TY - JOUR
T1 - Decomposition of Senesced Leaf Litter is Faster in Tall Compared to Low Birch Shrub Tundra
AU - Christiansen, Casper T.
AU - Mack, Michelle C.
AU - DeMarco, Jennie
AU - Grogan, Paul
N1 - Funding Information:
We are thankful for lab assistance from Yvette Chirinian, Olivia RoDee, and Samantha Miller. We also thank Mike Treberg and Robbie Hember for constructing the snowfences, and Karin Clark and Steve and Louise Matthews for logistical support at the Daring Lake TERS. Many helpful comments from two anonymous reviewers greatly improved the manuscript. This work was financed by NSERC and the Department of Environment and Natural Resources in the Government of the Northwest Territories. C.T.C. was financed by an Ontario Trillium scholarship from the Ontario Ministry of Training, Colleges and Universities. M.C.M. and J.D.’s participation was funded by NSF Grants DEB-0516041 and OPP-6767545.
Funding Information:
We are thankful for lab assistance from Yvette Chirinian, Olivia RoDee, and Samantha Miller. We also thank Mike Treberg and Robbie Hember for constructing the snowfences, and Karin Clark and Steve and Louise Matthews for logistical support at the Daring Lake TERS. Many helpful comments from two anonymous reviewers greatly improved the manuscript. This work was financed by NSERC and the Department of Environment and Natural Resources in the Government of the Northwest Territories. C.T.C. was financed by an Ontario Trillium scholarship from the Ontario Ministry of Training, Colleges and Universities. M.C.M. and J.D.’s participation was funded by NSF Grants DEB-0516041 and OPP-6767545. Author Contributions CTC and PG conceived the scientific objectives, and CTC analyzed the data and wrote the paper with contributions from all co-authors. PG established the experimental plots, and MCM and JD supplied the litter material. PG and CTC collected all field data, while CTC collected all lab data, except for fiber forage analysis (MCM).
Publisher Copyright:
© 2018, Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Many Low Arctic tundra regions are currently undergoing a vegetation shift towards increasing growth and groundcover of tall deciduous shrubs due to recent climate warming. Vegetation change directly affects ecosystem carbon balance, but it can also affect soil biogeochemical cycling through physical and biological feedback mechanisms. Recent studies indicate that enhanced snow accumulation around relatively tall shrubs has negligible physical effect on litter decomposition rates. However, these investigations were no more than 3 years, and therefore may be insufficient to detect differences in inherently slow biogeochemical processes. Here, we report a 5-year study near Daring Lake, Canada, comparing Betula neoalaskana foliar litter decay rates within unmanipulated and snowfenced low-stature birch (height: ~ 0.3 m) plots to test the physical effect of experimentally deepened snow, and within tall birch (height: ~ 0.8 m) plots to test the combined physical and biological effects, that is, deepened snow plus strong birch dominance. Having corrected for carbon gain by the colonizing decomposers, actual litter carbon loss increased by approximately 25% in the tall birch relative to both low birch sites. Decay of lignin-like acid unhydrolizable litter residues also accelerated in the tall birch site, and a similar but lower magnitude response in the snowfenced low birch site indicated that physical effects of deepened snow were at least partially responsible. In contrast, deepened snow alone did not affect litter carbon loss. Our findings suggest that a combination of greater litter inputs, altered soil microbial community, enhanced soil nutrient pools, and warmer winter soils together promote relatively fast decomposition of recalcitrant litter carbon in tall birch shrub environments.
AB - Many Low Arctic tundra regions are currently undergoing a vegetation shift towards increasing growth and groundcover of tall deciduous shrubs due to recent climate warming. Vegetation change directly affects ecosystem carbon balance, but it can also affect soil biogeochemical cycling through physical and biological feedback mechanisms. Recent studies indicate that enhanced snow accumulation around relatively tall shrubs has negligible physical effect on litter decomposition rates. However, these investigations were no more than 3 years, and therefore may be insufficient to detect differences in inherently slow biogeochemical processes. Here, we report a 5-year study near Daring Lake, Canada, comparing Betula neoalaskana foliar litter decay rates within unmanipulated and snowfenced low-stature birch (height: ~ 0.3 m) plots to test the physical effect of experimentally deepened snow, and within tall birch (height: ~ 0.8 m) plots to test the combined physical and biological effects, that is, deepened snow plus strong birch dominance. Having corrected for carbon gain by the colonizing decomposers, actual litter carbon loss increased by approximately 25% in the tall birch relative to both low birch sites. Decay of lignin-like acid unhydrolizable litter residues also accelerated in the tall birch site, and a similar but lower magnitude response in the snowfenced low birch site indicated that physical effects of deepened snow were at least partially responsible. In contrast, deepened snow alone did not affect litter carbon loss. Our findings suggest that a combination of greater litter inputs, altered soil microbial community, enhanced soil nutrient pools, and warmer winter soils together promote relatively fast decomposition of recalcitrant litter carbon in tall birch shrub environments.
KW - Arctic
KW - Betula
KW - climate warming
KW - deciduous shrubs
KW - deepened snow
KW - litter decomposition
KW - long-term investigation
UR - http://www.scopus.com/inward/record.url?scp=85044094167&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85044094167&partnerID=8YFLogxK
U2 - 10.1007/s10021-018-0240-6
DO - 10.1007/s10021-018-0240-6
M3 - Article
AN - SCOPUS:85044094167
SN - 1432-9840
VL - 21
SP - 1564
EP - 1579
JO - Ecosystems
JF - Ecosystems
IS - 8
ER -