The role of fires for tundra-forest transition in northwest Siberia

2021 ◽  
Author(s):  
Ekaterina Ezhova ◽  
Oleg Sizov ◽  
Petr Tsymbarovich ◽  
Andrey Soromotin ◽  
Nikolay Prihod'ko ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Growing Season ◽  
Climatic Conditions ◽  
Time Interval ◽  
Arctic Vegetation ◽  
Global Carbon Budget ◽  
Growing Season Length ◽  
Period Shift ◽  
Bioclimatic Model ◽  
Total Study Area

<p>Transition of arctic vegetation from tundra to shrubs and forest is an important process influencing global carbon budget. Transition is predicted due to warming and prolongation of the growing season but observations show that it is slower than expected. Fires are disturbances that could trigger a shift of biomes.</p><p>We studied the transition of dry tundra to forest and woodland in northwest Siberia for burned and background sites within the time interval of 60 years. We used meteorological data to estimate potential shifts in vegetation based on a bioclimatic model. To investigate fire and vegetation dynamics, we used historical and modern satellite imagery (Corona KH-4b, Landsat-5,7,8, Resurs-P, SPOT-6,7). We performed comparative analysis of vegetation using high-resolution satellite data from different years.</p><p>The growing season length increased by 20 days and the mean temperature of the growing season increased by 1°C making climatic conditions suitable for trees. We showed that ca 40% of the total study area experienced fires at least once during the last 60 years. Within this period, shift from dry tundra to tree-dominated vegetation occurred in 6-15% of the area in the non-disturbed sites compared to 40-85% of the area in the burned sites.</p>

scholarly journals Projections of Climate Suitability for Wine Production for the Cotnari Wine Region (Romania)

2019 ◽  
Vol 13 (1) ◽  
pp. 5-18 ◽  
Author(s):  
Irimia Liviu Mihai ◽  
Patriche Cristian Valeriu ◽  
LeRoux Renan ◽  
Quénol Herve ◽  
Tissot Cyril ◽  
...  
Keyword(s):  
Growing Season ◽  
Climatic Conditions ◽  
Climate Projections ◽  
Lower Zone ◽  
Wine Production ◽  
White Wines ◽  
Growing Season Length ◽  
Average Annual Temperature ◽  
Climate Suitability ◽  
Wine Region

Abstract Climate projections have revealed the perspective of changing the climate of the world's wine regions in the coming decades by diversifying heliothermal resources. Research in the Cotnari winegrowing region over the past decade has shown that the local climate has been affected by such developments especially after 1980. This research continues the series of studies on the climate of the Cotnari winegrowing region through projections of the climatic conditions for the 2020-2100 time period based on the RCP 4.5 scenario. Average annual temperature, warmest month temperature, precipitation during the growing season, length of the growing season and the Huglin, IAOe and AvGST bioclimatic indices for the 2020-2050, 2051-2080 and 2081-2100 time periods indicate the evolution of Cotnari area climate towards suitability for red wines and loss of suitability for the white wines. Climatic suitability classes for wine production, shift between 2020-2100 to the higher, cooler zone of the winegrowing region, narrowing down their surface and disappearing successively at the maximum altitude of 315 m asl. They are further replaced from the lower zone by classes specific to warmer climates. The suitability for white wines, specific to wine region, disappears at the maximum altitude of 315 m asl around 2060, being replaced by climate suitability for the red wine production. The average temperature of the growing season will exceed 19.5°C after 2080, becoming unsuitable for the production of red quality wines of Cabernet Sauvingnon variety. After 2050, in the lower zone of the winegrowing region the warm IH5 class, suitable for Mediterranean varieties such as Carignan and Grenache will install, as compared to temperate IH3 class which characterizes today the lower zone and allows the production of white wines of the local Feteasca albă, Grasa de Cotnari, Frâncușa and Tămâioasa românească varieties. The results suggest the need to develop strategies for adapting the viticulture of the Cotnari area to climate change.

scholarly journals High resistance to climatic variability in a dominant tundra shrub species

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6967 ◽  
Author(s):  
Victoria T. González ◽  
Mikel Moriana-Armendariz ◽  
Snorre B. Hagen ◽  
Bente Lindgård ◽  
Rigmor Reiersen ◽  
...  
Keyword(s):  
Climate Change ◽  
High Resistance ◽  
Climatic Variability ◽  
Growing Season ◽  
Climatic Conditions ◽  
Vegetative Cover ◽  
Growth And Survival ◽  
Growing Season Length ◽  
Temperature And Precipitation ◽  
Precipitation Regimes

Climate change is modifying temperature and precipitation regimes across all seasons in northern ecosystems. Summer temperatures are higher, growing seasons extend into spring and fall and snow cover conditions are more variable during winter. The resistance of dominant tundra species to these season-specific changes, with each season potentially having contrasting effects on their growth and survival, can determine the future of tundra plant communities under climate change. In our study, we evaluated the effects of several spring/summer and winter climatic variables (i.e., summer temperature, growing season length, growing degree days, and number of winter freezing days) on the resistance of the dwarf shrub Empetrum nigrum. We measured over six years the ability of E. nigrum to keep a stable shoot growth, berry production, and vegetative cover in five E. nigrum dominated tundra heathlands, in a total of 144 plots covering a 200-km gradient from oceanic to continental climate. Overall, E. nigrum displayed high resistance to climatic variation along the gradient, with positive growth and reproductive output during all years and sites. Climatic conditions varied sharply among sites, especially during the winter months, finding that exposure to freezing temperatures during winter was correlated with reduced shoot length and berry production. These negative effects however, could be compensated if the following growing season was warm and long. Our study demonstrates that E. nigrum is a species resistant to fluctuating climatic conditions during the growing season and winter months in both oceanic and continental areas. Overall, E. nigrum appeared frost hardy and its resistance was determined by interactions among different season-specific climatic conditions with contrasting effects.

scholarly journals How does soil water availability control phytotoxic O<sub>3</sub> dose to montane pines? Modelling and experimental study from two contrasting climatic regions in Europe

2017 ◽  
Author(s):  
Svetlana Bičárová ◽  
Zuzana Sitková ◽  
Hana Pavlendová ◽  
Peter Fleischer Jr. ◽  
Peter Fleischer Sr. ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Stomatal Closure ◽  
Growing Season ◽  
Climatic Conditions ◽  
Moisture Regime ◽  
Mediterranean Forests ◽  
Climatic Regions ◽  
Soil Moisture Regime ◽  
Swiss Stone Pine ◽  
The Mediterranean

Abstract. Montane forests are exposed to high ambient ozone (O3) concentrations that may adversely affect physiological processes in internal cells when O3 molecules enter the plants through the stomata. This study addresses the model results of Phytotoxic Ozone Dose metric (POD) based on estimation of stomatal O3 flux to dwarf mountain pine (Pinus mugo) and Swiss stone pine (Pinus cembra). We focused on two different bioclimatic regions: (1) the temperate mountain forests in the High Tatra Mts (SK–HT) of the Western Carpathians, and (2) the Mediterranean forests of the Alpes–Mercantour (FR–Alp) in the Alpes–Maritimes. Field measurement of O3 concentration and meteorological data incorporated into deposition model DO3SE showed lower O3 flux in FR–Alp than in SK–HT plots for the 2016 growing season. Model outputs showed that soil humidity play a key role in stomatal O3 uptake by montane pines at the alpine timberline. We found that temperate climatic conditions in SK–HT with sufficient precipitation did not limit stomatal conductivity and O3 uptake of P. mugo and P. cembra. On the other hand, the Mediterranean mountain climate characterised by warm and dry summer reduced stomatal conductance of pines in FR–Alp. POD without threshold limitation i.e. POD0 as a recently developed biologically sounded O3 metric varied near around and below critical level (CLef) depending upon different conditions of sunshine exposure in SK–HT plots. Field observation at these plots showed relatively weak visible O3 injury on P. cembra (2 % and 7 %) when compared with P. mugo (8 % and 18 %) for one year (C+1) and two year (C+2) old needles, respectively. Despite of low POD0 values, clearly below CLef, the highest level of visible O3 damage on average from 10 % (C+1) to 25 % (C+2) was observed on P. cembra needles in Mediterranean (FR–Alp) area. Further research is needed to clarify the effect of real soil moisture regime on stomatal closure in dry areas (FR–Alp) and resistance of pine species against visible O3 injury in wet subalpine zones (SK–HT). More attention should be paid to O3 fluxes covering a year-round growing season as well as intra-daily dynamics, especially the night hours, since these time spans appear to play significant role in O3 uptake by mountain conifers.

scholarly journals Volatile Organic Compound fluxes in a subarctic peatland and lake

2020 ◽  
Author(s):  
Roger Seco ◽  
Thomas Holst ◽  
Mikkel Sillesen Matzen ◽  
Andreas Westergaard-Nielsen ◽  
Tao Li ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Growing Season ◽  
Climatic Conditions ◽  
Mixing Ratios ◽  
Arctic Vegetation ◽  
Deposition Velocities ◽  
Volatile Organic ◽  
Ecosystem Level ◽  
Emission Models ◽  
Response To Temperature

Abstract. Ecosystems exchange climate-relevant trace gases with the atmosphere, including volatile organic compounds (VOCs) that are a small but highly reactive part of the carbon cycle. VOCs have important ecological functions and implications for atmospheric chemistry and climate. We measured the ecosystem-level surface-atmosphere VOC fluxes using the eddy covariance technique at a shallow subarctic lake and an adjacent graminoid-dominated fen in Northern Sweden during two contrasting periods: the peak growing season (mid July) and the senescent period post-growing season (September–October). In July, the fen was a net source of methanol, acetaldehyde, acetone, DMS, isoprene, and monoterpenes. All of these VOCs showed a diel cycle of emission with maxima around noon and isoprene dominated the fluxes (93 ± 22 µmol m−2 day−1, mean ± SE). Isoprene emission was strongly stimulated by temperature and presented a steeper response to temperature (Q10 = 14.5) than that typically assumed in biogenic emission models, supporting the high temperature sensitivity of arctic vegetation. In September, net emissions of methanol and isoprene were drastically reduced, while acetaldehyde and acetone were deposited to the fen, with rates of up to −6.7 ± 2.8 µmol m−2 day−1 for acetaldehyde. Remarkably, the lake was a sink for acetaldehyde and acetone during both periods, with average fluxes up to −19 ± 1.3 µmol m−2 day−1 of acetone in July and up to −8.5 ± 2.3 µmol m−2 day−1 of acetaldehyde in September. The deposition of both carbonyl compounds correlated with their atmospheric mixing ratios, with deposition velocities of −0.23 ± 0.01 and −0.68 ± 0.03 cm s−1 for acetone and acetaldehyde, respectively. Even though these VOC fluxes represented less than 0.5 % and less than 5 % of the CO2 and CH4 net carbon ecosystem exchange, respectively, VOCs alter the oxidation capacity of the atmosphere. Thus, understanding the response of their emissions to climate change is important for accurate prediction of the future climatic conditions in this rapidly warming area of the planet.

scholarly journals The Transformation of Agro-Climatic Resources of the Altai Region under Changing Climate Conditions

Agriculture ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 68 ◽  
Author(s):  
Nina Maximova ◽  
Komali Kantamaneni ◽  
Gennady Morkovkin ◽  
Darya Arnaut ◽  
Louis Rice
Keyword(s):  
Growing Season ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Integrated Analysis ◽  
Published Data ◽  
Climate Conditions ◽  
Related Data ◽  
Growing Season Length ◽  
Altai Region ◽  
The Past

This research examines the transformation of the agro-climatic conditions of the Altai region as a result of climate change. The climate of the Altai region in Russia is sharply continental and characterized by dry air and significant weather variability, both in individual seasons and years. The current study is determined by the lack of detailed area-related analytical generalizations for the territory of the Altai region over the past 30 years. Most of the published data dealing with an integrated analysis of the agro-climatic conditions in the Altai region date back to the late 1960s and early 1970s; in most cases, this data is from climate reference-books based on the generalized data from the first half of the 20th century. To make accurate forecasts and to efficiently manage agricultural production in the Altai region, area-related data on the state and dynamics of agro-climatic changes have been analysed. The results reveal that in the period between 1964 and 2017, significant climatic changes occurred in the territory of the Altai region. These climatic changes affected the growing season length, which increased due to a shift in the dates of the air temperature transition above 10 °C, to earlier dates in spring and to later dates in autumn. Furthermore, the current study also revealed that the foothills of the Altai Mountains are the most moistened parts of the region and the Kulunda lowland is the most arid part. In the Altai region, the accumulated temperatures and amounts of precipitation during the growing season increased significantly, and the values of integrated coefficients and indices that reflect the moisture supply conditions for the territory also changed significantly. Based upon the results, a schematic map of the current precipitation distribution on the Altai region’s territory has been generated. These results and this map may be used to conduct more detailed studies in the field of agro-climatology and to update the current borders of agro-climatic areas and revision of the agro-climatic zonation scheme.

scholarly journals Consistent Poplar Clone Ranking Based on Leaf Phenology and Temperature Along a Latitudinal and Climatic Gradient in Northern Europe

2021 ◽  
Author(s):  
Giulia Vico ◽  
Almir Karacic ◽  
Anneli Adler ◽  
Thomas Richards ◽  
Martin Weih
Keyword(s):  
Growing Season ◽  
Climatic Conditions ◽  
Northern Europe ◽  
Season Length ◽  
Spring Phenology ◽  
Phenological Data ◽  
Growing Season Length ◽  
Degree Day ◽  
Growing Conditions ◽  
The Baltic

AbstractIn Northern Europe, poplars (Populus) can provide biomass for energy and material use, but most available clones were developed for lower latitudes and are unlikely to be well adapted to higher latitudes, even under warmer climates. We thus need to understand how clones respond to climatic conditions and photoperiod, and how these responses can be predicted. We answer these questions exploiting leaf phenological data of Populus clones, grown in six sites across the Baltic region, in Northern Europe, for 2 years with contrasting climatic conditions. Regarding the effects of climatic conditions and photoperiod, within each site, higher temperatures advanced the timing and enhanced the speed of spring and autumn phenology, but reduced the effective growing season length. Across sites, latitude affected the timing of spring and autumn phenology, the speed of spring phenology, and the effective growing season length; clone affected only the timing of phenology. Regarding the predictability of clone response to growing conditions, the growing degree day (GDD) model could not predict spring phenology, because the growing degree day threshold for a specific phenological stage was not only clone-, but also latitude- and year-specific. Yet, this GDD threshold allowed a robust ranking of clones across sites and years, thus providing a tool to determine the relative differences across clones, independently of latitude and temperature. A similar, but not as strong, pattern was observed in the timing of spring and autumn phenological stages. Hence, while prediction of spring phenology remains elusive, the ranking of clones based on observations of their phenology in a single location can provide useful indications on the clones’ relative performance under different latitudes and climates.

scholarly journals A common soil temperature threshold for the upper limit of alpine grasslands in European mountains

Alpine Botany ◽  
2021 ◽  
Vol 131 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Sarah Bürli ◽  
Jean-Paul Theurillat ◽  
Manuela Winkler ◽  
Andrea Lamprecht ◽  
Harald Pauli ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Vascular Plant ◽  
Plant Cover ◽  
Growing Season ◽  
Climatic Conditions ◽  
Temperature Threshold ◽  
Season Length ◽  
Alpine Grasslands ◽  
Growing Season Length ◽  
Upper Limit

AbstractWhile climatic research about treeline has a long history, the climatic conditions corresponding to the upper limit of closed alpine grasslands remain poorly understood. Here, we propose a climatic definition for this limit, the ‘grassline’, in analogy to the treeline, which is based on the growing season length and the soil temperature. Eighty-seven mountain summits across ten European mountain ranges, covering three biomes (boreal, temperate, Mediterranean), were inventoried as part of the GLORIA project. Vascular plant cover was estimated visually in 326 plots of 1 × 1 m. Soil temperatures were measured in situ for 2–7 years, from which the length of the growing season and mean temperature were derived. The climatic conditions corresponding to 40% plant cover were defined as the thresholds for alpine grassland. Closed vegetation was present in locations with a mean growing season soil temperature warmer than 4.9 °C, or a minimal growing season length of 85 days, with the growing season defined as encompassing days with daily mean ≥ 1 °C. Hence, the upper limit of closed grasslands was associated with a mean soil temperature close to that previously observed at the treeline, and in accordance with physiological thresholds to growth in vascular plants. In contrast to trees, whose canopy temperature is coupled with air temperature, small-stature alpine plants benefit from the soil warmed by solar radiation and consequently, they can grow at higher elevations. Since substrate stability is necessary for grasslands to occur at their climatic limit, the grassline rarely appears as a distinct linear feature.

scholarly journals Indication of the Two Linear Correlation Methods Between Vegetation Index and Climatic Factors: An Example in the Three River-Headwater Region of China During 2000–2016

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 606
Author(s):  
Jiaxin Xu ◽  
Shibo Fang ◽  
Xuan Li ◽  
Zichun Jiang
Keyword(s):  
Correlation Coefficient ◽  
Linear Correlation ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Meteorological Data ◽  
Growing Season ◽  
Climatic Conditions ◽  
The Difference ◽  
The Impact ◽  
The Relationship

The within-growing-season correlations (WGSC) and the inter-growing-season correlations (IGSC) are widely used linear correlation analysis methods between vegetation index and climatic factors (such as temperature, precipitation, and so on). The WGSC method usually calculates the linear correlation coefficient between vegetation index and climatic factors of each month in all the growing seasons, for instance, whether vegetation index or temperature had data of 204 months (12 months × 17 years) during 2000–2016 to get the WGSC. The IGSC calculates the linear correlation coefficient between the vegetation index and climatic factors in the same month of each growing season among all the years, for example, only 17 couples’ data of vegetation index and temperature during 2000–2016 were used to get the linear correlation of IGSC. What is the difference between the results of the two methods and why do the results show that difference? Which is the more suitable method for the analysis of the relationship between the vegetation index and climatic conditions? To clarify the difference of the two methods and to explore more about the relationship between the vegetation index and climatic factors, we collected the data of 2000–2016 moderate resolution imaging spectroradiometer (MODIS) 13A1 normalized difference vegetation index (NDVI) and the meteorological data-temperature and precipitation, then calculated WGSC and IGSC between NDVI and the climatic factor in three river-headwater regions of China. The results showed that: (1) As for WGSC, the more of the years included, the higher the correlation coefficient between NDVI and the temperature/precipitation. The correlation coefficient of WGSC is dependent on how many years’ the data were included, and it was increased with the more year’s data included, while the correlation coefficients of IGSC are relatively independent on the amount of the data; (2) the WGSC showed a pseudo linear correlation between NDVI and climatic conditions caused by the accumulation of data amount, while the IGSC can more accurately indicate the impact of climatic factors on vegetation since it did not rely on the data amount.

DROUGHT OCCURRENCE UNDER LITHUANIAN CLIMATIC CONDITIONS

2015 ◽  
Author(s):  
Laima TAPARAUSKIENĖ ◽  
Veronika LUKŠEVIČIŪTĖ
Keyword(s):  
Meteorological Data ◽  
Standardized Precipitation Index ◽  
Vegetation Period ◽  
Climatic Conditions ◽  
Precipitation Record ◽  
Calculation Step ◽  
Drought Conditions ◽  
The Standardized Precipitation Index ◽  
June July

This study provides the analysis of drought conditions of vegetation period in 1982-2014 year in two Lithuanian regions: Kaunas and Telšiai. To identify drought conditions the Standardized Precipitation Index (SPI) was applied. SPI was calculated using the long-term precipitation record of 1982–2014 with in-situ meteorological data. Calculation step of SPI was taken 1 month considering only vegetation period (May, June, July, August, September). The purpose of investigation was to evaluate the humidity/aridity of vegetation period and find out the probability of droughts occurrence under Lithuanian climatic conditions. It was found out that according SPI results droughts occurred in 14.5 % of all months in Kaunas region and in 15.8 % in Telšiai region. Wet periods in Kaunas region occurred in 15.8 %, and in Telšiai region occurrence of wet periods was – 18.8 % from all evaluated months. According SPI evaluation near normal were 69.7 % of total months during period of investigation in Kaunas and respectively – 65.5 % in Telšiai. The probability for extremely dry period under Lithuania climatic conditions are pretty low – 3.0 % in middle Lithuania and 2.4 % in western part of Lithuania.

Experience of soybean cultivation in the Kaluga Department of Agricultural Machinery SC.

2020 ◽  
Author(s):  
N.V. Sergeev ◽  
◽  
A.Yu. Pivkin
Keyword(s):  
Seed Yield ◽  
Growing Season ◽  
Climatic Conditions ◽  
High Yield ◽  
Soybean Variety ◽  
Agricultural Machinery ◽  
Kaluga Region ◽  
High Seed Yield

The experience of cultivation of soybeans in SC "Agricultural machinery" of the Kaluga region on an area of 190 hectares shows that the soybean variety Alaska is sufficiently adapted to the soil and climatic conditions of this region, provides a high seed yield (up to 32 c / ha) and a high yield (up to 1344 kg / ha) relatively inexpensive protein. However, this variety has a long growing season (95-105 days) and therefore desiccation of crops is required for harvesting for seeds.

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