Advanced

Does exogenous carbon extend the realized niche of canopy lichens? Evidence from sub-boreal forests in British Columbia

Campbell, Jocelyn; Bengtson, Per LU ; Fredeen, Arthur L.; Coxson, Darwyn S. and Prescott, Cindy E. (2013) In Ecology 94(5). p.1186-1195
Abstract
Foliose lichens with cyanobacterial bionts (bipartite and tripartite) form a distinct assemblage of epiphytes strongly associated with humid microclimatic conditions in inland British Columbia. Previous research showed that these cyano- and cephalolichen communities are disproportionately abundant and species-rich on conifer saplings beneath Populus compared to beneath other tree species. More revealing, lichens with cyanobacterial bionts were observed beneath Populus even in stands that did not otherwise support them. We experimentally test the hypothesis that this association is due to the interception of glucose-rich nectar that is exuded from Populus extra-floral nectaries (EFN). Using CO2 flux measurements and phospholipid fatty acid... (More)
Foliose lichens with cyanobacterial bionts (bipartite and tripartite) form a distinct assemblage of epiphytes strongly associated with humid microclimatic conditions in inland British Columbia. Previous research showed that these cyano- and cephalolichen communities are disproportionately abundant and species-rich on conifer saplings beneath Populus compared to beneath other tree species. More revealing, lichens with cyanobacterial bionts were observed beneath Populus even in stands that did not otherwise support them. We experimentally test the hypothesis that this association is due to the interception of glucose-rich nectar that is exuded from Populus extra-floral nectaries (EFN). Using CO2 flux measurements and phospholipid fatty acid (PLFA) analysis with experimental applications of C-13(6)-labeled glucose, we demonstrate that cyano-and cephalolichens have a strong respiratory response to glucose. Lichens treated with glucose had lower net photosynthesis and higher establishment rates than control thalli. Furthermore, lichens with cyanobacterial bionts rapidly incorporate exogenous C-13 into lichen fatty acid tissues. A large proportion of the C-13 taken up by the lichens was incorporated into fungal biomarkers, suggesting that the mycobiont absorbed and assimilated the majority of applied C-13(6) glucose. Our observations suggest that both cyanolichens and cephalolichens may utilize an exogenous source of glucose, made available by poplar EFNs. The exogenous C may enable these lichens to become established by providing a source of C for fungal respiration despite drought-induced inactivity of the cyanobacterial partner. As such, the mycobiont may adopt an alternative nutritional strategy, using available exogenous carbon to extend its realized niche. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
C-13-glucose, cyanolichen, fatty acid, niche, Populus overstory, symbiosis
in
Ecology
volume
94
issue
5
pages
1186 - 1195
publisher
Ecological Society of America
external identifiers
  • wos:000318969800020
  • scopus:84878023175
ISSN
0012-9658
DOI
10.1890/12-1857.1
project
BECC
language
English
LU publication?
yes
id
eb038af0-3a8d-4eb0-9d07-f6a8ad7c1fec (old id 3932242)
date added to LUP
2013-07-15 13:41:52
date last changed
2019-03-26 13:18:10
@article{eb038af0-3a8d-4eb0-9d07-f6a8ad7c1fec,
  abstract     = {Foliose lichens with cyanobacterial bionts (bipartite and tripartite) form a distinct assemblage of epiphytes strongly associated with humid microclimatic conditions in inland British Columbia. Previous research showed that these cyano- and cephalolichen communities are disproportionately abundant and species-rich on conifer saplings beneath Populus compared to beneath other tree species. More revealing, lichens with cyanobacterial bionts were observed beneath Populus even in stands that did not otherwise support them. We experimentally test the hypothesis that this association is due to the interception of glucose-rich nectar that is exuded from Populus extra-floral nectaries (EFN). Using CO2 flux measurements and phospholipid fatty acid (PLFA) analysis with experimental applications of C-13(6)-labeled glucose, we demonstrate that cyano-and cephalolichens have a strong respiratory response to glucose. Lichens treated with glucose had lower net photosynthesis and higher establishment rates than control thalli. Furthermore, lichens with cyanobacterial bionts rapidly incorporate exogenous C-13 into lichen fatty acid tissues. A large proportion of the C-13 taken up by the lichens was incorporated into fungal biomarkers, suggesting that the mycobiont absorbed and assimilated the majority of applied C-13(6) glucose. Our observations suggest that both cyanolichens and cephalolichens may utilize an exogenous source of glucose, made available by poplar EFNs. The exogenous C may enable these lichens to become established by providing a source of C for fungal respiration despite drought-induced inactivity of the cyanobacterial partner. As such, the mycobiont may adopt an alternative nutritional strategy, using available exogenous carbon to extend its realized niche.},
  author       = {Campbell, Jocelyn and Bengtson, Per and Fredeen, Arthur L. and Coxson, Darwyn S. and Prescott, Cindy E.},
  issn         = {0012-9658},
  keyword      = {C-13-glucose,cyanolichen,fatty acid,niche,Populus overstory,symbiosis},
  language     = {eng},
  number       = {5},
  pages        = {1186--1195},
  publisher    = {Ecological Society of America},
  series       = {Ecology},
  title        = {Does exogenous carbon extend the realized niche of canopy lichens? Evidence from sub-boreal forests in British Columbia},
  url          = {http://dx.doi.org/10.1890/12-1857.1},
  volume       = {94},
  year         = {2013},
}