PHYSIOLOGICAL ECOLOGY - ORIGINAL PAPER Leaf hydraulic vulnerability influences species’ bioclimatic limits in a diverse group of woody angiosperms Chris J. Blackman • Tim J. Brodribb • Gregory J. Jordan Received: 28 July 2010 / Accepted: 23 June 2011 / Published online: 9 July 2011 Ó Springer-Verlag 2011 Abstract The ability of plants to maintain water flow through leaves under water stress-induced tension (asses- sed as the leaf hydraulic vulnerability; P50 leaf ) is intimately linked with survival. We examined the significance of P50 leaf as an adaptive trait in influencing the dry-end dis- tributional limits of cool temperate woody angiosperm species. We also examined differences in within-site vari- ability in P50 leaf between two high-rainfall montane rain- forest sites in Tasmania and Peru, respectively. A significant relationship between P50 leaf and the 5th per- centile of mean annual rainfall across each species distri- bution was found in Tasmania, suggesting that P50 leaf influences species climatic limits. Furthermore, a strong correlation between P50 leaf and the minimum rainfall availability was found using five phylogenetically inde- pendent species pairs in wet and dry evergreen tree species, suggesting that rainfall is an important selective agent in the evolution of leaf hydraulic vulnerability. Greater within-site variability in P50 leaf was found among domi- nant montane rainforest species in Tasmania than in Peru and this result is discussed within the context of differences in spatial and temporal environmental heterogeneity and parochial historical ecology. Keywords Adaptation  Functional traits  Hydraulic dysfunction  Water stress  Angiosperms Introduction The habitat preferences of species are often explained by invoking functional characteristics or traits that provide competitive advantages under certain environmental con- ditions. Functional traits are attributes that positively influence establishment, survival and/or reproduction, and are usually considered adaptive if the expression of trait- states correlates with variation in natural environments (Ackerly 2003). While many morphological and physio- logical traits change systematically along global and regional environmental gradients (Cavender-Bares et al. 2004; Wright et al. 2004), these traits are often secondary correlative indicators of function, and do not necessarily reflect direct adaptation to specific environmental stress. Leaf mass per unit area (LMA), for example, is an inte- grated functional trait that varies across broad environ- mental gradients (Reich et al. 1999). However, the functional relationship between LMA and specific envi- ronmental conditions such as aridity appears to be indirect and more likely reflects the need to protect long-lived leaves from a variety of damage types, especially under resource-poor conditions (Jordan et al. 2005; Turner 1994). An alternative to collecting large quantities of data for indirect functional traits is quantification of key functional traits that reflect direct adaptation to specific environmental stress. Such traits should exhibit a more quantitative rela- tionship with certain plant ecological strategy potentially allowing the likely impact of specific environmental changes on plant function and community dynamics to be predicted (McGill et al. 2006). In particular, traits that have Communicated by Frederick Meinzer. Electronic supplementary material The online version of this article (doi:10.1007/s00442-011-2064-3) contains supplementary material, which is available to authorized users. C. J. Blackman (&)  T. J. Brodribb  G. J. Jordan School of Plant Science, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia e-mail: cblackma@utas.edu.au 123 Oecologia (2012) 168:1–10 DOI 10.1007/s00442-011-2064-3