Mark Holton – MA, MFT, Co- Founder

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 Love – Business Management, Co-Founder

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.


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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.


Scotia Hammond – PhD, BCBA

Scotia is originally from South Florida and currently lives in Las Vegas, Nevada. Scotia earned her PhD in Special Education from the University of Nevada, Las Vegas. She is a board-certified behavior analyst and has extensive experience serving children and adolescents with autism spectrum disorder and emotional and behavioral disorders in the home, school, and clinic setting. She strives to create a client centered environment that embraces and values the strengths, culture, and opinion of each client. She focuses on creating a collaborative and supportive environment for every client to thrive. When not working, Scotia loves to travel, try new foods, and spend time with her cat, Muffin. 
jacob tonna

Alex Ivery BT, Administrative Assistant

Alex is originally from San Antonio, TX, but lived all over the world due to both parents being in the military.  She eventually landed in Colorado in 2000 and earned her license in therapeutic massage therapy.  She worked in higher education for six years working her way up from Admissions Representative to School Director then as a caregiver for approximately 10 years working privately with adults with varying disabilities including wheelchair dependent individuals, stroke survivors, and traumatic brain injuries.  Her compassion, patience, and creativity lend well to working with neurodivergent individuals.  She is currently working toward her Registered Behavior Technician credential, and enjoys traveling, learning about anything to do with holistic health and alternative living, camping, and creating music.  

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!

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!

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.

Yudislaine Pier, BCBA 

Yudi Pier is a Board Certified Behavior Analyst (BCBA) residing in Florida. She received her Bachelor’s degree in psychology from University of Oriente, in Cuba, where she is originally from. Yudi holds a Master’s degree in Education and Counseling from University Ana G. Mendez, Tampa Florida, and a Master in ABA Intervention and Autism and Developmental Disorders from ABA Spain. She has worked in the roles of Lead Analyst, Clinical Director. Yudi has over 16 years of experience working with individuals with varying disabilities and age
ranges in the areas of inclusion and Behavior Analysis.

Tania Isman – RBT

Tania has lived in the Cortez area most of her life. She loves traveling and going on as many adventures as possible. In her free time she enjoys hiking, kayaking, hot springs, anything to do with the outdoors. She is passionate about getting her clients motivated and into the outdoors or the community. 

Tania has several years of experience working with many different age ranges and abilities. Before PBS, she worked as a paraprofessional and a substitute in the school system. She received her Bachelors from Fort Lewis in Elementary Education.  She has been working as an RBT for the last 3 years with 1 year of serving the adult population in a community day program setting. She is currently attending Arizona State University working towards her Masters in ABA to further her education and career as a BCBA.

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 – RBT

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 – RBT

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 — RBT

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!

Roberta Mulnix-Duke BT

Born and raised in the for corners and  moved to Hermosa in April, 2021.

She is passionate to work with individuals with special needs. Roberta is currently working toward her BCBA. 
She is the mother of three adult children and a grandmother of thirteen grandchildren. Roberta has worked at the Bloomfield School District as a special needs aide, on buses, also a bus before and after school, as well as served as a computer lab teacher for kids at an alternative school.

Zachary Siegel – BT 

Zach was born in the four corners and has always wanted to contribute to society in a meaningful way. He graduates from Fort Lewis College, CO, in 2023 with a major in biology and minor in philosophy. While Zach is intelligent and meticulous, he takes pride in having a creative imagination and child-like wonder. This, along with a great virtue of patience, has greatly aided in creating natural and fun sessions with adolescent clients.

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!