Hydraulics and life history of tropical dry forest tree species: coordination of species’ drought and shade tolerance

Abstract

Summary• Plant hydraulic architecture has been studied extensively, yet we know little about how hydraulic properties relate to species' life history strategies, such as drought and shade tolerance. The prevailing theories seem contradictory.• We measured the sapwood (K s ) and leaf (K l ) hydraulic conductivities of 40 coexisting tree species in a Bolivian dry forest, and examined associations with functional stem and leaf traits and indices of species' drought (dry-season leaf water potential) and shade (juvenile crown exposure) tolerance.• Hydraulic properties varied across species and between life-history groups (pioneers vs shade-tolerant, and deciduous vs evergreen species). In addition to the expected negative correlation of K l with drought tolerance, we found a strong, negative correlation between K l and species' shade tolerance. Across species, K s and K l were negatively correlated with wood density and positively with maximum vessel length. Consequently, drought and shade tolerance scaled similarly with hydraulic properties, wood density and leaf dry matter content. We found that deciduous species also had traits conferring efficient water transport relative to evergreen species.• Hydraulic properties varied across species, corresponding to the classical tradeoff between hydraulic efficiency and safety, which for these dry forest trees resulted in coordinated drought and shade tolerance across species rather than the frequently hypothesized trade-off.

Trait-mediated assembly processes predict successional changes in community diversity of tropical forests

“…Additionally, we found that average species survival was greater for species with high LDMC values. Like WSG, high LDMC is associated with conservative resource use strategies and drought resistance (34,36,37). Our study sites are closed canopy midsuccessional and old-growth stands with low light availability, which may favor persistence of species with high LDMC and WSG that can avoid mortality by withstanding low resource availability.…”

“…SLA represents a major axis of variation between rapid resource acquisition for species with high SLA vs. conservative strategies with low tissue turnover for species with low SLA (32,35). Species with high LDMC have lower leaf protein and reduced ability to exploit resource-rich environments but better performance under low resources and drought (7,34,36,37). WSG is associated with a tradeoff between rapid growth rates for species with low WSG and high structural support and resistance to natural enemies for species with high WSG (9,33).…”

Contrasting taxonomic and functional responses of a tropical tree community to selective logging

“…These trait shifts underline the need to cautiously manage the rate of conversion to these habitats, especially if we consider that they may be reinforced with subsequent cutting cycles in areas that are already functionally degraded (Foley et al 2007). In particular, the lower wood density and leaf toughness and greater leaf-nutrient concentrations suggest that communities in logging gaps may have reduced capacities for carbon storage, drought tolerance and increased palatability to predators (Hurokawa, Peltzer & Wardle 2010;Markesteijn et al 2011). The potential cascading results to other trophic levels might be illustrated by an analysis of reproductive traits pertinent to animal communities (e.g.…”

Partitioning hydraulic resistance in Sorghum bicolor leaves reveals unique correlations with stomatal conductance during drought

“…In mesic systems where drought is typically moderate, minimising r * OLV and maximising the efficiency of water transport through the xylem to maintain hydrated cells should be advantageous. Indeed, within many ecosystems fast-growing species often have the highest stem hydraulic conductance (Brodribb and Feild 2000;Markesteijn et al 2011). In xeric systems where competition for water may not be as important as tolerating long periods of drought, conserving water may be advantageous to growth and survival (Fernández and Reynolds 2000).…”