Long‐term changes in regional vegetation cover along the west coast of southern Norway: The importance of human impact

Abstract

Questions How open was the landscape prior to agriculture? Did agriculture start earlier in the south than in the north? How did the vegetation change in different regions after the introduction of agriculture? Location Coast of SW and W Norway. Methods The REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) model is applied for pollen‐based vegetation reconstruction in 19 time windows over the last 9,000 years. Pollen data from 63 sites (lakes and bogs) are compiled and systematically used for data analysis so that the structure of vegetation change in space and time is captured. Results Estimated cover of selected trees, shrubs, Calluna, graminids and herbs indicate a partly open outer coast throughout the Holocene. The highest tree cover is estimated for 8,200–6,200 cal. BP. Broad‐leaved trees (Fraxinus, Quercus, Tilia and Ulmus) spread from south to north and were present in the whole region at the end of the Mesolithic (5,950 cal. BP). Larger spatial variation in tree cover and a step‐wise reduction in deciduous trees after 5,700 cal. BP is concordant with increases in open‐land taxa indicating human activity. Vegetation changes caused by agriculture are indicated in the very south from ca. 5,950 cal. BP. Distinct human‐induced vegetation changes with spatial differentiation took place from 4,200 to 1,700 cal. BP, when most of the areas earlier covered by deciduous woodland had been transformed to cultivated fields, grasslands and heathlands. Increased Poaceae cover from 1,700 cal. BP probably reflects the expansion of mown meadows in addition to pastures. Conclusions Capturing continuous changes of vegetation structure in space and time elucidates open areas along the western coast prior to the introduction of agriculture. Agriculture started earliest in the very south and spread rapidly along the whole coast prior to the Late Neolithic. Differences within the study area have existed in all time periods, reflecting different land‐use practices adapted to different natural conditions.

Grasslands of Northern Europe and the Baltic States

“…The decline of the megafauna was already in an advanced state by the onset of the Holocene (Barnosky et al 2004). Nonetheless, several palaeoecological studies have found that open vegeta9on persisted throughout the period in the Nordic-Bal9c region (Nielsen et al 2012;Theuerkauf et al 2014;Hjelle et al 2018) and the wider Western Palearc9c (Sommer et al 2011;Holm and Svenning 2014). However, palaeoecological methods have limited power in discrimina9on between open forests with a closed field layer ("savanna") or a mosaic of open grassland patches within dense forests ("forest steppe").…”

Bergkunst på Midt- og Sør-Jæren samt i Dalaneregionen, Rogaland. Motiver, historikk, naturmiljø og tilstand.

“…(og på ytterkysten tilbake i sein-mesolitikum), mens åkerbruket tidligst ekspanderer rundt 2300 f.Kr. Hjelle et al, 2018).…”

Environmental responses to the 9.7 and 8.2 cold events at two ecotonal sites in the Dovre mountains, mid-Norway

“…Today, numerical treatments of large pollen-data sets find regional patterns of vegetation and climate change (e.g. Seppä et al, 2007;Seddon et al, 2015;Hjelle et al, 2018). However, the number of sites may not be crucial for elaborating detailed geographical patterns of these events.…”