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

Daniel Fredh (1) , Anna Brostrom (2) , Mats Rundgren (1) , Per Lageras (3) , Florence Mazier (4) , Lovisa Zillen (1)

1 Department of Geology
2 Skane University Hospital [Lund]
3 Swedish National Heritage Board
4 GEODE - Géographie de l'environnement

This study explores the relationship between landuse and floristic diversity between 600BC and AD2008 in the uplands of southern Sweden. We use fossil pollen assemblages and the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model to quantitatively reconstruct land cover at a regional scale. Floristic richness and evenness are estimated using palynological richness and REVEALS-based evenness, respectively. We focus on the period AD350 to 750 to investigate the impact of an inferred, short-lived (<200 yr) period of land-use expansion and subsequent land abandonment on vegetation composition and floristic diversity. The observed vegetation response is compared to that recorded during the transition from traditional to modern land-use management at the end of the 19th century. Our results suggest that agricultural land use was most widespread between AD350 and 1850, which correlates broadly with high values of palynological richness. REVEALS-based evenness was highest between AD500 and 1600 which indicates a more equal cover among taxa during this time interval. Palynological richness increased during the inferred land-use expansion after AD350 and decreased during the subsequent regression AD550-750, while REVEALS-based evenness increased throughout this period. The values of palynological richness during the last few decades are within the range observed during the last 1650 yr. However, REVEALS-based evenness shows much lower values during the last century compared to the previous ca. 2600 yr, which indicates that the composition of presentday vegetation is unusual in a millennial perspective. Our results show that regional scale changes in land use have had clear impacts on floristic diversity in southern Sweden, with a vegetation response time of less than 20 to 50 yr. We show the importance of traditional land use to attain high biodiversity and suggest that ecosystem management should include a regional landscape perspective.

Mots clés: Floristic diveresity; land-use change; REVEALS; Sweden

Domaines: Géographie

Daniel Fredh, Anna Brostrom, Mats Rundgren, Per Lageras, Florence Mazier, et al.. The impact of land-use change on floristic diversity at regional scale in southern Sweden 600 BC-AD 2008. Biogeosciences, 2013, 10, pp.3159-3173. ⟨halshs-00959871⟩