Plants growing on unusual geologies and other extreme substrates are model organisms for the study of  ecology and evolution. My primary research focuses on using such plants and their habitats to explore questions on the role ecology plays in the evolution of individual plant species and the assembly of plant communities.

I am also interested in the effects of heavy metal contamination on plants and other biota, specifically research relating to metal transfer from contaminated soil via plants to other biota. Related areas of research include 1) phytoremediation, the use of plants to clean up metalcontaminated soil, and 2) the impacts of atmospheric deposition of  metals and nutrients on native and invasive plant interactions. Additional interests include tropical plant ecology & conservation and ethnobotany.


(Check New Site, 2017-)


Recent Research in California

Mike Fong MA ’11 (Former Graduate Student , San José State University)

1. Are morphotypes of Streptanthus polygaloides (Brassicaceae) distinct genotypes worthy of taxonomic subdivision and conservation?

Streptanthus polygaloides is a serpentine endemic found only in the western slopes of the Sierra Nevada in California. It can hyperaccumulate Ni (>0.1% of dry leaf tissue) and is one of only two Ni hyperaccumulators confirmed from continental North America. Its ability to hyperaccumulate Ni makes it a candidate for phytoremediation and phytomining. Further, a plant bug, Melanotrichus boydi, is endemic to and monophagous on S. polygaloides. Recent studies have shown S. polygaloides consists of four sepal color morphs differing in their Ni accumulation. Two of these morphs are restricted geographically, being found in only one or two counties. We aim to better characterize these morphotypes in terms of ecology, ion accumulation, taxonomically important traits, and inter-morph reproductive compatibility. If morphotypes are ecologically distinct, differ in taxonomically important traits, and show reduced reproductive compatibility, they may be worthy of both taxonomic subdivision and—depending on the abundance of each taxon—for subsequent listing for conservation. The work is done in collaboration with Mike Fong (MA 2011, SJSU), Nate Pope (UC Davis now UT Austin), and Dr. Robert Boyd, Department of Biological Sciences, Auburn University, Alabama. See recent publication.

In collaboration with Janis Strommen (SJSU, undergraduate) and Dr. Jeff Honda, we are also studying the life history and ecology of Melanotrichus boydi, an insect specializing on Streptanthus polygaloides. For additional research on M. boydi see here.

Dr. Kathleen Kay (L) and Teri Barry (R; MS Candidate, San José State University) on the serpentine outcrop at Jasper Ridge Biological Preserve, Stanford University

2. Demonstrating local adaptation in Lasthenia californica and L. gracilis at Jasper Ridge Biological Preserve, San Mateo, Co., California

Lasthenia californica complex has provided a model to explore the role soil conditions play in the radiation of races (A and C) and species (L. californica and L. gracilis) within closely related taxa (See Bohm and Rajakaruna 2006). Lasthenia californica (race A) and L. gracilis (race C) are restricted to edaphically distinct regions within the serpentine outcrop at Jasper Ridge Biological Preserve, Stanford University. The purpose of this study is, first, to show the two taxa at Jasper Ridge are locally adapted to distinct soil conditions within the serpentine outcrop.  Second, to determine if the distinct boundary between the taxa is present throughout the growing season (i.e. from time of germination), or if it only exists at the time of flowering.  Thus, two main hypotheses will be tested.  First, that both taxa will show higher fitness in their native localities within the outcrop.  This hypothesis will be tested by conducting a reciprocal transplant experiment and using standard selection gradient analysis.  Second, the taxa are found throughout the outcrop at the beginning of the season (i.e. at time of germination), then as the season progresses, changes in soil moisture (and other corresponding changes in soil chemistry) will lead to the distinct racial boundary previously documented at the time of flowering (see Rajakaruna and Bohm, 1999).  This second hypothesis will be tested using DNA analysis of individual plants collected throughout the season as per genotyping methods developed by Dr. Kathleen Kay, University of California, Santa Cruz.  At time of genotyping individual plants, soil physical and chemical information will also be recorded to determine if distributional changes of taxa correspond to seasonal changes in edaphic features. The work is done in collaboration with Teri Barry (MS Candidate, SJSU), Dr. Kathleen Kay and Jenn Yost. See recent publication.

From L-R: Erica Case (UC Davis), Suzie Woolhouse (MS Candidate, San José State U) and Annette Bieger (UC Davis; currently, ETH Zurich,
Institute of Integrative Biology Zurich, Plant Ecology)

3. Conservation Biology and Fire Ecology of Rare Serpentine Plants of Plumas National Forest, California

The Storrie Fire of 2002 affected large areas of serpentine soils on the Plumas National Forest.  Found on serpentine soils in this forest are 12 rare plant taxa, some of which are restricted (endemic) to serpentine, and others of which are partly restricted (indicator) or non-restricted (tolerator) taxa.  These are:  Monardella stebbinsii (CNPS List 1B.2; S1.2; endemic), M. follettii (List 1B.2; S1.2; endemic), Arabis constancei (List 1B.1; endemic), Sedum albomarginatum (List 1B.2; endemic), Cypripedium fasciculatum (List 4.2; serpentine indicator), C. californicum (List 4.2; endemic), Lewisia cantelovii (List 1B.2; indicator), Lupinus dalesiae (List 4.2; tolerator), Clarkia mildrediae subsp. mildrediae (List 1B.3; tolerator), Packera eurycephala var. lewisrosei (List 1B.2; endemic), Erigeron petrophilus var. sierrensis (List 4.3; endemic), and Frangula purshiana subsp. ultramafica (List 1B.2; endemic). We are involved in a four-year study to generate useful information for effective conservation of these 12 rare taxa.  Our study will compile existing information and gather new information to resolve important gaps in our knowledge of their conservation status (e.g. distribution, abundance); ecology (e.g., distributional requirements, phenology, pollinators, herbivores, reproductive biology); and management needs (e.g. potential mitigation for the effects of fire, logging, and/or climate change). Throughout the project, we will work closely with regional and Plumas National Forest ecologists and botanists, to ensure that our research addresses the USFS’ highest-priority objectives for conservation, management, and restoration of these plants.  The work is done in collaboration with Suzie Woolhouse (MS Candidate, SJSU), Dr. Susan Harrison, and Erica Case.

Additional Ongoing Research

Is postfire recruitment of chaparral shrubs constrained by local adaptation to soils (serpentine vs sandstone) or microclimates (north vs south slopes)?

Fire plays a key role in the ecology of chaparral, or evergreen shrublands, an ecosystem unique to the five Mediterranean-climate regions of the world including California. Seeds of many chaparral plants germinate only in the year after a fire, and so the age, reproduction, dispersal potential, and community composition of chaparral plants are controlled by the infrequent occurrence of fire, typically once every 1-10 decades. Prescribed burns are seldom possible in Californian chaparral. What research has been done on the fire ecology of this ecosystem has been largely opportunistic, taking advantage of naturally occurring fires. More than 5,000 hectares of accessible public lands burned in 2008, creating a rare opportunity to examine whether three dominant chaparral shrub species (Ceanothus cuneatus, Adenostoma fasciculatum, Eriodictyon californicum) are locally adapted to the sites on which they are found. Tests will be performed to determine if regeneration occurs only from seed produced on particular soil types (sandstone or serpentine) or on particular slope aspects (warm south-facing or cool north-facing), or whether seed produced in a particular habitat can successfully germinate and establish in other soil types or on slopes with different aspects. Results from this study will provide additional information for science-based management of chaparral ecosystems. This information will contribute to both the restoration of degraded chaparral and to the ability of resource managers to predict and plan for shifts in species distributions in response to climate change. The work is done in collaboration with Dr. Susan Harrison, Annette Bieger, and Jamie Horvath. See recent publication.

The role of adaptive evolution versus ecological sorting processes in the formation of serpentine chaparral in california

Tolerance to serpentine substrate may involve multiple functional traits relating to morphology and ecophysiology, making the study of serpentine chaparral an ideal model system to enhance our understanding of the relative importance of adaptive evolution and ecological sorting processes in the evolution of plant communities.

During my post-doctoral tenure with Dr. David Ackerly (2003-2004), I conducted a comparative study of functional traits of serpentine tolerant shrub species and their serpentine intolerant relatives from several common chaparral lineages to address the following questions:

1. What are the key traits relating to functional morphology and ecophysiology that differ between the serpentine species and their closest relatives found on non-serpentine soil.

2. Do the findings support the hypothesis of convergent evolution (i.e., traits giving adaptation to serpentine have evolved independently in different lineages) or exaptation (i.e., traits were already present in the ancestors and ecological sorting processes have allowed the formation of serpentine chaparral) or both.

The preliminary phase of my research involved field measurements of functional traits of eight species pairs belonging to six plant families. Measures were taken twice a year, in the spring and late summer of 2003. The second phase will include common garden studies involving hydroponic and greenhouse experiments to characterize potentially adaptive traits relating to the tolerance to heavy metals (Ni, Cr), nutrients (N, Ca/Mg) and water stress, features that appear to be distinct between the various species pairs. See recent publication partially resulting from data generated from the study.

Lichens of Serpentine Barrens and Cinnabar Mines of Clear Creek Management Area, San Benito County, CA. See Recent Publication.

Collaborators: Dr. Kerry Knudsen (UC Riverside), Dr. Alan Fryday (Michigan State University), Dr. Fred Olday (College of the Atlantic), Ryan O’Dell (Bureau of Land Management), Nate Pope (UC Davis) and Suzie Woolhouse (San José State University).

Current Research Collaborators

1. Dr. Bob Boyd, Auburn University, AL  (Evolutionary ecology of Streptanthus polygaloides)

2. Dr. Alan Fryday, Michigan State U, MI (Lichens of Serpentine/Cinnabar Barrens)

3. Dr. Stefan Siebert, North-West University, Pochefstroom, South Africa (Plant Diversity of Ultramafics of South Africa)

4. Dr. M. C. M. Iqbal and Dr. Meththika Vithanage, National Institute of Fundamental Studies, Kandy, Sri Lanka

5. Dr. Kathleen Kay, University of California, Santa Cruz, CA (Evolutionary ecology of serpentine-tolerant Monardella spp.)

6. Chris Hoess (Delaware Technical and Community College Stanton-Wilmington) and Dr. Yann Surget-Groba (Université du Québec en Outaouais): Evolutionary ecology of the Adiantum pedatumA. aleuticum complex

For a list of student-co-authored publications and presentations see here


Kelsey Munger (L), Nishi Rajakaruna (C), and Jill Gall (R) posing for a photo while collecting mosses and insects at the Cu- and Zn-contaminated Callahan Mine, Brooksville, Maine

Former Research Students (2004-2016)

1. Tanner Harris (MS 2010, University of MA, Amherst, MA; currently at WRA Environmental Consultants). See Tanner’s Bio.

2. Laura Briscoe (MS 2012, Plant Biology and Conservation, Northwestern University, IL; currently, Research/Collections Assistant, Cryptogam Herbarium, The Field Museum)

3. Kathleen Tompkins (Social/Clinical Research Screener, AIDS Clinical Trials Unit/Center for AIDS Research, UNC Infectious Disease Clinic, Chapel Hill, NC; currently, medical student @ UNC)

5. Naveed Davoodian (MA 2012, CUNY/New York Botanic Gardens, NY current Ph.D. Student;)

6. Nishad Jayasundara (Ph.D. 2012, Stanford University, CA; Postdoctoral Fellow, Duke University)

7. William Broussard (MS 2012, Antioch New England Graduate School, NH; currently, Outreach Coordinator for the Mount Washington Observatory)

8. Andrew Thrall (President, Native Landscape Design, Falmouth, ME)

9. Peter Pavicevic (Graduate Student, Landscape Architecture, City College of New York, Spitzer School of Architecture)

10. Neith Little (MS 2012, Crop and Soil Sciences, Cornell University, NY)

11. Jose Perez-Orozco (Certification Coordinator, Quality Certification Services, A Branch of Florida Organic Growers, Gainesville, FL; Currently MS student in Sustainable Development Practice at the University of Florida, Gainesville)

12. Ai Kitazumi (MS Student, Plant Molecular Genetics, School of Biology and Ecology, University of Maine, Orono, ME)

13. Jonathan Carver (MS Student, Department of Biology, University of Wisconsin-La Crosse, WI)

14. Nathaniel Pope (Research Assistant, Department of Entomology, University of California, Davis; currently Ph.D. Student @ University of Texas, Austin)

15. Brett Ciccotelli (Watson Fellow 2009-2010; Summer 2012, Field Studies Instructor @ COA)

16. Anna Fialkoff (Ecological Landscape Designer and Planner)

17. Sarah Neilson (MSc Student in Agriculture with a focus on Systems and Sustainability at Denmark’s University of Copenhagen)

18. Mike Fong (MA 2011, SJSU, CA; Adjunct Faculty, Evergreen Valley College, CA & Instructor, Mission College, CA). Thesis publication here.

19. Eva Dannenberg (Graduate Student, Antioch University)

20. Luka Negoita. Senior Project: Vascular Plants of Little Duck Island (currently, Ph.D. student at Syracuse University)

21. Hazel Stark. Senior Project: Ethnobotanical Guide to the Common Plants of New England

22. Joseph Layden. Senior Project: Algonquian Ethnobotany

23. Maggie Mansfield. Senior Project: Vascular Plants of the Cu- and Zn-enriched Callahan Mine, Brooksville, Maine (publication)

24. Robin Van Dyke. Independent Research: The role of edaphic stress in the maintenance of sex ratios in Silene vulgaris (Caryophyllaceae); Intraspecific variation in Achillea millefolium: Local Adaptation or Plasticity?

25. Suzie Woolhouse. MS 2012;  Research: The Biology and Ecology of Rare Plants found on Serpentine in Plumas National Forest, Northern Sierra Nevada, California. See CV here

26. Vivian Lambert. Senior Project: Earthenware and Healing (in 2013, completed a diploma at the Ayurvedic Institute)

27. Meg Trau. Senior Project: Human Ecology of Weeds (currently, at the Boston Museum of Science)

28. Jason Barton. Senior Project: Lichens and bryophytes of vernal pools of Acadia National Park (Collaborators: Fred Olday, Alison Dibble, Martha Reeve) – thesis publication

29. Margaret Stern. Senior Project: Limestone flora of Simonton Quarry, ME (publication in preparation)

30. Jillian Gall. Senior Project: Species Diversity and Heavy Metal Accumulation in Insects found on Serpentine and Granite Outcrops of Deer Isles, Maine

31. Katie Jumper. Independent Research: Macrofungi of serpentine and granite outcrops, Deer Isles, Maine (Collaborators: Naveed Davoodian and Dr. David Porter)

32. Erica Georgaklis. Independent Research: experimental studies on medicinal plants

33. Teri Barry. MS Research: Edaphic differentiation in Lasthenia californicaL. gracilis complex (Asteraceae). Thesis Publication here.

34. Janis Strommen. Independent Research Co-Supervised with Dr. Jeff Honda: Biology and ecology of Melanotrichus boydi, an insect feeding on the Ni-hyperaccumulating Streptanthus polygaloides (Brassicaceae)

35. Abbe Urban. Independent Research/Senior Project: High elevation plant communities in Baxter State Park (Collaborator: Glen Mittlehauser)

36. William Batt. Independent Research/Senior Project: Phytoremediation of Cu-, Zn-enriched soils of Callahan Mine, Brooksville, Maine: A greenhouse study to explore the use of soil amendments to restore contaminated soils with native plants

37. Steve Brown. Independent Research/Senior Project: Flora of Slave Island, Maine

38 Paul Excoffier. Independent Research/Senior Project: Bryophyte diversity within and among vernal pools of Acadia National Park, Maine

39. Ella Samuel: Independent Research/Senior Project: Mycoremediation of Callahan Mine soil

40. Ian Medeiros: Independent Research/Senior Project: Serpentine plants and lichens of serpentines of Massachusetts and projects on lichen, vascular plants, bryophytes, and algae of serpentine and other metal-enriched sites

41. Natasha Krell: ecotypic differentiation in yarrow and St. John’s Wort in response to serpentine and granite soils


Sunset from Mount Desert Rock

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