Holocene vegetation change and its correlates in fennoscandia

Abstract

Climatic and anthropogenic legacy has differently impacted vegetation and its community composition. To determine the extent and origin of changes across Fennoscandia, representative regions were defined that entailed sufficient spatial and temporal data. Fossil pollen grouped into land cover classes represented Fennoscandian vegetation types, and we focused our analyses and comparisons on woodlands versus anthromes (arable lands and pastures). To determine the correlate(s) of vegetation change, we regressed vegetation types against archaeological (summed probability distributions, representing human impact) and climatic data (mean annual temperature) with Granger causality tests. Additionally, multiple change point analyses were conducted on each single dataset in order to reveal the most significant time points of change. We show that humans have been the strongest correlate to changes in vegetation, especially after the onset of farming, while climate was a strong force in the centuries following the glacial retreat. Indications on the timing of establishment and abandonment of land-use practices such as deforestation in the southern and central regions or of animal husbandry in the North have been found and/or recovered based on the discovered change points. Furthermore, we show an increase in populations already at 7000 BP for the Southeast and sings of human induced homogenisation for the midwestern and central regions. These results taken together present a long view of vegetation change in response to both climate and anthropogenic pressures. The strong advantage of interdisciplinary studies like this one is that it enables us to look at a variety of data in a connected way, putting the current state of Fennoscandian biodiversity into context, and allowing for better projections in the future.