Soil organic matter dynamics in mountainous environments under a changing climate - Concepts and methodology

Transcription

1 Soil organic matter dynamics in mountainous environments under a changing climate - Concepts and methodology Frank Hagedorn and Stephan Zimmermann Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) Birmensdorf (CH)

2 1. Why to look at feedbacks climate change - SOM? 2. Experimental approaches 3. Case study: Treelines in the Ural mountains 4. Case study: Alpine treeline in Stillberg (Switzerland) 5. Learning from the global C distribution and past outline

3 outline Batjes, European Journal of Soil Science, 47, , 1996

4 Feedbacks: Warming C storage Warming Growth SOM-decay + _ atmospheric CO2 SOM increase background C storage

5 Will changes in soil organic carbon act as a positive or negative feedback on global warming? Miko U.F. Kirschbaum Biogeochemistry 48, 21-51, 2000 Feedbacks: SOM climate LGM: Last Glacial Maximum

6 Feedbacks: SOM climate

7 Van't Hoff, 1898: Change of reaction rates across 10K Q 10 = ( k 2 / k1) ( T 10 2 T 1) Temperature dependency SOM-decay + Warming atmospheric CO 2 _ Growth SOM increase C storage

8 1. Laboratory incubations Experimental approaches 2. Soil warming studies 3. Altitudinal/latitudinal transects

9 CO 2 -Production DOC-leaching Laboratory incubation

10 Temperature drives soil respiration Laboratory incubation From Reichstein et al. (2000): Soil Biol. Biochem. 32,

11 Q10 - Temperature dependent Laboratory incubation Ref.: Kirschbaum (1995): Soil Biol. Biochem. 27, Mikan et al. (2002): Soil Biol. Biochem. 34,

12 Summary laboratory incubation Temperature sensitivity greater at lower T Limitations More rapid losses of labile SOM at high T Disturbance, no input

13 Experimental Warming Soil warming studies Greenhouse-Warming Val Bercla, Switzerland Marion et al., Global Change Biology 3 (Suppl.1), 20-32, 1997 Hollister and Webber, Global Change Biology 6, , 2000

14 UV-Lamps Soil warming studies Problems: Decreasing air humidity Non-uniform heating

15 Heating cables Problems Soil Disturbance Soil warming studies Non-uniform heating

16 Warming: increased C losses Soil warming studies Ref.: Melillo et al. (2002): Science 298,

17 Warming: increased C losses Soil warming studies Ref.: Melillo et al. (2002): Science 298,

18 Summary soil warming studies Experimental warming Warming = Drying Uneven warming: C fluxes respond differently Response time dependent

19 Altitudinal transect Altitudinal transects Maly Iremel, Southern-Ural

20 Where to look? 1. Sensitive region Altitudinal transects 2. Low anthropogenic influence 3. Large areas

21 Global Warming - Greater warming in winter Summer Winter Altitudinal transects

22 Treeline is limited by summer temperature Altitudinal transects Ref.: Körner & Paulsen (2004): Journal of Biogeography 31,

23 Altitudinal transects Study Area - Treeline in the Ural mountains

24 Rising treelines 1929 Altitudinal transects (Moiseev, Shiyatov, 2003)

25 Rising treelines Altitudinal transects

26 Northern treeline Altitudinal transects

27 -10 January C Altitudinal transects Monthly Mean Temperature ( C) April +4.0 C July +0 C October +1.4 C Year South-Ural Taganai,1100 m Data from Fomin, Moiseev

28 Summary altitudinal transects 1. Treeline sensitive to temperature 2. Large scale changes of treelines in remote regions 3. Warming particular in winter (?)

29 Early Response Areas for Climate Change in Eurasia - Spatio-Temporal Dynamics of the Upper Tree-line in the Ural Mountains and Implications for Carbon Sequestration IPAE, USFEU Ekaterinburg SB RAS Krasnojarsk ETH Zürich Uni Halle WSL Birmensdorf Case study Ural EU-INTAS Diploma thesis of Adrian Kammer under the supervision of Dr. Frank Hagedorn, WSL Birmensdorf

30 Altitudinal Gradient: Space for time and climatic change Case study Ural Maly Iremel, Southern-Ural

31 Altitudinal Gradient Case study Ural Forest (1260m.a.s.l.) Treeline (1360m.a.s.l.) Mali Iremel (1449m.a.s.l) 0.3K 3km

32 C-pool estimates Case study Ural

33 C-pool estimates: C-Allocation Case study Ural Devy, Mazepa, Hagedorn, Rigling unpublished data

34 Transect: Space for time and climate change C-pools and productivity Case study Ural Maly Iremel, Southern-Ural

35 Rising treeline and soil carbon: mechanisms 1. Greater C-Input through more biomass (above-ground: 180 vs. 60 g C m -2 y -1 ) Case study Ural 2. Greater decomposition through warming?

36 Micro climate: air temperature Case study Ural Temperature ( C) Air Tundra 1350 m Forest 1250 m

37 Micro climate: soil temperature Air Case study Ural Temperature ( C) Soil Tundra 1350 m Forest 1250 m

38 Winter climate 1360 m 1300 m Case study Ural

39 Winter climate: Snow height and temperature Case study Ural Altitude (m.a.s.l.) Snow height (cm) Treeline Soil Wintertemperature ( C)

40 Sampling: soil C pools 3 altitudes 4 trees 2 profiles under trees and Case study Ural open land L, F, H, 0-7cm, 7-25cm, 25-C additional topsoil sampling areal and volume based sampling

41 Soils: Cambisols Tundra 1360 m a.s.l. Case study Ural Forest 1260 m a.s.l.

42 Case study Ural Altitudinal transect Ural: Soil profiles

43 Case study Ural Altitudinal transect Ural: Soil C pools

44 Case study Ural Altitudinal transect Ural: Soil C pools

45 Altitudinal transect Ural: Soil C-Pools Case study Ural Maly Iremel: Southern-Ural Kammer, Hagedorn unpublished data

46 Altitudinal transect Ural: Soil C-Pools and producitivity Case study Ural Maly Iremel: Southern-Ural Kammer, Hagedorn unpublished data

47 Case study Ural Altitudinal transect Ural: SOM quality changes from tundra to forest

48 Case study Ural Altitudinal transect Ural: SOM quality changes from tundra to forest

49 SOM < > climate change Rising treelines and C pools 1. Increasing biomass: 15 tc/ha 75 tc/ha Case study Ural 2. Tripling of litter input %-increase of soil C pool t C ha SOM quality increases

50 C-Mineralisation (SOM CO 2 ) Case study Ural

51 C-Mineralisation (SOM CO 2 ) Case study Ural

52 Case study Ural In situ decomposition (litter bags)

53 Annual C mineralization Modelling with soil temperatures and SOM pools ICBM (Andrén & Kätterer, 1997) Case study Ural

54 Annual C in- and outputs Case study Ural

55 Summary Rising treelines More biomass (15 75 t C ha -1 ) Better Decomposability Warmer microclimate Case study Ural Greater litter input Faster C-turnover compensated for greater C inputs How does it affect N-cycling? Greater decomposition

56 N-Mineralisation Case study Ural

57 Feedbacks: Winterwarming - Rising Treeline Warming Precipitation 1 Snow cover Plant (Tree)- growth Soil temperature Case study Ural N availability SOM turnover Microbial activity 1 Devi et al., Global Change Biology 14, , 2008

58 SOM <-> climate change: Summary Climatic change likely affects C in- and outputs in similar ways Total SOM pool (=C sink) remains unchanged Case study Ural SOM turnover increases

59 Case study Ural Thanks! M. Bauer, P. Egli, T. Handa, S. Hättenschwiler, J. Hutzler, T. Hollmann, A. Kammer, R. Köchli, Ch. Körner, W. Landolt, P. Moiseev, A. Rigling, M. Saurer, R. Siegwolf, D. Spinnler, D. Tarjan, A. Zürcher, Schweizer Nationalfonds, BAFU, EU-INTAS