Changes in south-Swedish vegetation composition over the last 200 years as described by species-specific indicator and trait values and documented by museum and literature records

Abstract

Vascular plant observances were compiled for 10 well-documented parishes in Scania, southernmost Sweden, from published floras, herbarium specimens, modern inventories, and a large citizen-science database to provide decade-level presence/absence data of species throughout the period 1800–2020. Species-specific plant traits and ecological indicator values were then used to examine functional and ecological changes based on the species composition, as well as the performance of particular vegetation types. The results were generally congruent among the 10 parishes, and indicate that several of the most important drivers of recent floristic changes, including climate changes, woody encroachment, and soil chemistry alterations have in fact acted continuously and concerted for more than a century. Floristic composition has shifted in favor of species with an affinity to higher N and P levels, as well as species which are generally more long-lived and competitive. Additionally, species less favored by grazing/mowing, and with lower demand for sunlight and moisture have increased. However, several of these trends appear to have accelerated over the past 50 years, and so has the increase of the proportion of alien invasive species in the flora. Species favored by climatic warming have also increased, at least since the 1970’s. The flora of different parts of the province has become more homogenous over time, indicating a loss of biodiversity at the regional, but not at the local scale. Instead, analyses of the biodiversity relevance, associated non-plant species and ecosystem services such as nectar production provided by the flora, suggest that local biodiversity is likely to have increased. The study demonstrates that even highly fragmented data, if compiled from a multitude of sources spanning centuries, may reveal congruent temporal changes in both biodiversity, ecosystem functions and ecological drivers and provide a historic context for monitoring recent and future changes.