Growth rates of Rhizocarpon geographicum: a review with new data from Iceland
This paper reviews evidence from previous growth-rate studies on lichens of the yellow-green species of Subgenus Rhizocarpon - the family most commonly used in lichenometric dating. New data are presented from Rhizocarpon section Rhizocarpon thalli growing on a moraine in southern Iceland over a per...
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ftnerc:oai:nora.nerc.ac.uk:2361 2024-06-09T07:46:58+00:00 Growth rates of Rhizocarpon geographicum: a review with new data from Iceland Bradwell, Tom Armstrong, R A 2007 text http://nora.nerc.ac.uk/id/eprint/2361/ https://nora.nerc.ac.uk/id/eprint/2361/1/BRADWELL_ARMSTRONG_2007_nora.pdf http://www3.interscience.wiley.com/cgi-bin/fulltext/113510816/PDFSTART en eng Wiley https://nora.nerc.ac.uk/id/eprint/2361/1/BRADWELL_ARMSTRONG_2007_nora.pdf Bradwell, Tom; Armstrong, R A. 2007 Growth rates of Rhizocarpon geographicum: a review with new data from Iceland. Journal of Quaternary Science, 22 (4). 311-320. https://doi.org/10.1002/jqs.1058 <https://doi.org/10.1002/jqs.1058> Ecology and Environment Earth Sciences Publication - Article PeerReviewed 2007 ftnerc https://doi.org/10.1002/jqs.1058 2024-05-15T08:42:16Z This paper reviews evidence from previous growth-rate studies on lichens of the yellow-green species of Subgenus Rhizocarpon - the family most commonly used in lichenometric dating. New data are presented from Rhizocarpon section Rhizocarpon thalli growing on a moraine in southern Iceland over a period of 4.33 yr. Measurements of 38 lichen thalli, between 2001 and 2005, show that diametral growth rate (DGR, mm yr-1) is a function of thallus size. Growth rates increase rapidly in small thalli (<10 mm diameter), remain high (ca. 0.8 mm yr-1) and then decrease gradually in larger thalli (>50 mm diameter). Mean DGR in southern Iceland, between 2001 and 2005, was 0.64 mm yr-1 (SD = 0.24). The resultant growth-rate curve is parabolic and is best described by a third-order polynomial function. The striking similarity between these findings in Iceland and those of Armstrong ([1983]) in Wales implies that the shape of the growth-rate curve may be characteristic of Rhizocarpon geographicum lichens. The difference between the absolute growth rate in southern Iceland and Wales (ca. 66% faster) is probably a function of climate and micro-environment between the two sites. These findings have implications for previous lichenometric-dating studies, namely, that those studies which assume constant lichen growth rates over many decades are probably unreliable. Article in Journal/Newspaper Iceland Natural Environment Research Council: NERC Open Research Archive Journal of Quaternary Science 22 4 311 320 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
topic |
Ecology and Environment Earth Sciences |
spellingShingle |
Ecology and Environment Earth Sciences Bradwell, Tom Armstrong, R A Growth rates of Rhizocarpon geographicum: a review with new data from Iceland |
topic_facet |
Ecology and Environment Earth Sciences |
description |
This paper reviews evidence from previous growth-rate studies on lichens of the yellow-green species of Subgenus Rhizocarpon - the family most commonly used in lichenometric dating. New data are presented from Rhizocarpon section Rhizocarpon thalli growing on a moraine in southern Iceland over a period of 4.33 yr. Measurements of 38 lichen thalli, between 2001 and 2005, show that diametral growth rate (DGR, mm yr-1) is a function of thallus size. Growth rates increase rapidly in small thalli (<10 mm diameter), remain high (ca. 0.8 mm yr-1) and then decrease gradually in larger thalli (>50 mm diameter). Mean DGR in southern Iceland, between 2001 and 2005, was 0.64 mm yr-1 (SD = 0.24). The resultant growth-rate curve is parabolic and is best described by a third-order polynomial function. The striking similarity between these findings in Iceland and those of Armstrong ([1983]) in Wales implies that the shape of the growth-rate curve may be characteristic of Rhizocarpon geographicum lichens. The difference between the absolute growth rate in southern Iceland and Wales (ca. 66% faster) is probably a function of climate and micro-environment between the two sites. These findings have implications for previous lichenometric-dating studies, namely, that those studies which assume constant lichen growth rates over many decades are probably unreliable. |
format |
Article in Journal/Newspaper |
author |
Bradwell, Tom Armstrong, R A |
author_facet |
Bradwell, Tom Armstrong, R A |
author_sort |
Bradwell, Tom |
title |
Growth rates of Rhizocarpon geographicum: a review with new data from Iceland |
title_short |
Growth rates of Rhizocarpon geographicum: a review with new data from Iceland |
title_full |
Growth rates of Rhizocarpon geographicum: a review with new data from Iceland |
title_fullStr |
Growth rates of Rhizocarpon geographicum: a review with new data from Iceland |
title_full_unstemmed |
Growth rates of Rhizocarpon geographicum: a review with new data from Iceland |
title_sort |
growth rates of rhizocarpon geographicum: a review with new data from iceland |
publisher |
Wiley |
publishDate |
2007 |
url |
http://nora.nerc.ac.uk/id/eprint/2361/ https://nora.nerc.ac.uk/id/eprint/2361/1/BRADWELL_ARMSTRONG_2007_nora.pdf http://www3.interscience.wiley.com/cgi-bin/fulltext/113510816/PDFSTART |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
https://nora.nerc.ac.uk/id/eprint/2361/1/BRADWELL_ARMSTRONG_2007_nora.pdf Bradwell, Tom; Armstrong, R A. 2007 Growth rates of Rhizocarpon geographicum: a review with new data from Iceland. Journal of Quaternary Science, 22 (4). 311-320. https://doi.org/10.1002/jqs.1058 <https://doi.org/10.1002/jqs.1058> |
op_doi |
https://doi.org/10.1002/jqs.1058 |
container_title |
Journal of Quaternary Science |
container_volume |
22 |
container_issue |
4 |
container_start_page |
311 |
op_container_end_page |
320 |
_version_ |
1801377019254013952 |