Science & Conservation Team

SDBG’s staff and research associates bring a wealth of experience, education, and expertise to our work.

Colin Khoury, Ph.D.

Senior Director of Science and Conservation. Colin was born and raised in the coastal sage scrub and the avocado and citrus orchards of San Diego County. He obtained a Master of Science in plant genetic resource conservation from the University of Birmingham, UK, and a PhD in production ecology and resource conservation from Wageningen University in the Netherlands. He has held science and conservation positions at academic, nonprofit, industry, government, and international organizations across the US and in Italy and Colombia. Colin is thrilled to be back home, working for the conservation and use of plant diversity for people and for the planet.

Ari Novy, Ph.D.

President and CEO. Dr. Novy is a plant biologist with a wide range of expertise in plant science and education. Before joining San Diego Botanic Garden, he was Chief Scientist at the Leichtag Foundation, also in Encinitas, CA, and before that, Executive Director of the United States Botanic Garden in Washington, DC. He is the author of numerous peer-reviewed scientific papers and regularly speaks on various horticultural and botanical topics nationally and internationally. Dr. Novy completed his graduate work at Rutgers University in New Jersey, where he conducted research on plant population genetics, invasive species, plant conservation, horticultural improvement, agronomic risk assessment, beekeeping management, plant evolution and agricultural economics and policy. He remains an active researcher, holding an appointment as Adjunct Associate Professor at Salk Institute for Biological Studies. For his complete bio, click here.

C. Benjamin (Ben) Naman, Ph.D.

Director of of Medicinal Plants Research. Ben joined SDBG in 2022 to develop a program of responsible and impactful scientific research studying the chemical biology of medicinal plants with the potential for commercial translation. Ben obtained a BS degree in Chemistry and Psychology from Carnegie Mellon University and PhD in Pharmaceutical Sciences with Specialization in Medicinal Chemistry and Pharmacognosy from The Ohio State University. He moved to California as a postdoctoral scholar at Scripps Institution of Oceanography, UC San Diego. Ben has four years industrial experience discovering new plant-derived natural flavors and fragrances to use as ingredients for food and beverage products. Ben also helped establish a new College of Food and Pharmaceutical Sciences in Ningbo, China, and there led a group studying South China Sea marine algae and selected plants used in Traditional Chinese Medicine. Ben is excited to work with the staff at SDBG and our external collaborators to better understand medicinal plants and their human health potential.

Rachel Sadowski

Conservation Specialist II (Lead). Rachel Sadowski received a B.S. in Environmental Science from University of Lynchburg and a Master of Advanced Studies (M.A.S.) in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. Her graduate school research focused on evaluating the long-term monitoring data on the plant communities in the salt marshes of the Tijuana River National Estuarine Research Reserve in order to establish a baseline for future sea-level rise and marsh migration. Rachel now works at the San Diego Botanic Garden, where she assists field surveys for plants of conservation interest, such as the threatened Encinitas baccharis (Baccharis vanessae) and the endangered Del Mar manzanita (Arctostaphylos glandulosa ssp. crassifolia). Her work also includes seed collection, propagation and nursery care for these plants and other California natives for the purpose of reintroduction through restoration projects.

Joe DeWolf

Conservation Specialist II (Lead). Having last worked at SDBG in 2014, Joe returns to the Garden’s conservation team in 2022 with extensive experience in restoration ecology and land management of natural areas. Most recently, he worked as an Associate Biologist for Nature Collective for six years, where he managed the community-based habitat restoration programs and spearheaded the San Elijo native plant nursery and propagation program. He also served as Park Ranger for the City of San Diego for seven years, where he focused on land management of open spaces, habitat restoration, biological monitoring, and protection of natural and cultural resources. Joe was previously a gardener for SDBG for four years, as well as a gardener for the City and County of San Francisco. He holds B.A. in Physical and Biological Anthropology from San Diego State University.

Sophie Henry

Conservation Specialist I. Sophie Henry received a B.A. in Environmental Studies and Studio Art from Lewis & Clark College and has expertise in field biology and horticulture. She is excited to join SDBG’s Science and Conservation team as a Conservation Specialist after working for the Institute of Natural Resources as a biological field technician in the high desert of Eastern Oregon. Previously, she worked as an insect management technician for the Oregon Department of Agriculture, a nursery tissue culture technician, and a gardener. She is particularly interested in the adaptations of plants in arid ecosystems. Having grown up in the hills and canyons of Encinitas and at the SDBG, she is delighted to participate in the restoration of these beloved landscapes. In her free time, she loves to hike, paint, cook and grow unique vegetables.

Tim Sisneros

Field, Laboratory, and Data Specialist. Tim Sisneros is a botanist with expertise in field botany and horticulture of California’s native flora. Born and raised near the American River in Sacramento County, he spent a lot of his childhood learning the plants growing around him – a passion that has only grown since moving to Southern California in 2010. He has extensive experience in horticulture, landscape design, ecological restoration, and database management spanning almost 20 years. Tim earned his B.S. in Ecology, Behavior, and Evolution from UCLA and is a CNPS Certified Field Botanist (CFB #0058). Tim is very excited to join SDBG and work to help conserve some of California’s most sensitive plant species and contribute to the garden’s mission to create, share, and apply plant wisdom in our world.

Research Associates

Research associates are distinguished researchers based at other institutions who work closely with San Diego Botanic Garden’s science and conservation staff to safeguard and sustainably utilize plant life on our planet.

Jade d’Alpoim Guedes, Ph.D.

Jade d’Alpoim Guedes is an Associate Professor of Anthropology and at the Scripps Institution of Oceanography at University of California, San Diego. She is a environmental archaeologist and computational modeller who studies how humans adapted their foraging practices and agricultural strategies to new environments. Jade earned her PhD at Harvard University in 2013 and carried out a postdoctoral fellowship in Earth Planetary Science where she developed computational models that charted the spread of agriculture to Southwest China and the Tibetan Plateau. She directs the paleoethnobotany laboratory at UCSD where she has analyzed material from a wide variety of contexts across China, Southeast Asia, Harappa and the Pacific Northwest. She currently directs an NSF funded interdisciplinary fieldwork project in the Jiuzhaigou National Park, Sichuan Province, China that uses a combination of computational modeling, ancient climate reconstruction and geomorphology to chart how humans adapted their agricultural strategies to the challenging environment of the foothills of the eastern Tibetan Plateau. This project also involves experimental research and field trials of crop landraces aimed at improving the models used to understand ancient crop distribution and their resistance to climate change.


Nassrine Azimi, Ph.D.

Nassrine Azimi co-founded and currently coordinates the Green Legacy Hiroshima Initiative a global campaign to disseminate and plant worldwide seeds and saplings of trees that survived the 1945 atomic bombing of Hiroshima. At the United Nations Institute for Training and Research (UNITAR) Azimi established the Hiroshima Office for Asia and the Pacific in 2003, and was its first director. Prior to her work in Hiroshima she had been UNITAR’s coordinator of environmental training programs, deputy to the executive director, and chief of the Institute’s New York Office, which she reopened in 1996 and directed for five years. She is currently the Institute’s senior advisor. Azimi has published extensively on UN peacekeeping and peace-building, post-conflict reconstruction, environmental and cultural governance, and Asia. She is the author of ‘Last Boat to Yokohama’ and ‘The United States and Cultural Heritage Protection in Japan, 1945-1952’ and teaches international peace and security at Doshisha Women’s College of Liberal Arts. She becomes SDBG research associate as of April 1, 2023.




Michelle Balk

Michelle Balk is a biologist and botanist with over 20 years of experience in California, focusing on rare plants. She is the founder and CEO of Balk Biological, Inc., a biological consulting firm headquartered in Carlsbad.







Jim A. Bartel

After retiring in 2014 from the U.S. Fish and Wildlife Service and his work on endangered species conservation, Jim continues his more than 40 years of botanical research on the genetics, ecology, and taxonomy of western or New World cypresses (Hesperocyparis) and their close allies. Much of his recent ecological work has focused on the effects of increasing fire frequency and related climate change impacts to the cypress stands in the western United States. Jim also continues his studies of the taxonomy and distribution of the succulent genus Dudleya in California.




Dan Carver

Dan Carver is a Technical Manager in the Geospatial Centroid at Colorado State University. Dan is excited to be collaborating with SDBG on a variety of projects associated with species and landscape conservation. Dan brings his background in geography and geospatial science, with an MA in Geography from the University of Colorado Denver, to provide quantitative measures of conservation status. His foundational experiences in the deciduous forest of Illinois and the mountains of Southern Colorado have cemented for him the importance of plants in wild places.





Lea Corkidi

A Biologist and Plant Ecologist by education, Lea’s professional development has also been closely related to the field of horticulture. She started doing applied research in plant production systems at Tree of Life Nursery in 2000, and for the last nine years, she has been part of the research team of the Nursery and Floriculture program at UC Cooperative Extension of San Diego County.  She has collaborated on studies about different aspects of propagation, nutrient, and pest management of California native and non-native plants. Lea recently participated in a multistate research effort to investigate the impact of horticultural management practices on pollinators, and is presently involved in a project to promote habitat for bees.

Dikko Jeff Gafna, MA

Dikko Jeff Gafna was born and raised along the shores of Lake Victoria, in Kenya. He obtained his bachelor’s degree in Geography from Moi University in Kenya, and an MA in Biogeography from Kenyatta University, Kenya. He is currently a PhD student with specialization in medicinal plants conservation ecology at Karlsruhe Institute of Technology, Germany. Dikko has a wealth of experience in medicinal plants surveying, modeling, and conservation. He is a visiting researcher at SDBG and is looking forward to collaboration aimed at enhancing medicinal plant species conservation in California, throughout the U.S., and beyond.



Todd P. Michael, Ph.D.

Todd fell in love with the diversity of plants back in the seventh grade after doing a leaf collecting project. He decided he wanted to understand the underlying code making plants so interesting, so he set off on a journey to sequence plant genomes. His lab at the Salk Institute for Biological Studies focuses on just that – sequencing and analyzing plant genomes. At the Salk Institute his group is part of the Harnessing Plant Initiative (HPI) that aims to develop crop plants that sequester more carbon via extensive root systems containing recalcitrant carbon polymers to fight climate change. In partnership with SDBG, Todd is continuing to explore the diversity of plant genomes with a focus on developing resources to preserve rare, medicinal, and regionally important plants. Todd received his PhD from Dartmouth College, and BA from the University of Virginia.

Sula Vanderplank, Ph.D.

Sula has been working on the flora and ecology of the Californias since 2004, with a focus on the peninsula of Baja California. She is particularly interested in cross-border initiatives and synthetic transdisciplinary studies, and she conducts mostly field-based research.

Pieter van Rooyen, Ph.D.

Pieter is the Founder and CEO of Pleno Inc., which seeks to revolutionize how genomic markers are detected by merging technologies from industries as disparate as telecommunications and genomics. Pieter has more than 30 years of experience inventing, developing and successfully commercializing technologies in industries including semiconductors, wireless, health care, life sciences, image processing, and retail automation. His passion for bringing to market innovative technologies has led to the formation and funding of a number of technology start-ups with significant global impact. Prior to founding Pleno, Pieter was co-founder of Edico Genome, which was acquired by Illumina in 2018, and whose technology forms a foundational part of all new sequencing instruments from Illumina, reducing data analysis time from days to minutes. Prior to Edico Genome, Pieter was involved in the emerging mobile health industry, in which mobile phone technology enables innovative health care delivery in underserved communities.