Dinâmica arbórea e a mudança do clima importância da topografia e das características funcionais na Amazônia central

Abstract

Droughts have been reported as the most significant negative impact of climate change to tropical forests. Yet, strong rainfall periods are becoming as frequent as droughts in Amazonia, with still unknown influence on forest dynamics. Moreover, drought studies have focused on upland forests with deep water tables, which experience higher water deficits and may be especially sensitive to drought. Here we analyzed how hydrological environments (water table depth, WTD), interacting with species functional traits, mediated tree responses to water-related climate anomalies over the past two decades. Both extreme water conditions, deficit and excess, decreased concurrent tree growth and survivorship, but legacy interactions had the highest impact, with water excess periods before or after drought sustaining growth and survival. Species hydro-topographic affiliation modulated drought effects, with species associated to deep WTD suffering more than those associated to shallow WTD. Thus, both high precipitation periods and shallow water-table environments acted as buffers of drought effects on trees. These results suggest that water excess events and local topography importantly modify Amazon forest resilience to climate change, with long-term implications for forest dynamics and potential compositional shifts.