Challenges in the presentation and analysis of plant-macrofossil stratigraphical data

Birks, H. John B.

doi:10.1007/s00334-013-0430-2

Cited by 48 publications

(48 citation statements)

References 226 publications

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“…For historical reasons and by convention, present is taken as AD 1950. Lohne, Mangerud, and Birks () estimated precise calibrated ages BP for the Younger Dryas boundaries in the Kråkenes sequence: Allerød (AL)–Younger Dryas (YD) 12,737 ± 31 cal yr BP; YD–Holocene (H) 11,546 ± 58 cal yr BP. The base of the sequence is dated to ca.…”

Section: Methodsmentioning

confidence: 99%

“…To reconstruct past biomes or investigate changes in environment based on changes in the macrofossil assemblages, we used community‐weighted means (CWM; Diekmann, ). Macrofossil assemblages do not directly reflect plant communities (Birks, ), so in this paper we refer to the means as assemblage‐weighted (AWM). Estimates for a biome or an environmental variable are derived by weighted average calibration (ter Braak, ).…”

Section: Methodsmentioning

confidence: 99%

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

Felde

Birks

2019

J Vegetation Science

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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.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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

Felde

Birks

2019

J Vegetation Science

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“…Variation in macrofossil abundance can often be interpreted as changes in past plant abundances (Birks, 2003(Birks, , 2014, but infrequent occurrences of macrofossil taxa likely reflect changes in source area (e.g. fluvial input vs. slope input) and a degree of serendipity in detection, with absence particularly hard to interpret.…”

Section: The Capacity Of Sedadna To Provide a Record Of Past Floramentioning

confidence: 99%

Sedimentary ancient DNA from Lake Skartjørna, Svalbard: Assessing the resilience of arctic flora to Holocene climate change

et al. 2015

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Reconstructing past vegetation and species diversity from arctic lake sediments can be challenging because of low pollen and plant macrofossil concentrations. Information may be enhanced by metabarcoding of sedimentary ancient DNA ( sedaDNA). We developed a Holocene record from Lake Skartjørna, Svalbard, using sedaDNA, plant macrofossils and sediment properties, and compared it with published records. All but two genera of vascular plants identified as macrofossils in this or a previous study were identified with sedaDNA. Six additional vascular taxa were found, plus two algal and 12 bryophyte taxa, by sedaDNA analysis, which also detected more species per sample than macrofossil analysis. A shift from Salix polaris-dominated vegetation, with Koenigia islandica, Ranunculaceae and the relatively thermophilic species Arabis alpina and Betula, to Dryas octopetala-dominated vegetation ~6600–5500 cal. BP suggests a transition from moist conditions 1–2°C warmer than today to colder/drier conditions. This coincides with a decrease in runoff, inferred from core lithology, and an independent record of declining lacustrine productivity. This mid-Holocene change in terrestrial vegetation is broadly coincident with changes in records from marine sediments off the west coast of Svalbard. Over the Holocene sedaDNA records little floristic change, and it clearly shows species persisted near the lake during time intervals when they are not detected as macrofossils. The flora has shown resilience in the presence of a changing climate, and, if future warming is limited to 2°C or less, we might expect only minor floristic changes in this region. However, the Holocene record provides no analogues for greater warming.

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“…Macrofossil analysis can also cover lake species persisting for many years on vegetative reproduction only (Birks, 2001). The record is continuous, although some bias in reconstruction must be taken into account (Birks, 2014). The reconstruction of lake-level fluctuation in deeper lakes is best archived using a transect of multiple cores recovered from a gently sloping littoral part of the lake (Digerfeld, 1986;Hannon & Gaillard, 1997).…”

Section: Evaluation Of Palaeolimnological Reconstruction Methodsmentioning

confidence: 99%

“…Palaeolimnology is a wellestablished method to approach these questions (Battarbee, 1999;Davidson et al, 2013) because the limitations of the methods are now well understood (e.g. Davidson et al, 2013;Birks, 2014) and multiproxy analyses can be used to reconstruct past macrophyte and biotic communities. Particularly effective are comparative studies of palaeo-records and historical archives (e.g.…”

Section: Introductionmentioning

confidence: 99%

Disentangling natural and anthropogenic drivers of changes in a shallow lake using palaeolimnology and historical archives

et al. 2015

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Shallow lakes are susceptible to catastrophic regime shifts characterised by the presence or absence or macrophytes. However, the long-term controls on macrophyte succession in shallow lakes are incompletely understood. To investigate this, we analysed multiple sediment proxies in Lake Rotcze (Eastern Poland), a small, shallow and densely macrophyte-covered lake to (1) reconstruct the 'reference conditions' (sensu WFD) and development of the lake in recent centuries, (2) compare historical evidence with the sedimentary record, and (3) identify the natural and anthropogenic drivers of macrophyte succession. Before the twentieth century, conditions in the lake may be referred to as 'reference conditions'. Subsequently forest clearance in the catchment resulted in lower water transparency, but concurrent catchment drainage lowered water levels and increased macrophyte development. Since 1950 elevated nutrient supply and climatically driven increases in water levels led to the deterioration of water transparency and partial macrophyte withdrawal. At the end of the twentieth century lake-level drawdown led to low phytoplankton biomass and clear water creating a novel ecosystem where macrophytes invade the whole lake. These patterns suggest that both natural and anthropogenically induced water level fluctuations have been critical drivers of macrophyte development.

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Challenges in the presentation and analysis of plant-macrofossil stratigraphical data

Cited by 48 publications

References 226 publications

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

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

Sedimentary ancient DNA from Lake Skartjørna, Svalbard: Assessing the resilience of arctic flora to Holocene climate change

Disentangling natural and anthropogenic drivers of changes in a shallow lake using palaeolimnology and historical archives

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