Participatory research among the Kaiabi people at Xingu Indigenous Park in the southern Brazilian Amazon was conducted to support sound natural resource management. We studied aspects of the ethnoecology of an understory herbaceous plant, arumã (Ischnosiphon gracilis, Marantaceae), used in basketry weaving by Kaiabi men. Results of a three-year survey comparing arumã populations and of a transplanting experiment evaluating the growth of arumã seedlings in four different habitat types are presented. These, combined with discussions with Kaiabi communities and with results of studies conducted in other parts of the Amazon Basin, support a five-year rotating management strategy that allows for regeneration of harvested arumã populations.