Abiotic constraints and biotic resistance control the establishment success of Humulus scandens
Humulus scandens (Cannabaceae: EPPO List of Invasive Alien Plants) is an annual climber vine originating from East Asia. Within the EPPO region, it is only recorded in France, Hungary and Italy where it showed invasive behavior. H. scandens reproduces by wind and water dispersed seeds. Preferring moist soils, it can form dense stands in floodplains and along stream banks and lake shores, but can also thrive in disturbed areas such as roadsides and urban lots. It can be found in full sun or shade. In the current study, the authors set out to determine what is the influence of increasing resource availability on the performance and plasticity of H. scandens compared to a functionally similar co-occurring native species? A survey was conducted along the River Gardon (Southern France) where detailed measurements of the population along with soil characteristics, light availability, and vegetation cover was taken. A greenhouse experiment was conducted to compare the performance of H. scandens to Galium aparine along a gradient of increasing water and nitrogen availability. H. scandens performed better and showed higher plasticity in plant height than G. aparine under increased resource availability while the biomass did not differ in the lower part of the resource gradient. The study shows that by combining field and experimental studies at different life stages, a more complete understanding of how ecological filters shape successful invasions in the course of the plant life cycle can be gained.
Sources
Fried G, Mahaut L, Pinston A, Carboni M (2017) Abiotic constraints and biotic resistance control the establishment success and abundance of invasive Humulus japonicus in riparian habitats. Biological Invasions. DOI: 10.1007/s10530-017-1533-y.