Proportion of fine roots, but not plant biomass allocation below ground, increases with elevation in arctic tundra
[1];
- Umeå Univ., Abisko (Sweden); Greifswald Univ., Greifswald (Germany)
- Umeå Univ., Abisko (Sweden)
- Univ. of Copenhagen, Copenhagen (Denmark); Univ. of Vermont, Burlington, VT (United States)
- Umeå Univ., Abisko (Sweden); Univ. of Copenhagen, Copenhagen (Denmark)
- Western Carolina Univ., Cullowhee, NC (United States)
Questions: Roots represent a considerable proportion of biomass, primary production and litter input in arctic tundra, and plant allocation of biomass to above- or below- ground tissue in response to climate change is a key factor in the future C balance of these ecosystems. According to optimality theory plants allocate C to the above- or below-ground structure that captures the most limiting resource. We used an elevational gradient to test this theory and as a space-for-time substitution to inform on tundra carbon allocation patterns under a shifting climate, by exploring if increasing elevation was positively related to the root:shoot ratio, as well as a larger plant allocation to adsorptive over storage roots.Location: Arctic tundra heath dominated by Empetrum hermaphroditum close to Abisko, Sweden. Methods: We measured root:shoot and fine:coarse root ratios of the plant communities along an elevational gradient by sampling above- and below-ground biomass, further separating root biomass into fine (<1 mm) and coarse roots. Results: Plant biomass was higher at the lower elevations, but the root:shoot ratio did not vary with elevation. Resource allocation to fine relative to coarse roots increased with elevation, resulting in a fine:coarse root ratio that more than doubled with in- creasing elevation. Conclusions: Contrary to previous works, the root:shoot ratio along this elevational gradient remained stable. However, communities along our study system were dominated by the same species at each elevation, which suggests that when changes in the root:shoot ratio occur with elevation these changes may be driven by differences in allocation patterns among species and thus turnover in plant community structure. Our results further reveal that the allocation of biomass to fine relative to coarse roots can differ between locations along an elevational gradient, even when overall above- vs below-ground biomass allocation does not. Given the functionally different roles of fine vs coarse roots this could have large implications for below-ground C cycling. Thus. our results highlight the importance of direct effects vs indirect effects (such as changes in plant community composition and nutrient availability) of climate change for future C allocation above and below ground.
- Research Organization:
- Univ. of Tennessee, Knoxville, TN (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- SC0010562
- OSTI ID:
- 1501424
- Journal Information:
- Journal of Vegetation Science, Vol. 29, Issue 2; ISSN 1100-9233
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Annual ring growth of a widespread high arctic shrub reflects past fluctuations in community‐level plant biomass
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journal | August 2018 |
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