Pollen and spore flora of an eocene forest, eastern Axel Heiberg Island, N.W.T.

doi:10.4095/131949

Report•DOI•

Pollen and spore flora of an eocene forest, eastern Axel Heiberg Island, N.W.T.

01 Jan 1991-

About: The article was published on 1991-01-01 and is currently open access. It has received 61 citations till now. The article focuses on the topics: Flora & Pollen.

...read moreread less

Citations

PDF

Open Access

More filters

Journal Article•DOI•

The Use of Geological and Paleontological Evidence in Evaluating Plant Phylogeographic Hypotheses in the Northern Hemisphere Tertiary

[...]

Bruce H. Tiffney, Steven R. Manchester

01 Nov 2001-International Journal of Plant Sciences

TL;DR: The history of the climatic and geographic features of the Tertiary of the Northern Hemisphere agrees with many phylogenetically based phylogeographic hypotheses of living angiosperm genera but indicates that some hypotheses require reanalysis.

...read moreread less

Abstract: Phylogeography posits that the sequence of speciation events within a clade should parallel the geographic migration and isolation of members of the clade through time. The primary historical features that govern migration and allopatry in land plants are changes in physical geography (e.g., oceans, mountains, and deserts) and in climate (e.g., moisture, temperature, and day length), features that are often interrelated. If we assume that living genera retain physiological stability through time, much as they retain the morphological features that allow their identification, then these environmental features of the geologic past may be used to test phylogeographic hypotheses of living genera based on phylogenetic analysis. The history of the climatic and geographic features of the Tertiary of the Northern Hemisphere agrees with many phylogenetically based phylogeographic hypotheses of living angiosperm genera but indicates that some hypotheses require reanalysis. While the parallel comparison of phylogene...

...read moreread less

564 citations

Cites background from "Pollen and spore flora of an eocene..."

...Middle or late Eocene floras from the Canadian Arctic (Basinger 1991; McIntyre 1991; McIver and Basinger 1999) suggest moist, equable climates and include evergreen (e.g., Pinaceae, Chamaecyparis) and deciduous (e.g., Metasequoia) conifers and many deciduous angiosperms....
[...]

Journal Article•DOI•

Sympatric parallel diversification of major oak clades in the Americas and the origins of Mexican species diversity

[...]

Andrew L. Hipp¹, Paul S. Manos², Antonio González-Rodríguez³, Marlene Hahn¹, Matthew A. Kaproth⁴, Matthew A. Kaproth⁵, John D. McVay², Susana Valencia Ávalos³, Jeannine Cavender-Bares⁵ - Show less +5 more•Institutions (5)

Morton Arboretum¹, Duke University², National Autonomous University of Mexico³, Minnesota State University, Mankato⁴, University of Minnesota⁵

01 Jan 2018-New Phytologist

TL;DR: A highly resolved phylogeny demonstrates sympatric parallel diversification in climatic niche, leaf habit, and diversification rates in the oaks, which has shaped the diversity of North American forests.

...read moreread less

Abstract: Summary Oaks (Quercus, Fagaceae) are the dominant tree genus of North America in species number and biomass, and Mexico is a global center of oak diversity. Understanding the origins of oak diversity is key to understanding biodiversity of northern temperate forests. A phylogenetic study of biogeography, niche evolution and diversification patterns in Quercus was performed using 300 samples, 146 species. Next-generation sequencing data were generated using the restriction-site associated DNA (RAD-seq) method. A time-calibrated maximum likelihood phylogeny was inferred and analyzed with bioclimatic, soils, and leaf habit data to reconstruct the biogeographic and evolutionary history of the American oaks. Our highly resolved phylogeny demonstrates sympatric parallel diversification in climatic niche, leaf habit, and diversification rates. The two major American oak clades arose in what is now the boreal zone and radiated, in parallel, from eastern North America into Mexico and Central America. Oaks adapted rapidly to niche transitions. The Mexican oaks are particularly numerous, not because Mexico is a center of origin, but because of high rates of lineage diversification associated with high rates of evolution along moisture gradients and between the evergreen and deciduous leaf habits. Sympatric parallel diversification in the oaks has shaped the diversity of North American forests.

...read moreread less

190 citations

Cites background or methods from "Pollen and spore flora of an eocene..."

...American oaks arose in the northern temperate zone and diversified southward in parallel Middle Eocene pollen records from Axel Heiberg Island (79°550N, 88°580W) indicate that oaks had arrived at high latitudes in North America by c. 45Ma (McIntyre, 1991)....
[...]
...A normal distribution with a median of 45Ma and 95% of the distribution between 42 and 48Ma was used for the root of the American oak clade (McIntyre, 1991; McIver & Basinger, 1999)....
[...]

Journal Article•DOI•

Life at the top of the greenhouse Eocene world--A review of the Eocene flora and vertebrate fauna from Canada's High Arctic

[...]

Jaelyn J. Eberle¹, David R. Greenwood²•Institutions (2)

American Museum of Natural History¹, Brandon University²

01 Jan 2012-Geological Society of America Bulletin

TL;DR: Early-middle Eocene (ca. 53-38 Ma) sediments of the Eureka Sound Group in Canada's Arctic Archipelago preserve evidence of lush mixed conifer-broadleaf rain forests, inhabited at times by alligators, turtles, and diverse mammals, including primates, tapirs, brontotheres, and hippo-like Coryphodon as mentioned in this paper.

...read moreread less

Abstract: Early–middle Eocene (ca. 53–38 Ma) sediments of the Eureka Sound Group in Canada’s Arctic Archipelago preserve evidence of lush mixed conifer-broadleaf rain forests, inhabited at times by alligators, turtles, and diverse mammals, including primates, tapirs, brontotheres, and hippo-like Coryphodon. This biota reflects a greenhouse world, offering a climatic and ecologic deep time analog of a mild ice-free Arctic that may be our best means to predict what is in store for the future Arctic if current climate change goes unchecked. In our review of the early–middle Eocene Arctic flora and vertebrate fauna, we place the Arctic fossil localities in historic, geographic, and stratigraphic context, and we provide an integrated synthesis and discussion of the paleobiology and paleoecology of these Eocene Arctic forests and their vertebrate inhabitants. The abundance and diversity of tapirs and plagiomenids (both rare elements in midlatitude faunas), and the absence of artiodactyls, early horses, and the hyopsodontid “condylarth” Hyopsodus (well represented at midlatitude localities) are peculiar to the Eocene Arctic. The Eocene Arctic macrofloras reveal a forested landscape analogous to the swamp-cypress and broadleaf floodplain forests of the modern southeastern United States. Multiple climate proxies indicate a mild temperate early–middle Eocene Arctic with winter temperatures at or just above freezing and summer temperatures of 20 °C (or higher), and high precipitation. At times, this high precipitation resulted in freshwater discharge into a nearly enclosed Arctic Ocean basin, sufficient to cause surface freshening of the Arctic Ocean, supporting mats of the floating fern Azolla . Fluctuating Arctic Ocean sea level due to freshwater inputs as well as tectonics produced temporary land bridges, allowing land plants and animals to disperse between North America and both Europe and Asia.

...read moreread less

156 citations

Journal Article•DOI•

Multiple nuclear genes stabilize the phylogenetic backbone of the genus Quercus

[...]

François Hubert¹, Guido W. Grimm², Emmanuelle Jousselin³, Vincent Berry⁴, Alain Franc¹, Antoine Kremer¹ - Show less +2 more•Institutions (4)

University of Bordeaux¹, Swedish Museum of Natural History², Institut national de la recherche agronomique³, University of Montpellier⁴

15 Oct 2014-Systematics and Biodiversity

TL;DR: Using a dating approach, an Eocene age for the primary divergences in Quercus and a root age of about 50–55 Ma agrees with palaeobotanical evidence, indicating that morphological differentiation pre-dates genetic isolation in this clade.

...read moreread less

Abstract: Phylogenetic relationships among 108 oak species (genus Quercus L.) were inferred using DNA sequences of six nuclear genes selected from the existing genomic resources of the genus. Previous phylogenetic reconstructions based on traditional molecular markers are inconclusive at the deeper nodes. Overall, weak phylogenetic signals were obtained for each individual gene analysis, but stronger signals were obtained when gene sequences were concatenated. Our data support the recognition of six major intrageneric groups Cyclobalanopsis, Cerris, Ilex, Quercus, Lobatae and Protobalanus. Our analyses provide resolution at deeper nodes but with moderate support and a more robust infrageneric classification within the two major clades, the ‘Old World Oaks’ (Cyclobalanopsis, Cerris, Ilex) and ‘New World Oaks’ (Quercus, Lobatae, Protobalanus). However, depending on outgroup choice, our analysis yielded two alternative placements of the Cyclobalanopsis clade within the genus Quercus. When Castanea Mill. was chosen as ...

...read moreread less

115 citations

Journal Article•DOI•

The Arctic Forest of the Middle Eocene

[...]

A. Hope Jahren¹•Institutions (1)

Johns Hopkins University¹

30 Apr 2007-Annual Review of Earth and Planetary Sciences

TL;DR: The Fossil Forest site, located on Axel Heiberg Island, Canada, has yielded a particularly rich assemblage of plant macro- and micro-fossils, as well as paleosols, all exquisitely preserved as mentioned in this paper.

...read moreread less

Abstract: Lush forests, dominated by deciduous conifers, existed well north of the Arctic Circle during the middle Eocene (∼45 Ma). The Fossil Forest site, located on Axel Heiberg Island, Canada, has yielded a particularly rich assemblage of plant macro- and microfossils, as well as paleosols—all exquisitely preserved. Methods ranging from classical paleobotany, to stable-isotope geochemistry, have been applied to materials excavated from the Fossil Forest and have revealed layers of diverse conifer forests with a rich angiosperm understory that successfully endured three months of continuous light and three months of continuous darkness. Paleoenvironmental reconstructions suggest a warm, ice-free environment, with high growing-season-relative humidity, and high rates of soil methanogenesis. Methods to evaluate intraseasonal variability highlight the switchover from stored to actively fixed carbon during the short annual growing season.

...read moreread less

82 citations

Cites background or methods from "Pollen and spore flora of an eocene..."

...…E. chrysolepis) Chinquapin Palynomorph McIntyre (1991) Family Ericaceae (Ericipites spp.) N.E. Palynomorph McIntyre (1991) Fagus sp. Beech Palynomorph McIntyre (1991) Fraxinus sp. Ash Palynomorph McIntyre (1991) Gothanipollis sp. N.E. Palynomorph McIntyre (1991) Ilex sp. Holly Palynomorph…...
[...]
...…twig, wood LePage & Basinger (1991) Metasequoia sp. Dawn redwood Cone, leaf, stem, palynomorph, wood Basinger (1991), Greenwood & Basinger (1993), McIntyre (1991), McIver & Basinger (1999), Richter & LePage (2005), Williams, et al. (2003) Metasequoia occidentallis Dawn redwood Leaf, twigs, cone…...
[...]
...Polypodium sp. Fern Palynomorph McIntyre (1991) Radialisporis radiatus N.E. Palynomorph McIntyre (1991) aNone extant....
[...]
...…Palynomorph McIntyre (1991) Fagus sp. Beech Palynomorph McIntyre (1991) Fraxinus sp. Ash Palynomorph McIntyre (1991) Gothanipollis sp. N.E. Palynomorph McIntyre (1991) Ilex sp. Holly Palynomorph McIntyre (1991) Intratriporopollenites sp. (cf. Reevesia) No extant Palynomorph McIntyre (1991) Juglans…...
[...]
...…(1991) Lonicera sp. Honeysuckle Palynomorph McIntyre (1991) Family Menispermaceae Leaf McIver & Basinger (1999) Myrica sp. Sweetgale Palynomorph McIntyre (1991) Nordenskioldia borealis N.E. Fruit, leaf McIver & Basinger (1999) Nyssa sp. Tupelo Fruit, palynomorph McIntyre (1991), McIver &…...
[...]

Collapse

Pollen and spore flora of an eocene forest, eastern Axel Heiberg Island, N.W.T.

Citations

Cites background from "Pollen and spore flora of an eocene..."

Cites background or methods from "Pollen and spore flora of an eocene..."

Cites background or methods from "Pollen and spore flora of an eocene..."

Related Papers (5)