Tanka Fund is a 501(c)(3) corporation located in Kyle, South Dakota, on the Pine Ridge Reservation. Our Native-led Board of Directors and Executive Director provide leadership, direction, and expertise in our work to make The Return a reality in Indian Country.

Executive Director


Trudy Ecoffey

Executive Director

Trudy Ecoffey

Dr. Trudy Ecoffey has over 20 years of experience working on research, management, and ecology of bison.  Dr. Ecoffey started working with bison and bison related issues when she wrote a curriculum for tribal colleges for her MS degree in Range Ecology and Wildlife from the University of Nebraska.   She then completed her PhD from South Dakota State in Biology with a dissertation that investigated tribal bison herds which focused on culture, ecology, management and financing.  She later assisted on writing a management guide to help tribal bison managers. Her focus was on disease and health issues for the InterTribal Buffalo Council. 

Dr. Ecoffey worked as an instructor and later a department chair at Oglala Lakota College in the Agriculture and Natural Resources Department. She then worked for over 8 years at the Oglala Sioux Parks and Recreation Authority as Senior Biologist.  Her focus while senior biologist was on research on range ecology, wildlife, and bison management of the tribal herds.  For the last 5 years, Dr. Ecoffey has been working with the USDA Natural Resources Conservation Service as Tribal Liaison for the Pine Ridge Reservation where she has been working with the Oglala Sioux Tribe and tribal producers on land management projects.  She resides with three children and Hunka’ granddaughter on the Pine Ridge Reservation where she spends her leisure time working with horses, hiking and attending her children and granddaughter’s sporting events. 

Please join us in welcoming Dr. Trudy Ecoffey!

Board of Directors


Zach Ducheneaux


Zach Ducheneaux, President

Zach Ducheneaux works with the Intertribal Agriculture Council (IAC), an organization focused on efforts to improve American Indian communities by strengthening the food economy of Indian Country. The organization is involved with farmers at an individual level, providing technical assistance and education, and also works at a policy level, interacting with tribal, local, state, and federal authorities to give Native agricultural ventures better access to financial resources. In addition to his work with the IAC and the IAC’s emerging community development financial institution (CDFI), Zach is a third-generation rancher on his family’s land on the Cheyenne River Sioux Reservation in north-central South Dakota. He has also served on the Cheyenne River Sioux Tribal Council and is a board member of several nonprofits and foundations. With nearly three decades of work in Indian Country to close the gaps in Indian Country’s agricultural economy, Ducheneaux is leading critical efforts to restore food sovereignty, health and local self-sufficiency.


Mark Tilsen


Mark Tilsen, Vice President

Mark Tilsen is the co-founder and former President of Native American Natural Foods. Tilsen has more than 38 years of experience in nonprofit fundraising, marketing, and community development and 25 years in special events marketing and productions. A recipient of numerous marketing awards, including the 2016 Specialty Food Association Leadership Award for Citizenship and the 2011 Social Venture Network Innovation Award for his work with Native American Natural Foods, Tilsen is a lifelong Native ally. He began his career working as a volunteer in 1973 for the Wounded Knee Defense Offense Committee, which his parents co-founded. Since that time, he has honed his skills coordinating award-winning, database-driven direct marketing campaigns that have raised millions for Native American educational and environmental organizations. Tilsen has co-founded several successful community organizations and businesses, including KILI Radio, the largest indigenous community-owned radio station in North America and Lakota Express, a direct marketing agency on the Pine Ridge Indian Reservation.


Nick Hernandez


Nick Herndandez, Secretary-Treasurer

Nick Hernandez is Director of Food Sovereignty Initiative for Thunder Valley Community Development Corporation on the Pine Ridge Indian Reservation. He is a tribally enrolled member of the Oglala Sioux Tribe. Nick is a Graduate of Fort Lewis College, Durango, CO and is currently in the Graduate Studies Program for Lakota Leadership and Management at Oglala Lakota College in Kyle, SD. As part of the Food Sovereignty Initiative, Nick directs the operations of a model poultry-centered demonstration farm in partnership with Main Street Project and coordinates the Oglala Lakota Food Sovereignty Coalition. With many years dedicated to gardening and creating self-sufficiency, he is now on the pathway to researching, creating and demonstrating a sovereign food system on the Pine Ridge Indian Reservation at Thunder Valley.


Dawn Sherman

Member at Large

Dawn Sherman, Member at Large Oglala Lakota, Shawnee and Delaware

Dawn Sherman was born and raised in and around Rapid City, South Dakota. She is Oglala Lakota, Delaware and Shawnee. Dawn served as Business Manager for the Native American Natural Foods (NANF) for over five years and is now the Chief Operations Officer. Through the Democracy Collaborative and NWAF labs, Dawn helped create employee ownership opportunities at NANF. She is skilled in customer service, marketing, accounting and financial analysis.

Thanks to our partners and supporters:

Tanka Fund directs funds from people like you who care about the Earth and social justice to Native buffalo ranchers.

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Returning Buffalo to Native Lands