Sensitivity of Siberian larch forests to climate change

AbstractThe monitoring of the spatial and temporal dynamics of vegetation productivity is important in the context of carbon sequestration by terrestrial ecosystems from the atmosphere. The accessibility of the full archive of medium-resolution earth observation data for multiple decades dramatically improved the potential of remote sensing to support global climate change and terrestrial carbon cycle studies. We investigated a dense time series of multi-sensor Landsat Normalized Difference Vegetation Index (NDVI) data at the southern fringe of the boreal forests in the Mongolian forest-steppe with regard to the ability to capture the annual variability in radial stemwood increment and thus forest productivity. Forest productivity was assessed from dendrochronological series of Siberian larch (Larix sibirica) from 15 plots in forest patches of different ages and stand sizes. The results revealed a strong correlation between the maximum growing season NDVI of forest sites and tree ring width over an observation period of 20 years. This relationship was independent of the forest stand size and of the landscape’s forest-to-grassland ratio. We conclude from the consistent findings of our case study that the maximum growing season NDVI can be used for retrospective modelling of forest productivity over larger areas. The usefulness of grassland NDVI as a proxy for forest NDVI to monitor forest productivity in semi-arid areas could only partially be confirmed. Spatial and temporal inconsistencies between forest and grassland NDVI are a consequence of different physiological and ecological vegetation properties. Due to coarse spatial resolution of available satellite data, previous studies were not able to account for small-scaled land-cover patches like fragmented forest in the forest-steppe. Landsat satellite-time series were able to separate those effects and thus may contribute to a better understanding of the impact of global climate change on natural ecosystems.

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Fungi and plant co-variation in Arctic Siberia inferred from sedimentary ancient DNA metabarcoding during the last 45.000 years

10.5194/egusphere-egu21-14604 ◽

2021 ◽

Author(s):

Barbara von Hippel ◽

Kathleen R. Stoof-Leichsenring ◽

Luise Schulte ◽

Peter Seeber ◽

Laura S. Epp ◽

...

Keyword(s):

Climate Change ◽

Ancient Dna ◽

Mycorrhizal Fungi ◽

Vegetation Change ◽

Sediment Cores ◽

Siberian Larch ◽

Biotic Interactions ◽

Arctic Ecosystems ◽

Arctic Regions ◽

Arctic Siberia

<p>Climate change has a great impact on boreal ecosystems including Siberian larch forests. As a consequence of warming, larch grow is possible in areas where climate used to be too cold, leading to a shift of the tree line into more arctic regions. Most plants co-exist in symbiosis with heterotrophic organisms surrounding their root system. In arctic ecosystems, mycorrhizal fungi are a prerequisite for plant establishment and survival because they support nutrient uptake from nutrient-poor soils and maintain the water supply. Until now, however, knowledge about the co-variation of vegetation and fungi is poor. Certainly, the understanding of dynamic changes in biotic interactions is important to understand adaptation mechanisms of ecosystems to climate change.</p><p>We investigated sedimentary ancient DNA from Lake Levinson Lessing, Taymyr Peninsula (Arctic Siberia, tundra), Lake Lama, Lake Kyutyunda (both northern Siberia, tundra-taiga transition zone) and Lake Bolshoe Toko (southern Siberia, forest area) covering the last about 45.000 years using ITS primers for fungi along with the chloroplast P6 loop marker for vegetation metabarcoding. We found changes in the fungal communities that are in broad agreement with vegetation turnover. To our knowledge, this is the first broad ecological study on lake sediment cores to analyze fungal biodiversity in relation to vegetation change on millennial time scales.</p>

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Vegetation Indices Do Not Capture Forest Cover Variation in Upland Siberian Larch Forests

Remote Sensing ◽

10.3390/rs10111686 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1686 ◽

Cited By ~ 8

Author(s):

Michael Loranty ◽

Sergey Davydov ◽

Heather Kropp ◽

Heather Alexander ◽

Michelle Mack ◽

...

Keyword(s):

Carbon Storage ◽

Vegetation Change ◽

Vegetation Index ◽

Forest Cover ◽

Global Climate ◽

Vegetation Indices ◽

Temporal Trends ◽

Siberian Larch ◽

Field Observations ◽

Larch Forests

Boreal forests are changing in response to climate, with potentially important feedbacks to regional and global climate through altered carbon cycle and albedo dynamics. These feedback processes will be affected by vegetation changes, and feedback strengths will largely rely on the spatial extent and timing of vegetation change. Satellite remote sensing is widely used to monitor vegetation dynamics, and vegetation indices (VIs) are frequently used to characterize spatial and temporal trends in vegetation productivity. In this study we combine field observations of larch forest cover across a 25 km2 upland landscape in northeastern Siberia with high-resolution satellite observations to determine how the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) are related to forest cover. Across 46 forest stands ranging from 0% to 90% larch canopy cover, we find either no change, or declines in NDVI and EVI derived from PlanetScope CubeSat and Landsat data with increasing forest cover. In conjunction with field observations of NDVI, these results indicate that understory vegetation likely exerts a strong influence on vegetation indices in these ecosystems. This suggests that positive decadal trends in NDVI in Siberian larch forests may correspond primarily to increases in understory productivity, or even to declines in forest cover. Consequently, positive NDVI trends may be associated with declines in terrestrial carbon storage and increases in albedo, rather than increases in carbon storage and decreases in albedo that are commonly assumed. Moreover, it is also likely that important ecological changes such as large changes in forest density or variable forest regrowth after fire are not captured by long-term NDVI trends.

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Assessing Forest Ecosystems across the Vertical Edge of the Mid-Latitude Ecotone Using the BioGeoChemistry Management Model (BGC-MAN)

Forests ◽

10.3390/f10060523 ◽

2019 ◽

Vol 10 (6) ◽

pp. 523 ◽

Cited By ~ 2

Author(s):

Cholho Song ◽

Stephan A. Pietsch ◽

Moonil Kim ◽

Sungeun Cha ◽

Eunbeen Park ◽

...

Keyword(s):

Transition Zone ◽

Primary Productivity ◽

Forest Ecosystems ◽

Net Primary Productivity ◽

Northeast Asia ◽

Siberian Larch ◽

Management Model ◽

High Mountain ◽

Specific Information ◽

Larch Forests

The mid-latitude ecotone (MLE)—a transition zone between boreal and temperate forests, which includes the regions of Northeast Asia around 30°–60° N latitudes—delivers different ecosystem functions depending on different management activities. In this study, we assessed forest volume and net primary productivity changes in the MLE of Northeast Asia under different ecological characteristics, as well as various current management activities, using the BioGeoChemistry Management Model (BGC-MAN). We selected five pilot sites for pine (Scots pine and Korean red pine; Pinus sylvestris and P. densiflora), oak (Quercus spp.), and larch forests (Dahurian larch and Siberian larch; Larix gmelinii and L. sibirica), respectively, which covered the transition zone across the MLE from Lake Baikal, Russia to Kyushu, Japan, including Mongolia, Northeast China, and the Korean Peninsula. With site-specific information, soil characteristics, and management descriptions by forest species, we established their management characteristics as natural preserved forests, degraded forests, sandy and cold forest stands, and forests exposed to fires. We simulated forest volume (m3) and net primary productivity (Mg C ha−1) during 1960–2005 and compared the results with published literature. They were in the range of those specified in previous studies, with some site-levels under or over estimation, but unbiased estimates in their mean values for pine, oak, and larch forests. Annual rates of change in volume and net primary productivity differed by latitude, site conditions, and climatic characteristics. For larch forests, we identified a high mountain ecotype which warrants a separate model parameterization. We detected changes in forest ecosystems, explaining ecological transition in the Northeast Asian MLE. Under the transition, we need to resolve expected problems through appropriate forest management and social efforts.

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Wildfires Dynamics in Siberian Larch Forests

Forests ◽

10.3390/f7060125 ◽

2016 ◽

Vol 7 (12) ◽

pp. 125 ◽

Cited By ~ 42

Author(s):

Evgenii Ponomarev ◽

Viacheslav Kharuk ◽

Kenneth Ranson

Keyword(s):

Siberian Larch ◽

Larch Forests

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Functioning of the Leaf Apparatus, Root System and Biological Productivity of Siberian Larch on the Level of the Organism in Ontogeny (the Case of Larch Forests of the Arkhangelsk Region)

Lesnoy Zhurnal (Forestry Journal) ◽

10.17238/issn0536-1036.2018.3.9 ◽

2018 ◽

pp. 9-19

Author(s):

V.M. Lebedev ◽

◽

E.V. Lebedev

Keyword(s):

Root System ◽

Siberian Larch ◽

Biological Productivity ◽

Arkhangelsk Region ◽

Larch Forests

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Water, Energy, and Carbon Dioxide Circulation in Eastern Siberian Larch Forests: GAME, CREST and RIHN Results

JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES ◽

10.3178/jjshwr.29.294 ◽

2016 ◽

Vol 29 (5) ◽

pp. 294-312

Author(s):

Takeshi OHTA ◽

Tetsuya HIYAMA ◽

Ayumi KOTANI ◽

Takeshi YAMAZAKI ◽

Trofim C. MAXIMOV

Keyword(s):

Carbon Dioxide ◽

Siberian Larch ◽

Larch Forests

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Siberian larch forests and the ion content of thaw lakes form a geochemically functional entity

Nature Communications ◽

10.1038/ncomms3408 ◽

2013 ◽

Vol 4 (1) ◽

Cited By ~ 19

Author(s):

Ulrike Herzschuh ◽

Luidmila A. Pestryakova ◽

Larissa A. Savelieva ◽

Liv Heinecke ◽

Thomas Böhmer ◽

...

Keyword(s):

Siberian Larch ◽

Ion Content ◽

Functional Entity ◽

Larch Forests ◽

Thaw Lakes

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Development of multistemmed life forms of Siberian larch as an indicator of climate change in the timberline ecotone of the Polar Urals

Russian Journal of Ecology ◽

10.1134/s1067413607060112 ◽

2007 ◽

Vol 38 (6) ◽

pp. 440-443 ◽

Cited By ~ 2

Author(s):

V. S. Mazepa ◽

N. M. Devi

Keyword(s):

Climate Change ◽

Siberian Larch ◽

Life Forms ◽

Polar Urals ◽

Timberline Ecotone ◽

The Polar Urals

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Evaluating the Differenced Normalized Burn Ratio for Assessing Fire Severity Using Sentinel-2 Imagery in Northeast Siberian Larch Forests

Remote Sensing ◽

10.3390/rs13122311 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2311

Author(s):

Clement J. F. Delcourt ◽

Alisha Combee ◽

Brian Izbicki ◽

Michelle C. Mack ◽

Trofim Maximov ◽

...

Keyword(s):

Boreal Forests ◽

Fire Severity ◽

Siberian Larch ◽

Fire Scars ◽

Differenced Normalized Burn Ratio ◽

Larch Forests ◽

Normalized Burn Ratio ◽

Burn Depth ◽

Field Plots ◽

Sentinel 2

Fire severity is a key fire regime characteristic with high ecological and carbon cycle relevance. Prior studies on boreal forest fires primarily focused on mapping severity in North American boreal forests. However, the dominant tree species and their impacts on fire regimes are different between North American and Siberian boreal forests. Here, we used Sentinel-2 satellite imagery to test the potential for using the most common spectral index for assessing fire severity, the differenced Normalized Burn Ratio (dNBR), over two fire scars and 37 field plots in Northeast Siberian larch-dominated (Larix cajanderi) forests. These field plots were sampled into two different forest types: (1) dense young stands and (2) open mature stands. For this evaluation, the dNBR was compared to field measurements of the Geometrically structured Composite Burn Index (GeoCBI) and burn depth. We found a linear relationship between dNBR and GeoCBI using data from all forest types (R2 = 0.42, p < 0.001). The dNBR performed better to predict GeoCBI in open mature larch plots (R2 = 0.56, p < 0.001). The GeoCBI provides a holistic field assessment of fire severity yet is dominated by the effect of fire on vegetation. No significant relationships were found between GeoCBI components (overall and substrate stratum) and burn depth within our fires (p > 0.05 in all cases). However, the dNBR showed some potential as a predictor for burn depth, especially in the dense larch forests (R2 = 0.63, p < 0.001). In line with previous studies in boreal North America, the dNBR correlated reasonably well with field data of aboveground fire severity and showed some skills as a predictor of burn depth. More research is needed to refine spaceborne fire severity assessments in the larch forests of Northeast Siberia, including assessments of additional fire scars and integration of dNBR with other geospatial proxies of fire severity.

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