Embolism resistance drives the distribution of Amazonian rainforest tree species along hydro-topographic gradients

作者：Oliveira, Rafael S.^*; Costa, Flavia R. C.; van Baalen, Emma; de Jonge, Arjen; Bittencourt, Paulo R.; Almanza, Yanina; Barros, Fernanda de V.; Cordoba, Edher C.; Fagundes, Marina V.; Garcia, Sabrina; Guimaraes, Zilza T. M.; Hertel, Mariana; Schietti, Juliana; Rodrigues-Souza, Jefferson; Poorter, Lourens

来源：NEW PHYTOLOGIST, 2019, 221(3): 1457-1465.

DOI：10.1111/nph.15463

• drought vulnerability
• forest resilience
• functional ecology
• hydrological niches
• P-50
• phosphorus
• tropical forests
• water table

Species distribution is strongly driven by local and global gradients in water availability but the underlying mechanisms are not clear. Vulnerability to xylem embolism (P-50) is a key trait that indicates how species cope with drought and might explain plant distribution patterns across environmental gradients. Here we address its role on species sorting along a hydro-topographical gradient in a central Amazonian rainforest and examine its variance at the community scale. @@@ We measured P-50 for 28 tree species, soil properties and estimated the hydrological niche of each species using an indicator of distance to the water table (HAND). @@@ We found a large hydraulic diversity, covering as much as 44% of the global angiosperm variation in P-50. We show that P-50: contributes to species segregation across a hydro-topographic gradient in the Amazon, and thus to species coexistence; is the result of repeated evolutionary adaptation within closely related taxa; is associated with species tolerance to P-poor soils, suggesting the evolution of a stress-tolerance syndrome to nutrients and drought; and is higher for trees in the valleys than uplands. @@@ The large observed hydraulic diversity and its association with topography has important implications for modelling and predicting forest and species resilience to climate change.

• 出版日期2019-2