NATURAL AND ANTHROPOGENIC DEGRADATION PROCESSES DESERTED STEPPES OF THE UBSUNUR BASIN

Author(s):  
Anna Sambuu ◽  
B. Mongush ◽  
Sh. Mongush

Steppes in Tuva occupy intermountain basins with altitudes of 550-1200 m above sea level, the lower parts of mountain slopes, and high terraces of river valleys. Large massifs of steppes are typical for the Ulugh-Khem and Ubsunur basins. Studies to assess the state of soil and vegetation cover were conducted in the North-Eastern (Tuva) part of the drainless Ubsunur basin in July-August 1997-2020 using the route method. The location of the basin between the boreal landscapes of Siberia and the desert-steppe landscapes of Central Asia is characterized by a variety of landforms, heterogeneity of soil and vegetation cover, and a unique distribution of climatic factors and geological history. The source material was our own data from soil and geobotanical studies and remote materials from different observation periods. Observation data from different survey years were linked to the Landsat satellite image for July-August 1997-2019. Route studies were carried out on the main geomorphological profiles from the southern foothills of the Western and Eastern Tannu-Ola ranges to the coast of oz. Ubsa-Nur (from North to South). Reference soil sections were laid at key sites, morphological descriptions of soil profiles and horizon-based sampling were carried out. Soil samples were taken to determine the humus content, granulometric composition, size and nature of salinity-the main indicators of soil desertification. Observations also covered the Eastern and Western parts of the basin, which revealed the direction of degradation of desolate steppes in different geomorphological positions of the territory, but also with different nature and intensity of anthropogenic impact.

2002 ◽  
pp. 22-31 ◽  
Author(s):  
T. V. Maltseva ◽  
N. I. Makunina

The North-Eastern Altai is an ultra-humid area with climax vegetation represented by tall-herb fir (Abies sibirica) dark-coniferous forest. Its meadows belong to the class Molinio-Arrhenatheretea. The typical asso­ciation Aegopodio podagrariae—Dactyletum glomeratae originates in the watershed clearings after climax forests whereas ass. Hyperici perforati—Agrostietum giganteaereplaces the previous one under mowing and grazing. The Molinietalia wet meadows are widespread in the river valleys. The meadows of ass. Cirsio heterophylli—Calama­grostietum langsdorffii occur on wet soils in small depressions and along floodplain mire margins, and ass. Ca­rici ovalis—Deschampsietum cespitosae comprises typical floodplain hay-meadows on moist, nutrient-rich soils.


2021 ◽  
Vol 10 (1) ◽  
pp. 157-162
Author(s):  
Vera Valentinovna Solovieva

The study covered 10 small rivers in the North-Eastern part of the Samara Volga region. The author studied the vegetation cover, which is understood as a set of phytocoenoses and their constituent plant species. On the territory of Pokhvistnevsky District, there are two groups of river valleys that are heterogeneous in geobotanical terms. The first group includes the rivers with forested valleys (Kutlugush, Murakla, Karmalka). Their slopes are more or less symmetrical and steep. The vegetation cover of an undeveloped floodplain is usually uniform, and there is usually no belt. The valleys of the second group are treeless; their slopes are sharply asymmetrical (Amanak, Tergala, Talkish). The right-bank tributary of the Maly Kinel River the Lozovka River with its length of 20 km and the left tributary Kuvayka River with its length of 16 km were studied on the territory of Kinel-Cherkassky District. The Padovka and Zaprudka rivers and the right tributaries of the Bolshoi Kinel River (Kinelsky District) were also studied. The most common associations are (Salix fragilis heteroherbosa, Scirpus sylvaticus purum, Agrostis stolonifera Amoria repens, Elytrigia repens + Poa angustifolia heteroherbosa). In total, 19 types of phytocoenoses were noted, 4 of them are found in half of the studied rivers. In the plant communities of small river valleys there are 232 species of higher wild plants, which belong to 139 genera from 48 families. This is 60% of the total number of higher plants registered in the flora of small river valleys of the Samara Region. Rare protected plant species are registered here: Adonis volgensis Steven ex DC., Cacalia hastata L., Delphinium cuneatum Stev. ex DC., Globularia punctata Lapeyr.


2007 ◽  
Vol 60 ◽  
pp. 137-140 ◽  
Author(s):  
J.D. Shepherd ◽  
J.R. Dymond ◽  
J.R.I. Cuff

The spatial change of woody vegetation in the Canterbury region was automatically mapped between 1990 and 2001 using Landsat satellite image mosaics The intersection of valid data from these mosaics gave coverage of 84 of the Canterbury region Changes in woody cover greater than 5 ha were identified Of the 5 ha areas of woody change only those that were likely to have been a scrub change were selected using ancillary thematic data for current vegetation cover (eg afforestation and deforestation were excluded) This resulted in 2466 polygons of potential scrub change These polygons were rapidly checked by visual assessment of the satellite imagery and assigned to exotic or indigenous scrub change categories Between 1990 and 2001 the total scrub weed area in the Canterbury region increased by 3600 400 ha and indigenous scrub increased by 2300 400 ha


2016 ◽  
Vol 12 (29) ◽  
pp. 204
Author(s):  
Avy StéphaneKoff ◽  
Abderrahman Ait Fora ◽  
Hicham Elbelrhiti

The purpose of this study is to determine the state of the vegetation cover in the region of Korhogo through remote sensing. Nowadays, the problem of desertification in the Sahel is serious. This could be explained by the phenomenon of climate change. We want to map the state of the vegetation cover in the study area. This study therefore focuses on the state of the vegetation cover in the region of Korhogo in northern Côte d’Ivoire. We will use one Landsat satellite image from December 16th 2000 and proceed with image processing. Processing techniques by the normalized difference vegetation index, the index armor and colorful composition 472. After these treatments in our pictures, we observe the behavior of vegetation. We can then get an overview of the vegetation in this area.


Biologia ◽  
2019 ◽  
Vol 75 (1) ◽  
pp. 53-70
Author(s):  
Igor Goncharenko ◽  
Mykola Kozyr ◽  
Olexander Senchylo

Author(s):  
Alexey Verkhoturov ◽  
Vyacheslav Melkiy

Explosive volcanic eruptions pose certain danger for natural environment, transport communications and other objects of human economic activity due to the fact that during such eruptions, up to several cubic kilometers of volcanic ash and aerosols can enter to atmosphere in long time. The research of extent of the impact of volcanic eruptions on surrounding area and the determination of their consequences contributes to reasonable assessment of volcanic hazard and possible risks in time conduct of economic activities and ensuring for safe location of settlements, enterprises, sea way and air lines. Chikurachki volcano is one from most active on territory of the Kuril Island Arc. In articles of volcanologists is information about eruptions in 1853–1859, 1958, 1961, 1964, 1973, 1986, 2002, 2003, 2005, 2007, 2008, 2015, 2016. The vegetation index (NDVI) used as means of assessing state of the natural environment. The boundary dividing areas with disturbed and healthy vegetation cover taken along isoline with NDVI value of 0.4. Schematic maps of the dynamics of boundary isolines according for the vegetation index from 1972 to 2020 has been compiled. The dynamics of vegetation cover in the north-eastern, south-eastern and southern sectors relative to Chikurachki volcano is revealed. The north-eastern sector experienced strong negative impact of eruption of the Chikurachki volcano in 1853, at later (2007 and 2015) only ash falls were observed in this direction. The vegetation cover outside the isoline NDVI = 0.4 has almost completely recovered to 2020. The south-eastern sector damaged during eruption of 1986, and was also subject for periodic tephra precipitation and ash falls during 2002–2016. Vegetation was completely destroyed at distance of 9 km from the crater of the volcano, and also valley forests on Tukharka River were destroyed. In southern sector in upper part of the Vernadsky Ridge, harsh growing conditions do not allow vegetation to recover for decades. At the same time, on eastern and western slopes of the ridge, after eruptions with deposition of tephra by layer of small thickness, alder elfin restoration few years. The results of the recearch can be used in forecasting volcanic hazards and rapid assessment of impact on natural environment of territories adjacent to volcanoes of this type as a result of volcanic eruptions.


2001 ◽  
pp. 36-42 ◽  
Author(s):  
N. A. Sekretareva

The north-eastern part of the Koryak Highlands be­longs to the tall «stlanik» (prostrate elfin woodland, composed of Pinus pumila and Alnus fruticosa) subzone which corresponds to the subalpine belt of the North-Asian eastern highlands but holds a zonal position in the cis-Beringian areas. Communities of willow scrub are mostly restricted to river valleys here, because the more compe­titively strong mountain pine or alder «stlanik» commu­nities play the major role on mountain slopes and their trains. In the upper reaches of the Dlinnaya River willow scrub composed of Salix alaxensis, S. lanata subsp. richardsonii и S. pulchra with herb ground layers are growing in the riverbed-adjoining floodplain and on the low, periodically flooded river terraces. On the terraces of the upper level communities of Salix krylovii, S. pulchra and Betula nana subsp. exilis with dwarfshrubs and mosses in the ground layers are developed. Willow scrub commu­nities occur more seldom at the mountain slope bottoms or on the slope trains; here they wind along the mountain streams.


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