Our Executive Staff

Get to Know Us

Grand Canyon Conservancy has staff at Grand Canyon National Park, and in Flagstaff and Phoenix, Arizona. We work in a variety of roles in fundraising, educational programs, marketing, strategic planning, accounting, retail, and administrative positions to make sure your support makes a difference.

Theresa McMullan
Chief Executive Officer

Theresa leads the organization’s diverse activities in raising private funds to benefit Grand Canyon National Park, growing earned income streams through operating retail stores within the park, and providing educational and adventure opportunities through the Grand Canyon Conservancy Field Institute. Theresa joined Grand Canyon Conservancy as a board member in 2014 and transitioned to staff in June 2015. As the previous Chief Operating Officer for GCC, she provided oversight of retail operations, human resources, publishing, IT, and facilities management. Through her leadership, retail sales increased 66 percent in four years. She also served as the acting chief financial officer for eight months in 2016. She has worked closely with the NPS staff at Grand Canyon to implement special projects related to major fundraising initiatives and has participated with the park’s Inter-tribal Working Group to further the visitor connection to the 11 associated American Indian tribes to Grand Canyon National Park. Prior to GCC, Theresa was the Vice President of Marketing & Merchandising for SkyMall (the company that produced the in-flight shopping catalog) in Phoenix, Arizona and the co-founder and president of a strategic marketing firm. Theresa is an avid hiker and enjoys exploring the Grand Canyon backcountry.

Mike Buchheit
Director, Field Institute

Mike has been with Grand Canyon Conservancy since 1997. In addition to overseeing all aspects of the Field Institute, he has been a mentor/consultant on program development and risk management for a number of sister institutes, a facilitator for National Park Service training events, an active board member for experiential youth groups in the region, and a regular field instructor and public speaker. Mike is also actively involved in Grand Canyon Conservancy's fundraising initiatives in his capacity as a Major Gifts Advisor, is a frequent host to park VIPs, and a subject matter expert for wide-ranging media projects. In his spare time he is a professional landscape photographer and frequent backpacker and river runner throughout his beloved Southwest.

Marie Buck
Chief Operating Officer

Marie spent over 20 seasons with ISM Raceway (formerly Phoenix Raceway) as Senior Director of Business Operations, where she helped lead the business through the development of two NASCAR Monster Energy Cup Series events, the return of the Indy Car Series to the circuit, and a $178 million expansion and redevelopment of the facility. She is an active leader in the community, having served on the Board of Directors for WESTMARC and in an advisory role to Raceway Charities, a donor-advised fund to the NASCAR Foundation. Marie grew up backpacking and rafting Grand Canyon with her father, Sven Jarnlof. She is an avid lover of the outdoors and enjoys sharing her passion for Grand Canyon with others. Marie has worked over 20 river trips rowing baggage and guiding customers on Colorado River rafting trips. 


Darin Geiger
Director of Operations

Darin joined Grand Canyon Conservancy in 2018. He brings with him 30 years of retail experience, spanning a wide range of disciplines, including management positions in operations, merchandising, buying, product development, and e-commerce. Darin’s first trip to the canyon was a river trip 20 years ago, and in his free time today, you’ll most likely find him on a trail somewhere below the rim or visiting one of Grand Canyon Conservancy’s eight retail locations to thank the hard-working and passionate staff who serve Grand Canyon’s visitors year-round. "Being involved with a mission-focused organization is extremely fulfilling, both personally and professionally."

Laura Jones
Chief of Staff

Laura moved from Illinois to Grand Canyon in 1995 to enjoy a summer out west. She immediately fell in love with Arizona and decided to make the move a permanent one. After working in the hospitality industry for 14 years, Laura transitioned to Grand Canyon Conservancy hoping for a new challenge working in the rewarding setting of a nonprofit organization. Laura serves as an advocate for the changes that make Grand Canyon Conservancy a stronger partner to the park by leading annual planning processes, strategic initiatives, and special projects critical to GCC’s long-term success. She is an effective facilitator and champion for many critical strategic initiatives involved in growing the organization. "Working for GCC has given me the opportunity to ensure future generations have the opportunity to explore and connect to a place I will forever call home."

Mindy Riesenberg
Director of Marketing and Communications

Mindy first saw Grand Canyon National Park when she was four years old, while moving from the east coast to the west coast with her family, and it left a remarkable impression on her. She has over 20 years of experience as a marketing and communications executive, and has lived and worked across the United States. Most of her career was spent in marketing leadership positions at major art museums, including the Kimbell Art Museum (Fort Worth, Texas), the Walters Art Museum (Baltimore, Md.) and Phoenix Art Museum. Prior to joining GCC in 2017, she worked with the Center for the Future of Arizona and wrote and reported stories for Cronkite News, covering the topics of borderlands and sustainability. Mindy has a B.A. in journalism from San Diego State University and a master’s degree from ASU’s Walter Cronkite School of Journalism and Mass Communication. She has been a featured speaker on the topic of nonprofit marketing for the American Marketing Association, Texas Association of Museums, and Texas A&M University, among others. In her free time, Mindy is a professional singer who loves to ski, do yoga, and spend time with her dog.

Susan Schroeder
Chief Executive Officer Emerita

Susan is the immediate past CEO of Grand Canyon Conservancy. In her tenure, Susan's knowledge and experience in organizational development, fundraising, strategic planning, and nonprofit governance led to significant organizational growth to support the mission of GCC. Under her leadership, GCC also incorporated fundraising into its mission––a major cultural shift. The redevelopment of Bright Angel Trailhead, the renovation of historic Kolb Studio and a new greenhouse at the South Rim were all major fundraising projects overseen by Susan. She also spearheaded GCC’s first-ever fundraising campaign, “A Grand Vision,” which by the end of 2019 will have raised $15 million for four priorities at Grand Canyon National Park: Trails Restoration, Preserving Dark Skies, Desert View Inter-tribal Heritage Site enhancements, and Discovery & Exploration (expanding youth education programs and supporting science in the park).

Prior to joining GCC in 2008, she held leadership positions at Northern Arizona University (NAU) within the NAU Foundation, University Advancement, Center for Sustainable Environments and Grants and Contracts. Preceding her time at NAU, Susan was the managing partner in a market research consulting firm specializing in the tourism, recreation, and healthcare industries. Early in her career she worked with an interpretive planning and design firm to create visitor-centered experiences for both public and private visitor centers and museums.

Her first visit to Grand Canyon was in 1985, a life-changing river trip through the Grand Canyon.

Susan is on the Board of the Northern Arizona Leadership Alliance, the Advisory Board of the Arizona Community Foundation of Flagstaff, and the national Friends Alliance Steering Committee. Susan and her husband enjoy living in Northern Arizona and exploring the rich natural and cultural surroundings of the southwest.

Andy Vikta
Chief Financial Officer

Andy brings a diverse set of business and personal experiences to Grand Canyon Conservancy. Prior to joining GCC in October 2016, Andy was the CFO of the Adelante Development Center, one of New Mexico's largest nonprofits that serves the developmentally disabled, disadvantaged, and senior populations. This experience was Andy's first in the nonprofit sector after many years of senior financial management and leadership in complex food and aircraft manufacturing, sales, and distribution. Andy's career has supported his love of travel, including living and working with people from around the world in places like Lithuania, Turkey, and France with many other stops in different countries along the way. As CFO at GCC, he now celebrates the chance to support the majestic Grand Canyon, allowing him to return, full-time, to his love of nature and the great outdoors.

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