The impact of land-use change on floristic diversity at regional scale in southern Sweden 600 BC–AD 2008

[摘要] This study explores the relationship between land-use and floristicdiversity between 600 BC and AD 2008 in the uplands of southern Sweden. Weuse fossil pollen assemblages and the Regional Estimates of VegetationAbundance from Large Sites (REVEALS) model to quantitatively reconstructland cover at a regional scale.Floristic richness and evenness areestimated using palynological richness and REVEALS-based evenness,respectively. We focus on the period AD 350 to 750 to investigate the impactof an inferred, short-lived (< 200 yr) period of land-useexpansion and subsequent land abandonment on vegetation composition andfloristic diversity. The observed vegetation response is compared to thatrecorded during the transition from traditional to modern land-usemanagement at the end of the 19th century. Our results suggest thatagricultural land use was most widespread between AD 350 and 1850, whichcorrelates broadly with high values of palynological richness. REVEALS-basedevenness was highest between AD 500 and 1600 which indicates a more equalcover among taxa during this time interval. Palynological richness increasedduring the inferred land-use expansion after AD 350 and decreased during thesubsequent regression AD 550–750, while REVEALS-based evenness increasedthroughout this period. The values of palynological richness during the lastfew decades are within the range observed during the last 1650 yr.However, REVEALS-based evenness shows much lower values during the lastcentury compared to the previous ca. 2600 yr, which indicates that thecomposition of present-day vegetation is unusual in a millennialperspective. Our results show that regional scale changes in land use havehad clear impacts on floristic diversity in southern Sweden, with avegetation response time of less than 20 to 50 yr. We show the importanceof traditional land use to attain high biodiversity and suggest thatecosystem management should include a regional landscape perspective.

[学科分类] 地球化学与岩石