The paper examines Muhlhausler's thesis that to understand the decline and loss of small languages we must examine a large range of 'ecological' factors which comprise the support system within which the language has integrity and meaningfulness. Taking the case study of the Harakmbut peoples of Southeastern Peru, it examines the Harakmbut concept of territory (wandari) which provides parameters for understanding the linguistic ecology and the nature and degree of change in the social, cultural and natural environments in which the Harakmbut and Spanish languages are used. It considers the role of intercultural bilingual education in a context of increasing use of Spanish language and shrinking physical, social and cultural domains of Harakmbut language use. A survey of education programmes in the Peruvian Amazon, and among other indigenous peoples, focused on language maintenance suggests critical directions for sustaining the Harakmbut language.