SGI Staff

Dwayne estes ph.d., executive director

Dwayne Estes serves as executive director at SGI. He is a Full Professor of Biology, Director of the APSU Herbarium, and Principal Investigator for the Center of Excellence for Field Biology. In January 2017, he co-founded SGI with colleague, Theo Witsell. Under his leadership as director of SGI, the fledgling organization has secured more than $2 million dollars in funding, and in the past five years he and his collaborators have been awarded three grants from the National Science Foundation. Dwayne’s research interests include the flora, ecology, history, biodiversity, and biogeography of the Southeastern U.S. with emphasis on grasslands. He has published 20+ publications and co-authored the Guide to the Vascular Plants of Tennessee published in 2015 by the University of Tennessee Press. He enjoys mentoring his six graduate students and working hand-in-hand with a dedicated SGI team. He has been active in building diverse support for Southeastern US grasslands conservation, including bringing together philanthropists, government agencies, non-profits, corporate and small-business partners, private landowners and ranchers, historians, educators, and citizen scientists.



Theo Witsell works to explore our native grasslands and gathers and synthesizes data on their ecological and historical significance, providing scientific direction and ecological context for the program. He is regarded as one of the most experienced field botanists in the Southeast, and he has some of the sharpest eyes in the business. Theo has worked as senior botanist and ecologist for the Arkansas Natural Heritage Commission since 2000 and in 2013 was invited to serve as a research associate with BRIT. He publishes regularly and has authored or co-authored more than 30 scientific publications and book chapters, including the description of new species. In addition to his scientific expertise, Theo is intimately familiar with practical on-the-ground management of natural areas and conservation strategies and brings unique expertise in this area. 


Alan Weakley, ph.D., CHIEF botanist for sgi

Alan Weakley, is widely regarded as one the leading botanists and plant community ecologists in the eastern U.S. with extensive on-the-ground experience in all Southeastern states. He holds a B.S. degree in botany from the University of North Carolina-Chapel Hill and a Ph.D. in botany from Duke University. He currently serves as Director of the Herbarium at the North Carolina Botanical Garden and adjunct professor at UNC.  In his 40-year career, he has served as Senior Regional Ecologist for The Nature Conservancy and Chief Ecologist for NatureServe. He served as Trustee of the N.C. Natural Heritage Trust Fund from 2008-2013 and Chair of the N.C. Plant Conservation Program’s Scientific Advisory Committee. He is the author of Flora of the Southern & Mid-Atlantic States, a botanical manual covering about 7000 plant species, now the standard in use across much of the southeastern U.S., and has been a leader in the development of the U.S. National Vegetation Classification System.  

Alan's University of North Carolina Page

Alan's Linkedin Page


Gregg Elliott, Director of Communications

Gregg leads innovative efforts to efficiently connect with partners, volunteers, members, donors, the media, and others to spread the word about SGI. Gregg has run a successful conservation communications business from Memphis, TN for 10 years, serving federal and state wildlife agencies and conservation nonprofits.

Gregg’s LinkedIn Page

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Kathy Marquart, SGI Administrative Assistant

Kathy is the amazingly efficient human who holds SGI together, keeping the growing SGI organization running smoothly on a daily basis. Her duties include coordinating scheduling among all team members, helping set up contracts, assisting with grant writing, preparing budgets, ordering, processing receipts, proofing, and managing the office. Contact Kathy if you have any questions about SGI and she can direct you to the right place. (


Cooper Breeden, Plant conservation coordinator

Cooper serves as SGI's Plant Conservation Coordinator and dually serves as statewide rare plant coordinator for the Tennessee Plant Conservation Alliance. Cooper works directly on conservation of rare species and communities, in concert with partners such as the U.S. Fish and Wildlife Service and Tennessee Division of Natural Areas, and he also works with volunteers across Tennessee. Additionally, he is finishing up a masters degree at APSU where he is using dendrochronology to investigate the changes in tree communities in a limestone cedar glade complex.


Mason brock, botanist

Mason is a recent graduate of Austin Peay State University Biology Department's graduate program and currently serves as Collections Manager for the APSU Herbarium, a collection of 120,000 specimens. For his graduate work, Mason documented the flora and plant communities of riparian grasslands, shrublands, and woodlands along the Caney Fork River in east-central Tennessee. He also serves as Research Associate for SGI.


Claire Ciafre, Grassland Ecologist

Claire is first-year graduate student in the Biology Department at Austin Peay State University and is a Research Associate for SGI. She is leading efforts to document the highest quality wet grasslands in Tennessee and will soon be working on a project to document riparian grasslands on the Cumberland Plateau. For her thesis, she is studying the flora and community ecology of rare depression ponds that support marsh vegetation and that historically were embedded in open oak savannas. 


Zach Irick, Grassland Ecologist

Zach is a second-year graduate student in the Biology Department at Austin Peay State University and is a Research Associate for SGI. He is currently working in northeastern Alabama to document the flora, rare plants, and plant communities associated with the riparian corridor of the Little River at Little River Canyon National Preserve. For his thesis, Zach is conducting a taxonomic study of a group of herbaceous vines of the genus Clematis (leatherflowers), which includes several undescribed species, including a few that are endemic to grassland habitats. 

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Michelle mcinnis, volunteer engagement coordinator

Michelle joined the SGI team at the very end of 2018. Thanks to her previous experience with volunteer coordination in New England, Chicago, and the Everglades, she hit the ground running even while also working to obtain her master's degree at APSU studying the biodiversity of rare riparian grasslands in Southern Appalachia.

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Brittney Viers, Interior Plateaus Grasslands Coordinator

Brittney Viers is SGI's first ever grasslands coordinator now serving the Interior Plateaus and part of the East Gulf Coastal Plain ecoregions. She oversees our Natural Resources Conservation Service (NRCS) Regional Conservation Partnership Program (RCPP) grant working with a total of 11 partners led by the American Bird Conservancy. The programs under our Grasslands RCPP include EQIP, CSP, and WRE, which provide financial assistance for landowners who wish to pursue native grassland restoration. Brittney embarks on this 5-year funded position in a joint role with SGI and Quail Forever. She brings a 10-year track record of working successfully with private landowners to design native grassland seed mixes and restore habitat, putting her Master's in Botany to good use. Additionally she will inspire and work with dozens of volunteers to develop community-led grassland conservation teams throughout the Interior Low Plateau focal region.

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Jeremy French, Farm Bill Wildlife Biologist under RCPP

Jeremy is jointly affiliated with SGI and our partner, Quail Forever, working with 10 partner organizations to implement the restoration of thousands of acres of grassland on private lands in central and western Tennessee and Kentucky funded by a multimillion dollar USDA Natural Resources Conservation Service Regional Conservation Partnership Program grant. Jeremy’s love of grasslands began in childhood in the Everglades of south Florida and continued as a biology student at William Penn University, IA where he conducted research on herpetofauna response to bison grazing in tall grass prairie remnants and restoration of oak savanna habitat. Jeremy now brings his experience working with herpetofauna and as habitat management specialist working in critically endangered grasslands to 26 counties inTennessee assisting with RCPP projects.


Darrell Brandon, Collections Manager for the University of Memphis Herbarium

Darrell is reviving the 18,000-specimen collection that had fallen into disuse. He is currently pursuing his Master's degree at Austin Peay State University where his graduate work is examining the grassland plant communities of Tennessee's power line Rights-of-Way (ROWs). In this capacity he serves as SGI’s lead field botanist for our Powerline Rights-of-Way assessment project.

Darrell received his B.S. in Plant Biology from the University of California Davis, and currently holds a Research Associate position at the Botanical Research Institute of Texas.