent Lab Members:

  1. Rebecca Kartzinel – Post-doc, studies of genetic variation and scales of gene flow in Wisconsin plants – Research Assistant Professor of Biology, Brown University –

  2. Daniel Spalink – Post-doc, phylofloristic assembly of the Wisconsin flora, genetic variation and gene flow in plants from Wisconsin and the Sonoran Desert, evolution of Orchidaceae and Liliales – Genomics Post-doc, University of Utah (Lynn Bohs)

  3. Emily Sessa – PhD on phylogenetics and physiological ecology of Dryopteris (Dryopteridaceae – Assistant Professor of Biology, University of Florida –

  4. Robert Wernerehl – Ph.D. on community and physiological ecology of prairie grasses – State Botanist of Massachusetts

  5. Stephanie Lyon – Ph.D. on the molecular phylogenetics and historical biogeography of Corybas (Orchidaceae)
 – Assistant Professor of Biology, University of Wisconsin, Stevens Point

  6. Rebecca Montgomery – Post-doc, field and common-garden studies on adaptation of Hawaiian lobeliads to light availability) – Associate Professor of Forest Resources, University of Minnesota –

  7. Jonathan Coop – Ph.D. on causes and historical dynamics of reversed treelines in the Valles Caldera National Preserve, New Mexico – Assistant Professor of Environment and Sustainability, Western State Colorado University –

  8. Austin Mast – Ph.D. on phylogeny and biogeography of Banksia and Dryandra in Australia – Professor and Director of the Robert K. Godfrey Herbarium, Florida State University –

  9. José Antonio Vázquez Gárcia G. (Ph.D. on gradients in composition and structure of cloud forests in the Sierra de Manatlán – Professor and Director, Botanical Institute, University of Guadalajara –

© 2017 University of Wisconsin Department of Botany

Last updated: 13 September 2017