Hydrological conditions explain wood density in riparian plants of south-eastern Australia

1. Wood density is a key plant functional trait which integrates the trade-offs characteristic to riparian plant ecological strategies. Although high-density wood is costly to construct, it confers mechanical stiffness to stems, increasing a plant's capacity to withstand flooding, and also enables increased tolerance to water stress. For riparian plants, fluctuations in soil moisture driven by surface hydrology should therefore be an important driver of variation in wood density. 2. We asked the following questions in the study: (1) Does wood density increase with increasing frequency and magnitude of flood disturbance? (2) Does wood density increase with increasing unpredictability of water availability in the riparian zone? (3) Does dispersion of wood density peak at intermediate levels of hydrological disturbance? 3. We surveyed wood density of dominant species at 15 riparian sites along flow-gauged rivers across south-eastern Australia. Due to the broad range of hydrological variabi...