Difference in phenology of Lupinus polyphyllus over a latitudinal gradient
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. L. polyphyllus occurs from the north to the south of Europe except for the Mediterranean areas of the Iberian Peninsula and Italy. The timing of flowering, temperature dependency of flowering and fruiting, and the performance (canopy height, seed production) was studied across a 2 000 km latitudinal gradient from Luxembourg to Umeå in Northern Sweden (49°38' N – 63°49 N). Twenty-two sites were sampled, and parameters were estimated from 220 individual plants in total. The variation in phenology of flowering and fruiting was estimated using >1600 digital images of inflorescences taken weekly at each site. The day of the year at which different phenological phases (first open flower; half the length of the inflorescence has open flowers; first black ripe pod appears) were reached, increased by 1.3–1.8 days per degree latitude, whereas the growing degree days (GDD) required for these phenological phases decreased 5–16 GDD per degree latitude. It is expected that the invasion of L. polyphyllus will further increase in the northern part of Europe over the next decades due to climate warming. For the control of L. polyphyllus in countries with a large latitudinal extent, the mowing date should shift by approximately one week per 500 km at sites with similar elevations. Therefore, lower latitude populations should be mowed earlier to prevent dispersal of ripened seed.
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Ludewig K, Klinger YP, Donath TW, Bärmann L, Eichberg C, Thomsen JG, Görzen E, Hansen W, Hasselquist EM, Helminger T, Kaiskog F, Karlsson E, Kirchner T, Knudsen C, Lenzewski N, Lindmo S, Milberg P, Pruchniewicz D, Richter E, Sandner TM, Sarneel JM, Schmiede R, Schneider S, Schwarz K, Tjäder Å, Tokarska-Guzik B, Walczak C, Weber O, Żołnierz L, Eckstein RL (2022) Phenology and morphology of the invasive legume Lupinus polyphyllus along a latitudinal gradient in Europe. NeoBiota 78, 185–206.