In the islands of the Anavilhanas, the herbaceous species Ischnosiphon polyphyllus, known as "arumã", occupies the understory of flooded black water forest. This plant is utilized by local human populations to produce handcrafts. The aim of the present study is to describe the ecological and biological characteristics of the species, taking into account the criteria of selection of stems used by regional craftsmen. We sampled 153 plots on 27 islands to determine the distribution and abundance of plants along the inundation gradient. In addition, 120 plant tufts distributed on 8 islands were sampled to obtain data on population structure. Higher densities of I. polyphyllus were found in the gradient subject to 2 and 4 m of inundation. This distribution indicates that the species maximize development in the higher positions in the plains where the abundance of mature stems utilized by the craftsmen is higher. The period of inundation may affect the plant's physiology, morphology, and the reproductive strategies. Vegetative reproduction may play an important role in population survival under conditions of inundation stress. An adequate management of the species is necessary to maintain the species and the local craft activities in a sustainable equilibrium. This is particularly true for the stems removed in the critical position on plains, for example those between 2 and 4 m of flooding.
Amazonia; "arumã"; flooding period; handcraft; management
