Light limitation and litter of an invasive clonal plant, Wedelia trilobata, inhibit its seedling recruitment

• Published in: Annals of botany Vol. 114; no. 2; pp. 425 - 433
• Main Authors: Qi, Shan-Shan, Dai, Zhi-Cong, Miao, Shi-Li, Zhai, De-Li, Si, Chun-Can, Huang, Ping, Wang, Rui-Ping, Du, Dao-Lin
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.08.2014
• Subjects: Analysis of Variance; Biological invasions; canopy; China; Clonal Plant Ecology; Clone Cells; Ecological consequences of plant clonality; Germination - drug effects; Germination - radiation effects; Inflorescences; Invasive species; laboratory experimentation; leaf extracts; Light; Plant Extracts - pharmacology; Plant Leaves - drug effects; Plant Leaves - physiology; Plant Leaves - radiation effects; Plant litter; Plant Weeds - drug effects; Plant Weeds - physiology; Plant Weeds - radiation effects; Poultry litter; recruitment; Reproduction, Asexual; Seed germination; Seedling growth; Seedlings; Seedlings - drug effects; Seedlings - growth & development; Seedlings - radiation effects; Seeds; Sexual reproduction; Sphagneticola trilobata; surveys; vegetative propagation; Wedelia - drug effects; Wedelia - physiology; Wedelia - radiation effects; China; seedling recruitment inhibition; reproductive strategy; Clonal plant ecology; invasive plant; biological invasion; Asteraceae; leaf litter; light limitation; Wedelia trilobata
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/aob/mcu075

Background and AimsInvasive clonal plants have two reproduction patterns, namely sexual and vegetative propagation. However, seedling recruitment of invasive clonal plants can decline as the invasion process proceeds. For example, although the invasive clonal Wedelia trilobata (Asteraceae) produces numerous seeds, few seedlings emerge under its dense population canopy in the field. In this study it is hypothesized that light limitation and the presence of a thick layer of its own litter may be the primary factors causing the failure of seedling recruitment for this invasive weed in the field.MethodsA field survey was conducted to determine the allocation of resources to sexual reproduction and seedling recruitment in W. trilobata. Seed germination was also determined in the field. Effects of light and W. trilobata leaf extracts on seed germination and seedling growth were tested in the laboratory.Key ResultsWedelia trilobata blooms profusely and produces copious viable seeds in the field. However, seedlings of W. trilobata were not detected under mother ramets and few emerged seedlings were found in the bare ground near to populations. In laboratory experiments, low light significantly inhibited seed germination. Leaf extracts also decreased seed germination and inhibited seedling growth, and significant interactions were found between low light and leaf extracts on seed germination. However, seeds were found to germinate in an invaded field after removal of the W. trilobata plant canopy.ConclusionsThe results indicate that lack of light and the presence of its own litter might be two major factors responsible for the low numbers of W. trilobata seedlings found in the field. New populations will establish from seeds once the limiting factors are eliminated, and seeds can be the agents of long-distance dispersal; therefore, prevention of seed production remains an important component in controlling the spread of this invasive clonal plant.