Rainfall and topographic position determine tree embolism resistance in Amazônia and Cerrado sites

• Published in: Environmental research letters Vol. 18; no. 11; pp. 114009 - 114021
• Main Authors: Mattos, Caio R C, Mazzochini, Guilherme G, Rius, Bianca F, Penha, Deliane, Giacomin, Leandro L, Flores, Bernardo M, Silva, Mateus C, Xavier, Rafael O, Nehemy, Magali F, Petroni, Amanda R, Silva, Julliene S G M, Schlickmann, Monique B, Rocha, Mayda, Rodrigues, Gleicy, Costa, Soliane S, Barros, Fernanda V, Tavares, Julia V, Furtado, Mariana N, Verona, Larissa S, Oliveira-Alves, Maria J, Oliveira, Rafael S, Fan, Ying, Hirota, Marina
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01-11-2023
• Subjects: Drought; drought resistance; Embolism; Embolisms; functional ecology; Groundwater; Hills; hydrologic niche; Hydrology; Plant species; Rain; Rainfall; Topography; Tropical environments; tropical forests; tropical savannas; Valleys
• ISSN: 1748-9326; 1748-9326
• DOI: 10.1088/1748-9326/ad0064

Abstract
Droughts are predicted to increase in both frequency and intensity by the end of the 21st century, but ecosystem response is not expected to be uniform across landscapes. Here we assess the importance of the hill-to-valley hydrologic gradient in shaping vegetation embolism resistance under different rainfall regimes using hydraulic functional traits. We demonstrate that rainfall and hydrology modulate together the embolism resistance of tree species in different sites and topographic positions. Although buffered by stable access to groundwater, valley plants are intrinsically more vulnerable to drought-induced embolism than those on hills. In all study sites, the variability in resistance to embolism is higher on hills than on valleys, suggesting that the diversity of strategies to cope with drought is more important for tree communities on hills. When comparing our results with previously published data across the tropics, we show greater variability at the local scale than previously reported. Our results reinforce the urgent need to extend sampling efforts across rainfall regimes and topographic positions to improve the characterization of ecosystem resistance to drought at finer spatial scales.