Givnish Lab


Current Lab Members:

  1.  Evan Eifler – PhD candidate – I am using hybrid DNA enrichment and next-generation sequencing to reconstruct phylogeny, historical biogeography, and adaptive radiation in substrate, climate, and floral form in the remarkable South African genus Geissorhiza (Iridaceae) and its close relatives in subfamily Crocoideae. Geissorhiza provides a powerful 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. The Cape Floristic Province is one of the world’s great biodiversity hotspots, and Geissorhiza is notable for being perhaps the largest genus restricted to the CFP, and for having differentiated about equally in both renosterveld and fynbos.

  2. Patty Chan – PhD student – I am broadly interested in plant reproductive ecology and evolution, as well as creative approaches to scientific education and outreach. My current research centers on exploring the genetic and ecological drivers of plant evolution and geographic distribution. In investigating this, I will employ phylogenomic data, involving the sequences of whole plastomes and hundreds of single-copy nuclear loci, to reconstruct phylogeny, ploidy changes, floral adaptation to insects, birds, and marsupials, and genetic differentiation within species, spatial scales of gene flow, and speciation at very small spatial scales in Western Australian species of Darwinia (Myrtaceae). I will also be collaborating with Dr. Matt Barrett (James Cook University) and Dr. Barbara Rye (Western Australian Herbarium) on this study. The Southwestern Australian Floristic Province is perhaps second only to the Cape Floristic Province in plant diversity among temperate hotspots, with disproportionately few phylogenomic and historical biogeographic studies in this region.

  3. Bing Li – PhD student – I am tentatively planning to use phylogenomic data to study evolution in the fascinating genus Pitcairnia (Bromeliaceae). Pitcairnia has roughly 400 species, with a center of diversity in the Andes, perhaps the richest of all global biodiversity hotspots. I am hoping to focus on the detailed historical biogeography of Pitcairnia, and characterize evolution in flower size in relation to hummingbird pollinators.

  4. Amanda Salvi – recent PhD – 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 compared the mesophyll sensitivities of (1) ten closely related species of Eucalyptus that are differentially distributed along a moisture gradient in Victoria, Australia, as part of the large Givnish-McCulloh-Smith-Adams-Buckley study; and (2) a variety of plants from Oregon, USA, that differ in stringency of stomatal control (from isohydry to anisohydry). I found that drier environments are associated with lower mesophyll sensitivity, but at the cost of reduced maximum rates of photosynthesis at full hydration. These results open a new dimension of studies on the adaptive evolution of plant drought tolerance. Furthermore, greater mesophyll sensitivity – associated with plants from moister environments – is coupled to greater degrees of isohydry, that is, greater stomatal control of leaf water potential within a narrow range. Both of these results are consistent with the Givnish 1986 model for optimal stomatal conductance; the latter is predicted only by the Givnish mode, and not the widely cited ∂A/∂E model. 

  5. Nisa Karimi – Post-doctoral research associate – – Post-doctoral research associate – My research focuses on plant evolution at varying scales, from populations to across species, including how hybridization/introgression and plant-pollinator interactions influence patterns (amount and direction) of gene flow regionally and ultimately diversification. I primarily utilize phylogenomic approaches though I also incorporate techniques in population genetics and pollination biology. I am particularly interested in practical implications of species delimitation and evolutionary studies for biodiversity conservation. Ongoing projects include using a targeted sequence capture approach to explore the phylogeographic history of the baobab trees, species delimitation in the Malagasy baobabs, and intraspecific variation in the pollination ecology of the African baobab. Current projects include investigating patterns of phylogeny, gene flow, species diversification, and floral evolution in the genus Calochortus.

  6. Duncan Smith – Post-doctoral research associate – The core of my interests is about how plants stay alive (or not) under stressful conditions; how they coordinate physiological processes; how they sometimes optimize traits. I am primarily interested in hydraulic and photosynthetic trats, from the whole plant to the cellular level. In the Givnish lab group, I run the common garden experiment in Victoria, Australia where we study traits in ten Eucalyptus species grown in four common gardens, from tall wet sclerophyll forest to mallee. We are interested in learning how this large and diverse genus has adapted and differentiated across a landscape of contrasting water availabilities. I enjoy using coding (R, Python, CRBasic, ImageJ) to facilitate data acquisition, analysis and visualization.

Recent Lab Members:

  1. Daniel Spalink – Post-doc, studying phylogenetic assembly of the Wisconsin flora, genetic variation, gene flow, and relation to rapid speciation in desert winter annuals from the Sonoran Desert, and evolution of Orchidaceae and Liliales – Assistant Professor, Texas A&M University.–

  2. Rebecca Kartzinel – Post-doc, investigation of genetic variation and scales of gene flow in Wisconsin plants – Assistant Professor of Biology and Director of the Herbarium, Brown University.–

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

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

  5. Stephanie Lyon – PhD on the molecular phylogenetics and historical biogeography of Corybas (Orchidaceae)
 – Assistant Professor of Biology, Director of the UWSP Herbarium, Director of the UWSP Tropical Conservatory, University of Wisconsin, Stevens Point. –

  6. Rebecca Montgomery – Post-doc, field and common-garden studies on adaptation of Hawaiian lobeliads to light availability, and shade tolerance as a function of time of leafing in southern Appalachian trees – Professor of Forest Resources, Fellow of the Institute on the Environment, University of Minnesota. –

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

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

  9. David Foster – PhD on gradient analysis of understory herb communities on the Upper Peninsula. Professor of Biology and Environmental Science, Messiah College. –

  10. Mark Leach – PhD on patterns fo species loss from Wisconsin prairies, and gradient analysis of Midwestern oak savannas. Member of the Board of Directors, The Prairie Enthusiasts

  11. José Antonio Vázquez Gárcia G. – PhD on gradients in composition and structure of cloud forests in the Sierra de Manatlán – Professor and Director, Botanical Institute, University of Guadalajara, and discoverer of several dozen new species of Magnolia and Talauma. –

© 2021 University of Wisconsin Department of Botany

Last updated: 13 September 2021