Effects of salinity on competitive interactions between two Juncus species

• Published in: Aquatic botany Vol. 90; no. 1; pp. 23 - 29
• Main Authors: Greenwood, M.E., MacFarlane, G.R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2009; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Autoecology; Biological and medical sciences; Competition; Conservation, protection and management of environment and wildlife; Environmental degradation: ecosystems survey and restoration; Fundamental and applied biological sciences. Psychology; Invasive species; Juncus; Juncus kraussii; Plants and fungi; Restoration; Salinity; Australia; Competition; Invasive species; Juncus; Restoration; Salinity; Monocotyledones; Interaction; Environmental factor; Juncaceae; Angiospermae; Spermatophyta; Ecological recovery; Aquatic plant
• ISSN: 0304-3770; 1879-1522
• DOI: 10.1016/j.aquabot.2008.05.001

A glasshouse study investigated the effect of salinity on growth and competitive interactions between two closely related rush species, an Australian native ( Juncus kraussii) and an exotic ( J. acutus) species. Overall, both species exhibited decreases in height and total biomass with increasing salinity, although tolerance of J. acutus was marginally lower. We observed asymmetric responses at each salinity, due to the presence of the other species. In fresh-water, co-presence of J. kraussii facilitated the growth (increases in height and total biomass) of J. acutus. However, at 10 ppt salinity direct interspecific competition with J. kraussii adversely affected total biomass of J. acutus. When grown with J. acutus, at 5 ppt but not at 10 ppt, salinity reduced total biomass of J. kraussii. We suggest that interspecific interactions vary with salinity, dependant on relative salinity tolerance of each species. It would appear that in areas receiving regular fresh-water inputs, which reduce salinity stress, J. acutus has the potential to displace J. kraussii.