scholarly journals ГИГРОТОП И ТРОФОТОП БИОГЕОЦЕНОЗОВ СТЕПНОГО ПРИДНЕПРОВЬЯ КАК ДЕТЕРМИНАНТЫ β-РАЗНООБРАЗИЯ СООБЩЕСТВ ДОЖДЕВЫХ ЧЕРВЕЙ (LUMBRICIDAE)

Author(s):  
A. V. Zhukov ◽  
D. B. Shatalin

<p>The role of the hygrotope and trophotope of the steppe Pridniprovie biogeoceonosis has been discussed in present article as being determinants of the β-diversity of earthworms (Lumbricidae) communities. Material has been colected to the period 1997-2015. 180 sample polygons have been studied which located in various types of biogeoceonosis. Biogeoceonotic characteristic of the sample polygons have been made on the basis of professor A.L. Belgard forest typology of a steppe zone of Ukraine. Earthworm communities of the steppe Pridniprovie have been established to be presented by 16 species. Hygrotopes, trophotopes and bitope ceonosis features have been shown to be able to explain 72.4 % of a communities’ abundance variation and 73.7 of their % α-diversity by means of second order model. Earthworm communities’ abundance reache their maximum values at a combination of conditions of humidity from hygromesophilous to hygrophilous and conditions of edaphotope trophicity from D<sub>c</sub> (linden oakwood) to D<sub>n </sub>(elm-ashen oakwood and alder forests). The maximum diversity of earthworm communities has been stated to be characteristic for a combination of mesohygrophilous conditions and a trophicity mode D<sub>c</sub>, that there corresponds to forest type a linden oakwood with aegopodium. The coenomorphic structure of the biogeocoenosis is statistically significant predictors of both abundance and α-diversity of earthworm communities. Earthworm communities of marsh monocoenosis, meadow-steppe amphicoenosis and steppe monocoenosis have been found as being characterised by minimum abundance and diversity. Moderate level abundance and diversity are characteristic for meadow-forest amphicoenosis, forest pseudomonocoenosis with elements of transformation to steppe and forest-steppe amphicoenosis. High levels of these indexes are typical for forest monocoenosis. Given other conditions of humidity and edaphotope trophicity being equal in forest monocoenosis abundance and diversity of earthworm communities will be higher than in other biogeocoenosis types. The MDM-analysis (<em>Multinomial</em><em> </em><em>Diversity</em><em> </em><em>Model</em>) reveals that habitats coenotic features define 12.61 % of all entropy of earthworm communities, hygrotopes – 24.12 %, trophotopes – 12.3 %. The square-law hygrotope member defines 10.93 %, and trophotope – 2.05 %. Hygrotope and trophotope interaction defines 1.53 % of entropy of earthworm communities. Sites (<em>α</em> -diversity) define 36.45 % of entropy. There are other factors which influence a diversity of earthworm communities besides a humidity, trophicity and habitat coenotic features. Steppe Pridniprovie earthworm complexes have been divided into ecological groups on the basis of relation to humidity (hygromorphes) and to edaphotope trophicity (trophocenomorphes). Earthworms hygromorphes are presented by xerophylous (2 species), mesophylous (9 species), hygrophylous (4 species), ultrahygrophylous (1 species). Trophocoenomorphes are presented by oligotrophocoenomorphes (1 species), oligomesotrophocoenomorphes (4 species)<em>, </em>mesotrophocoenomorphes (9 species)<em>, </em>megatrophocoenomorphes (2 species)<em>.</em></p><p> </p>

2020 ◽  
Vol 648 ◽  
pp. 19-38
Author(s):  
AI Azovsky ◽  
YA Mazei ◽  
MA Saburova ◽  
PV Sapozhnikov

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.


2004 ◽  
Vol 94 (2) ◽  
pp. 111-121 ◽  
Author(s):  
P.A.V. Borges ◽  
V.K. Brown

AbstractThe arthropod species richness of pastures in three Azorean islands was used to examine the relationship between local and regional species richness over two years. Two groups of arthropods, spiders and sucking insects, representing two functionally different but common groups of pasture invertebrates were investigated. The local–regional species richness relationship was assessed over relatively fine scales: quadrats (= local scale) and within pastures (= regional scale). Mean plot species richness was used as a measure of local species richness (= α diversity) and regional species richness was estimated at the pasture level (= γ diversity) with the ‘first-order-Jackknife’ estimator. Three related issues were addressed: (i) the role of estimated regional species richness and variables operating at the local scale (vegetation structure and diversity) in determining local species richness; (ii) quantification of the relative contributions of α and β diversity to regional diversity using additive partitioning; and (iii) the occurrence of consistent patterns in different years by analysing independently between-year data. Species assemblages of spiders were saturated at the local scale (similar local species richness and increasing β-diversity in richer regions) and were more dependent on vegetational structure than regional species richness. Sucking insect herbivores, by contrast, exhibited a linear relationship between local and regional species richness, consistent with the proportional sampling model. The patterns were consistent between years. These results imply that for spiders local processes are important, with assemblages in a particular patch being constrained by habitat structure. In contrast, for sucking insects, local processes may be insignificant in structuring communities.


2021 ◽  
Vol 901 (1) ◽  
pp. 012007
Author(s):  
V M Kosolapov ◽  
V I Cherniavskih ◽  
E V Dumacheva ◽  
M N Marinich ◽  
L D Sajfutdinova ◽  
...  

Abstract We evaluated the stability of perennial legume and cereal grass species in artificial plant communities on permanent anti-erosion watercourses in the agroecosystems of the Belgorod region with active development of linear soil erosion. In the conditions of steppe and forest-steppe zones of the Belgorod region on permanently grassed watercourses in 2017-2019. varieties of perennial leguminous and cereal grasses: ‘Krasnoyaruzhskaya 1’ and ‘Krasnoyaruzhskaya 2’ (Medicago varia), ‘Kazatsky’ (Trifolium pratense), ‘Olshanka’ and ‘Ivica’ (Festuca arundinacea), ‘Streletsky’ and ‘Stepnyak’ (Lolium perenne)) obtained using local genetic material were studied. All varieties showed their resistance in agro-ecosystems with active development of linear erosion in the forest-steppe and steppe zones. Projective cover on watercourses in the steppe zone in all variants of experience was on average 83,4 %, in the forest-steppe zone - 86,3 %. In the third year of the tests on permanently irrigated watercourses in the steppe zone, the share of cereal and legume grass species was quite high and varied from 88 % in the variant M. varia + Onobrychis arenaria to 92 % in the variants M. varia + Bromopsis inermis and O. arenaria. In the forest-steppe zone, the share of cereal and legume grass species varied from 86 % in the variant L. perenne to 94 % in the variant L. perenne + B. inermis.


Author(s):  
Tatyana Aleksandrovna Khlyzova

Satyr fauna of the Southern trans-Urals is represented by 24 species, 2 of which - P. afra and E. medusa - are included in the Red Book of the Kurgan region as species of vanishing number and range. In terms of the wintering phases of satyrs of the Kurgan region, they are possible to be divided into 2 ecological groups: wintering caterpillars (19 species) and wintering pupae (2 species). The hibernating phases of C. hero , P. afra and C. persephone haven’t been identified. Among satyrs divided by the wideness of trophic specialization of caterpillars there exist broad oligophages and broad polyphages. According to the flight terms of imago satyrs of the Southern trans-Urals, they can be divided into 3 phenological groups: early-summer (6 species), summer (15 species) and late-summer (1 species). Satyr fauna in the region generally can be called forest-steppe. According to the peculiarities of the passage of the main parts of the areas, the satyrs can be divided into 3 groups. The first group unites 4 species that are widespread in the northern and southern forest-steppe, the herbage-grass-turf-grass steppe. The second group includes 16 species that occur only in the forest-steppe zone. The third group consists of 4 species, whose most favorable habitats are located in the herbage-turf-grass steppe. According to the landscape-biotope confinement, regional satyrs can be divided into 4 ecological groups: inhabitants of pine-small-leaf forests, inhabitants of the small forest - campestral landscape, inhabitants of steppes and steppe areas, eurybionts. The fauna of glades of pine-small-leaf forests is mostly rich in species. The generality of the species composition of the satyrs of the small forest - campestral and steppe landscapes reaches 53%. First of all, this is due to the quick spread of cereals in these landscapes, which are fodder plants for caterpillars of most species of this family.


2014 ◽  
Vol 74 (2) ◽  
pp. 267-273 ◽  
Author(s):  
VC. Oliveira ◽  
EA. Gonçalves ◽  
RG. Alves

Riparian vegetation along streams in the Atlantic Forest in Brazil contributes to the formation of a highly heterogeneous leaf litter in streambeds. To investigate the structure and composition of the aquatic invertebrate community during the process of leaf decomposition of two plant species present along the banks of the stream studied, 21 plastic mesh bags containing 2.5g (dry weight) of leaf matter from each species (Alchornea glandulosa (Vell) and Cabralea canjerana End. and Poeppig), for a total of 5.0g, were placed in the streambed. Three bags were removed after 3, 6, 9, 12, 24, 48 and 96 days. The taxonomic density was negatively correlated with the remaining weight. The high density of collector organisms, such as Chironomidae, Oligochaeta and Amphipoda, on the last day of incubation, probably occurred due to the increased amount of fine organic matter in the more advanced decomposition stages. The highest α diversity (Shannon-Wiener) values were observed for the 3rd and 96th days of the experiment, while the β diversity values showed that these days presented the highest variation in the taxonomic composition, thus presenting a different faunistic composition. This study showed that the trophic structure and composition of aquatic invertebrates changes during the decomposition of leaf litter. The faunistic abundance and diversity observed in this study indicate that the entrance of material from plants growing along streams provides favorable conditions for the colonisation and establishment of invertebrates in lower-order streams, and thus points to the need to preserve riparian vegetation.


2021 ◽  
Vol 15 (3) ◽  
pp. 61-72
Author(s):  
T. Shupova ◽  
◽  
A. Chaplygina ◽  

Background. In the 21st century, landscape transformation processes are underway in large cities, which affects the stability of wildlife habitats. Habitat transformations often reduce species richness due to a decrease in the population sizes of some species, and therefore, small in number and rare species are eliminated from bird communities. Rare species can have unique consortive relationships, which makes them particularly important for the long-term ecosystem functioning. A study of the avifauna of forest parks makes it possible to develop an algorithm for the coexistence of human and birds. Methods. The number and distribution of birds were determined by route counting. The total length of the fixed route was 5.7 km in Kyiv and 3.5 km in Kharkiv. On each route, observations were carried out annually with three repetitions during the nesting period when the birds are most attached to their habitats (end of April–May–June). The average data for the total study period (2013–2017) were calculated for each city. For the average number, the standard deviation was calculated. An analysis of the faunogenetic structure of avifauna was carried out according to the method developed by V.P. Belik. A faunogenetic complex is a group of animal species associated by a common origin with ecosystems of a certain landscape-geographical zone. We also classified bird species into ecological groups according to the patterns of microhabitat choice. To compare the α-diversity of bird in the forest-park zones of cities, a number of commonly accepted indices that express the correlation between the number and density of species were calculated: 1) Berger–Parker dominance index: DBP = Nimax / N; 2) Shannon diversity index: H´ = -∑(Pi × LnPi); 3) Pielou evenness index: E = H´ / LnS; where: Nі– the number of each species; Nimax – the maximum value of Nі; N = ∑Ni – the total number of all species (pairs/km); Pi = Ni / N – the ratio of each species; S – total number of the species. Results. The study presents a comparative analysis of diversity and faunogenetic structure of avifauna in the forest park zones of Kyiv and Kharkiv, inhabited by 71 breeding species of birds that belong to 10 orders. In the eastern region, the proportion of birds of the boreal and the European forest-steppe complex decreases, but the share of the desert-mountain complex increases. The fauna of the European nemoral complex dominates (32.8 % in Kyiv and 40.4 % in Kharkiv). The basis of the communities are dendrophils: 83.6 % (n = 67) in Kyiv and 82.7 % (n = 52) in Kharkiv. The dominant species in all forest parks are the great tit (Parus major) and chaffinch (Fringilla coelebs). Conclusions. The differences in the faunogenetic structure of bird communities are due to the proximity of model forest parks on the territory of Kyiv to the forest natural geographical zone, and on the territory of Kharkiv to the steppe, which leads in the eastern region to a decrease in the proportion of birds of the boreal and the European forest-steppe complex while the proportion of desert-mountain complex increases. Dendrophils predominate significantly, and the share of sclerophils and limnophils in total is less than 20 % of the bird community in the forest parks of each city. As a consequence of the fragmentation of the Kiev forest park zone, the diversity of nesting birds communities in the forest-park zone of Kyiv is slightly lower than of Kharkiv, and the pressure of the dominant species is more significant.


2021 ◽  
Vol 51 (1) ◽  
pp. 25-32
Author(s):  
A. A. Malyuga ◽  
N. S. Chulikova

Long-term studies (2014–2019) of the population dynamics of the fungus Rhizoctonia solani Küch. were carried out in the soil on the Purple Majesty, Vitelotte and Fioletovy potato varieties and preceding crops (potatoes, oats and tendergreen). The study was carried out in Novosibirsk region in the soil and climatic conditions typical of the forest-steppe zone of Western Siberia. To study the peculiarities of R. solani fungus population dynamics in potato plantations, soil samples were taken from under the plants during the entire growing season. The accumulation of rhizoctonia propagules in the soil was determined using the method of multiple soil pellets. The difference in the amount and rate of accumulation of the fungus R. solani on different varieties, as well as the influence of previous crops on this process, was established. Two peaks of the fungus accumulation were observed on the Purple Majesty variety: the first (48.7 propagules/100 g of soil) – during the full germination period, the second (57.2 propagules/100 g of soil) – at the end of the crop maturation phase. One peak was observed in the population dynamics of the fungus on Vitelotte and Fioletovy varieties, at the end of the ripening period (59.0 and 49.1 propagules/100 g soil, respectively). The smallest amount of R. solani fungus in the soil on average during the growing season was noted on the Fioletovy variety – 33.3 propagules/100 g of soil. In the Purple Majesty and Vitelotte varieties, this figure was 41.5 and 40.4 propagules/100 g of soil, respectively. When potato variety Agata was cultivated as monoculture, there was a rapid and significant accumulation of the fungus R. solani in the soil (from 34.6 to 126.8 propagules/100 g of soil). When this variety was cultivated following tendergreen or oats, the amount of the pathogen varied to a lesser extent (25.1–52.2 and 19.8–41.0 propagules/100 g of soil, respectively). No sharp increases in the number of propagative structures of the phytopathogen in the soil were noted.


2021 ◽  
Author(s):  
Ezequiel Santillan ◽  
Stefan Wuertz

Diversity is frequently linked to the functional stability of ecological communities. However, its association with assembly mechanisms remains largely unknown, particularly under fluctuating disturbances. Here, we subjected complex bacterial communities in bioreactor microcosms to different frequencies of organic loading shocks, tracking temporal dynamics in their assembly, structure and function. Null modelling revealed a stronger role of stochasticity at intermediate disturbance frequencies, preceding the formation of a peak in α-diversity. Communities at extreme ends of the disturbance range had the lowest α-diversity and highest within-treatment similarity in terms of β-diversity, with stronger deterministic assembly. Stochasticity prevailed during the initial successional stages, coinciding with better specialized function (nitrogen removal). In contrast, general functions (carbon removal and microbial aggregate settleability) benefited from stronger deterministic processes. We showed that changes in assembly processes predictably precede changes in diversity under a gradient of disturbance frequencies, advancing our understanding of the mechanisms behind disturbance-diversity-function relationships.


Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 763
Author(s):  
Andrey Novoselov ◽  
Alexandr Konstantinov ◽  
Artem Lim ◽  
Katja Goetschl ◽  
Sergey Loiko ◽  
...  

The formation of Mg-rich carbonates in continental lakes throughout the world is highly relevant to irreversible CO2 sequestration and the reconstruction of paleo-sedimentary environments. Here, preliminary results on Mg-rich carbonate formation at the coastal zone of Lake Vtoroe Zasechnoe, representing the Setovskiye group of water bodies located in the forest-steppe zone of Southwest Western Siberia, are reported. The Setovskiye lakes are Cl−–Na+–(SO42−) type, alkaline, and medium or highly saline. The results of microscopic and mineralogical studies of microbialites from shallow coastal waters of Lake Vtoroe Zasechnoe demonstrated that Mg in the studied lake was precipitated in the form of hydrous Mg carbonates, which occur as radially divergent crystals that form clusters in a dumbbell or star shape. It is possible that hydrous Mg carbonate forms due to the mineralization of exopolymeric substances (EPS) around bacterial cells within the algal mats. Therefore, the Vtoroe Zasechnoe Lake represents a rare case of Mg-carbonates formation under contemporary lacustrine conditions. Further research on this, as well as other lakes of Setovskiye group, is needed for a better understanding of the possible role of biomineralization and abiotic mechanisms, such as winter freezing and solute concentration, in the formation of authigenic Mg carbonate in modern aquatic environments.


2020 ◽  
Vol 161 ◽  
pp. 01102
Author(s):  
Alfia Razina

Energy-saving technologies of wheat cultivation limit the buffer role of the agrotechnical method in reducing the spread of root rot. This situation calls for using increased volumes of pesticides in order to decrease harvest losses arising from actions of harmful organisms, which does not allow to produce organic food.Considering this, evaluation of the efficiency of agrotechnical methods of cultivating spring wheat aimed at enhancing phytosanitary conditions of crops is very important. The goal of our work was to evaluate the role of predecessors, methods of soil preparation,organic fertilizers, new varieties of spring wheat, and the timing of planting in limiting the spread and reducing the harmfulness of root rot. Our study has been conducted in the forest-steppe zone of Eastern Siberia. We have established that green manure in crop rotationandfallow arable land with introduction of 30 t/ha of organic manure fertilizer with a disc harrow to a depth of 10–12 cmreduce the spread and severity of root rot and increase wheat yields. In the plantings of the new variety of spring wheat Marsianka, the spread of the disease was reliably less,and the yield was higher compared to the control variety Tulunskaya 11. The optimal planting date for the average of two years was May 25, the crops planted then compared to those planted on May 30 were 9.4% less affected by the disease and gave a reliable increase in the harvest of 0.15 tons/ha. Our studies have shown that during production of organic wheat we can limit the spread andharmfulness of root rot withagrotechnical methods.


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