A botanical attraction
Fritillaria meleagris (Swedish Kungsängslilja) is blooming in thousands on the King’s meadow in Uppsala, Sweden, every year in May and has been studied in this location for over 80 years. In my interview with Håkan Rydin, emeritus professor at Uppsala University, we explore how this popular plant that is native to the Mediteranian and Caucasian region has ended up in Uppsala, why it has become so popular and why the king’s meadow and Fritillaria have been of interest for research.
Serendipity on the King’s meadow
Fritillaria meleagris is a plant species native to the Mediteranian and Caucasian region. It was introduced to Sweden in the 18th century and initially grown in the botanical garden of Uppsala. With organic waste from the botanical garden, it must have come to the King’s meadow where it has been thriving since then and established a very stable population of about 1 million plants. Håkan Rydin explains that while bulb reproduction is efficient, it is rather slow for building a population of the size as we see it today. Therefore, it is assumed that seed dispersal has had a significant contribution to the establishment of the population on the King’s meadow. Fritillaria seeds are numerous and germinate well after a cold winter. Furthermore, floading helps the seeds to spread as they float on water and then germinate in a new place.
Why does flower number vary from year to year?
Already the Swedish botanist Carl von Linné noted its copious nature in the 18th century when the population was establishing on this field south of the city of Uppsala. It started to attract interest from scientists like him as well as common people who would pick it for decorative purposes. Since the 1940th the number of flowering Fritillaria meleagris plants has been counted in six squares of 10x10m size. Over these 80 years this number has been fairly stable in a long-term perspective, but strongly fluctuated from year to year. As we discuss in the interview, there was a peak of flowers between 1980 and 1990 where the numbers went up from 1695 to 4454 flowers within 3 years. However, correlations with weather data and precipitation have not been able to explain that sudden increase and the decrease back to 1960 flowers in the following three years. Today we have about the same number of Fritillaria flowers in the measured zone as compared to 80 years ago, and even today we see similar, non-explained yearly variations.
Factors that can explain why the number of flowering plants varies from year to year are changes in the total number of plants as plants die and new ones emerge, as well as differences in flowering of the existing plants. About 30% of the plants have been observed to bloom, with some variation. However, little is know about whether it’s the same plant that flowers from one year to the other or whether there are different ones.
The mystery of the white morphs
Interestingly, 5 to 10% of all Fritillaria meleagris plants, both on the King’s meadow and also in other parts of Europe, do not show the purple chequered flowers, but have white flowers. The percentage of the white flower is surprisingly stable. It’s a genetic color morph that has equal success in pollination, seed production and germination as their purple equivalents. F. meleagris is mostly pollinated by bumblebees and the white and purple ones seem to have similar attractiveness. Why the white morphs are so stable over time in their percentage is yet an unexplained phenomenon, especially given that they were preferentially picked in the beginning of the 20th century.
The King’s meadow – a historical semi-natural grassland
The King’s meadow, a semi-natural grassland, is generally a very interesting study area. The rising land (isostatic rebound) in Sweden has brought the meadow above sea-level only about 700 years ago and since the medieval times it has been used for hay production for agricultural purposes. It is therefore an important remnant of Swedish agricultural history. Farmers would use the meadow to produced hay used for feeding cows, of which the manure would be used for fertilization of arable fields to grow crops. Since the 1940th when modern agriculture developed, introducing mechanization and chemical fertilization, this type of agricultural practice was ended and biodiversity in these grasslands changed. Also hay was moved back in the times rather for quantity than quality and taken earlier during the year, whereas today meadows are mowed later in the season.
How mowing at the right moment favours biodiversity
Fritillaria is an indicator how well the traditional meadow has been preserved in modern times. Not much decline in biodiversity has been observed on the King’s meadow since the 1940th when agricultural practices changed. The fact that fertilization and draining were avoided on this meadow have kept the quality of the seminatural grassland intact. Furthermore mowing has been voluntarily done after seedset of flowers to conserve their spread and development. From an ecological point, mowing favours small plants with lower competitive ability such as fritillaria. Taking away the longer grass limits shading of the smaller plants that have their leaves close to the ground. Also, on meadows where hay is harvested, soils get depleted from nitrogen. This in turn increased the biodiversity of these meadows. Especially on dry meadows the biodiversity of flowering plants is favored. In comparison, the King’s meadow is rather wet and does not contain many rare plant species.
It’s time for a visit!
If you are close to Uppsala, pay the King’s meadow a visit in May. Uppsala university has made efforts to promote interest for biodiversity and arranged a voting where you can guess how many flowering Fritillaria meleagris there are in the 6 10x10m plots previously mentioned. In the podcast interview Håkan Rydin shares some tips on how to make educated guesses on this numbers. Pass by the King’s meadow, make your guess and take part in the voting.
If you are living elsewhere in Sweden, you can use Artportalen in order to find out where F. meleagris is flowering close to you. More information about this species can also be obtained from the virtual Flora at the Swedish Museum of Natural History.