Cortaderia selloana seed germination under different ecological conditions

Biological invasions are causing the extinction of native species and modifying ecosystem functions. Invasion success depends, among other factors, on the biological attributes of the invaders and the abiotic characteristics of the recipient community. Cortaderia selloana is a gynodioecious perennial grass native to South America which is considered invasive worldwide. It is known that seedlings of this species tolerate a wide range of environmental conditions. However, the abiotic factors that may favour its seed germination have not been studied in much detail. For this reason, we conducted an array of germination tests with different degrees of shading, soil textures and water availability. Although C. selloana usually grows in disturbed sites where light is highly available, we found that seed germination was higher under shaded conditions than under 100% light. Seed germination was higher in sandy soil textures and decreased in soils which contained increased levels of clay. Mature C. selloana plants have been reported to tolerate water stress, yet we found that the shortage of water availability constrained seed germination to approximately 60%. Overall, C. selloana seeds seem to germinate under a wide range of environmental conditions, yet germination rate can be improved under shading, high levels of sand and with high water availability. (c) 2007 Published by Elsevier Masson SAS.