The Effect of Competition Between Plants on the Treatment Performance of Stormwater Biofiltration Systems
(2008 – current)
Biofiltration systems are low-energy treatment technologies that are becoming increasingly popular for stormwater management. The vegetation used in a biofilter enhances the pollutant removal performance, however, different plant species vary in their contribution to pollutant removal.
Competition between plants in biofilters is an issue which can alter the community composition and affect treatment performance. Lomandra longifolia and Carex appressa are two plants frequently used in biofilters and observations of existing systems have shown that Lomandra replaces the Carex plants in the planted community over time. Unfortunately, Lomandra longifolia has poor capabilities for extracting pollutants from stormwater, whereas Carex appressa is an excellent choice for this task. Over time, this shift in community composition may leave a biofilter with a monoculture of Lomandra longifolia and a diminished capacity for filtering stormwater. An improved understanding of how plants suitable for use in biofilters interact with each other is required to ensure that biofilters vegetated with mixed species will function effectively. Therefore, the aim of this project is to quantify how competitive effects between these two plants alter the community composition of a biofilter and thus the stormwater treatment capacity.