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Questions: Plants largely vary in their capacity for foliar water uptake (FWU), that is, the capacity to increase leaf water content by directly absorbing water from leaf‐wetting events. Climate change will reduce leaf wetting and increase drought events. Therefore, we need a better understanding of the underlying traits and mechanisms that facilitate FWU. Location: Seasonally dry tropical montane grasslands in Brazil (Campos de Altitude). Methods: We measured FWU and leaf traits related to wettability, surface conductance, water potential and water storage on up to 55 plant species. By using Direct Acyclic Graph theory and Bayesian modelling, we tested how those leaf traits affect FWU. Results: We found that stomatal conductance largely explained interspecific variation in FWU, which was also favoured in species with hydrophilic leaves, high cuticular conductance, more negative leaf water potentials, low dry‐matter content, isohydric behaviour, and more elastic cell walls. Conclusions: Due to the existence of trade‐offs, not all species exhibit an optimal combination of traits that favours FWU. Instead, co‐occurring species have achieved a similar capacity for FWU through distinct trait combinations. Consequently, species engaged in FWU may exhibit differential vulnerabilities to climate change as they can cope with drought using other strategies beside FWU. [ABSTRACT FROM AUTHOR]

In 2015/16, a strong El Niño event caused anomalously high temperatures and reduced precipitation resulting in Pantropical drought‐induced diebacks and wildfires. Although many studies have documented the El Niño impacts on tropical forests, little we know about its effects on tropical grasslands. Here, we investigated plant drought responses during and after the 2015/16 El Niño event (Jun 2016 to Aug 2017) in 12 species with contrasting drought strategies (tolerance, avoidance and escape) in a Brazilian tropical montane grassland. We tested if (1) the El Niño event induced meteorological drought anomalies, (2) the atmospheric and/or soil drought led to plant water stress and (3) plants showed signs of drought recovery. In contrast to other tropical areas, we found that the 2015/16 El Niño event did not strongly affect precipitation in our study site. However, it increased air temperature and vapour pressure deficit, thus pushing all grassland species, even the most drought‐tolerant ones, beyond their hydraulic safety margins during the dry season. Most species showed signs of drought recovery, returning to positive hydraulic margins in the wet season after the El Niño. However, the finding that all evaluated species, regardless of their drought‐response strategy, are already operating close to their hydraulic safe thresholds for stomatal closure and turgor loss suggests that this cool–humid tropical montane grassland is especially vulnerable to meteorological extremes exacerbated by the additive effects of El Niño and climate change. [ABSTRACT FROM AUTHOR]

Occult precipitation events (fog, dew and light rain) can alter plant water and nutritional status, both directly through the aerial uptake of surface water and nutrients, and indirectly via redistribution of atmospheric resources to the soil. However, current frameworks that explain niche segregation, species interactions and coexistence still consider that ground‐rooted plants obtain resources almost exclusively via root absorption from soil.Here, we expand the plant hydrological niches model to incorporate both soil and atmospheric resource‐axes, thus providing a more complete picture of how ground‐rooted terrestrial plants obtain, remobilise, share and compete for water and soluble nutrients.First, we describe how plants with different water acquisition strategies access directly or indirectly atmospheric resources. Then, we discuss how the use of such resources may promote spatiotemporal niche segregation, contributing to shape species distribution and abundance within plant communities. We illustrate this argument with examples from arid, mesic and wet vegetation types. Finally, we examine how climate and land‐use changes may influence plant hydrological niches, potentially altering community structure.Synthesis. Understanding how available atmospheric resources influences niche segregation in plant communities is a crucial step towards better predictions of species responses (e.g. changes in distribution, abundance and interactions) to climate change. [ABSTRACT FROM AUTHOR]

Aim: Rainfall manipulation experiments are essential tools for deciphering the mechanisms leading to variation in ecosystem stability across sites. Here, we gathered articles reporting results of experimental droughts on the above‐ground biomass of grasslands to identify which indices have been used to assess stability, to evaluate the overall grassland responses to drought and to quantify the relative importance of drought characteristics and climatic conditions for explaining variation in stability. Location: Global. Time period: 1989–2018. Major taxa studied: Grasslands. Methods: We used meta‐analytical approaches to evaluate overall grassland stability in terms of resistance, recovery and resilience, and multi‐model inference to assess the relative importance of different moderators on explaining the variability of those three stability properties. Results: Numerous indices of stability have been used, but they are inadequate for comparisons across sites. After applying standardized indices, we found that grasslands were resilient (biomass remained unchanged 1 year after drought) and exhibited a trade‐off between low resistance (biomass was lost during drought) and high recovery (new biomass was produced after drought). Overall, climatic conditions and drought characteristics (intensity, duration and frequency) were not important to explain the differences in stability observed across grasslands. Main conclusions: Grasslands are resilient, but if drought events last > 1 year, there might be long‐term declines of biomass production owing to incomplete recovery. Despite the hundreds of experiments conducted in grasslands across the globe, the results are still inconclusive because of four important shortcomings: 50% of the studies have failed to create drought; 81% have not included recovery and resilience, assessing only resistance; 87% have not applied quantitative indices to assess stability; and < 1% of the studies were conducted on tropical grasslands. We discuss how to overcome those limitations to improve our ability to ensure stable grassland productivity under climate change. [ABSTRACT FROM AUTHOR]