Leaf traits and fog harvest potential in xerophytic plants

Abstract

Fog is an important water resource for ecosystems in arid zones, where plants play a key role in fog harvest. Studies on adaptive traits for fog interception have been addressed mainly in terms of forest tree species, considering stand distribution, shoot architecture, and leaf inclination angle, with less emphasis on leaf surface traits. Moreover, xerophytic shrubs, whose role in fog capture is only recently being recognized, have been barely studied in this regard. We analyzed leaf traits, and fog throughfall in 11 and 12 xerophytic species of two sites (xeric and mesic) in semi-arid northern-central Chile, with a combination of laboratory and field experiments. According to principal component analyses, in the xeric site, leaf water retention capacity was positively associated with fog drip. In the mesic site, hydrophobic leaves dripped less fog water than the hydrophilic ones. The magnitude of the variability depended on the xeric or mesic nature of sites, suggesting a differential adaptation to fog abundance on these sites. Overall, our results show leaf functional traits of xerophytic plants associated to the capacity of fog water capture and retention. The relation between leaf traits and fog harvest is species- specific, since every species is a mixture of different traits that do not necessarily optimize fog harvest. This research opens prospects for the screening of mechanisms and ecosystem services of xerophytes as natural fog catchers.