The Influence of Fire and Deforestation on the Floral Symmetry and Fitness of Adenocalymma nodosun (Bignoniaceae)

Abstract

Burnings and deforestation are severe disturbances to plants and may represent a stressful situation for plant growth, and they can also affect plant-pollinator interactions and the reproductive success of plants. In this study, we verified the variation in floral symmetry of Adenocalymma nodosum (Bignoniacea) in two areas, one post-fire and other after deforestation. We also verified the effects on plant-pollinator interactions and fruit set production. Results showed that A. nodosum flowers were more asymmetric in mowing areas than in fire areas. Asymmetrical flowers presented low nectar concentration and bee visitation rates. Although mowed environments produce fewer fruits and seeds than areas affected by fire, the change was not significant. Soil from the burnt area showed higher nutrient and organic matter concentration and less aluminum than that of mowed areas. Our results showed that A. nodosum flowers in the deforestation area are more asymmetric than those in the post-fire area. This result suggest that Cerrado plants may be less adapted to deforestation than to fire, since they have been facing fire events for thousand years in this biome. We suggest that the effects of environmental stress on the development and fitness of plants may provide an important breakthrough to the understanding of insect-plant interactions in Cerrado savanna, where burnings and deforestation are frequent anthropogenic effects.