Grand theft hydro? Stemflow interception and redirection by neighbouring Tradescantia ohiensis Raf. (spiderwort) plants

Abstract

AbstractWhen it rains over vegetation, plants have an opportunity to get a limited supply of freshwater. A portion of rain drains directly to the soil down a plant stem in a hydrologic flux called “stemflow.” For short plants with shallow roots, which provide ground cover for most vegetated ecosystems around the globe (including forest understories), stemflow has rarely been examined although it may be ecologically important. This study investigates how much rainwater is funnelled into stemflow for a perennial herb that can densely populate urban environments, Tradescantia ohiensis Raf., spiderwort), in Savannah, Georgia (USA). Given the stem density of spiderworts (19–31 stems m−2), experiments were conducted to assess whether and how much stemflow can be passively intercepted and diverted by leaves in contact with neighbouring plant stems. Spiderworts' stemflow represented a significant portion (20%–60%) of rain and neighbouring plants intercepted and diverted ~50% of another plants' stemflow. This is the first documentation of stemflow interception and redirection by neighbouring plants, to the authors' knowledge. Because physical contact between plants occurs in various vegetated ecosystems (like lianas in forests), future research on this topic may be merited.