Ecohydrology of Sphagnum moss hummocks: mechanisms of capitula water supply and simulated effects of evaporation

• DOI: 10.1002/eco.1313
• Publication Date: 2012-09-27T06:21:11Z
• Authors: Colin P. R. McCarter; Jonathan S. Price
• Keywords: Sphagnum

ABSTRACT Maintaining sufficiently high surface (capitula) soil‐water pressures to avoid the draining of hyaline cells (desiccation) is paramount hummock‐forming Sphagnum species' survival; however, mechanisms capitula water supply are poorly understood. This study investigates how hydraulic characteristics different species ( fuscum , rubellum and magellanicum ) contribute desiccation avoidance, on basis numerical simulations parameterized with measured soil for each species. Although having similar unsaturated conductivity values, upper 5 cm S. retains ~20% less moisture under tension than ; in fact, average retained slightly more . Hydrus‐1D was used simulate daytime nighttime conditions over a 7‐day period, where daily potential evaporation 4 mm, explore governing controlling capitula. The showed that were able retain content prevailing simulated demand sustain pressure heads (greater −100 cm), whereas could not prevent depressurization concomitant its layer. A number same size pores observed all species; there lower pore connectivity leading Contrary previous studies, results this indicate it only retention but also allows hummock thrive above table. Copyright © 2012 John Wiley & Sons, Ltd.