Using species attributes to characterize late‐glacial and early‐Holocene environments at Kråkenes, western Norway

Abstract

Aim We aim to use species attributes such as distributions and indicator values to reconstruct past biomes, environment, and temperatures from detailed plant‐macrofossil data covering the late glacial to the early Holocene (ca. 14–9 ka). Location Kråkenes, western Norway. Methods We applied attributes for present‐day geographical distribution, optimal July and January temperatures, and Ellenberg indicator values for plants in the macrofossil data‐set. We used assemblage weighted means (AWM) to reconstruct past biomes, changes in light (L), nitrogen (N), moisture (F), and soil reaction (R), and temperatures. We compared the temperature reconstructions with previous chironomid‐inferred temperatures. Results After the start of the Holocene around 11.5 ka, the Arctic‐montane biome, which was stable during the late‐glacial period, shifted successively into the Boreo‐arctic montane, Wide‐boreal, Boreo‐montane, Boreo‐temperate, and Wide‐temperate biomes by ca. 9.0 ka. Circumpolar and Eurasian floristic elements characteristic of the late‐glacial decreased and the Eurosiberian element became prominent. Light demand (L), soil moisture (F), nitrogen (N), and soil reaction (R) show different, but complementary responses. Light‐demanding plants decreased with time. Soil moisture was relatively stable until it increased during organic soil development during the early Holocene. Soil nitrogen increased during the early Holocene. Soil reaction (pH) decreased during the Allerød, but increased during the Younger Dryas. It decreased markedly after the start of the Holocene, reaching low but stable levels in the early Holocene. Mean July and January temperatures show similar patterns to the chironomid‐inferred mean July temperature trends at Kråkenes, but chironomids show larger fluctuations and interesting differences in timing. Conclusion Assigning attributes to macrofossil species is a useful new approach in palaeoecology. It can demonstrate changes in biomes, ecological conditions, and temperatures. The late‐glacial to early‐Holocene transition may form an analogue for changes observed in the modern arctic and in mountains, with melting glaciers, permafrost thaw, and shrub encroachment into tundra.

Postglacial species arrival and diversity buildup of northern ecosystems took millennia

“…3 ). Similarly, Felde and Birks ( 34 ) found highly fluctuating mean trait values at 14.0 to 9.0 cal ka BP based on analyses of 58 taxa recorded as macrofossils in southwestern Norway. This is as expected, given that this was a period with large climate fluctuations through the Late Glacial Interstadial-Stadial Complex ( Figs.…”

Reflections on the Use of Ecological Attributes and Traits in Quaternary Botany

“…As documented above, there is a long history of ecological attributes (including traits) being used in Quaternary botany extending over nearly 120 years. The main use of attributes has been to aid in the reconstruction of past environments such as climate (e.g., Kühl, 2003), soil conditions (e.g., Felde and Birks, 2019), or vegetation (e.g., Zanon et al, 2018). Traits have also been used to investigate taxon responses to past environmental changes (e.g., Lacourse, 2009) or to generate hypotheses about the underlying drivers of past vegetation dynamics (e.g., Iversen, 1960).…”

“…Identifications at the family or genus levels pose problems in the assignment of attribute or trait values to such taxa. Plant macrofossils have the advantage over pollen in that fossil seeds and fruits can often be identified to species level (Birks and Birks, 2000;Birks, 2001Birks, , 2003Birks, , 2014, thereby allowing an effective use of attributes such as indicator values with macrofossil assemblages (e.g., Felde and Birks, 2019). Despite detailed macrofossil identifications, traits have rarely been used in macrofossil studies (Birks, 2014), possibly because of some important limitations of macrofossil data, such as the abundance of zero values, mixed (nominal, qualitative, and quantitative) data types, and problems of false absences (=false negatives; Birks, 2014).…”

“…They have been used primarily with macrofossil assemblages where species-level identifications are often possible (Birks, 2001(Birks, , 2013(Birks, , 2014. EIVs have been used to infer local-scale conditions of light, soil reaction (=calcium and hence pH: Schaffers and Sýkora, 2000), soil nitrogen (=soil fertility or aboveground productivity: Hill and Carey, 1997), and soil moisture from late-glacial macrofossil assemblages (e.g., Mortensen et al, 2011;Felde and Birks, 2019), from assemblages associated with archeological sequences (e.g., Wasylikowa, 1978;Wasylikowa et al, 1985;Wasylikowa, 1989;Cappers, 1993Cappers, /1994, and from fossil bryophyte assemblages (e.g., Odgaard, 1981;Jonsgard and Birks, 1995;Lamentowicz et al, 2015;Zechmeister et al, 2019).…”

Mire plant diversity change over the last 10,000 years: Importance of isostatic land uplift, climate and local conditions

“…Moisture levels, light conditions, reaction (pH), temperature and nutrient availability have been highlighted as important drivers (or consequences) of mire succession and diversity changes (Laine et al., 2018; Tuittila et al., 2007). Because it is not always possible to measure the relevant environmental parameters, indicator values, such as Ellenberg indicators (EIVs; Ellenberg et al., 1991), that use plants' known environmental preferences to make inferences about site conditions provide a useful tool in plant ecology and palaeoecology (Diekmann, 2003; Felde & Birks, 2019).…”