Preston, Katherine , Cornwell, William , DeNoyer, Jeanne .
Wood density and vessel traits as distinct correlates of ecological strategy in 51 California coast range angiosperms.
WOOD density and vessel characteristics are functionally interrelated, yet they may have distinct ecological associations. In a comparative study of 51 angiosperm species, we examined patterns of covariation among wood density, average vessel lumen area, and vessel density (#/mm2), and ecological correlates of each trait. We had three primary goals: (1) to decompose variation in wood density into variation in vessel traits; (2) to test existing hypotheses about ecological trends in wood density, vessel area, and vessel density, examining each trait individually; and (3) to examine the evolutionary history of these functionally interdependent characters by quantifying the morphological similarity among close relatives (phylogenetic signal) and correlated evolution among wood and vessel traits. We sampled the most common woody angiosperms at Jasper Ridge Biological Preserve, San Mateo Co, California, USA. Habitats included riparian forest, evergreen broadleaf forest, oak woodland, open scrubland, and chaparral. We considered factors related to site (soil water, insolation), growth habit (maximum height, canopy position), and site plus morphology and physiology (minimum leaf water potential). Wood density ranged only narrowly and was negatively associated with both vessel lumen area and vessel density. Vessel traits ranged widely and were themselves inversely correlated, generating diverse vessel size and density combinations within the narrow range of wood density. Each trait had a distinct pattern of ecological correlation: wood density was most strongly associated with soil water; vessel traits showed opposing relationships with plant height. Wood density and vessel traits thus appear to describe two distinct ecological axes among the species in our study. We also found evidence for inversely correlated evolutionary change in vessel traits, which was only weakly associated with changes in wood density. This result suggests that a range of ecologically significant vessel strategies may evolve somewhat independently of wood density per se.[c.e.:srb]
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1 - Stanford University, Biological Sciences, 371 Serra Mall, Stanford, California, 94305, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 10:30 AM