The Archaic Floras (original) (raw)

The Pleistocene Floras (2.4-0.8 Ma) - Shaping the Modern Vegetation of Iceland

Late Cainozoic Floras …, 2011

The Pleistocene vegetation history of Iceland is closely linked to the onset of large scale northern hemisphere glaciations. The first regional glaciation in Iceland occurred at ca 2.5 Ma (Praetiglian), just before the deposition of the oldest Pleistocene plant-bearing sediments in Iceland (Brekkukambur Formation, 2.4-2.1 Ma). Both the macro-and microfloras of the Brekkukambur Formation are not very well preserved and do not allow detailed interpretations of the palaeoenvironment. However, based on plant and insect remains from the coeval Kap København Formation of northern Greenland, this time marked a last phase of global warmth with boreal forests extending as far north as 82°N. Younger plantbearing sedimentary formations in Iceland investigated here are ca 1.7, 1.1, and 0.8 Ma in age. They were deposited during interglacials and their floras are very similar to the modern flora of Iceland. It is unclear at the moment whether and how frequently plants survived in Iceland during cold phases. Dispersal mechanisms of plant taxa found in interglacial deposits show that all of them are dispersed by wind or birds over long distances and hence Iceland could have been re-colonized within a rather short period after each cold phase. The composition of the modern flora of Iceland is the result of the dispersal modes and climatic tolerances (competitiveness) of its members. These general conditions appear to have controlled the flora and vegetation of Iceland in a similar way since more than 1.7 million years.

Late Cainozoic Floras of Iceland

Topics in Geobiology, 2011

The Topics in Geobiology series covers the broad discipline of geobiology that is devoted to documenting life history of the Earth. A critical theme inherent in addressing this issue and one that is at the heart of the series is the interplay between the history of life and the changing environment. The series aims for high quality, scholarly volumes of original research as well as broad reviews. Geobiology remains a vibrant as well as a rapidly advancing and dynamic field. Given this field's multidiscipline nature, it treats a broad spectrum of geologic, biologic, and geochemical themes all focused on documenting and understanding the fossil record and what it reveals about the evolutionary history of life. The Topics in Geobiology series was initiated to delve into how these numerous facets have influenced and controlled life on Earth. Recent volumes have showcased specific taxonomic groups, major themes in the discipline, as well as approaches to improving our understanding of how life has evolved. Taxonomic volumes focus on the biology and paleobiology of organisms-their ecology and mode of life-and, in addition, the fossil record-their phylogeny and evolutionary patterns-as well as their distribution in time and space. Theme-based volumes, such as predator-prey relationships, biomineralization, paleobiogeography, and approaches to high-resolution stratigraphy, cover specific topics and how important elements are manifested in a wide range of organisms and how those dynamics have changed through the evolutionary history of life. Comments or suggestions for future volumes are welcomed.

Vegetation history since the mid-Holocene in northeastern Iceland

Écoscience, 2018

Palynological analysis of peat cores collected near two abandoned farms in the Svalbarðstunga Valley of the Þistilfjorður region of northeastern Iceland was used to reconstruct the mid-Holocene vegetation history and to distinguish climatic and anthropogenic impacts on terrestrial ecosystems since colonization. The first site, Hjálmarvík, is located along the coast of Þistilfjorður, while Kúðá is located 12 km inland. From 6430 to ca. 4500 cal BP, shrub tundra and birch woodland dominated the landscape. Between ca. 4500 and ca. 1170 cal BP, cooler and wetter conditions favored peatland species, while birch significantly declined. From 1170 cal BP to the present, grassland and peatland were prevalent. Birch woodland had virtually disappeared from the inland regions by 5810 cal BP and from the coast by 3450 cal BP. However, isolated trees persisted in certain areas. Following the initial Norse settlement of Svalbarðstunga at about 1000 AD, the development of agriculture and sheep grazing promoted the spread of sedges and facilitated the introduction of new plant species. Ecological changes linked to the Norse landnám were more limited in Svalbarðstunga than elsewhere in Iceland, where abrupt changes such as woodland clearance and erosion have been associated with human settlement.