Interspecific variation of functional traits in saplings of three Amazonian species under drought stress and recovery

Extreme events (e.g. severe drought) can hinder the establishment of saplings in tropical forest plantations. To assess the resistance and recovery of three commercially important Amazonian tree species under drought conditions and to identify their key functional strategies for drought response, we conducted a controlled drought experiment exposing saplings of <i>Bertholletia excelsa</i>, <i>Dipteryx odorata</i>, and <i>Tachigali vulgaris</i> to water deficit followed by recovery. <i>Tachigali vulgaris</i> (fast-growing species) was more vulnerable to drought, as 80% of the drought-treated plants died. Nevertheless, the individuals who survived demonstrated a rapid recovery of physiological performance following rewatering. <i>Bertholletia excelsa</i> and <i>D. odorata</i> (slow-growing species) were more resistant to drought stress, as evidenced by lack of mortality in these species. Drought-stressed plants had the lowest growth rates, more biomass allocated to roots and less leaf biomass. The greater biomass allocation to roots in <i>B. excelsa</i> and <i>D. odorata</i>, together with their more conservative functional traits compared to <i>T. vulgaris</i>, appears to play an important role in their lower sensitivity to drought. These species exhibited strategies consistent with drought avoidance. Our results highlight the specific strategies of these species under water-deficit conditions and can help guide decisions on species selection and plantation management for reforestation under climate change scenarios.