Comparison of wild edible plant diversity and foraging strategies in two aboriginal communities of northwestern Patagonia

We have compared edible plant richness, diversity and differential patterns of use in two Mapuche communities of Argentina. The populations of Rams and Cayulef are located in a herbaceous steppe, far from the temperate forests of northwestern Patagonia where their ancestors lived in the past. Ecological concepts and methods, such as diversity indices, niche breadth and optimal foraging theory have been used in this comparative study. Our results indicate that the diversity of wild plants used in Rams and Cayulef is associated with the variety of gathering environments they visit. When comparing diversity indices among the three environments within each community, in Cayulef we found the highest diversity indices for steppe species and the lowest for forest plants. In contrast, in Rams the niche breadth is similar in all environments, indicating an ample exploration and use of edible wild plants. Cost and benefit trade-offs seem to be considered in both communities when edible plants are collected. Nevertheless, we found that the people from Rams not only utilize a greater richness of wild plants than the Cayulef people, but also use more nutritious resources, spend more time traveling to the gathering sites and a longer handling time in preparing these edible plants. This study has quantitatively shown that the restricted access to Pehuen forest (Araucaria araucana) is the main factor which seems to limit wild plant diversity used in these Mapuche communities.