scholarly journals Bioenvironmental characteristics of Robinia pseudoacacia steppe plantations in dependence to changes in some climatic factors

2021 ◽  
Vol 50 ◽  
pp. 3-11
Author(s):  
L. V. Dotsenko ◽  
V. I. Chorna ◽  
Yu. I. Hrytsan ◽  
N. V. Voroshylova ◽  
V. V. Katsevych
Keyword(s):  
Climatic Factors ◽  
Abiotic Factors ◽  
Robinia Pseudoacacia ◽  
Great Majority ◽  
Tree Plantations ◽  
Limiting Factor ◽  
Age Composition ◽  
Plant Associations ◽  
Precipitation Decrease ◽  
Rapid Spread

Сlimatic factors play the most important role in the plant associations formation. Sunlight is one of the leading factors that determine the appearance of a particular community and very often plays the limiting factor role. In the conditions of the Steppe Dnipro Region, its limiting role can be expressed only in its excess. The great majority of autochthonous steppe flora plant species has strongly pronounced adaptations to excessive solar insolation. With the development of forest biogeocenology and steppe forestry, more and more attention is paid to the issues of forest climatology. It is shown that climatic factors have an imperative effect on the formation of soils, plant associations, fauna and ecosystems in general. Artificial plantations consisting of fast-growing hardwoods, such as Robinia pseudoacacia, have been studied. The complex of abiotic factors in robinia plantations and in open areas has its own characteristics. The processes of reflection, transformation and accumulation of solar energy in tree plantations have a slightly different character than in forest-free areas. In the Dnipropetrovsk region, the populations of Robinia pseudoacacia are represented mainly by young plants that have already entered the phase of active fruiting. No plants older than 100 years were found in the populations. Thus, the price spectrum of the age composition of the population of Robinia pseudoacacia in the Dnipropetrovsk region has a pronounced left-sided character, ie shifted towards young individuals that are actively fruiting. This indicates that the processes of expansion of Robinia pseudoacacia to natural biogeocenoses will be actively continued. Despite the fact that this breed has a number of positive qualities (excellent medonis, root mycorrhiza with azotobacter, high gas resistance, etc.), the processes of uncontrolled active settlement of this species is a matter of serious concern. This breed is capable of rapid spread and disruption of successional processes occurring in the area. In the conditions of the forecasted climate changes towards temperature increase and precipitation decrease this breed receives more and more advantages.

scholarly journals Mycobacterium ulcerans dynamics in aquatic ecosystems are driven by a complex interplay of abiotic and biotic factors

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Andrés Garchitorena ◽  
Jean-François Guégan ◽  
Lucas Léger ◽  
Sara Eyangoh ◽  
Laurent Marsollier ◽  
...  
Keyword(s):  
Climatic Factors ◽  
Abiotic Factors ◽  
Aquatic Organisms ◽  
Freshwater Ecosystems ◽  
Mycobacterium Ulcerans ◽  
Environmental Data ◽  
Limiting Factor ◽  
Biotic Factors ◽  
Abiotic And Biotic Factors ◽  
Chemical Conditions

Host–parasite interactions are often embedded within complex host communities and can be influenced by a variety of environmental factors, such as seasonal variations in climate or abiotic conditions in water and soil, which confounds our understanding of the main drivers of many multi-host pathogens. Here, we take advantage of a combination of large environmental data sets on Mycobacterium ulcerans (MU), an environmentally persistent microorganism associated to freshwater ecosystems and present in a large variety of aquatic hosts, to characterize abiotic and biotic factors driving the dynamics of this pathogen in two regions of Cameroon. We find that MU dynamics are largely driven by seasonal climatic factors and certain physico-chemical conditions in stagnant and slow-flowing ecosystems, with an important role of pH as limiting factor. Furthermore, water conditions can modify the effect of abundance and diversity of aquatic organisms on MU dynamics, which suggests a different contribution of two MU transmission routes for aquatic hosts (trophic vs environmental transmission) depending on local abiotic factors.

scholarly journals Vegetation dynamics under non-strong agricultural impact (by the example of Oktyabrsk village environs in the Uchalinskiy District of the Republic of Bashkortostan)

2021 ◽  
Vol 10 (1) ◽  
pp. 121-127
Author(s):  
Nazar Nikolayevich Nazarenko ◽  
Svetlana Yuryevna Batyusheva
Keyword(s):  
Plant Communities ◽  
Vegetation Dynamics ◽  
Vascular Plants ◽  
Abiotic Factors ◽  
Pasture Digression ◽  
Plant Associations ◽  
Republic Of Bashkortostan ◽  
Principal Factors ◽  
The Republic ◽  
Agricultural Impact

Vegetation and its biotopes that are transitional between ruderal and natural ones have been researched in Oktyabrsk village environs (Uchalinskiy District of the Republic of Bashkortostan). The studied vegetation is characterized by rather low biodiversity values and high values of dominance 56 species of vascular plants are identified, 10-species plant communities with 23 clear identified dominant and co-dominant species prevail. Ruderal species are dominant and co-dominant for the majority of plant communities. Fifteen plant associations and specific biotopes have been defined by multivariate statistics methods. The identified associations are phytometers for detected principal abiotic factors. The detected associations form ordination series the authors have identified three biotopical centers (ruderal, birch forest and steppe), three biotopical series and three coenotic series, which are associated with high and temperate pasture loading levels and pasture digression series, forming an integrated succession system of the studied territory. It has been established that principal factors of associations forming is pasture loading level and the principal factors of biotopes forming are soil moistening and its variability, ombroregime (humidification level), termoregime and regime of continentality (temperature-varying amplitude).

scholarly journals Seasonal and annual variation of carbon fluxes in a young Siberian larch (<i>Larix sibirica</i>) plantation in Iceland

2009 ◽  
Vol 6 (4) ◽  
pp. 6601-6634 ◽  
Author(s):  
B. Bjarnadottir ◽  
B. D. Sigurdsson ◽  
A. Lindroth
Keyword(s):  
Carbon Balance ◽  
Climatic Factors ◽  
Ecosystem Respiration ◽  
Abiotic Factors ◽  
Gross Primary Production ◽  
Seasonal Pattern ◽  
Soil Water Potential ◽  
Siberian Larch ◽  
Frost Damage ◽  
Spring Frost

Abstract. This study reports 3-year measurements (2004–2006) of net ecosystem exchange (NEE) over a 12–14 year old Siberian larch forest in Iceland established on previously grazed heath land pasture that had been site-prepared prior to planting. The study evaluated interannual and seasonal variation of NEE and its component fluxes, gross primary production (GPP) and ecosystem respiration (Re), with the aim to clarify how climatic factors controlled the site's carbon balance. The young plantation acted as a relatively strong sink for CO2 during all of the three years, with a net sequestration of −375, −566 and −245 g CO2 m−2 for years 2004, 2005 and 2006, respectively. The annual carbon balance was strongly influenced by climatic factors leading to a high inter-annual variability in NEE. This variation was more related to variation in carbon efflux (Re) than carbon uptake (GPP). The abiotic factors that showed the strongest correlation to Re were air temperature during the growing season and soil water potential. The GPP mostly followed the seasonal pattern in irradiance, except in 2005, when the plantation experienced severe spring frost damage that set the GPP back to zero. It was not expected that the rather slow-growing Siberian larch plantation would be such a strong sink for atmospheric CO2 only twelve years after site preparation and afforestation.

The impact of drought on tree growth in Mediterranean sites

2021 ◽  
Author(s):  
Giovanna Battipaglia ◽  
Francesco Niccoli ◽  
Arturo Pacheco-Solana
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Sustainable Forest Management ◽  
Climatic Factors ◽  
Management Strategies ◽  
Ring Width ◽  
Limiting Factor ◽  
Individual Tree ◽  
Annual Growth Rings ◽  
The Impact

&lt;p&gt;Climate-induced forest mortality is a critical issue in the Mediterranean basin, with major consequences for the functioning of these key ecosystems. Indeed, in Mediterranean ecosystems, where water stress is already the most limiting factor for tree performance, climatic changes are expected to entail an increase in water deficit. In this context, annual growth rings can provide short- (e.g., years) and long-term (e.g., decades) information on how trees respond to drought events. With climate change, &lt;em&gt;Pinus pinaster&lt;/em&gt; and &lt;em&gt;Pinus pinea&lt;/em&gt; L. are expected to reduce their distribution range in the region, being displaced at low altitudes by more drought tolerant taxa such as sub Mediterranean &lt;em&gt;Quercus&lt;/em&gt; spp.&lt;/p&gt;&lt;p&gt;This study aims was to assess the physiological response of &lt;em&gt;Pinus&lt;/em&gt; and &lt;em&gt;Quercus&lt;/em&gt; species growing in the Vesuvio National park, located in Southern Italy and where an increase of temperature and drought events has been recorded in the recent years. Our preliminary results underlined the importance of temperature on the tree ring width of all the analyses species. The high temperatures can cause a change in the constant kinetics of the RuBisCo, leading to a consequent decrease in carboxylation rate and thus to a reduction in tree growth. On the other hand, also precipitation seemed to affect the growth of the sampled trees: indeed, in all the chronologies a reduction in growth was found after particular dry years: for example, the low rainfall in 1999 (455 mm/year) determined a drastic decline in growth in 2000 in all the species. In addition to the climatic factors, competition can also play an important role in the growth rate: dendrochronological analyzes have highlighted how stand specific properties (i.e. density, structure and composition) can influence individual tree responses to drought events. The knowledge of those researches should be integrated into sustainable forest management strategies to minimize the potential impacts of climate change on forest ecosystems.&lt;/p&gt;

Treatment of Metastatic Breast Cancer with Cyclophosphamide, Methotrexate, Vincristine and Fluorouracil.

1973 ◽  
Vol 59 (1) ◽  
pp. 11-24 ◽  
Author(s):  
Mario De Lena ◽  
Giuseppe Maria De Palo ◽  
Gianni Bonadonna ◽  
Gianni Beretta ◽  
Emilio Bajetta
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Combination Chemotherapy ◽  
Metastatic Breast ◽  
Great Majority ◽  
Bone Lesions ◽  
Limiting Factor ◽  
Response Table ◽  
Effective Combination ◽  
Number Of Cycles

From November 1970 to June 1972, 55 patients with metastatic breast cancer were treated with a 4-drug combination (cyclophosphamide, Methotrexate, vincristine and fluorouracil) administered intravenously over a 5-day period (table 1). Treatment was repeated after a 2-week interval for the first 3 cycles, then after 4 weeks. Six more patients were incompletely treated but found evaluable for the toxicity study. The great majority of cases (51/55) was pretreated with radiotherapy, hormone and/or chemotherapy (table 3). The overall response rate was 69 %. Complete (CR) plus partial (PR) remissions (> 50 %) were 46 %. From this evaluation bone lesions was arbitrarily not included since recalcification occurs rarely after chemotherapy. The medium duration of CR was 8 months, that of PR 4 months (table 4). The most responsive lesions were those localized in the soft parts (75%) followed by metastases to lung (55%), pleura and liver (40%). Recalcification of bone lesions was observed in 17 % of cases (table 6). The number of cycles required to produce a regression was found proportional to the degree of response, with a mean of 2 cycles to obtain a PR and a mean of 3 cycles to obtain a CR (table 7). The longest regression was seen in patients with lung or liver involvement (table 8). The duration of the free interval was a positively correlated with the type of response (table 9). The dose limiting factor was represented by bone marrow depression which often required a dose attenuation schedule (table 10 and 11). The actuarial analysis of survival curves (fig.1) showed that patients achieving CR+PR lived longer than those with static disease or progression during combination chemotherapy (P < 0.05). It is concluded that combination chemotherapy can prolong the survival of responsive patients with metastatic breast cancer. The most effective combination can be found only through appropriate controlled clinical trials.

Corrigendum to: Influence of climatic factors on variation in the Normalised Difference Vegetation Index in Mongolian Plateau grasslands

2018 ◽  
Vol 40 (2) ◽  
pp. 205
Author(s):  
Xu-Juan Cao ◽  
Qing-Zhu Gao ◽  
Ganjurjav Hasbagan ◽  
Yan Liang ◽  
Wen-Han Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Growing Season ◽  
Limiting Factor ◽  
Spatial And Temporal Variability ◽  
Climate Factors ◽  
Mongolian Plateau ◽  
Normalised Difference Vegetation Index

Climate change will affect how the Normalised Difference Vegetation Index (NDVI), which is correlated with climate factors, varies in space and over time. The Mongolian Plateau is an arid and semi-arid area, 64% covered by grassland, which is extremely sensitive to climate change. Its climate has shown a warming and drying trend at both annual and seasonal scales. We analysed NDVI and climate variation characteristics and the relationships between them for Mongolian Plateau grasslands from 1981 to 2013. The results showed spatial and temporal differences in the variation of NDVI. Precipitation showed the strongest correlation with NDVI (43% of plateau area correlated with total annual precipitation and 44% with total precipitation in the growing season, from May to September), followed by potential evapotranspiration (27% annual, and 30% growing season), temperature (7% annual, 16% growing season) and cloud cover (10% annual, 12% growing season). These findings confirm that moisture is the most important limiting factor for grassland vegetation growth on the Mongolian Plateau. Changes in land use help to explain variations in NDVI in 40% of the plateau, where no correlation with climate factors was found. Our results indicate that vegetation primary productivity will decrease if warming and drying trends continue but decreases will be less substantial if further warming, predicted as highly likely, is not accompanied by further drying, for which predictions are less certain. Continuing spatial and temporal variability can be expected, including as a result of land use changes.

scholarly journals Dynamics of mixed lowland forests in Central Bohemia over a 20-year period

2020 ◽  
Vol 66 (No. 2) ◽  
pp. 49-62
Author(s):  
Anna Prokůpková
Keyword(s):  
Radial Growth ◽  
Climatic Factors ◽  
European Beech ◽  
Quercus Petraea ◽  
Climatic Conditions ◽  
Limiting Factor ◽  
Ecological Stability ◽  
Diameter Increment ◽  
Lower Productivity ◽  
Lowland Forests

The paper deals with the effect of environmental factors and management on various mixed lowland forests in the Medník National Natural Monument, Czech Republic, over a 20-year period. The objectives were to evaluate the structure, production, dynamics and radial growth in relation to climatic conditions in the mixed hornbeam-oak, herb-rich beech and spruce forest stands. The tree density decreased by 8.5% (to 120–1,364 trees·ha<sup>–1</sup>), while stand volume increased by 28.0% (to 244–767 m<sup>3</sup>·ha<sup>–1</sup>) from 1998 to 2018. Large-leaved lime (Tilia platyphyllos Scop.) and Norway spruce (Picea abies /L./ Karst.) showed high variability and sensitivity to climatic factors in radial growth compared to stability and resistance in sessile oak (Quercus petraea /Matt./ Liebl.) and European beech (Fagus sylvatica L.). April, June and July were determined as the most significant months in relation to diameter increment. The synergism of precipitation deficit and high air temperature was a limiting factor of growth in the studied lowland area. The frequency of negative pointer years with extremely low radial growth has been increasing recently. Generally, hornbeam-oak stands are characterized by rich structure, high density and lower productivity, herb-rich beech stands represent rich structured productive forests and spruce forests are very productive stands but with low ecological stability.

scholarly journals Features of ecological differentiation of halophytic, steppe and petrophytic vegetation in the valley of the Liman Kuyalnik (Odesa Oblast)

2019 ◽  
Vol 27 (3) ◽  
pp. 205-213
Author(s):  
D. V. Dubyna ◽  
T. P. Dziuba ◽  
L. P. Vakarenko ◽  
A. A. Ennan ◽  
H. M. Shykhaleeva ◽  
...  
Keyword(s):  
Plant Communities ◽  
Climatic Factors ◽  
Ecological Factors ◽  
Carbonate Content ◽  
Limiting Factor ◽  
Edaphic Factors ◽  
Key Factors ◽  
Ecological Differentiation ◽  
Steppe Vegetation ◽  
Steppe Communities

Assessment of key environmental factors that influence vegetation distribution and formation of plant communities is one of the most important challenges in modern phytocenology. Nowadays, several bioindication systems are applied to determine ecological specificity of plant communities and to establish the leading factors for their environmental differentiation. The system most widely used in Europe, that of H. Ellenberg, contains a numerical score on 6 ecological factors. On the example of vegetation of the valley of the Liman Kuyalnik, Y. Didukh developed the synphytoindication method based on evaluation of phytocenoses with respect to 12 ecological factors: 7 edaphic factors and 5 climatic factors; the method determines a more accurate and complete presentation of the analysis. In the valley of the Liman Kuyalnik (Odesa Oblast) the largest area is covered with halophytic and steppe vegetation. Halophytic vegetation (Therosalicornietea, Festuco-Puccinellietea classes, Juncetea maritimi, Bolboschoenetea maritimi) predominated in the shoreline areas of the valley, whereas steppe (Festuco-Brometea) and petrophytic (Sedo-Scleranthetea) vegetation dominated on the slope sites. With the application of DCA-ordination and synphytoindication methods it was established that distribution of plant communities in the hyper-space of the environmental conditions was most strongly correlated with edaphic factors, whereas microclimatic (light intensity) and climatic (thermo-regime) conditions had somewhat less influence on their differentiation. Water regime and level of soil salinity served as key factors for syntaxa of halophytic vegetation; moisture variability and salt regime, as well as soil moisture and carbonate content were key factors for the steppe vegetation, and thermo-regime was the main factor for petrophytic-steppe and petrophytic vegetation. The "eco-spaces" of these groups largely overlap. Halophytic cenoses are characterized by quite wide ecological ranges by most ecological factors. Steppe communities show much less ecological diversity. In the valley of the liman, all the steppe communities were characterized by stenotopicity in relation to most ecological factors; these factors complexly determine the specificity and diversity of biotopes within the valley, which are unique and require protection and the taking of appropriate measures, depending on the changes in activity of one or another limiting factor. Nowadays, the valley of the Liman Kuyalnik is in a state of environmental disaster. The established relationships in ecological differentiation of plant communities will be applied to further monitoring of biodiversity state, preservation and possible restoration of vegetation types that were native for this unique territory.

scholarly journals Growth variability of European beech (Fagus sylvatica L.) natural forests: Dendroclimatic study from Krkonoše National Park

2019 ◽  
Vol 65 (2) ◽  
pp. 92-102 ◽  
Author(s):  
Václav Šimůnek ◽  
Zdeněk Vacek ◽  
Stanislav Vacek ◽  
Ivo Králíček ◽  
Karel Vančura
Keyword(s):  
Fagus Sylvatica ◽  
Climatic Factors ◽  
Climate Extremes ◽  
European Beech ◽  
Climatic Conditions ◽  
Forest Growth ◽  
Limiting Factor ◽  
Radial Increment ◽  
Natural Forests ◽  
Growth Variability

Abstract Long-term temporal development of beech stands in relation to climatic conditions is well documented by dendrochronological analyses. The study aims to identify and describe growth factors affecting natural European beech stands (Fagus sylvatica L.) on permanent research plots in the eastern Krkonoše Mountains, the Czech Republic. The paper focus on radial growth dynamics, frequency and cyclicity, and the effect of climatic factors on diameter increment of beech stands since 1850. The growth development of beech stands was significantly affected by air pollution load in 1977–1989, and increasingly frequent climate extremes in recent years (since 2010). Periodic increment events recurred in approximately 10–18 years’ periods. Stands on research plots responded differently to climatic factors, the main limiting factor being low temperatures during the growing season, frost damages and extreme droughts. The positive influence of temperatures on beech increments was recorded in winter, early spring, and especially in July and August of the current year. Conversely, precipitation in the previous year had higher impact on radial increment, with prevailing negative correlation. The plots were negatively affected by the decrease in sum of precipitation in February and March, but it was the temperature that influenced the beech increment most significantly. Dendrochronological analysis of close-to-nature beech stands provides valuable information on radial forest growth in response to changing climatic conditions.

scholarly journals A 333-year record of the mean minimum temperature reconstruction in the Western Tianshan Mountains, China

2019 ◽  
Vol 46 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Liang Jiao ◽  
Shengjie Wang ◽  
Yuan Jiang ◽  
Xuerui Liu
Keyword(s):  
Minimum Temperature ◽  
Large Scale ◽  
Climatic Factors ◽  
Moving Average ◽  
Temperature Reconstruction ◽  
Warming Trend ◽  
Limiting Factor ◽  
Western Tianshan ◽  
The Mean ◽  
The Relationship

Abstract In this paper, a fragile ecological area in the Western Tianshan National Nature Reserve of China was selected as the research region, and Picea schrenkiana, which is sensitive to climate change, was selected as the research object. The mean minimum temperature in the growing season of the previous year (May to September) was the main limiting factor for tree radial growth based on an analysis of the relationship between chronological series and climatic factors during 1959–2012 (r = –0.792, p < 0.05). Moreover, the relationship was stable, which showed that tree rings can be used as alternative materials for climate reconstruction. Therefore, the mean minimum temperature of the previous year in 1680–2012 was reconstructed, and the explained variance of the reconstruction equation was 62.7% (R2adj = 62.0%, F = 85.8). The 31 dramatically altered years were found via characteristic year analyses, and extreme changes occurred most often under relatively warm conditions. The mean minimum temperature in the reconstruction shows a clear warming trend by the 11-year moving average of the reconstructive series since the 1950s (the temperature increase: 0.341°C/decade). The driving factors of the mean minimum temperature were influenced mainly by the interaction of solar activity and large-scale atmospheric–oceanic variability, especially the westerly circulations.

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