Exploração ilegal de madeira no arquipélago de Anavilhanas (Amazônia central): variáveis humanas que determinam a distribuição espacial da exploração e efeitos estruturais sobre os táxons mais explorados

Abstract

The Anavilhanas’ National Park is an Amazonian protected area facing nowadays the challenge of controlling illegal logging. To aid this task, this study aimed to determine (1) the densities of the exploited species in this area; (2) the spatial distribution of logging; (3) the effect of logging on population structure; (4) the growth rate of each species and (5) analyze the effects of human communities’ distance and wood value in the logging intensity. All trees with DBH >10 cm of the five most exploited species and the logging vestiges were registered on 84 transects uniformly distributed over the Anavilhanas Archipelago. Growth rates were measured by dendrocronology. Medium and large sized trees (10-30 and > 60cm DBH) of Virola surinamensis and Lauraceae spp (10-30 cm DBH) decreased in abundance as harvesting intensity increased. However, since growth rates of Ocotea cymbarum (Lauraceae) were high, it may recover fast if harvesting pressure stops. There was no evidence of negative effects of harvesting on the population structure of Calophyllum brasiliense, but its low growth rate and grouped distribution suggest that continued exploitation may endanger the population. There were no negative effects of logging for Macrolobium acaciifolium and Hevea spp., and their high growth rates and high abundances indicate that these species have a potential for management. Harvesting is concentrated in the southern region of the archipelago, next to the human concentrations, for most species, except for Lauraceae spp., whose timber is more valuable. The model tested indicated no relationship between the intensity of harvesting activities and the geographic distances to human communities, but a trend to choose harvesting places with greater concentration of more valuable resources. Thus, a strategy to control the illegal logging in the Anavilhanas Archipelago would be to encourage a sustainable logging plan on the buffer zone of the Park and to stimulate tourism on the South of the archipelago, where tourist presence could inhibit illegal activities.