Aspects of the ecology of mat-forming lichens
Lichen species in the genera Cladonia (subgenus Cladina), Cetraria, Stereocaulon and Alectoria are important vegetation components on well-drained terrain and on elevated micro-sites in peatlands in boreal-Arctic regions. These lichens often form closed mats, the component thalli in which grow verti...
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Language: | English |
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Septentrio Academic Publishing
2000
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ftunitroemsoe:oai:ojs.henry.ub.uit.no:article/1508 2023-05-15T14:56:23+02:00 Aspects of the ecology of mat-forming lichens Crittenden, P. D. 2000-03-01 application/pdf https://septentrio.uit.no/index.php/rangifer/article/view/1508 https://doi.org/10.7557/2.20.2-3.1508 eng eng Septentrio Academic Publishing https://septentrio.uit.no/index.php/rangifer/article/view/1508/1415 https://septentrio.uit.no/index.php/rangifer/article/view/1508 doi:10.7557/2.20.2-3.1508 Copyright (c) 2015 P. D. Crittenden http://creativecommons.org/licenses/by/3.0/ CC-BY Rangifer; Årg 20 Nr 2-3 (2000); 127-139 Rangifer; Vol 20 No 2-3 (2000); 127-139 1890-6729 lichen ecology acid rain allelopathy grazing growth lichens nitrogen fixation recycling trampling Arctic info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2000 ftunitroemsoe https://doi.org/10.7557/2.20.2-3.1508 2021-08-16T14:58:21Z Lichen species in the genera Cladonia (subgenus Cladina), Cetraria, Stereocaulon and Alectoria are important vegetation components on well-drained terrain and on elevated micro-sites in peatlands in boreal-Arctic regions. These lichens often form closed mats, the component thalli in which grow vertically upwards at the apices and die off in the older basal regions; they are therefore only loosely attached to the underlying soil. This growth habit is relatively unusual in lichens being found in <0.5% of known species. It might facilitate internal nutrienr recycling and higher growth rates and, together with the production of allelochemicals, it might underlie the considerable ecological success of mat-forming lichens; experiments to critically assess the importance of these processes are required. Mat-forming lichens can constitute in excess of 60% of the winter food intake of caribou and reindeer. Accordingly there is a pressing need for data on lichen growth rates, measured as mass increment, in order to help determine the carrying capacity of winter ranges for rhese herbivores and to better predict recovery rates following grazing. Trampling during the snow-free season fragments lichen thalli; mat-forming lichens regenerate very successfully from thallus fragments provided trampling does nor re-occur. Frequent recurrence of trampling creates disturbed habitats from which lichens will rapidly become eliminated consistent with J.P. Grime's CSR strategy theory. Such damage to lichen ground cover has occurred where reindeer or caribou are unable to migrate away from their winter range such as on small islands or where political boundaries have been fenced; it can also occur on summer range that contains a significant lichen component and on winter range where numbers of migrarory animals become excessive. Species of Stereocaulon, and other genera that contain cyanobacteria (most notably Peltigera and Nephroma), are among the principal agents of nitrogen fixation in boreal-arctic regions. Stereocaulon-dominated subarctic woodlands provide excellent model systems in which to investigate the role of lichens in nitrogen cycling. Mat-forming lichens are sensitive indicators of atmospheric deposition partly because they occur in open situations in which they intercept precipitation and particulates directly with minimal modification by vascular plant overstoreys. Data from both the UK and northern Russia are presented to illustrate geographical relationships between lichen chemistry and atmospheric deposition of nitrogen and acidity. The ecology of mat-fotming lichens remains under-researched and good opportunities exist for making significant contributions to this field including areas that relate directly to the management of arctic ungulates. Article in Journal/Newspaper Arctic Rangifer Subarctic University of Tromsø: Septentrio Academic Publishing Alectoria ENVELOPE(-58.640,-58.640,-63.977,-63.977) Arctic Rangifer 20 2-3 127 |
institution |
Open Polar |
collection |
University of Tromsø: Septentrio Academic Publishing |
op_collection_id |
ftunitroemsoe |
language |
English |
topic |
lichen ecology acid rain allelopathy grazing growth lichens nitrogen fixation recycling trampling Arctic |
spellingShingle |
lichen ecology acid rain allelopathy grazing growth lichens nitrogen fixation recycling trampling Arctic Crittenden, P. D. Aspects of the ecology of mat-forming lichens |
topic_facet |
lichen ecology acid rain allelopathy grazing growth lichens nitrogen fixation recycling trampling Arctic |
description |
Lichen species in the genera Cladonia (subgenus Cladina), Cetraria, Stereocaulon and Alectoria are important vegetation components on well-drained terrain and on elevated micro-sites in peatlands in boreal-Arctic regions. These lichens often form closed mats, the component thalli in which grow vertically upwards at the apices and die off in the older basal regions; they are therefore only loosely attached to the underlying soil. This growth habit is relatively unusual in lichens being found in <0.5% of known species. It might facilitate internal nutrienr recycling and higher growth rates and, together with the production of allelochemicals, it might underlie the considerable ecological success of mat-forming lichens; experiments to critically assess the importance of these processes are required. Mat-forming lichens can constitute in excess of 60% of the winter food intake of caribou and reindeer. Accordingly there is a pressing need for data on lichen growth rates, measured as mass increment, in order to help determine the carrying capacity of winter ranges for rhese herbivores and to better predict recovery rates following grazing. Trampling during the snow-free season fragments lichen thalli; mat-forming lichens regenerate very successfully from thallus fragments provided trampling does nor re-occur. Frequent recurrence of trampling creates disturbed habitats from which lichens will rapidly become eliminated consistent with J.P. Grime's CSR strategy theory. Such damage to lichen ground cover has occurred where reindeer or caribou are unable to migrate away from their winter range such as on small islands or where political boundaries have been fenced; it can also occur on summer range that contains a significant lichen component and on winter range where numbers of migrarory animals become excessive. Species of Stereocaulon, and other genera that contain cyanobacteria (most notably Peltigera and Nephroma), are among the principal agents of nitrogen fixation in boreal-arctic regions. Stereocaulon-dominated subarctic woodlands provide excellent model systems in which to investigate the role of lichens in nitrogen cycling. Mat-forming lichens are sensitive indicators of atmospheric deposition partly because they occur in open situations in which they intercept precipitation and particulates directly with minimal modification by vascular plant overstoreys. Data from both the UK and northern Russia are presented to illustrate geographical relationships between lichen chemistry and atmospheric deposition of nitrogen and acidity. The ecology of mat-fotming lichens remains under-researched and good opportunities exist for making significant contributions to this field including areas that relate directly to the management of arctic ungulates. |
format |
Article in Journal/Newspaper |
author |
Crittenden, P. D. |
author_facet |
Crittenden, P. D. |
author_sort |
Crittenden, P. D. |
title |
Aspects of the ecology of mat-forming lichens |
title_short |
Aspects of the ecology of mat-forming lichens |
title_full |
Aspects of the ecology of mat-forming lichens |
title_fullStr |
Aspects of the ecology of mat-forming lichens |
title_full_unstemmed |
Aspects of the ecology of mat-forming lichens |
title_sort |
aspects of the ecology of mat-forming lichens |
publisher |
Septentrio Academic Publishing |
publishDate |
2000 |
url |
https://septentrio.uit.no/index.php/rangifer/article/view/1508 https://doi.org/10.7557/2.20.2-3.1508 |
long_lat |
ENVELOPE(-58.640,-58.640,-63.977,-63.977) |
geographic |
Alectoria Arctic |
geographic_facet |
Alectoria Arctic |
genre |
Arctic Rangifer Subarctic |
genre_facet |
Arctic Rangifer Subarctic |
op_source |
Rangifer; Årg 20 Nr 2-3 (2000); 127-139 Rangifer; Vol 20 No 2-3 (2000); 127-139 1890-6729 |
op_relation |
https://septentrio.uit.no/index.php/rangifer/article/view/1508/1415 https://septentrio.uit.no/index.php/rangifer/article/view/1508 doi:10.7557/2.20.2-3.1508 |
op_rights |
Copyright (c) 2015 P. D. Crittenden http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.7557/2.20.2-3.1508 |
container_title |
Rangifer |
container_volume |
20 |
container_issue |
2-3 |
container_start_page |
127 |
_version_ |
1766328414882496512 |