Mark Holton, MA, MFT  – Owner

Mark has over 20 years of experience in the behavioral health, mental health and supported employment fields. As a behavioral analyst, licensed marriage family therapist and rehabilitation counselor, Mark enjoys his work and brings all his experience from these treatment fields to the table to create a person centered, evidenced based approach for his clients and the teams he works with. Marks ability to create positive treatment outcomes with his clients has been documented with great success over his career.

sarah holton

Sarah Holton – Director of Operation, Co-owner

Sarah, born and raised in the four corners, is passionate about the community she grew up in. She was called to this work through the needs of a family member.  Sarah has experience in business and organizational management and a passion for creating avenues for all people to thrive within their communities.


Tonya Shangraw – PhD, BCBA-D, Clinical Director

Tonya is originally from Russia and lives in Alaska. Tonya got her BCBA-D certification in 2012 with a PhD in developmental psychology, offering a great perspective to help with better understanding of typical development and milestones. Tonya has been a Clinical Director for ABA agencies since 2013. Her areas of expertise include language and communication developments, functional assessments, play and social skills development, and working with problem behaviors. She enjoys using natural environment and items that are already in child’s natural environment. While working with clients and families she finds it especially important that all the goals are functional and make sense for the family.


Pamela B

Pam Bartsch – MA, BCBA

Pam is originally from Southern California and now resides in Southwest Idaho. She has over 11 years of special education experience, working with children with profound disabilities as well as those with a mental health diagnosis. Pam has an extensive background in working with families that have a child with a diagnosis of Autism as well as 11+ years working in the ABA field. Pam’s passion is in working with families to be able to support their children in ways the families did not think were possible and seeing clients growth over time. When not at work, you will find Pam and her family camping, in the summer, playing in the snow in the winter, and on the sports fields in the fall and spring.


jacob tonna

Jacob Tonna – M.Ed, BCBA

Jacob in a newly Colorado transplant, originally from Michigan but Florida raised with 8 plus years of behavioral health (ABA), mental health, and substance abuse experience. Starting as an RBT in 2014 Jacob quickly learned his passion for working with others. Jacob earned his master’s degree in education at the University of Cincinnati to become a Board Certified Behavior Analyst. Jacob enjoys training new and seasoned RBTs, assisting with functional communication training, social skills, and the overall development of the clients we serve as a whole individual. During his free time, Jacob enjoys hiking, mountain biking, canoeing, and traveling abroad.


Devon Parson – M.ed, Lead Behaviorist

Independence here in Durango, Devon has over 4 years experience in writing and implementing behavioral support plans for individuals with intellectual and developmental disabilities, Autism and other learning disorders. He holds a Masters degree in Special Education and is currently working on acquiring his BCBA through The University of Colorado Applied Behavior Analysis Program. His dedication and leadership in our local community for people with disabilities is recognized by Fort Lewis College, 9r school district, community center boards, vocational rehabilitation programs, parents, families and the individuals he works with. Thanks Devon!


Misti Burton — Administrator

Misti is originally from North Carolina and has resided in Colorado for the past 6 years. She is a dedicated Mother of two children. Misti enjoys out door activities and line dancing. Misti is passionate about making a difference in lives of children with a focus to help them learn and grow. Thanks Misti!

kelli hallman

Kelli Holman — MA, BCBA

Kelli is a Colorado native currently living on the Western Slope. Her background in serving children began in Junior High when she was given the opportunity to help in a Middle School level 2 classroom. She quickly fell in love with the population and now has 18 years of professional experience working with children and their families in a variety of settings including residential, foster care, in-home services, and clinical care. Kelli earned her master’s in special education through ASU and have since used her experience and education to support behavioral change in children of all ages and abilities. She is passionate about providing care in a fun and supportive manner that emphasizes compassion and focuses on independence. In her spare time, she enjoys spending time with family as well as almost anything outdoors.

Tania Isman – Registered Behavioral Technician (RBT)

Tania has been married 16 years with Three children. Tania enjoys being outdoors and going on adventures. She is passionate about getting kids active with yoga and exercise and into the outdoors as much as possible. She recently graduated with a bachelor’s degree in elementary education. Tania hopes to become a BCBA in the future. Thanks Tania!

Alex Noble – RBT

Alex is originally from Montana and was drawn to the dramatic views and mountains of Durango. She has eight years of experience in working with children of differing abilities. Alex is working towards getting her ABA Master’s Certification and is eager to make an impact in her client’s lives. Outside of work Alex enjoys rock climbing, mountain biking, and photography. Thanks Alex!

Brandee Muzzy – RBT Mentor, Administrator 

Brandee is a Registered Behavior Technician with PBS of the 4 Corners. Her dedication and experience working with children with Autism is extensive. Her calmness and effective use of ABA therapy has been supportive and life changing with the children and families she works with. I am truly impressed with her compassion, flexible thinking skills, and her ability to effectively run behavior programs with our clients, families, and staff. Thanks so much Brandee!


Amber Goldberg — RBT

Amber has as lived in the four corners area for 16 years. Amber served honorably in the Air Force for four years. Currently pursuing a degree in Psychology. A natural empath and loves to connect with and help people. Enjoys anything outdoors, animals, and being active. Thanks Amber!


Arnelda Hathale – Behavior Technician

Arnelda Hathale was born in Tuba City, AZ. but moved to Cortez, CO many years ago. Her empathy and inquisitive nature are a plus. She is a keen observer with loads of patience. Arnelda has experience in the hospitality industry so she understands the value and importance of our clients. The care and personal attention to each and every client’s need is of the utmost important to Arnelda. Our clients deserve it. Thanks Arnelda!

Stacey Watson – Behavior Technician

Stacey is a former thirteen year veteran of Re-1 School District. During that time, Stacey worked in Special Education, teaching children diagnosed with Autism, ADHD, and other Learning Disabilities. I her spare time, Stacey enjoys reading, coloring, painting, working in her yard, hiking, fishing, and time outdoors. Thanks Stacey!

bryanne goddard

BryAnne Goddard – Behavior Technician

BryAnne has lived in the area for over 20 years. She has worked with a variety of children over the past two decades as a teacher, director, and parent educator. She is passionate about helping all children live healthy and happy lives. In her spare time, BryAnne gardens as often as possible and enjoys spending time outdoors with her family.


Emily Jeremiah — BT

Emily grew up here in the Dolores/Cortez area. She has always had a passion for working with children and became an ESS Life skills Paraprofessional at a local Elementary school for 4 years. Emily loves working with significant needs students and decided to join the team here at PBS. Emily enjoys plants, learning, and exploring the outdoors with her husband and Australian Shepherd, Koa! Thanks Emily!

Kathy Flannery, BS, Behavior Technician

Kathy holds a Bachelor’s degree in Family Life Studies. Kathy enjoyed her time working as a Family Educator for Early Head Start for several years as well as a head start teacher for 3 years. She enjoys spending time with her grandkids. Kathy’s Motto is “Tomorrow offers the promise of being better than today if you so choose it to be.” Thanks Kathy!

Bear Messinger, RBT

Bear is from Northern California. He is attending Fort Lewis College, majoring in psychology. His goal is to help people feel better about themselves through greater self confidence, acceptance and socialization. Thanks Bear!

Cammy Lirot — BT

After living in Washing and discovering that she had a passion for working with children of all different backgrounds, Cammy moved back to Colorado to pursue her dreams to become a BCBA and work with neurodivergent children to help create a better life for them. Her other passions and hobbies include hiking, white water rafting, camping and sitting down with a good book. Thanks Cammy!

terri lawson

Terri Lawson — BT

Terri’s background is in special education teaching. Over the course of her 20 years in education she developed a skill set directly relevant to working with autism spectrum disorder and multiple disabilities. Terri has worked with a diverse range of emotional, physical and cultural backgrounds. Because of her history in the classroom, she connects well with parents and can take a pro-active problem-solving approach. Through the years, working with colleagues and parents, she has gained a broader understanding on how best to service the needs of clients. Thanks Terri!

Sherry Marcum PBS4C – Job Coach

She has worked successfully with with individuals with special needs for over 20 years. Her experience is seen in the amazing work she does with individuals with disabilities on and off the job. She has a diverse history of training and has worked in many settings with individuals with disabilities. Sherri will be acquiring her national supported employment certification this year. Thanks Sherry!