TY - JOUR
T1 - Patterns of bryophyte succession in a 160-year chronosequence in deciduous and coniferous forests of boreal Alaska
AU - Jean, Mélanie
AU - Alexander, Heather D.
AU - Mack, Michelle C.
AU - Johnstone, Jill F.
N1 - Funding Information:
We would like to thank Alix Conway, Xanthe Walker, Nicolas Boldt, Patricia Tomchuk, and Dominic Olver from the University of Saskatchewan and Kamala Earl, Camilo Mojica, Nils Pederson, Leslie Boby, Mindy Sun, and Jennifer Stanley from the University of Florida for their help in the field and laboratory and Dr. Terry McIntosh for his support in verification of the 2013-2015 bryophyte specimens. We appreciate the assistance of the U.S. Army for allowing access to burned areas on military lands. Funding for this research was provided by the Department of Defense’s Strategic Environmental Research and Development Program (SERDP) under project RC-2109, the Natural Science and Engineering Research Council of Canada (NSERC), the Northern Scientific Training Program (NSTP), NASA Ecosystems and Carbon Cycle Grant NNX08AG13G, the National Science Foundation’s Bonanza Creek Long Term Ecological Research Site program funded by NSF DEB-0620579, and USDA Forest Service, Pacific Northwest Research Station, grant PNW01-JV11261952-23.
Publisher Copyright:
© 2017, Published by NRC Research Press.
PY - 2017
Y1 - 2017
N2 - Bryophytes are dominant components of boreal forest understories and play a large role in regulating soil microclimate and nutrient cycling. Therefore, shifts in bryophyte communities have the potential to affect boreal forests’ ecosystem processes. We investigated how bryophyte communities varied in 83 forest stands in interior Alaska that ranged in age (since fire) from 8 to 163 years and had canopies dominated by deciduous broadleaf (Populus tremuloides Michx. or Betula neoalaskana Sarg.) or coniferous trees (Picea mariana Mill B.S.P.). In each stand, we measured bryophyte community composition, along with environmental variables (e.g., organic layer depth, leaf litter cover, moisture). Bryophyte communities were initially similar in deciduous vs. coniferous forests but diverged in older stands in association with changes in organic layer depth and leaf litter cover. Our data suggest two tipping points in bryophyte succession: one at the disappearance of early colonizing taxa 20 years after fire and another at 40 years after fire, which corresponds to canopy closure and differential leaf litter inputs in mature deciduous and coniferous canopies. Our results enhance understanding of the processes that shape compositional patterns and ecosystem services of bryophytes in relation to stand age, canopy composition, and changing disturbances such as fire that may trigger changes in canopy composition.
AB - Bryophytes are dominant components of boreal forest understories and play a large role in regulating soil microclimate and nutrient cycling. Therefore, shifts in bryophyte communities have the potential to affect boreal forests’ ecosystem processes. We investigated how bryophyte communities varied in 83 forest stands in interior Alaska that ranged in age (since fire) from 8 to 163 years and had canopies dominated by deciduous broadleaf (Populus tremuloides Michx. or Betula neoalaskana Sarg.) or coniferous trees (Picea mariana Mill B.S.P.). In each stand, we measured bryophyte community composition, along with environmental variables (e.g., organic layer depth, leaf litter cover, moisture). Bryophyte communities were initially similar in deciduous vs. coniferous forests but diverged in older stands in association with changes in organic layer depth and leaf litter cover. Our data suggest two tipping points in bryophyte succession: one at the disappearance of early colonizing taxa 20 years after fire and another at 40 years after fire, which corresponds to canopy closure and differential leaf litter inputs in mature deciduous and coniferous canopies. Our results enhance understanding of the processes that shape compositional patterns and ecosystem services of bryophytes in relation to stand age, canopy composition, and changing disturbances such as fire that may trigger changes in canopy composition.
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U2 - 10.1139/cjfr-2017-0013
DO - 10.1139/cjfr-2017-0013
M3 - Article
AN - SCOPUS:85026639184
SN - 0045-5067
VL - 47
SP - 1021
EP - 1032
JO - Canadian Journal of Forest Research
JF - Canadian Journal of Forest Research
IS - 8
ER -