Details
| Original language | English |
|---|---|
| Pages (from-to) | 1570-1583 |
| Number of pages | 14 |
| Journal | Global change biology |
| Volume | 15 |
| Issue number | 6 |
| Publication status | Published - 4 May 2009 |
Abstract
Historical photographs document that during the last century, forests have expanded upwards by 60-80 m into former tundra of the pristine Ural mountains. We assessed how the shift of the high-altitude treeline ecotone might affect soil organic matter (SOM) dynamics. On the gentle slopes of Mali Iremel in the Southern Urals, we (1) determined the differences in SOM stocks and properties from the tundra at 1360m above sea level (a.s.l.) to the subalpine forest at 1260 m a.s.l., and (2) measured carbon (C) and nitrogen (N) mineralization from tundra and forest soils at 7 and 20°C in a 6-month incubation experiment. C stocks of organic layers were 3.6±0.3 kg C m-2 in the tundra and 1.9±0.2 kg C m-2 in the forest. Mineral soils down to the bedrock stored significantly more C in the forest, and thus, total soil C stocks were slightly but insignificantly greater in the forest (+3 kg C m-2). Assuming a space for time approach based on tree ages suggests that the soil C sink due to the forest expansion during the last century was at most 30 g C m-2 yr-1. Diffuse reflective infrared spectroscopy and scanning calorimetry revealed that SOM under forest was less humified in both organic and mineral horizons and, therefore, contained more available substrate. Consistent with this result, C mineralization rates of organic layers and A horizons of the forest were two to four times greater than those of tundra soils. This difference was similar in magnitude to the effect of increasing the incubation temperature from 7 to 20°C. Hence, indirect climate change effects through an upward expansion of forests can be much larger than direct warming effects (Δ0.3K across the treeline). Net N mineralization was 2.5 to six times greater in forest than in tundra soils, suggesting that an advancing treeline likely increases N availability. This may provide a nutritional basis for the fivefold increase in plant biomass and a tripling in productivity from the tundra to the forest. In summary, our results suggest that an upward expansion of forest has small net effects on C storage in soils but leads to changes in SOM quality, accelerates C cycling and increases net N mineralization, which in turn might stimulate plant growth and thus C sequestration in tree biomass.
Keywords
- Carbon sequestration, Climate change, Decomposition, Microclimate, Nitrogen mineralization, Siberia, Soil incubation, Temperature dependency, Tundra
ASJC Scopus subject areas
- Environmental Science(all)
- Global and Planetary Change
- Environmental Science(all)
- Environmental Chemistry
- Environmental Science(all)
- Ecology
- Environmental Science(all)
Sustainable Development Goals
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In: Global change biology, Vol. 15, No. 6, 04.05.2009, p. 1570-1583.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Treeline shifts in the Ural mountains affect soil organic matter dynamics
AU - Kammer, Adrian
AU - Hagedorn, Frank
AU - Shevchenko, Ilya
AU - Leifeld, Jens
AU - Guggenberger, Georg
AU - Goryacheva, Tamara
AU - Rigling, Andreas
AU - Moiseev, Pavel
PY - 2009/5/4
Y1 - 2009/5/4
N2 - Historical photographs document that during the last century, forests have expanded upwards by 60-80 m into former tundra of the pristine Ural mountains. We assessed how the shift of the high-altitude treeline ecotone might affect soil organic matter (SOM) dynamics. On the gentle slopes of Mali Iremel in the Southern Urals, we (1) determined the differences in SOM stocks and properties from the tundra at 1360m above sea level (a.s.l.) to the subalpine forest at 1260 m a.s.l., and (2) measured carbon (C) and nitrogen (N) mineralization from tundra and forest soils at 7 and 20°C in a 6-month incubation experiment. C stocks of organic layers were 3.6±0.3 kg C m-2 in the tundra and 1.9±0.2 kg C m-2 in the forest. Mineral soils down to the bedrock stored significantly more C in the forest, and thus, total soil C stocks were slightly but insignificantly greater in the forest (+3 kg C m-2). Assuming a space for time approach based on tree ages suggests that the soil C sink due to the forest expansion during the last century was at most 30 g C m-2 yr-1. Diffuse reflective infrared spectroscopy and scanning calorimetry revealed that SOM under forest was less humified in both organic and mineral horizons and, therefore, contained more available substrate. Consistent with this result, C mineralization rates of organic layers and A horizons of the forest were two to four times greater than those of tundra soils. This difference was similar in magnitude to the effect of increasing the incubation temperature from 7 to 20°C. Hence, indirect climate change effects through an upward expansion of forests can be much larger than direct warming effects (Δ0.3K across the treeline). Net N mineralization was 2.5 to six times greater in forest than in tundra soils, suggesting that an advancing treeline likely increases N availability. This may provide a nutritional basis for the fivefold increase in plant biomass and a tripling in productivity from the tundra to the forest. In summary, our results suggest that an upward expansion of forest has small net effects on C storage in soils but leads to changes in SOM quality, accelerates C cycling and increases net N mineralization, which in turn might stimulate plant growth and thus C sequestration in tree biomass.
AB - Historical photographs document that during the last century, forests have expanded upwards by 60-80 m into former tundra of the pristine Ural mountains. We assessed how the shift of the high-altitude treeline ecotone might affect soil organic matter (SOM) dynamics. On the gentle slopes of Mali Iremel in the Southern Urals, we (1) determined the differences in SOM stocks and properties from the tundra at 1360m above sea level (a.s.l.) to the subalpine forest at 1260 m a.s.l., and (2) measured carbon (C) and nitrogen (N) mineralization from tundra and forest soils at 7 and 20°C in a 6-month incubation experiment. C stocks of organic layers were 3.6±0.3 kg C m-2 in the tundra and 1.9±0.2 kg C m-2 in the forest. Mineral soils down to the bedrock stored significantly more C in the forest, and thus, total soil C stocks were slightly but insignificantly greater in the forest (+3 kg C m-2). Assuming a space for time approach based on tree ages suggests that the soil C sink due to the forest expansion during the last century was at most 30 g C m-2 yr-1. Diffuse reflective infrared spectroscopy and scanning calorimetry revealed that SOM under forest was less humified in both organic and mineral horizons and, therefore, contained more available substrate. Consistent with this result, C mineralization rates of organic layers and A horizons of the forest were two to four times greater than those of tundra soils. This difference was similar in magnitude to the effect of increasing the incubation temperature from 7 to 20°C. Hence, indirect climate change effects through an upward expansion of forests can be much larger than direct warming effects (Δ0.3K across the treeline). Net N mineralization was 2.5 to six times greater in forest than in tundra soils, suggesting that an advancing treeline likely increases N availability. This may provide a nutritional basis for the fivefold increase in plant biomass and a tripling in productivity from the tundra to the forest. In summary, our results suggest that an upward expansion of forest has small net effects on C storage in soils but leads to changes in SOM quality, accelerates C cycling and increases net N mineralization, which in turn might stimulate plant growth and thus C sequestration in tree biomass.
KW - Carbon sequestration
KW - Climate change
KW - Decomposition
KW - Microclimate
KW - Nitrogen mineralization
KW - Siberia
KW - Soil incubation
KW - Temperature dependency
KW - Tundra
UR - http://www.scopus.com/inward/record.url?scp=65549147223&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2486.2009.01856.x
DO - 10.1111/j.1365-2486.2009.01856.x
M3 - Article
AN - SCOPUS:65549147223
VL - 15
SP - 1570
EP - 1583
JO - Global change biology
JF - Global change biology
SN - 1354-1013
IS - 6
ER -