I did mention this. There is an inherent distrust because of theft of knowledge. That's why taking the time to establish a relationship with these individuals so you can build that trust.... Why would they want to share that knowledge with you if they feel that it might not be used in a good way that's going to benefit not only them, but their community and all the living beings around there?
Take the time to get to know these individuals, to get to know the historical aspects of what that community has faced and is facing, and go into that relationship to build trust and really establish a basis for doing this work together. If there's a willingness to learn, a willingness to hear the answer “no, that is not our priority”, I think that positions this kind of work in a different way. Indigenous communities and knowledge-keepers are much more likely to want to participate when things are done a bit differently.