Calibrating pollen data in climatic terms: Improving the methods

Howe, Sally E.; Webb, Thompson

doi:10.1016/0277-3791(83)90003-3

Cited by 73 publications

(24 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Davis, , 1986M.B. Davis, , 1990Faegri et Iversen, 1964;Gajewski, 1993;Howe et Webb, 1983 ;MacDonald et Edwards, 1991 ;Webb et Bartlein, 1988 ;Webb et Clark, 1977). Ces connaissances permettent aujourd'hui de circonscrire les limites et les possibilités de la méthode à l'égard de ces mentionned in text.…”

Section: Cadre Généralunclassified

Le couvert végétal du Québec-Labrador il y a 6000 ans BP : essai

Richard¹

2007

gpq

View full text Add to dashboard Cite

Une carte du couvert végétal du Québec-Labrador est proposée pour l'époque des 6000 ans BP, à partir des données paléopalynologiques et paléobotaniques. Une Toundra arbustive dense s'interposait entre les mers de Tyrrell ou d'Iberville et les glaces résiduelles qui occupaient alors plus de 100 000 km2 en Ungava (Nunavik) et jusque dans la région de Schefferville. Étroite au sud des glaciers, cette Toundra s'étalait à l'est des glaces sur plus de 400 km jusqu'à la mer du Labrador, au nord du 54° de latitude. La limite des arbres s'établissait donc alors à peu près au centre de l'actuelle zone de Taïga (Forêt boréale ouverte), mais la limite nord de la Forêt fermée correspondait déjà à peu près à la position moderne. Comme la Toundra, la Taïga de l'époque était arbustive, plus dense et plus diversifiée qu'actuellement, sans doute en raison d'un climat favorable, mais aussi d'une plus grande richesse des sols en éléments nutritifs. Les domaines forestiers méridionaux des Pessières, des Sapinières et des Érablières atteignaient dans l'ensemble les limites modernes de leur aire de peuplement, mais l'abondance de certaines essences compagnes différait le plus souvent de l'actuelle. Ces différences sont attribuables 1) à une migration tardive de certaines essences, telles le pin gris (Pinus banksiana) dans les Pessières occidentales ou le hêtre à grande feuilles (Fagus grandifolia) dans les Érablières, 2) à une incidence généralement plus faible des feux naturels, 3) à un entourbement moindre des stations hydriques, et 4) à un climat dans l'ensemble plus clément. L'analyse régionale permet d'identifier des gradients et des champs phytogéographiques plus nuancés éventuellement influencés par le climat, notamment en zones montagnardes et subalpines.A cartographie reconstruction of the vegetational cover of Québec-Labrador for 6 ka BP is based on palynological and plant macrofossil records. A dense Shrub Tundra occupied the stretches of land between marine waters (Tyrrell Sea or d'lberville Sea) and the residual ice masses that still occupied over 100 000 km2, from Ungava (Nunavik) to the Schefferville area. This Tundra belt was narrow along the southern limit of glaciers but expanded eastward to a width of more than 400 km, extending to the Labrador Sea north of latitude 54°. The tree-line thus ran approximately through the middle of the present-day Taiga zone (open boreal forest), but the northern limit of the Closed Forest already corresponded to its modern position. Like the Tundra, the 6 ka BP Taiga was shrubby, more dense, and more diversified than todays, probably due to favorable climatic conditions but also because soils contained more nutrients than today. The southern forest vegetation zones, dominated respectively by spruce, fir, and maple, generally occupied their modern positions, but the abundance of some companion tree-species differed markedly from the modern. The differences are attributed 1) to delayed migration, as in the case of jack pine (Pinus banksiana) in the Western Spruce Forest domain or America...

show abstract

Section: Cadre Généralunclassified

Le couvert végétal du Québec-Labrador il y a 6000 ans BP : essai

Richard¹

2007

gpq

View full text Add to dashboard Cite

show abstract

“…Such deletions greatly reduce instability problems in statistical analyses, such as in standardised principal components analysis (Prentice 1980), and is regularly used in analyses of pollen data sets (e.g., Howe & Webb 1983, Lamb 1984. Table i lists the 17 taxa retained.…”

Section: Development Of the Pollen Data Setmentioning

confidence: 99%

Quantitative analyses of modern pollen-climate relationships in New Zealand indigenous forests

Norton

McGlone²,

Wigley

1986

New Zealand Journal of Botany

View full text Add to dashboard Cite

Modern arboreal pollen data from 161 sites throughout New Zealand were collated and then analysed by means of principal components and cluster analyses to identify sites with common assemblages of pollen taxa. These pollen assemblages are directly comparable with the main associations of tree species. Simple correlation coefficients calculated between the modern pollen and climate data from the same sites show some significant relationships, particularly with precipitation. Multiple regression analysis was used to calibrate transfer functions linking the pollen data and three climate variables: mean summer temperature, annual temperature range, and the logarithm of mean annual precipitation. The regressions were verified on independent data, but those for mean summer temperature and annual temperature range failed to verify significantly. The log-precipitation transfer function performs best, with the pollen data explaining 55% of the precipitation variance in calibration, and 46% in verification. The explained variance values are lower than those obtained in eastern North America. However, it appears that with a denser, and more selective set of modern pollen sites, transfer functions could be developed in New Zealand which would make possible quantitative reconstructions of postglacial climates.

show abstract

“…For this reason numeric pollen reconstructions of climate conditions (e.g. temperatures, precipitation) relying on the climate-equilibrium assumption have to be taken with due care, particularly if they are in contrast with other palaeoclimatic evidence (Howe and Webb 1983;Seppä et al 2004;Finsinger et al 2010;Abrantes et al 2012;Luterbacher et al 2012).…”

Section: What Is Natural?mentioning

confidence: 99%

Holocene vegetation and fire history of the mountains of Northern Sicily (Italy)

Tinner

Vescovi

Leeuwen

et al. 2016

Veget Hist Archaeobot

View full text Add to dashboard Cite

Knowledge about vegetation and fire history of the mountains of Northern Sicily is scanty. We analysed five sites to fill this gap and used terrestrial plant macrofossils to establish robust radiocarbon chronologies. Palynological records from Gorgo Tondo, Gorgo Lungo, Marcato Cixé, Urgo Pietra Giordano and Gorgo Pollicino show that under natural or near natural conditions, deciduous forests (Quercus pubescens, Q. cerris, Fraxinus ornus, Ulmus), that included a substantial portion of evergreen broadleaved species (Q. suber, Q. ilex, Hedera helix), prevailed in the upper meso-mediterranean belt. Mesophilous deciduous and evergreen broadleaved trees (Fagus sylvatica, Ilex aquifolium) dominated in the natural or quasi-natural forests of the oro-mediterranean belt. Forests were repeatedly opened for agricultural purposes. Fire activity was closely associated with farming, providing evidence that burning was a primary land use tool since Neolithic times. Land use and fire activity intensified during the Early Neolithic at 5000 BC, at the onset of the Bronze Age at 2500 BC and at the onset of the Iron Age at 800 BC. Our data and previous studies suggest that the large majority of open land communities in Sicily, from the coastal lowlands to the mountain areas below the thornycushion Astragalus belt (ca. 1,800 m a.s.l.), would rapidly develop into forests if land use ceased. Mesophilous Fagus-Ilex forests developed under warm mid Holocene conditions and were resilient to the combined impacts of humans and climate. The past ecology suggests a resilience of these summer-drought adapted communities to climate warming of about 2°C. Hence, they may be particularly suited to provide heat and drought-adapted Fagus sylvatica ecotypes for maintaining drought-sensitive Central European beech forests under global warming conditions.

show abstract

Calibrating pollen data in climatic terms: Improving the methods

Cited by 73 publications

References 29 publications

Le couvert végétal du Québec-Labrador il y a 6000 ans BP : essai

Le couvert végétal du Québec-Labrador il y a 6000 ans BP : essai

Quantitative analyses of modern pollen-climate relationships in New Zealand indigenous forests

Holocene vegetation and fire history of the mountains of Northern Sicily (Italy)

Contact Info

Product

Resources

About