A 12,000-yr pollen record off Cape Hatteras — Pollen sources and mechanisms of pollen dispersion

Large Scale Anthropogenic Reduction of Forest Cover in Last Glacial Maximum Europe

“…The second marine core (MD04-2845), from farther offshore western France, does not have any samples that cover the LGM period that is the subject of this study. Nevertheless, we expect that any glacial-age anthropogenic burning signal would be difficult to detect at a marine location for the following reasons: 1) in our simulations, the increase in fire frequency caused by humans is modest, 2) the sedimentation process at deep-water marine core sites is highly uncertain–rapid fluctuations in sea level and ocean circulation during the last glacial period could mask an onshore trend [26, 27]– 3) the large magnitude of climate fluctuations between stadials and interstadials would overshadow human-induced changes when observing a period covering several cycles, and 4) the marine sediment records integrate over very large areas, e.g., mountains and lowlands, while the potential influence of humans on the landscape might have been more localized. A more illustrative test of our hypothesis would be to contrast paleoenvironmental reconstructions of full-glacial conditions recovered at a terrestrial site.…”

Terrestrial plant microfossils in palaeoenvironmental studies, pollen, microcharcoal and phytolith. Towards a comprehensive understanding of vegetation, fire and climate changes over the past one million years

“…The Late Holocene increased humidity suggested by vegetation changes in Northeast (NE) US (e.g. Naughton et al, 2015) is supported by tree ring, varve thickness and lake level data (Marlon et al, 2017). A cooling trend in this region over the last 2.5 millennia is also shown by pollen-based summer and annual temperature reconstructions (Marlon et al, 2017 and reference therein).…”

“…Due to a long history in palynological research in North America, more than 1 300 pollen sequences are included in the Neotoma paleoecology database (Williams et al, 2018) covering entirely or part of the last 20 kyr, although most of them only contain the Holocene period. Several state of the art papers aim at retracing the North American postglacial vegetation history, such as Gavin and Hu (2013), Wigand (2013), Whitlock and Brunelle (2007) and Whitlock (1992) for the western part of the sub-continent, Williams and Shuman (2013), Willard (2013), Grimm and Jacobson Jr (2004), Webb et al (2003), Davis (2015), Davis (1984), Naughton et al (2015) and Blarquez and Aleman (2016) for the eastern part and Bigelow (2013) for regions above 60°N. In North America, the deglacial warming (19-11 ka) along with the retreat North American ice-sheets resulted in large range shifts of terrestrial ecosystems.…”

“…Quercus became the dominant forest element in the oak-pine association developing in the southeast due to warmer but persistent dry conditions while in the northeast, white pine, oak and hemlock expanded in areas formerly occupied by cold-tolerant taxa in response to increased warmth and moisture availability (e.g. Naughton et al, 2015;Willard, 2013). In the northeast, temperature and humidity continues to increase in the northern areas to reach a maximum during the Mid-Holocene as suggested by the expansion of pine in New England and oak with some mesic tree taxa toward the south during the Early Holocene followed by hemlock and beech during the Mid-Holocene (Naughton et al, 2015;Williams and Shuman, 2013).…”

“…Naughton et al, 2015;Willard, 2013). In the northeast, temperature and humidity continues to increase in the northern areas to reach a maximum during the Mid-Holocene as suggested by the expansion of pine in New England and oak with some mesic tree taxa toward the south during the Early Holocene followed by hemlock and beech during the Mid-Holocene (Naughton et al, 2015;Williams and Shuman, 2013). In the southeast, the increase in humidity only occurred in the Mid-Holocene as indicated by the widespread oak-dominated forest decline and pine expansion.…”