DEFORESTATION ALTERS PHYTOTELM HABITAT AVAILABILITY AND MOSQUITO PRODUCTION IN THE PERUVIAN AMAZON

Abstract

We quantified the effects of deforestation, and subsequent cultivation and forest regeneration, on the abundance and composition of mosquito larval habitats, specifically phytotelmata (plant-held waters), in the western Amazon basin. Recently deforested sites were characterized by increased phytotelm density (1.6 phytotelmata/m2) and greater relative abundance of fallen-plant-part phytotelmata (76%) compared to intact forests (0.9 phytotelmata/m2 and 25% fallen plant parts). As a result, the total volume of colonizable phytotelm water was significantly larger in new clearings. Subsequent cultivation of cleared land with mixed crops including pineapple and plantain had similar consequences: phytotelm density (2.2 units/m2) was significantly larger in plantations than in forests due to greater relative abundance of water-filled plant axils (71% vs. 39% in forest). Such axils are the preferred larval habitats for Wyeomyia spp. mosquitoes, which showed a similarly significant increase in production in plantations (0.25 larvae/m2) vs. forests (0.04 larvae/m2). Likewise, Limatus spp. mosquitoes were an order of magnitude more abundant in altered landscapes (especially in recently deforested and cultivated areas) than in mature forest, due to increased abundance of fallen-plant-part phytotelmata, in which they are typically the most common colonists. Because they are potential vectors of pathogens in a region of high endemic and emergent virus activity, increases in local abundance of Limatus spp. and Wyeomyia spp. due to large-scale deforestation and agriculture may influence rates of disease transmission.