Clonal integration increases relative competitive ability in an invasive aquatic plant

Area of Science:

• Ecology
• Plant Biology
• Invasive Species Management

Background:

• Connected ramets in clonal plants improve individual performance.
• The competitive advantage of clonal integration in mixed-species communities is not well-established.

Purpose of the Study:

• To investigate if clonal integration enhances the competitive ability of invasive aquatic plants in mixed communities.
• To test this hypothesis using Pistia stratiotes and Eichhornia crassipes.

Main Methods:

• Ramets of Pistia and Eichhornia were grown in monoculture or mixed stands.
• New ramets (offspring) were either connected or severed (fragmented).
• Offspring production and dry mass were measured after 6 weeks.

Main Results:

• Fragmentation reduced the competitive ability of Pistia, but not Eichhornia.
• Pistia accumulated significantly less dry mass when fragmented in mixed stands.
• Pistia offspring were consistently smaller than Eichhornia offspring.

Conclusions:

• Clonal integration can indeed increase competitive ability in certain clonal species.
• Integration may help smaller offspring (Pistia) compete with larger ones (Eichhornia).
• Reduced fragmentation may favor the production of numerous, smaller offspring in clonal plants.