title: Leaf hydraulic vulnerability to drought is linked to site water availability across a broad range of species and climates.
abstract: OBJECTIVE
  Vulnerability of the leaf hydraulic pathway to water-stress-induced dysfunction is a key component of drought tolerance in plants and may be important in defining species' climatic range. However, the generality of the association between leaf hydraulic vulnerability and climate across species and sites remains to be tested.
  
  
  METHODS
  Leaf hydraulic vulnerability to drought (P50leaf, the water potential inducing 50 % loss in hydraulic function) was measured in a diverse group of 92 woody, mostly evergreen angiosperms from sites across a wide range of habitats. These new data together with some previously published were tested against key climate indices related to water availability. Differences in within-site variability in P50leaf between sites were also examined.
  
  
  RESULTS
  Values of hydraulic vulnerability to drought in leaves decreased strongly (i.e. became more negative) with decreasing annual rainfall and increasing aridity across sites. The standard deviation in P50leaf values recorded within each site was positively correlated with increasing aridity. P50leaf was also a good indicator of the climatic envelope across each species' distributional range as well as their dry-end distributional limits within Australia, although this relationship was not consistently detectable within sites.
  
  
  CONCLUSIONS
  The findings indicate that species sorting processes have influenced distributional patterns of P50leaf across the rainfall spectrum, but alternative strategies for dealing with water deficit exist within sites. The strong link to aridity suggests leaf hydraulic vulnerability may influence plant distributions under future climates.
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, NSW 2753, Australia c.blackman@uws.edu.au.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Blackman
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia.
authors.forename: Sean M
authors.initials: SM
authors.lastname: Gleason
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia.
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Cook
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia.
authors.forename: Claire
authors.initials: C
authors.lastname: Laws
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Westoby
mesh_terms: D001315:Australia; D002980:Climate; D055864:Droughts; D017753:Ecosystem; D019684:Magnoliopsida / Q000502:physiology*; D010568:Peru; D018515:Plant Leaves / Q000502:physiology*; D018526:Plant Transpiration; D014197:Trees / Q000502:physiology; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water
keywords: Leaf hydraulic vulnerability; aridity; climate change; drought; interspecific variation; rainfall; species distribution