Plant Ecology & Conservation Lab
Jon Evans, Ph.D.
Sewanee Herbarium
Jon Evans
Professor of Biology, Director of the Sewanee Herbarium
I study the dynamics of plant populations and the processes that determine the composition and structure of plant communities over time and across landscapes. I am specifically interested in the role of clonal growth as a mechanism for population persistence in plant communities. As a conservation biologist, I am interested in the consequences of land-use history, global climate change, and exotic species introductions on ecological communities. I am a strong advocate for the use of science to better inform management and public policy decision-making, so as to sustain biodiversity across the globe.
Mary Priestley
Herbarium Associate
Mary is editor and illustrator of the Friends of the Herbarium’s newsletter, The Sewanee Plant Press. Active in the Tennessee Native Plant Society, she has served as the society’s president and assisted in writing and editing the TNPS field guide,Wildflowers of Tennessee, the Ohio Valley, and the Southern Appalachians. In 2011 she authored William’s Wildflowers, a guide to wildflowers of the Southern Appalachians. In 2014, she published Fiery Gizzard: Voices From the Wilderness.
Yolande Gottfried
Herbarium Associate
Yolande had a link with botany Professor emeritus George Ramseur through Dr. Albert E. Radford of the University of North Carolina, his Ph. D. advisor and her M.A. thesis advisor, which led to her becoming active in the management of the herbarium. She contributes to the herbarium newsletter, The Sewanee Plant Press, and arranges and helps lead wildflower walks and other activities.
Jonathan Ertelt
Herbarium Associate
From the time that Jonathan graduated and initially left Sewanee in 1978, he has held various titles from botanist and horticulturist through greenhouse manager, supervisor, and lecturer. Jonathan has spent more than 45 years growing, teaching and sharing plants and plant information while working at several academic institutions as well as botanical gardens and the National Aquarium in Baltimore. Now a freelance consultant, he continues to write and speak about plants as well as still growing well over 400 species and hybrids at home, inside and out. And as of November 2022, his home is now here in Sewanee, after facilitating the transfer of many of the plants in the Webb Greenhouse from his last job as the greenhouse manager at Vanderbilt University.
Izzy Schutte
Graduate Fellow
Izzy is a PhD student in Dr. Sarah Neumann's Forest Ecology Lab at Tennessee State University. I serve on her graduate committee. Her research is focussed on the role of plant-soil interactions in controlling tree species distribution and regeneration. She is funded by the three year grant from the USDA-NIFA program that Dr. Neumann and I received in 2023. She led the crew of interns from Sewanee and TSU in the summer 2023 field season at Franklin State Forest.
Oliver Hutchens ‘23
Keller Post-Baccalaureate Fellow
Block Undergraduate Herbarium Fellow (2021-2023)
Oliver arrived at Sewanee in 2020 as a transfer student and immediately connected with all things botanical at Sewanee. He was any easy choice for a Block Fellowship with the Herbarium. Given his passion for horticulture, he was appointed Student Manager of the Webb Greenhouse and has made the plant collection thrive and be accessible to students. As part of his study away program with OTS in South Africa, Oliver worked with Laurence Kruger doing research on clonal shrubs in the Serengeti. Oliver transformed this into his Honors Thesis: Difference in proportion of root suckering between populations suggests root suckering as a post disturbance response in Dichrostachys cinerea in KNP, SA. As a Senior, Oliver received the Yeatman Prize from the Biology Department for his passion, service and scholarship. In the spring 2023, he was awarded a Keller Post-Baccalaureate Fellowship in Conservation Horticulture from the GardenClub of America. This competitive award is funding Oliver to work in my lab this coming academic year and will provide him with an 3 month opportunity to receive additional training at the Atlanta Botanical Garden.
Current Block Fellows
J.T. Michel ‘24
Block Undergraduate Herbarium Fellow (2022-2024)
Student Herbarium Curator
My passion for herbaceous organisms began with a fascination for houseplants. I wanted to feel nature and plants all around me, but it wasn't until soon after I came to Sewanee that I began positioning myself in the outdoors to learn about the flora, rather than bringing plants indoors. As a Fellow in the Sewanee Herbarium, I am within reach of a vast biodiversity of native greenery on the Domain, as well as tropical plants in the Webb Greenhouse. My true love for these organisms has grown into a calling to pursue ethnobotany, merging my greatest interests in plants and culture, reflected in my majors; Biology and Anthropology. My interest in human interactions with a variety of biota manifests in being President of the Farm Club at Sewanee as well. Additionally, I am fostering intimate connections and learning from the native flora of the South through foraging and wildcrafting.
Nneka Okolo ‘24
Block Undergraduate Herbarium Fellow (2021-2024)
Over the course of my life, I have benefitted from ample exposure to the outdoors and natural world. On both sides of my family, I have witnessed a particular concern for the ecological world as informed by agriculture and everyday life. From Anambra State, Nigeria, the entirety of my father’s side demonstrates a rich appreciation for plant and animal life due to the extensive degree to which they coexist. Observing the consideration given to their actions in light of the potential repercussions for surrounding lifeforms taught me to do the same. Likewise, outside of Birmingham, Alabama, my maternal grandparents are able to sustainably grow the majority of their food by means of diligent maintenance of their land and regenerative agricultural approaches. Here, in Sewanee, as co-founder of the Farm Club (alongside J.T.) and having worked as a Bonner Leader on the University Farm since my freshman year, I have cultivated my own passion for plants through the lens of food and community. As an Herbarium Fellow, my work is directly influenced by a conservationist sentiment given the intrinsic value of plants to our overall well-being and nutrition.
Keegan Congleton ‘25
Block Undergraduate Herbarium Fellow (2023-2025)
Student Greenhouse Manager
Rob Phillips ‘25
Block Undergraduate Herbarium Fellow (2023-2025)
Lab Alumni
Izzie Berthelot ‘23
Block Undergraduate Herbarium Fellow (2021-2023)
Senior Project: Mapping Arundinaria appalachiana rhizome spatial displacement
George Burruss C'22
Block Undergraduate Herbarium Fellow (2018-2022)
Honors thesis: The effect of dune age and microtopography on Triadica sebifera (Chinese tallow tree) recovery from hurricane disturbance
Awarded the Yeatman Prize (Sewanee Biology Department)
Angus Pritchard C'22
Block Undergraduate Herbarium Fellow (2018-2022)
Honors thesis: Climate-driven hydrologic change linits oak recruitment in a forested wetland
Awarded the Yeatman Prize (Sewanee Biology Department)
Publication:
Evans, J., *S. McCarthy- Neumann, *A. Pritchard, J. Cartwright, B. Wolfe. 2022. A forested wetland at a climate-induced tipping-point: 17-year demographic evidence of widespread tree recruitment failure. Forest Ecology and Management 517:120247.
Lucy Rudman C'22
Block Undergraduate Herbarium Fellow (2021-2022)
Cade Sterling C'22
Block Undergraduate Herbarium Fellow (2020)
Lillian Fulgham C'21
Block Undergraduate Herbarium Fellow (2018-2021)
Sidnee Everhart C'21
Block Undergraduate Herbarium Fellow (2019-2021)
Honors thesis: Environmental correlates of Arundinaria appalachiana (hillcane) distribution and abundance
Shelby Meckstroth C'17
Herbarium Post-Baccalaureate Fellow (2017-2018)
Honors thesis: The amelioration of grazing and sand burial through physiological integration by a clonal dune plant. Poster.
Awarded the McCrady prize for the best poster in the biological sciences at Scholarship Sewanee (April 2017).
Publication:
Evans, J., *S. Meckstroth, and J. Garai. 2023. The amelioration of grazing through physiological integration by a clonal dune plant. Plants 12(4):724.
Current Position: Medical student at LSU
Callie Oldfield C'15
Herbarium Post-Baccalaureate Fellow (2015-2016)
Honors thesis: Twelve years of repeated wild hog activity promotes population maintenance of an invasive clonal plant in a coastal dune ecosystem. Poster. News.
Awarded the Yeatman Prize (Sewanee Biology Department).
Publications:
*Oldfield, C.A., J.P. Evans, and *S.C. Oldfield. 2020. Long-term demography and matrix modeling reveal mechanisms of chestnut oak (Quercus montana) population persistence through sprouting and decline. Forest Ecology and Management 483:118736
Evans, J.P., *C.A. Oldfield, and *J.L. Reid. 2019. Differential resistance to tree species loss between two dominant communities in a resilient southeastern landscape. Natural Areas Journal 39:182-188. Blog Feature
Evans, J.P., K. K. Cecala, B. R. Scheffers, C.A. Oldfield, N. Hollingshead, D. Haskell, and B. McKenzie. 2017. Widespread degradation of vernal pools in the southeastern United States: Challenges to current and future management. Wetlands 37:1093-1103. Press Release
Evans, J.P., C.A. Oldfield, M.P. Priestley, Y.M. Gottfried, L.D. Estes, A. Sidik, and G.S. Ramseur. 2016. The vascular flora of the University of the South, Sewanee, Tennessee. Castanea 81: 206-236.
Evans, J.P., C.A. Oldfield, K.K. Cecala, J.K. Hiers, C. Van De Ven, and M.A. Armistead. 2016. Pattern and drivers of white-tailed deer (Odocoileus virginianus) herbivory on tree saplings across a plateau landscape. Forests 7:101. Press release News
Oldfield, C.A. and J.P. Evans. 2016. Twelve years of repeated wild hog activity promotes population maintenance of an invasive clonal plant in a coastal dune ecosystem. Ecology and Evolution 6: 2569–2578. Press release News
Evans, E.J. and C.A. Oldfield. 2014. Coral preference of the polychaete Spirobranchus giganteus in the Belizean Barrier Reef. Papers and Publications: Interdisciplinary Journal of Undergraduate Research. 3:1-7.
Recent Position: Director of Research, Phinizy Center for Water Sciences
Thomas Walters C'15
Senior Research Paper: Disturbance ecology of hill cane (Arundinaria appalachiana) on the Cumberland Plateau. Poster.
Recent Position: Wildland Firefighter with the US Forest Service
Meg Armistead C'14
Honors thesis: Spatial assessment of deer browse impacts on the Domain. Poster. News
Awarded the Yeatman Prize (Sewanee Biology Department).
Publication: Evans, J.P., C.A. Oldfield, K.K. Cecala, J.K. Hiers, C. Van De Ven, and M.A. Armistead. 2016. Pattern and drivers of white-tailed deer (Odocoileus virginianus) herbivory on tree saplings across a plateau landscape. Forests 7:101. Press release News
Recent Position: Program Technician at USDA Farm Service Agency
Ashley Block C'13
Herbarium Post-Baccalaureate Fellow (2015)
Honors thesis: The King Farm: a case study in the effect of agricultural legacies on forest change dynamics. Seminar. Awarded the Yeatman Prize (Sewanee Biology Department).
Sarah Delong C'13
Honors thesis: The effect of Kalmia latifolia as a persistent understory on oak regeneration.
Nathan Bourne C'11
Herbarium Post-Baccalaureate Fellow (2012-2013)
Planning document: Contributing editor of the Sustainability Master Plan for the University of the South. 2013.
Recent Position: Curate at St. John's Episcopal Church in New Hampshire
Sean McKenize C'11
Honors thesis: Spatiotemporal correlations of land-use and non-equilibrium successional trajectories in Sewanee forests.
Awarded the Yeatman Prize (Sewanee Biology Department).
Recent Position: Graduate Fellow at the Rockefeller University
Alfire Sidik C'09
Publication: Evans, J.P., C.A. Oldfield, M.P. Priestley, Y.M. Gottfried, L.D. Estes, A. Sidik, and G.S. Ramseur. 2016. The vascular flora of the University of the South, Sewanee, Tennessee. Castanea 81: 206-236.
Recent Position: Graduate Student at the University of Texas at Austin
Eric Keen C'08
Post-Baccalaureate Fellow (2010-2011)
Honors thesis: Pignut hickory (Carya glabra) recruitment failure on a Georgia barrier island.
Publication: Evans, J.P. and E.M. Keen. 2013. Regeneration failure in a remnant stand of pignut hickory (Carya glabra) on a protected barrier island in Georgia, USA. Natural Areas Journal 33(2):171-176.
Recent Position: Visiting Professor in Biology at the University of the South!
Matt Hess C'07
Honors thesis: The effect of an introduced ambrosia beetle (Xyleborus glabratus) on red bay (Persea borbonia) mortality in maritime forest communities of St. Catherine’s Island, GA.
Publication: J.P. Evans, B.R. Scheffers, and M. Hess. 2013. Effect of laurel wilt invasion on redbay populations in a maritime forest community. Biological Invasions 16:1581-1588. Press release News.
Recent Position: Treasurer, Board of Directors, Communities for Sustainable Monterey County
Valerie Moye C'07
Honors thesis: Habitat suitability analysis for a potential mountain lion population on the southern Cumberland Plateau in Tennessee and Alabama.
Leighton Reid C'06
Herbarium Post-Baccalaureate Fellow (2007)
Honors thesis: Three decades of forest change on the Cumberland Plateau.
Publications:
Evans, J.P., *C.A. Oldfield, and *J.L. Reid. 2019. Differential resistance to tree species loss between two dominant communities in a resilient southeastern landscape. Natural Areas Journal 39:182-188. Blog Feature
Reid, J.L., J.P. Evans, J.K. Hiers, and J.B.C. Harris. 2008. Ten years of forest change in two adjacent communities on the southern Cumberland Plateau. Journal of the Torrey Botanical Society 135:224-235.
Recent Position: Assistant Professor and Restoration Ecologist at Virginia Tech University
Brett Scheffers C'05
Herbarium Post-Baccalaureate Fellow (2005)
Honors thesis: The location and fate of ephemeral ponds on the Cumberland Plateau, Tennessee.
Publications:
Evans, J.P., K. K. Cecala, B. R. Scheffers, C.A. Oldfield, N. Hollingshead, D. Haskell, and B. McKenzie. 2017. Widespread degradation of vernal pools in the southeastern United States: Challenges to current and future management. Wetlands 37:1093-1103. Press Release
Scheffers, B.R., B.L. Furman, and J.P. Evans. 2013. Salamanders continue to breed in ephemeral ponds following the removal of surrounding terrestrial habitat. Herpetological Conservation and Biology 8: 715-723.
Evans, J.P., B.R. Scheffers, and M. Hess. 2013. Effect of laurel wilt invasion on redbay populations in a maritime forest community. Biological Invasions 16:1581-1588. Press release News
Recent Position: Assistant Professor and Global Change Biologist at University of Florida
John Williamson C'04
Honors thesis: Quercus prinus: the stable sprouter, overtopping the wake of oak decline in the absence of fire?
Awarded the Yeatman Prize (Sewanee Biology Department).
Derek LeMoine C'03
Post-Baccalaureate Fellow (2003-2004)
Senior research paper: Remotely sensing the sustainability of timber harvesting.
Publication: Lemoine, D., J.P. Evans, and K.C. Smith. 2006. A landscape-level geographic information system (GIS) analysis of streamside management zones on the Cumberland Plateau. Journal of Forestry 104: 125-131. News
Recent Position: Associate Professor at the University of Arizona
Caitlin Elam C'03
Senior research paper: The flora of sandstone outcrops on the Cumberland Plateau.
Received a 2003 Young Botanist Award from the Botanical Society of America.
Recent Position: Botanist with TN Department of Environment and Conservation
Sarah Raines C'01
Senior research paper: Regeneration in a chestnut oak (Quercus prinus) stand in Sewanee, TN
Recent Position: Land Trust for Tennessee
Katherine Crook C'00
Senior research paper: Two decades of change in an eastern deciduous forest on the Cumberland Plateau, TN.
Recent Position: Neurology/Neurosurgeon at the Charleston Veterinary Referral Center
Sarah McCarthy Neumann C'99
Herbarium Post-Baccalaureate Fellow (2000-2001)
Senior research paper: Population dynamics of overcup oak (Quercus lyrata) in a seasonally flooded karst depression. Received a 1999 Young Botanist Award from the Botanical Society of America.
Publications:
Evans, J., *S. McCarthy- Neumann, *A. Pritchard, J. Cartwright, B. Wolfe. 2022. A forested wetland at a climate-induced tipping-point: 17-year demographic evidence of widespread tree recruitment failure. Forest Ecology and Management 517:120247.
Wolfe, W.J., .P. Evans, S.E. McCarthy, W.S. Gain, and B.A. Bryan. 2004. Tree-regeneration and mortality patterns and hydrologic change in a forested karst wetland—Sinking Pond, Arnold Air Force Base, Tennessee. US Department of the Interior, US Geological Survey, Water-Resources Investigations Report 03-4217. (Agency Peer-Reviewed)
McCarthy, S.E. and J.P. Evans. 2000. Population dynamics of overcup oak (Quercus lyrata) in a seasonally flooded karst depression. Journal of the Torrey Botanical Society 127: 9-18.
Recent Position: Assistant Professor, Tennessee State University
Madelaine Haddican C'98
Senior Research Paper: Effectiveness of the Tennessee Greenbelt Law as an incentive to protect biodiversity in Franklin County, TN: an analysis of landowner attitudes and intentions.
Recent Position: Physician at Westwood Dermatology
Alex MacKinlay C'98
Honors thesis: The effect of weevil (Curculio spp.) larvae predation on chestnut oak (Quercus prinus) seeds on the Cumberland Plateau.
Received a 1998 Young Botanist Award from the Botanical Society of America.
Ashley Brigham Morris C'97
Publications:
Evans, J.P., and *A. Morris. 2016. Isolated coastal populations of Tilia americana var. caroliniana persist long-term through vegetative growth. American Journal of Botany 103: 1687-1693. AJB Noteworthy Article
Senior research paper: Reproductive biology of a gynodioecious plant (Hydrocotyle bonariensis)
Recent Position: Associate Professor at Furman University
David Royal C'97
Senior research paper: The impact of feral horses on spatial and temporal changes in plant community composition and structure in a coastal dune system.
Recent Position: Medical Science Liaison at EVERSANA, Neurology & Immunology
Steven Howell C'97
Honors thesis: Effects of herbivory and resource availability on seedling establishment and recruitment in a chestnut oak population (Quercus prinus) on the Cumberland Plateau in SE TN.
Recent Position: Ophthalmologist in Louisville KY
Kevin Hiers C'96
Senior research paper: Effect of anthracnose blight on dogwood mortality and forest community structure in SE TN.
Publications:
Evans, J.P., C.A. Oldfield, K.K. Cecala, J.K. Hiers, C. Van De Ven, and M.A. Armistead. 2016. Pattern and drivers of white-tailed deer (Odocoileus virginianus) herbivory on tree saplings across a plateau landscape. Forests 7:101. Press release News
Hiers, J.K. and J.P. Evans. 1997. Effects of anthracnose on dogwood mortality and forest composition of the Cumberland Plateau (U.S.A). Conservation Biology 11: 1430-1435.
Recent Position: Wildland Fire Scientist at Tall Timbers Reseach Station
Emily Sprouse C'95
Senior research paper: A computer tool for studying the biodiversity of Franklin, Marion, and Grundy Counties.
John Queng C'94 (Rice University)
Honors thesis: Clonal plant response to heterogeneous environments in Dichondra carolinensis.
Recent Position: Family Medicine at Austin Regional Clinic
Sherri Whitney C'88 (Duke University)
Honors thesis: Integration as a mechanism in a clonal plant (Hydrocotyle bonariensis) to alleviate salt stress.
Publication: Evans, J.P. and S. Whitney. 1992. Clonal integration across a salt gradient by a non-halophyte, Hydrocotyle bonariensis. American Journal of Botany 79:1344-1347
Sylvia Subong C'87 (Duke University)
Honors thesis: Structural responses in a rhizomatous perennial herb (Hydrocotyle bonariensis) to a variable nitrogen environment.
Leslie Davis C'87 (Duke University)
Honors thesis: Plant community succession on dredge spoil habitats in the Rachel Carson National Estuarine Reserve.
Shauna Tilly C'86 (Duke University)
Honors thesis: Intraclonal translocation of nitrogen in a rhizomatous plant, Hydrocotyle bonariensis.
