President

Marcie Haley has been leading Twelve Hills Nature Center since 2012 when she became president of the board of directors. In 2011, she brought Twelve Hills into the North Texas Chapter of Texas Master Naturalists and continues to act as project manager.

The cornerstone of her efforts and founding concept of Twelve Hills has been the restoration of formerly disturbed land into a five-acre Backland Prairie ecosystem. Additionally, under her stewardship, regularly occurring nature education programs for local schools and the community were established. She collaborates with talkSTEM.org, SMU and NSF as a partner site in Mathfinder.org. A major goal is to communicate the importance of land conservation by providing a variety of opportunities for people of all ages to become familiar with nature.

Marcie earned a B.S. in Biology at Indiana University of PA and worked as a medical technologist in microbiology. Actively pursuing her lifelong interests in nature and science after raising a family, Marcie certified as a North Texas Master Naturalist in 2009. She enjoys all aspects of nature, but concentrates her time on prairie restoration, nature education, birding, native plants, and an annual survey of endangered orchids.

Treasurer

Shannon Christopher has dedicated over 20 years to Nonprofit Administration, with a focus on strategic planning and process implementation. She has held key positions at prominent organizations such as The Dallas Zoo, The Perot Museum, and The Witte Museum. Currently, Shannon runs her own consulting firm, assisting small- and mid-size nonprofits in maximizing their resources to fulfill their missions.

In her personal life, Shannon enjoys cooking and gardening with her young children. She was also certified as a Master Gardener in Bexar County. As a proud Oak Cliff native, Shannon serves as Treasurer for both the Twelve Hills Nature Center and the Rosemont Elementary PTA.

Secretary

Dr. Garcia has worked in healthcare and medical education for over 30 years. She retired from the Cancer Prevention and Research Institute of Texas (CPRIT) in 2019 where she was Chief Prevention and Communications Officer. Prior positions include Vice President, Health Sciences, at the Komen Breast Cancer Breast Cancer Foundation and Education and Academic Affairs Director at the American College of Emergency Physicians.

Dr. Garcia earned a bachelor’s degree in medical technology and a master’s degree in biomedical communications from the University of Texas Health Science Center at Dallas. She received a doctorate in Higher Education with emphasis on adult education from the University of North Texas.

Her hobbies include gardening with Texas native plants and organic methods. She received a certificate of competence for completing the NPSOT Native Landscaping Certification Program. She currently serves on the Board of Directors for Twelve Hills Nature Center.

Mr. Crownover is an attorney for the US Small Business Administration, where he leads a legal team that handles loans to small businesses whose owners have died. Prior to this, he worked as a trial lawyer for a national insurance company and for a local plaintiff’s firm.

Mr. Crownover graduated from Baylor University with majors in finance and management of information systems. He then obtained his law degree from Southern Methodist University.

His hobbies include beekeeping, writing fiction, playing guitar and ukulele, hiking and camping, and playing pickleball.

Ms. Knight has worked in marketing for 15 years. She is currently the operations manager for The Social Robin, a marketing firm based in North Texas. Prior positions include operations manager at Real News PR and web developer at Fource Communications.

Ms. Knight is passionate about spreading knowledge about nature. She teaches Rosemont Elementary students about local ecology through the Nature Leaders program, serves on the program committee for North Texas Master Naturalists, and manages social media for THNC.

Her hobbies include beekeeping, birding, cataloging species through iNaturalist, sketching, playing the guitar and banjo, and replacing the St. Augustine grass in her yard with native plants

Kellie Lawson has over 24 years’ experience as an educator. From 1998 – 2022 she was the Visual Art Educator, K-12, with Rosemont Elementary/Middle School in the Dallas ISD, retiring from Dallas ISD in 2022. Prior to that she was an Architectural designer (retail, commercial, and residential) and historical researcher.

Ms. Lawson earned a Bachelor of Fine Arts and a Master of Architecture, from the University of Texas at Arlington. She received an All Level in Visual Arts, K-12, from the Texas Women’s University.

She currently serves on the Board of Directors for the Nasher Sculpture Center, Education Advisory Board and has served on the Twelve Hills Nature Center board since 2013. Past Board of Director positions include past president of Keep North Oak Cliff Beautiful, 1988 – 1990 and past president of Keep Dallas Beautiful, Inc, 1990 – 1992. Other community Involvement and interests include volunteering with the SPCA of Texas Foster program and the SPCA of Texas/ASPCA Feline Transport program. She enjoys gardening, using and sharing Texas native plants.

Carolyn has worked in landscape architecture for over 28 years. She is currently a principal at Studio Outside where she is committed to designing quality and functional outdoor spaces. She has worked on wide variety of project types all over the world including urban living, corporate campus, environmental education, and resorts. By developing designs with great attention to detail and working with the project from early conceptual design to final construction documents and construction observation, Carolyn strives for successful detailed implementation. Previous positions include 6 years at TBG Partners and 9 years at SWA.

Carolyn earned her degree from Heriot-Watt University (Edinburgh, Scotland) with MA in Landscape Architecture and moved to Dallas in 1996. Having done an exchange program at LSU for one year and a year-long internship in Tokyo, Japan she was looking for opportunities away from London where she grew up to start her career.

She has been an Oak Cliff resident for 26 years and enjoys Pilates and sailing when she is not busy volunteering for her children’s schools and sports teams. In 2004 she put together a winning design submission for the front entrance at Twelve Hills and worked with the board over a period of 5 years to prepare marketing graphics for fundraising, construction documents for bid, and finally overseeing the implementation of the project in 2009. After several years focusing on her family, Carolyn recently joined the Board of Directors. This property has always been a special place for her family, and she is excited to see the success and continued support that the community brings to Twelve Hills Nature Center.

Amanda works as a creative director, illustrator, and human-centered designer. With a focus on the user, she creates engaging experiences and deepens connections with brands through visual and verbal storytelling.

Amanda graduated with a BFA in Communication Design from the School of Visual Arts at the University of North Texas.

She began gardening over 30 years ago and focuses on native planting to provide habitat and support wildlife. Amanda completed her Texas Master Naturalist certification in 2018 and began her volunteer service with Twelve Hills at that time — serving on the board for Twelve Hills since 2019.

Jimena Vivanco has worked for Trinity Park Conservancy starting in 2021 and is the
current Conservation Manager who oversees educational programs and projects.
Jimena also works for the Texas Conservation Alliance as the Lights Out Dallas
Coordinator. Both positions have an emphasis on citizen science, community
engagement, and municipal engagement.

Jimena earned a bachelor’s degree in Ecology for Environmental Science with a minor in
Geology from the University of North Texas. Additional educational background includes
a certification in water resources from UNT and graduation through the UNT Honors
College.

Her hobbies birding at local nature parks, running along the Trinity River trails, and rock
climbing.

John Wilt earned a bachelor’s degree in biology from Colgate University then attended
USAF Pilot Training where he received his wings and went to fighter jets. He served in the USAF and Air National Guard for nine years and retired with the rank of Captain.

John’s aviation career continued at American Airlines where he spent 30 years. During that time and into his retirement John was CEO of his own construction company. He built numerous custom homes in Dallas.

He has had a life-long passion for nature. He joined the Texas Master Naturalists in
2014 and accumulated over 10,000 volunteer hours in just nine years. He is also an active Citizen Forester and has planted or help plant hundreds of trees throughout
Dallas County. He has served on the Board of Directors of Texas Discovery Gardens
and is currently on the Twelve Hills Nature Center Board of Directors.

John is currently a Sustainability project leader at Dallas College which comprises seven junior college campuses. This position primarily involves the restoration of wildscapes and native tall grass prairies.