scholarly journals Seasonal population dynamics of Brachyiulus jawlowskii (Diplopoda, Julidae) in the Dnieper river arena

2016 ◽  
Vol 24 (2) ◽  
Author(s):  
N. G. Gudym
Keyword(s):  
Population Dynamics ◽  
Nature Reserve ◽  
Deciduous Forest ◽  
Steppe Zone ◽  
Absolute Number ◽  
Oak Forest ◽  
Wide Range ◽  
Full Picture ◽  
Seasonal Population ◽  
Forest Habitats

We have researched the population dynamics of Brachyiulus jawlowskii Lohmander, 1928 in the arena of the Dnepr river (within the "Dnieper-Orilsky” Nature Reserve) and also present a full picture of the habitat distribution of Julidae within the researched area. The tested models were basic types of arena biogeocenosis: sand steppe, black maple forests, artificial pine plantations, deciduous forest, meadow and swamp. Variation in population density of B. jawlowskii is determined by biotopical features. The swamp and meadow habitats can be characterized by the highest level of population dynamics. B. jawlowskii plays the greatest role in the herpetobiont grouping in swamp and oak forest habitats (6.7% and 4.6% respectively). In other types of habitat this species composes 0.1–3.5% of the total abundance of this group. The highest abundance dynamic was reached by the Julidae cenopopulations which inhabit the swamp, oak forest and meadow habitats. B. jawlowskii occupies a relatively significant share in the herpetobiont communities of these habitats. Thus, the indicators of absolute number of this species and its relative participation in the herpertobiont grouping indicate the preference of this species for marsh, oak forest and meadow habitats. These habitats can be characterized by an excessive or moderate level of edaphotopic humidification. The ecosystem of the steppe zone of Ukraine is subject to significant human impact. In nature reserves, this effect is minimized, which permits research to be conducted on regimes of natural population dynamics. We established that B. jawlowskii inhabits all habitats investigated within the arena zone of the Dnepr river. This indicates that this is an environmentally flexible Julidae species. The population dynamics of B. jawlowskii can be characterized by three distinct periods: spring-summer, summer and autumn. Each of these periods is characterized by a distinct population dynamic, but throughout the study period the metapopulation of B. jawlowskii remained stable. This is due to the redistribution of representatives of the biotopical metapopulation over a wide range. The conservation regime within the "Dnieper-Orilsky" Nature Reserve had a positively effect on the state of the B. jawlowskii population. Within the reserve on the territory of the arena of the Dnepr river B. jawlowskii uses a wide variety of types of habitats. 

scholarly journals Vegetation cover and small mammals as the components of biocoenosis in the conditions of the Volga Upland

2017 ◽  
Vol 6 (2) ◽  
pp. 18-23
Author(s):  
Elena Evgenievna Boryakova
Keyword(s):  
Small Mammals ◽  
Vegetation Cover ◽  
Nature Reserve ◽  
Complex Structure ◽  
Distinct Group ◽  
Steppe Zone ◽  
Point Of View ◽  
Forest Steppe ◽  
Oak Forest ◽  
The Village

The study of the nature reserve oak forest near the village of Pelya-Khovanskaya ecosystem was done in the region of Nizhny Novgorod. The investigated wood is unique for its complex structure. It is situated in the forest-steppe zone, characterized by a high species diversity of small mammals and vegetation, which indicates the complexity of trophic and spatial connections. Several series of sample plots were described: 41 of 2020 m and a number of 11 m sites, totaling 300. Abundance of species by Brown-Blanke scale and the number of specimens of adolescence were specified for each 1 sq. m. plot. Mammals were trapped with the help of trapping grooves and transects method. Vegetation cover is characterized by the presence of a clear intra-differentiation as well as the existence of two basic ecologo-coenotic groups/cores - the nemoral (with Pulmonaria obscura Dum. as the center species of the core) and the meadow-fringe. The most distinct group is formed by forest-shoot species. It can be explained by more forest-steppe rather than nemoral nature of vegetation. Small mammals are represented by the following species: common and small shrews, small forest mouse, yellow-throated and field mice and harvest mouse, vole-housekeeper, common, plowed and red voles, European mole. Two species among them - vole-housekeeper and mouse-baby - are listed in the Red Book of the Nizhny Novgorod Region. Matching burrows of mouse-like rodents with soil richness with nitrogen and humidity, two well-defined peaks are observed. The greatest number of burrows is found in places where the soil is high in nitrogen. Moles were found in areas with a large projective coating of Primula veris: coefficient Spearman rank 0,50. There was a negative correlation of the number of moles and vegetation covering of Pyrethrum corymbosum (-0,46), which is the marker of the driest parts in the forest. In general, the nature reserve oak forest near the village of Pelya-Khovanskaya is of considerable interest, both from botanical and from zoological point of view. Long-term studies of biocoenosis will allow to monitor the facility and to correct the proposed protective measures.

The relationship between soybean cyst nematode seasonal population dynamics and soil texture

Nematology ◽  
2004 ◽  
Vol 6 (4) ◽  
pp. 511-525 ◽  
Author(s):  
Felicitas Avendaño ◽  
Francis J. Ierce ◽  
Haddish Melakeberhan
Keyword(s):  
Population Dynamics ◽  
Soil Texture ◽  
Soybean Cyst Nematode ◽  
Reproductive Potential ◽  
Cyst Nematode ◽  
Stable Relationship ◽  
Wide Range ◽  
The Relationship ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

Abstract The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, cyst population densities at planting and at harvest have been related to soil texture but the seasonal mechanisms by which these correlations are established are less well known. The purpose of this work was to analyse the relationship of SCN life stages and reproductive potential (number of eggs per cyst) with soil texture. Cyst population density was positively correlated with sand and negatively correlated with clay and silt percentage in the soil within the ranges of 45-80% sand, 8-23% clay, and 8-43% silt in one field, but not in the other at five sampling times. The relationship between soil texture and juvenile stages in roots was weak. The stable relationship between SCN spatial and seasonal population dynamics and soil properties provides further support for potential delineation of management zones in SCN infested fields with a wide range of soil textures.

Long-term population dynamics of the red deer and European roe deer at the protected and not-protected areas in Mountain Crimea

2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev
Keyword(s):  
Population Dynamics ◽  
Protected Areas ◽  
Red Deer ◽  
Nature Reserve ◽  
Roe Deer ◽  
Precipitation Amount ◽  
Annual Precipitation ◽  
Population Number ◽  
The Impact

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>

The vegetation of the small rivers of Novosibirsk Region (a syntaxonomic essay)

2019 ◽  
pp. 3-27 ◽  
Author(s):  
L. M. Kipriyanova ◽  
M. A. Kleshchev
Keyword(s):  
Anthropogenic Impact ◽  
West Siberia ◽  
Steppe Zone ◽  
Small Rivers ◽  
Forest Steppe ◽  
Aquatic Communities ◽  
Emergent Plants ◽  
Novosibirsk Region ◽  
General Chemical ◽  
Wide Range

Information on the aquatic and semiaquatic vegetation of the major watercourses of West Siberia is relatively scarce, while this of small rivers is practically absent. There are 430 rivers whose length exceeds 10 km within the Novosibirsk Region. The aim of our work was to study the phytocenotic diversity of their aquatic and semiaquatic vegetation. 130 geobotanical relevés were performed by the authors in July–August 2003–2005. The object was aquatic communities formed by true aquatic (submergent and floating-leaved) plants and semiaquatic ones with emergent plants and these of water′s edge. In total 10 watercourses were studied (Table 1): 2–3 in each of five geomorphologic regions within the forest-steppe zone (Table 2). The upper, middle and lower courses (Fig. 1, Table 1) with the length of 2–2.5 km were studied in each case to ensure the 4–5 repetition of main elements (stream pools and ridges) that would give a reliable information on their flora and vegetation. The sample plots were selected above the settlements, whenever possible in sites with no to intensive anthropogenic impact. The data were collected according to J. Braun-Blanquet (1964) approach. The relevés were done on the sample plot of 100 m2 placed in the most homogeneous part of the community or, in case of its smaller area, within the natural boundaries. The following scale was used for abundance estimation: r — the species is extremely rare; + — rare, small cover; 1 — the number of individuals is large, the cover is small or individuals are sparse, but the cover is large; 2 —cover of 5–25 %; 3 — 26–50 %; 4 — 51–75 %; 5 — more than 75 %. The date on water depth, transparency (on a white Secchi disk with a diameter of 30 cm), temperature and the flow rate were obtained. The soil mechanical composition and color, the degree and nature of anthropogenic impact on vegetation and river banks were quantified. Water samples for general chemical analysis were taken in the middle course of each river. Computer programs TURBOVEG and MEGATAB (Hennekens, 1996) were used for database. The syntaxonomic affiliation of phytocenoses was determined using modern literature (Bobrov, Chemeris, 2006; Vegetace..., 2011; Chepinoga, 2015; Landucci et al. 2015; Mucina et al., 2016, etc.). 36 associations and 3 communities belonging to 12 alliances, 9 orders, and 5 classes have been identified (Tables 3–14, Fig. 2–9). Such great syntaxonomic diversity is determined by the significant ecotopic variety, the variability of substrates, the wide range of water flow rates and the different water trophicity. For comparison, 26 associations, 13 variants, 2 communities were identified in the study of 50 rivers of Lithuania (Sinkyavichene, 1992); altogether 84 associations are known for the Upper Volga region as a whole (Bob­rov, Chemeris, 2006), while 45 ones were recorded previously in 130 watercourses of this region (Bobrov, 1999). Information on small river macroalgae cenoses in the study area is partially reflected in the paper published earlier (Bobrov et al., 2005).

scholarly journals A Model for Analysing the Collective Dynamic Behaviour and Characterising the Exploitation of Population-Based Algorithms

2014 ◽  
Vol 22 (1) ◽  
pp. 159-188 ◽  
Author(s):  
Mikdam Turkey ◽  
Riccardo Poli
Keyword(s):  
Population Dynamics ◽  
Dynamic Behaviour ◽  
Fitness Landscape ◽  
Population Based ◽  
Levels Of Abstraction ◽  
Collective Dynamic ◽  
Model Studies ◽  
Proposed Model ◽  
Wide Range ◽  
Multiple Levels

Several previous studies have focused on modelling and analysing the collective dynamic behaviour of population-based algorithms. However, an empirical approach for identifying and characterising such a behaviour is surprisingly lacking. In this paper, we present a new model to capture this collective behaviour, and to extract and quantify features associated with it. The proposed model studies the topological distribution of an algorithm's activity from both a genotypic and a phenotypic perspective, and represents population dynamics using multiple levels of abstraction. The model can have different instantiations. Here it has been implemented using a modified version of self-organising maps. These are used to represent and track the population motion in the fitness landscape as the algorithm operates on solving a problem. Based on this model, we developed a set of features that characterise the population's collective dynamic behaviour. By analysing them and revealing their dependency on fitness distributions, we were then able to define an indicator of the exploitation behaviour of an algorithm. This is an entropy-based measure that assesses the dependency on fitness distributions of different features of population dynamics. To test the proposed measures, evolutionary algorithms with different crossover operators, selection pressure levels and population handling techniques have been examined, which lead populations to exhibit a wide range of exploitation-exploration behaviours.

scholarly journals Inter-seasonal population dynamics and pest status of Bemisia tabaci (Gennadius) biotype B in an Australian cropping system

2008 ◽  
Vol 99 (4) ◽  
pp. 325-335 ◽  
Author(s):  
R.V. Sequeira ◽  
A. Shields ◽  
A. Moore ◽  
P. De Barro
Keyword(s):  
Population Dynamics ◽  
Bemisia Tabaci ◽  
Cropping System ◽  
Late Summer ◽  
System Component ◽  
Cotton Production ◽  
Pest Status ◽  
Weed Host ◽  
Biotype B ◽  
Seasonal Population

AbstractBemisia tabaci, biotype B, commonly known as the silverleaf whitefly (SLW) is an alien species that invaded Australia in the mid-90s. This paper reports on the invasion ecology of SLW and the factors that are likely to have contributed to the first outbreak of this major pest in an Australian cotton cropping system. Population dynamics of SLW within whitefly-susceptible crop (cotton and cucurbit) and non-crop vegetation (sowthistle, Sonchus spp.) components of the cropping system were investigated over four consecutive growing seasons (September–June) 2001/02–2004/05 in the Emerald Irrigation Area (EIA) of Queensland, Australia. Based on fixed geo-referenced sampling sites, variation in spatial and temporal abundance of SLW within each system component was quantified to provide baseline data for the development of ecologically sustainable pest management strategies. Parasitism of large (3rd and 4th instars) SLW nymphs by native aphelinid wasps was quantified to determine the potential for natural control of SLW populations. Following the initial outbreak in 2001/02, SLW abundance declined and stabilised over the next three seasons. The population dynamics of SLW is characterised by inter-seasonal population cycling between the non-crop (weed) and cotton components of the EIA cropping system. Cotton was the largest sink for and source of SLW during the study period. Over-wintering populations dispersed from weed host plant sources to cotton in spring followed by a reverse dispersal in late summer and autumn to broad-leaved crops and weeds. A basic spatial source-sink analysis showed that SLW adult and nymph densities were higher in cotton fields that were closer to over-wintering weed sources throughout spring than in fields that were further away. Cucurbit fields were not significant sources of SLW and did not appear to contribute significantly to the regional population dynamics of the pest. Substantial parasitism of nymphal stages throughout the study period indicates that native parasitoid species and other natural enemies are important sources of SLW mortality in Australian cotton production systems. Weather conditions and use of broad-spectrum insecticides for pest control are implicated in the initial outbreak and on-going pest status of SLW in the region.

Little Bustard (Tetrax tetrax Linnaeus, 1758) Number Observation on the Rostov Nature Reserve Grounds the Middle of 20th Century to 2020

2021 ◽  
pp. 113-121
Author(s):  
Victor A. Minoranskiy ◽  
Yulia V. Malinovskaya ◽  
Vasily I. Dankov ◽  
Sergey I. Kolesnikov
Keyword(s):  
Twentieth Century ◽  
Economic Activity ◽  
Nature Reserve ◽  
Positive Impact ◽  
Steppe Zone ◽  
Eastern European ◽  
Steppe Species ◽  
Animal Tracking ◽  
Number Of Factors ◽  
Tetrax Tetrax

The purpose of the work. Elucidation of changes in the number and distribution of little bustard (Tetrax tetrax Linnaeus, 1758) on the territory of the Rostov Nature Reserve in the 20th-21st centuries and the reasons for their transformation. Place and methods of work. The reserve is located in the arid Eastern European steppes. The authors used their own observations from 1959 and publications on Tetrax tetrax L. The materials are collected using regular route methods and animal tracking at individual sites, as well as analysis of published information. Results. The little bustard is a characteristic steppe species that historically lived on the Don land. Since the mid-twentieth century, the steppes have experienced deep anthropogenic changes, which have had a great impact on this species. Currently, the little bustard in the steppe zone is a rare species. The creation of the reserve has had a positive impact on this species. In it, the little bustard is a small breeding species, and its number is constrained by a number of factors. The intensification of economic activity in the region and the aridization of the climate make it necessary to improve environmental protection work.

Influence of operating conditions on population dynamics in nitrifying biofilms

1999 ◽  
Vol 39 (7) ◽  
pp. 5-11 ◽  
Author(s):  
Valentina Lazarova ◽  
Danièle Bellahcen ◽  
Jacques Manem ◽  
David A. Stahl ◽  
Bruce E. Rittmann
Keyword(s):  
Population Dynamics ◽  
Ammonia Oxidation ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Stable Operation ◽  
N Removal ◽  
Wide Range ◽  
Total Nitrogen Removal ◽  
Nitrite Oxidizers

TURBO N® is a circulating-bed biofilm reactor that provides stable operation and high N removal for a wide range of N and BOD loadings. This paper describes the influence of operating conditions on biofilm composition and population dynamics when the TURBO N® is operated to achieve tertiary nitrification, simultaneous carbon and ammonia oxidation and total nitrogen removal when coupled with a pre-denitrification fixed floating bed reactor. In situ specific nitrification rates and respiration tests showed that ammonium and nitrite oxidizers became less active in the biofilm once oxidation of influent BOD became important. Analyses of community structure with oligonucleotide probes targeted to the 16S rRNA showed the same general trends for nitrifiers, but also suggested shifts in the makeup of the ammonium and nitrite oxidizers that could not be detected with respirometry or specific nitrification rates.

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