Impact of Lupinus polyphyllus on native biodiversity
Lupinus polyphyllus (Fabaceae: EPPO Observation List) is a short-lived perennial nitrogen-fixing herb, native to North America. It is invasive in a number of EPPO countries as well as Australia and New Zealand. Lupinus polyphyllus can form dense stands (70% cover) and thrive in a variety of open habitats. In Finland, it frequently occurs in nutrient-poor, well-drained and ruderal habitats. In the invaded range, L. polyphyllus is associated with declines in both vascular plant and insect species richness in various open habitats such as grasslands, sparse forests, road verges and wastelands in Northern Europe. A study was conducted to assess the impact of L. polyphyllus on native biodiversity in the Lahti area, southern Finland, where L. polyphyllus was first recorded in 1936. In total, 18 gravelly or sandy semi-natural grassland sites were selected, which were partially invaded by L. polyphyllus and for which it was possible to estimate time since invasion. The sites were divided as: 7 sites invaded in the last 5 years or less; 7 sites invaded 10 years ago; 4 sites invaded for 15 years or more. At each site, the plant community was recorded using 10 randomly placed 1m2 quadrats in the invaded and uninvaded vegetation from mid-July to early August 2018. All plants were identified to species level and the abundance of each species was estimated as the percentage cover of a species. L. polyphyllus was associated with lower species richness in invaded plant communities but this effect did not change with time since invasion. To conclude, L. polyphyllus can reduce plant species richness, but the ecological impact might not dramatically change or accumulate with time since invasion.
A new global distribution map has been added to EPPO Global Database: https://gd.eppo.int/taxon/LUPPO/distribution.
Sources
Prass M, Ramula S, Jauni M, Setää H, Kotze DJ (2021) The invasive herb Lupinus polyphyllus can reduce plant species richness independently of local invasion age. Biological Invasions. https://www.doi.org/10.1007/s10530-021-02652-y