Response of the Amazon Tropical Forests to Deforestation, Climate, and Extremes, and the Occurrence of Drought and Fire
To the extent that many studies of the last two decades deepen the understanding about the Amazon tropical forest and more is known about the environmental services it offers, they also increased our level of awareness about the growing threats that this system has been subjected to. In addition to the process of uncontrolled expansion of the agriculture frontier, the Amazon, for its large scale, is an ecosystem highly susceptible to climate at regional and global scales. In this chapter we address issues related to environmental drivers of change in the Amazon: deforestation, climate, climate extremes, and fire. The goal is to present aspects of a synergistic action of these effects and the possible responses of Amazonian ecosystems to these drivers of change: (1) short-term responses as the mortality of some species (biodiversity loss), loss of living biomass with consequent influence on storage, and exchanges of carbon with the atmosphere to (2) long-term responses, such as ‘savannization’ and Amazon dieback. On the other hand, it has been hypothesized that the forest may show some degree of resilience to tolerate those impacts before starting to respond with degradation of the ecosystems. One of the challenges of Amazonian science today is to find out how close those drivers might be from exceeding ‘tipping points’ of stability of the Amazonian system.