Early Holocene hybridisation between Betula pubescens and B. nana in relation to birch vegetation in Southwest Iceland

Karlsdóttir, Lilja; Hallsdóttir, Margrét; Thórsson, Ægir Th.; Anamthawat‐Jónsson, Kesara

doi:10.1016/j.revpalbo.2012.05.001

Cited by 14 publications

(14 citation statements)

References 41 publications

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“…High proportion of non-triporate pollen therefore indicates the presence of hybrids and, in turn, the presence of both parent species in the region. The proportion of non-triporate pollen during this period ranges between 2% and 9% ( Figure 6), which indicates hybridization already taking place during the early Holocene, similar to what has been observed in other early-Holocene pollen records from Iceland (Karlsdóttir, 2014;Karlsdóttir et al, 2009Karlsdóttir et al, , 2012.…”

Section: Environmental Instability Local Increase In Juniperus Commusupporting

confidence: 84%

Life on the periphery is tough: Vegetation in Northwest Iceland and its responses to early-Holocene warmth and later climate fluctuations

2015

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Long-and short-term climate variations in the North Atlantic have been of sufficient magnitude to leave a discernible mark on the history of vegetation and landscape stability in Iceland during the Holocene. A reconstruction of early-and mid-Holocene vegetation around Lake Kagaðarhóll, Northwest Iceland, examines how climate fluctuations have affected the terrestrial ecosystem. A thorough reconstruction has been made using pollen and plant macrofossil analyses combined with proxies for organic and inorganic matter. The record shows the development from a period of pioneer vegetation towards a woodland ecosystem. The deposition of the Saksunarvatn tephra at c. 10,300 cal. yr BP caused a 100-year period of instability, followed by a gradual trend of stabilization over several centuries while material left behind by retreating glaciers and tephra was being contained by expanding and developing vegetation. Early-Holocene warmth is indicated by high pollen production of Juniperus communis around the lake by c. 10,100 cal. yr BP and birch woodland being established around the lake by c. 9200 cal. yr BP, much earlier than previously believed for this locale. Cooling climate between c. 8700 and 8200 cal. yr BP halted woodland development, with reduced plant reproduction likely caused by cold spring and summer temperatures. Woodlands became re-established from c. 7900 cal. yr BP before entering a decline from c. 6000 cal. yr BP, with harsher environmental conditions apparent after c. 4200 cal. yr BP. The Kagaðarhóll record compares favourably with other palaeoclimatic data from the North Atlantic, demonstrating the potential of pollen and macrofossil data for reconstructions of environmental change in Iceland and as an indicator of climate variability in the North Atlantic during the Holocene.

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Section: Environmental Instability Local Increase In Juniperus Commusupporting

confidence: 84%

Life on the periphery is tough: Vegetation in Northwest Iceland and its responses to early-Holocene warmth and later climate fluctuations

2015

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“…Leaves of all the woody species had relatively high P concentration in comparison with that in A. pratensis . The lower concentration of P in the leaves of B. nana than in B. pubescens may possibly be associated with lower genome size, as B. nana is diploid (2 n = 28) and B. pubescens is a tetraploid (2 n = 56) species (Karlsdóttir et al ., ). The existence of both higher P requirements and higher P concentration in grassland species with large genomes than in species with smaller genome size has been recorded previously (Šmarda et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Forage quality of leaf fodder from the main woody species in Iceland and its potential use for livestock in the past and present

Hejcman

Hejcmanová

Pavlů

et al. 2016

Grass and Forage Science

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Woody species played, and in many Nordic regions still play, a very important role in livestock feeding. However, forage quality (contents of macroelements and fibre fractions) of the leaves of common woody species is often inadequate. The aim of our study was to determine forage quality of leaves of Betula nana, Betula pubescens, Salix lanata, Salix phylicifolia and Sorbus aucuparia from Iceland and to compare it with the forage quality of the common native grass Deschampsia cespitosa and the introduced grass Alopecurus pratensis used by contemporary Icelandic farmers for forage production. Samples were collected at four localities in Iceland in late June 2013 and analysed for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), neutral and acid-detergent fibre and lignin concentration. Analyses were compared with the optimum range for cattle and sheep nutrition. The nutritive value of leaves of the Icelandic woody species was relatively high, and analysis showed their nutritive content satisfied both cattle and sheep nutrient requirements for N, P, K, Ca and Mg, but the relatively high content of indigestible lignin in all woody species could cause problems for livestock metabolism. Grasses were characterized by lower P, Ca and Mg, but substantially higher K concentrations, and higher N:P and K:(Mg + Ca) ratios. The forage quality of leaves of woody species increased in the order B. nana < B. pubescens < S. phylicifolia < S. aucuparia < S. lanata. Results are discussed in relation to use of leaf fodder in the past, when woody species, particularly Salix spp., are likely to have played an important role in livestock feeding.

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“…Non-triporate Betula pollen grains increase to~9% (Fig. 6), probably due to increased hybridization between Betula nana and B. pubescens as B. pubescens colonized land previously occupied by B. nana (Karlsd ottir et al 2008(Karlsd ottir et al , 2009(Karlsd ottir et al , 2012Karlsd ottir 2014).…”

Section: Stable Woodland C 8000 To 6700 Cal a Bpmentioning

confidence: 99%

“…), probably due to increased hybridization between Betula nana and B. pubescens as B. pubescens colonized land previously occupied by B. nana (Karlsdóttir et al . , , ; Karlsdóttir ).…”

Section: Holocene Environmental Dynamics At Barðalækjartjörnmentioning

confidence: 99%

Climate change and human impact in a sensitive ecosystem: the Holocene environment of the Northwest Icelandic highland margin

Eddudóttir

Erlendsson

Tinganelli

et al. 2016

Boreas

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Complex interactions of climate and volcanic activity have shaped the environment of Iceland during the Holocene. Palaeoecological records from Iceland offer a unique look at a Holocene environment that was uninhabited by humans and free of mammal herbivores until about AD 870. We present a new reconstruction of Holocene vegetation and landscape dynamics from a small lake, Barðalækjartjörn, located near the highland margin in Northwest Iceland. A multi‐proxy approach was used to reconstruct vegetation based on pollen and plant macrofossil analysis and landscape stability based on lithological proxies. The record covers the period c. 10 300–200 cal. a BP. For the first two millennia aeolian processes probably played a part in vegetation development. This period is characterized by high input of minerogenic material into the lake and a vegetation assemblage in which plants tolerant of aeolian deposition are prominent. Betula pubescens woodland reached a maximum between c. 7400 and 6500 cal. a BP. Betula nana‐dominated dwarf shrub heath replaced woodland after c. 4000 cal. a BP, following the onset of Neoglaciation. Land use following human settlement caused an environmental shift at the highland margin. Betula pubescens probably disappeared from the vicinity of the lake soon thereafter. Large‐scale soil erosion began at c. 1000 cal. a BP in the wake of human activities, such as introduction of grazing livestock and woodcutting. This study offers an important long‐term perspective of the development of the highland ecosystem under both wholly natural and human‐influenced conditions.

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Early Holocene hybridisation between Betula pubescens and B. nana in relation to birch vegetation in Southwest Iceland

Cited by 14 publications

References 41 publications

Life on the periphery is tough: Vegetation in Northwest Iceland and its responses to early-Holocene warmth and later climate fluctuations

Life on the periphery is tough: Vegetation in Northwest Iceland and its responses to early-Holocene warmth and later climate fluctuations

Forage quality of leaf fodder from the main woody species in Iceland and its potential use for livestock in the past and present

Climate change and human impact in a sensitive ecosystem: the Holocene environment of the Northwest Icelandic highland margin

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