Архив метки: plant communities

GEOBOTANICAL CHARACTERISTICS OF COMMUNITIES WITH THE PARTICIPATION OF SALSOLA DAGHESTANICA (TURCZ.) TURCZ.) ON THE ARID SLOPES OF RIDGES EASTERN CAUCASUS

Arid Ecosystems

UDC 574.3:581 (470.67)

Magomedova B.M., Asadulaev Z.M. GEOBOTANICAL CHARACTERISTICS OF COMMUNITIES WITH THE PARTICIPATION OF SALSOLA DAGHESTANICA (TURCZ.) TURCZ.) ON THE ARID SLOPES OF RIDGES EASTERN CAUCASUS // Arid ecosystems. 2022. V.28. № 3 (92). P. 72-78. | PDF

The results of the study of communities with the participation of Dagestan saltwort (Salsola daghestanica (Turcz.) Turcz.) in Piedmont and Inner-mountain Dagestan, where 108 species of flowering plants were identified, among which are: Caragana grandiflora (M. Bieb) DC.); endemics of the Greater Caucasus: Matthiola caspica (Busch) Grossh., Salvia canescens CA Mey, Elytrigia gracillima Nevski; endemic of Dagestan Convolvulus ruprechtii Boiss., as well as a species listed in the Red Data Book of Russian Federation Artemisia salsoloides Willd. Identified associations with the growth of a rare endemic species of Dagestan S. daghestanica Salsolosum graminioso-xeroherbosum, Salsolosum graminioso-artemisosum, Caraganetum varioherboso-graminosum, Caraganetum salsoloso-artemisosum are found only in the territory of the Eastern Caucasus. Caraganetum salsoloso-artemisosum was described on three sample plots on the northwestern and eastern slopes of the Nadyrbek Ridge with a steepness of 30-40º (near the village of Dubki, Piedmont Dagestan). The shrub layer (crown density up to 45%) is formed by 12 species, dominated Salsola daghestanica (Turcz.) Turcz. and Caragana grandiflora (M. Bieb) DC. The total cover of the grass-shrub layer is up to 60%; the species richness is relatively low (40 species), dominated by Artemisia taurica Willd. Caraganetum varioherboso-graminosum is described on the northwestern slope of the Nadyrbek Ridge (near the village of Dubki, Foothill Dagestan) with a steepness of 40º. The shrub layer (total crown density 29%) is formed by 9 species, the dominant is the large-flowered Caragana grandiflora DC., the occurrence of which is 20%. The herb-shrub layer is sparse, with a coverage of 4-5% there are Artemisia taurica Willd., Stipa caragana Trin., Salvia canescens C.A. Mey., Melica transsilvanica Schur. Salsolosum graminioso-artemisosum communities are described on the slopes of the Chakulabek Ridge in the vicinity of the village of Tsudahar (Inner mountain Dagestan). In a sparse tree-shrub (12%), S. daghestanica dominates with a crown density of 10%, prevails Colutea orientalis L., Spiraea hypericifolia L. The total projective cover of the grass-shrub layer is 54%; species richness is relatively low; Artemisia taurica Willd is dominant in abundance and projective cover (50%). Salsolosum graminioso-xeroherbosum is described on the slopes of the Chonkataw Ridge in the vicinity of the village Gubden (Foothill Dagestan). The tree-shrub layer is dominated by S. daghestanica with a crown density of 42%. In the grass-shrub layer, the dominant species with a projective cover of 3 to 5% are Artemisia taurica Willd (4%) and representatives of the Poaceae family: Festuca varia Haenke (4%), Elytrigia gracillima (3%), Stipa daghestanica Grossh.) (3%).

It is necessary to create protected areas in the areas of growth of the studied species for the conservation of plants in situ. The results of community studies are presented for the first time and can be used in monitoring work on rare endemic species.

Keywords: Salsola daghestanica, Dagestan, Red Book, plant communities, flora, endemic.

Financing. The work was carried out on the topic of the State Task of the Mountain Botanical Garden of the Dagestan Federal Research Center of the Russian Academy of Sciences «Geoclimatic features of distribution and description of communities with populations of rare and resource tree species of the North Caucasus» No. 1021032423798-8-1.6.11.

DOI: 10.24412/1993-3916-2022-3-72-78

CHANGES IN ECOSYSTEM COMPONENTS OF REclaimed SOLONETZES IN THE PRIERGENINSKAYA PLAIN DURING THE GROWING PERIOD (REPUBLIC OF KALMYKIA)

Arid Ecosystems

UDC 581.5

Novikova N.M., Konyushkova M.V., Ulanova S.S., Volkova N.A., Chemidov M.M., Bembeeva O.G., Fedorova N.L. CHANGES IN ECOSYSTEM COMPONENTS OF RECLAIMED SOLONETZES IN THE PRIERGENINSKAYA PLAIN DURING THE GROWING PERIOD (REPUBLIC OF KALMYKIA) // Arid ecosystems. 2022. V.28. № 3 (92). P. 79-93. | PDF

During the growing season of 2021, in early May, late June and early September, observations were carried out on the functioning of the main components of ecosystems recovering after reclamation at 8 sites of the IV experiment of the Arshan-Zelmen hospital, where reclamation work that lasted 20 years was stopped almost 50 years ago. Currently, soils belong to one type of highly transformed soils, the deep-saline agrozems. Arable (0-45 cm) and sub-arable (50-60 cm) horizons have been preserved in the soil profile. In 2018 in most areas, the content of salts and, in particular, chlorine ion increased in the subsurface horizon. These changes have not been reflected in vegetation, and the formation of plant communities characteristic of the final stages of secondary succession of light chestnut soils, not saline, continues. Hydrothermal conditions in 2021 during the observation period (May-September) can be assessed as arid – the doubly increased value of the average temperature for each month turned out to be higher than the value of precipitation that fell that month. Precipitation fell every month except July. The precipitation that fell during this period (176 mm) exceeded the average annual amount for these months of 2011-2021 by 1.3 times, and the sum of temperatures only by 2°C. Therefore, the hydrothermal conditions of the growing season of 2021 can be assessed as more favorable for the functioning of ecosystem components than in other years.

Comparison of data characterizing the salt profile of soils during the growing season showed that the content of water-soluble salts (in % per 100 g of soil) in the horizons from September to May changed in the range from -1.42 to +0.36. At different periods of observations, both unidirectional changes  in the salt content and multidirectional changes were observed in the same soil horizons. In May, the upper horizons of all soils, including virgin soils, up to a depth of 30 cm were unsalted, they remained in the same category of salinity by September. In the profile of virgin soils, salinization began from a depth of 30-40 cm and intensified downwards, reaching values of strong salinization in the horizon of 70-100 cm (1.1-2%). By the end of the growing season, the salt content in these horizons decreased to an average (0.5-1%). In soils that had previously experienced forest reclamation, the lower horizons that were slightly saline in May (80-100 cm) moved to the category of non-saline by autumn. In previously reclaimed soils under the former arable land, on the contrary, previously unsalted lower horizons have moved into the category of slightly saline. The magnitude of the change in salinity of soil horizons has a high tightness of connection (r=0.89) with the chlorine ion.

The vegetation cover is relatively sparse; the total projective coverage ranges from 35% to 73%. The average values from May to June varied from 43% to 52% and by September decreased to 47%. Throughout the year, the communities are dominated by bulbous bluegrass (Poa bulbosa) and Lerch’s wormwood (Artemisia lerchiana). Chamomile (Tanacetum achilleifolium) is present in all areas, and in some, including virgin lands, acts as a codominant. In May, the volosnets (Leymus ramosus) aspect, in June and in September – annuals Anisantha tectorum and Atriplex tatarica, respectively. The aboveground phytomass of most plant communities increases from spring to autumn from 4-5 c/ha to 10-25 c/ha. In some areas, mainly previously forested and some virgin, the maximum values were reached at the end of June and decreased by autumn due to a significant decrease in the phytomass of perennial cereals. Plant communities by species composition and dominance during the entire growing season Artemisia lerchiana and Poa bulbosa should be attributed to the pasture variant of zonal semi-shrubby-tyrsikov (Stipa sareptana) plant communities characteristic of the desolate steppe on chestnut unsalted and slightly saline soils.

The novelty of this study is associated with new quantitative data on changes in the characteristics of the main components of the ecosystems of the desolate steppes during the vegetation period.

Keywords: Caspian lowland, virgin salt flats, land reclamation, irrigated afforestation with irrigation, irrigated arable land, hydrothermal conditions, vegetation period, salinization-desalinization of soils, species richness, plant communities, aboveground phytomass.

Financing. The work was carried out within the the State Task of the Water Problems Institute of the Russian Academy of Sciences, topic No. FMWZ-2022-0002,f «Research of geoecological processes in hydrological systems of land, formation of surface and groundwater quality, problems of water resources management and water use in conditions of climate change and anthropogenic impacts».

DOI: 10.24412/1993-3916-2022-3-79-93

THE CLIMATIC FLUCTUATIONS IN DRY STEPPES AND THEIR ROLE IN THE PROCESS OF REGENERATION

Arid Ecosystems

Pugacheva A.M. The Climatic Fluctuations in Dry Steppes and Their Role in the Process of Regeneration // Arid ecosystems. 2020. V. 26. № 3 (84). P. 14-22. | PDF

For the first time a research paper presents the results of the analyses of moisture-providing during the active growing seasons in dry steppes. The climatic fluctuations were examined together with the defining their characteristics. Contrary to the common opinion, that the steppe zone receives the highest rainfall in summer and that fact becomes its special feature including subzones, the analyses of 64 years show that the dry steppes of Lower Volga region received the highest rainfall in summer only in 39 % of years, in spring – in 27% of years and in autumn – in 34% of years. The time-series analysis during the seasons of moisture-providing for more than 50 years identified the general trend of decrease in summer rainfall and the increase of spring and autumn rainfall. The processing of time-series by  exponential smoothing and the regression analysis points to the rate of humidity increase in spring after the critical years of 1990 and 1991, which is proved by Student’s t-test (probability 0,00005) together with the humidity decrease in autumn (probability 0,01). These features characterize the regeneration processes of secondary phytocenoses on fallow lands in the form of domination of loose bunch cereaks and dense cereals in them because the moisture-providing in late spring (May) and early summer (June) has the primary importance for their development. In addition, the characteristics of moisture-providing show a tendency towards aridization. The number of species of Poaceae family  in the examined phytocenoses is 28 with 24.5% of representation. Moreover, this fact characterizes the existence of ephemeral plants and ephemeroids in the plant community, because their vital activity mainly depends on the spring rainfall. The number of their species is 8% of the total.

Keywords: climatic fluctuations, dry steppes, regeneration, plant communities, phytocenoses, exponential smoothing, regression analysis.

DOI: 10.24411/1993-3916-2020-10102