Drawing on knowledge gained through her talks with Elders, and on remembrances from her childhood, when she and her siblings would accompany her parents and grandparents on trips into the woods to harvest traditional plants, Mary Thomas became known as an expert on traditional plants and their uses. She shared this information with others eager to learn, and even worked to help researchers document the environmental changes that occurred in her lifetime and the effect those changes have had on plant life.
Thomas’ work as an environmentalist was coloured by her respect for mother nature and her understanding that no more should be taken from the earth than is truly needed—a philosophy she tried to pass on to future generations.
She was concerned about preserving and protecting traditional plants so they would be there for future generation, but she was also concerned about broader environmental issues as well—protection of the air, the earth, the water and the animals. And she recognized that all people, both Aboriginal and non-Aboriginal, must work together to deal with conservation and environmental issues because everyone, regardless of their cultural background, is equally affected by threats to mother earth.