[Japan-Russia Scientific Forum] Online Workshop“Japan-Russia Collaboration for Ecosystem Monitoring”

Russian-Japanese collaborative studyof ecosystem monitoringin eastern Siberia
Graduate School of Bioagricultural Sciences, Nagoya University

Ayumi Kotani

Forest/Tundra observation stations in eastern Siberia
Kodac (70o37′N 147o54′E) 2013- [RU-JP]

Kytalyk (70o49′N 147o29′E)
2003- [RU-EU]

Spasskaya Pad (62o15′N 129o37′E) 1998[RU-JP-EU]

Larch forest
Pine forest

Annual mean temp. (oC)JJA mean temp. (oC)Annual prec. (mm y-1)
JJA prec. (mm)Canopy height (m)Forest

Tundra-8.3
17.5
236
109
20-13.1
8.3
207
77－

Larch forest
Elgeeii (60o01′N 133o49′E) 2009- [RU-JP]Forest hydrometeorology observation system

Leaf measurement

Biomass measurements

3

Monitoring of ecosystem scale fluxes
CO2 flux

CO2 concentration
wind speed

Solar radiation

30m height

Air temperature
HumidityWind

Soil temperature
Soil moisture
Tower observation system
Observation tower

Eddy covariance method

Measuring CO2 concentration and vertical wind speed
to calculate CO2 exchange between forest and atmosphere
Applicable to other GHG (H2O, CH4) and heat flux.

4Energy cycle

Carbon cycle

Solar energy
CO2 Uptake(assimilation)
CO2 Emission(respiration)

Water cycle

Precipitation
Heat(warming air) Evapotranspiration(cooling air)water inplant

C in plant

RunoffC in soil/litter

C in soil
C in frozen soil (permafrost)

Energy into soil
(Thawing soil)

Water in soil

Elgeeii
Tundra site

Spasskaya Pad

Cumulative carbon accumulation in eastern Siberia (Maximov et al. 2019)
Net balance↓ net uptake

Photosynthesis

Respiration

Seasonal variation of CO2 fluxes in eastern Siberia(Tei et al. 2020, Polar Science)● Forest (SPA) ● Forest (ELG) ● Tundra (CHK) ● Boundary (KOD)

Arctic-Boreal CO2 Flux database(Virkkal et al 2021., )Estimated starting date

Modeling start/end date of plant growing season based on
phenological images and true color SENTINEL-2 satellite
images at Spasskaya Pad (Nagai et al 2020, Polar Science)Too much water affects ecosystem

Sparse larch forest in taiga-tundra boundary area (Chokurdakh)
Extreme flooding in summer of 2017 (due to anomalous snow runoff)

2006Aug.

2008JulyMature larch forest in middle of taiga region (Yakutsk)
Extreme wetting of active layer in 2005-07 due to perennial wet years

Tei et al (2020)

Larch dieback due to soil saturation

Iijima et al (2014)

Iwasaki et al (2010)

NL: normal larch
YBL: yellowing-browning

Mature larch trees
suffered bysaturated water
due to deeper
seasonal thawing.
Larch trees on saturation soil suffered.
Iwasaki et al (2010)(Iijima and Fedrov 2019)

1998

Vegetation changes
density (ha-1)
larch 848
birch 1224
willow216
alder 1241998c)

0trees /0.25ha2014

2014 (main stems only)

200density (ha-1)
larch 760
birch 1892
willow 1128
alder 68

150
10050

Evergreen cowberry
covering floor

10203040

5101520502014d)

00in August, 1997

253035in June, 2009

Developing birches andrapid increasing willows
with recently invading grass

Tree height distribution, crown spatial distribution in 50x50m plot.
• Small changes of mature larch trees• Increase and growth of birch and willow trees of mid-under storley.

in July, 2014

Kotani et al (2019)CO2 exchange changes
Ecosystem scale

drying soil years*observation at June 2011 was unavailable

Understory vegetation

drying soil years

Net CO2exchange(negative= uptake)

Photosynthesis(assimilation)

Respiration(emission)

Warm season CO2 fluxes of ecosystem scale and understory vegetation

The decline in the larch contribution can be compensated for by understory growth,
resulting in a relatively stable ecosystem-scale exchange rate during this study period.

• Processes of ecohydrology,permafrost hydrology, meteorology,
and climatology in the context ofwater, energy, and carbon
exchanges in the Arctic circumpolar
region of eastern Siberia• Unique water and carbon cycle
system in the permafrost region ineastern Siberia• Water-carbon dynamics influenced
by the changing permafrost
environment in recent decades

IBPC, MPI (RU) &Nagoya, Hokkaido, Mie Univ., JAMSTEC (JP)At presentSep. 2019 new tower constructedby colleagues of IBPC
New devices waiting for shippingat Nagoya (hope starting soon!)2020 new tower at Spasskaya Pad