6,787 research outputs found

    Application of geographically weighted principal components analysis based on soybean yield spatial variation for agro-ecological zoning of the territory

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    ArticleIn this study, the geographically weighted principal components analysis as an alternative method for agro-ecological characterization of the region was provided. The spatial and temporal distribution pattern of soybean yield was analyzed by using spatial statistics technology, which provided a good reference for agricultural development planning. The soybean yield was selected for the present study because it is a comprehensive indicator reflecting the production potential of the regional agroecosystems. The organized data set, which included the average per year yields of soybean in 10 regions (206 administrative districts) of Ukraine, was used for analysis. The regular temporal trend, specific for each district, was previously extracted from the time series data. The principal components analysis of the detrended data allowed to identify four principal components, which altogether can explain 58% of the soybean yield variation. The geographically weighted principal components analysis allowed to reveal that four spatially determined processes were influencing the yield of soybeans and had the oscillatory dynamics of different periodicity. It was hypothesized that the oscillating phenomena were of ecological nature. Geographically weighted principal component analysis revealed spatial units with similar oscillatory component of soybean yield variation. Our study confirmed the hypothesis that within the studied territory there are zones with the specific patterns of the temporal dynamics of soybean yield, which are uniform within each area but qualitatively different between zones. The territorial clusters within which the temporal dynamics of soybean yield is identical can be considered as agro-ecological zones for soybean cultivation

    The spatio-temporal trend of rapeseed yields in Ukraine as a marker of agro-economic factors influence

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    The paper demonstrates the applicability of several statistical methods to the analysis and interpretation of the average rapeseed yield data. It proves our hypothesis that the general trend of rapeseed yield variations in Ukraine during 1991–2017 occurred due to agro-economic and agro-technological factors, which are the determinants of the revealed general trend. The temporal trend of rapeseed yield in most administrative districts can be described by a fourthdegree polynomial, namely, its characteristic points enabled us to describe and interpret the dynamics of rapeseed yields. The absolute term of the polynomial shows the initial conditions of the process, and its mapping allows us to identify the areas with the most favorable soil-climatic conditions for the rapeseed cultivation. Indicators of the maximum rate of growth and decrease of yields are the markers of stability of agro-ecosystems to the external influences. Therefore, the mapping of the maximum rate of decline and increase of yields reveal areas in which yields respond rapidly (increasing / falling) to the changes in agro-economic and agro-technological conditions, as well as areas where yields are more stable and change gradually. Thus, the form of the yield trend is determined by the influence of agro-technological and agro-economic factors, whose contribution to the fluctuation in rapeseed yields varies from 53% to 90%

    Phytoindication approach to assessing factors determining the habitat preferences of red deer (Cervus elaphus)

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    The study examined the possibility of using the phytoindication technique to describe habitat preferences of red deer in a relatively homogeneous area. Two alternative hypotheses were tested. Hypothesis 1 suggests that the relationship between red deer and vegetation is due to a trophic factor, so preferences for individual plant species cause vegetation to influence the distribution of animal numbers. Hypothesis 2 suggests that environmental factors influence vegetation, structuring and determining the productive level of the community as a whole. Therefore, environmental factors, rather than individual plant species, cause vegetation-animal interactions. The research was conducted on Biryuchiy Island Spit, where the Azov-Sivash National Nature Park is located. The geobotanical surveys were performed in three types of ecosystems: sandy steppe (vegetation class Festucetea vaginatae), saline meadows (vegetation class Festuco–Puccinellietea), and artificial forest plantation (vegetation class Robinietea). 250 releves were recorded according to the Brown-Blanquet approach. The number of fecal pellets and the number of groups of pellets of red deer was recorded together with geobotanical surveys in the same sample plots. The pellet groups counted in the field were converted to deer densities in specific vegetation classes taking into account the number of pellet groups on the site and the decay rate of the fecal pellets. The vegetation types were distinguished by the number of deer fecal pellets per unit area. The highest number of fecal pellets was found for the plant class Festucetea vaginatae, somewhat fewer fecal pellets were in the plant class Robinietea, and the lowest number was in the plant class Festuco-Puccinellietea. A geometric distribution model is adequate for explaining the experimental data on the number of fecal pellets. A total of 59 species of flowering plants were found. Based on the species composition and projective cover of species, the ecological regimes of ecotopes were identified by phytoindication. The correspondence analysis of the vegetation revealed two ordination axes. The ordination axis 1 (CA1) was able to explain 11.3% of community inertia, and the ordination axis 2 (CA2) was able to explain 5.2% of community inertia. The maximum excretory activity of animals was recorded for the central part of the ordination space, indicating the presence of an optimum zone in the gradient of environmental factors that structure plant communities. The forward selection procedure allowed the Nutrients Availability variable to be selected as the most important variable to explain variation in the plant community structure. The number of deer fecal pellets exhibited different patterns of response in the Nutrients Availability gradient. The response within the plant class Festucetea vaginatae could best be explained by Model III from the list of HOF-models. The response of the excretory activity of deer within the class Festuco-Puccinellietea could best be fitted by the model IV, which represents a symmetric Gaussian curve. The response of excretory activity in the Robinietea vegetation class was asymmetrical bimodal. The ecological properties of the red deer ecological niche in both the drier and less mineralized part of the range of ecological conditions and the wetter and more mineralized part should be assessed in the context of the prospects for future studies

    Diversity of diversity indices: Which diversity measure is better?

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    The article evaluates the dependence of the most common indices of species diversity on sample size and determines their ability to differentiate between different types of ecosystems, with a special emphasis on discriminating between natural and anthropogenic ecosystems. An approach to adjusting the indices to reduce their dependence on sample size was also proposed. The study was conducted in seven types of ecosystems: four were natural and three were anthropogenically transformed. Samples of soil animals were selected in 2011–2013 and 2021 using the same methods. A total of 20,518 soil animal specimens belonging to 202 species were collected in all study locations. The null alternative was generated by randomly selecting samples containing 2, 3, ..., 110 soil animals from the combined soil animal sample. For each gradation of sample size, 200 sample variants were formed. The density of soil macrofauna in natural ecosystems ranged from 3.6 ± 1.5 to 15.2 ± 6.9 specimens per sample, and in artificial ecosystems – from 13.2 ± 7.6 to 21.0 ± 11.9 specimens per sample. The number of species ranged from 22–80 species, and in artificial ecosystems it was 38–99 species. Indicators of species diversity correlated with each other. A high level of correlation was observed between indicators within groups of indices: indices of species richness and indices of heterogeneity and evenness. Fisher’s log-series alpha and the fundamental parameter of biodiversity were highly correlated with each other, as well as with the Margalef, species richness, and Chao’s species abundance indices. The log-normal distribution best describes the dominance patterns in terms of abundance in the natural ecosystems, and the Zipf-Mandelbrot distribution best describes the dominance patterns in terms of abundance in the artificial ecosystems. Diversity indices were ordered in the space of two dimensions, one explaining the variation between ecosystems and the other depending on sample size. The ordering of the traditional indices showed that there is a vacancy for the best index in the sense that such an index should best explain differences between ecosystems and differences between natural and artificial ecosystems. It should also be independent of sample size. The Simpson heterogeneity index and the Simpson evenness index were the best of the traditional indices, but they did not explain differences between ecosystems very well, especially when it came to distinguishing between natural and artificial ecosystems. The Margalef index, which is supposed to be independent of sample size, on the other hand, showed a very high level of dependence. Such a dependence was also found for the Menhinick index, though to a lesser extent. Obviously, size dependence negatively affects the differential ability of the indices. The corrected indices of species richness and the Shannon index are practically independent of sample size and have a greater ability to differentiate ecosystems by the level of diversity, with natural ecosystems characterized by consistently higher values of the corrected indices than artificial ecosystems. The dependence on the sample size makes indices from different ecosystems practically incomparable, which makes their use meaningless. Even minor differences in sample size can lead to significant deviations in the values of diversity indices. The application of the Michaelis-Menten model allowed us to suggest a method of correction of species richness indices and the Shannon index. After the correction, the indices are practically independent of the sample size, and their differential ability to characterize individual ecosystems and the level of anthropogenic transformation increases significantly

    Application of remote sensing data for monitoring eutrophication of floodplain water bodies

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    The aim of this article was to investigate the influence of structural features of the floodplain water network on the spatial and temporal dynamics of chlorophyll-a concentration as an indicator of eutrophication. The research was conducted in the waters of the “Dnipro-Orilskiy” Nature Reserve. The geographic information base with polygonal objects which represented water bodies of the reserve was created on the basis of detailed geographical maps and the high resolution space images. The water bodies were characterized using such parameters as the distance of the water body centroid from the nearest shore of the Dnipro River, the area of the water body, the order of the water body and the connectivity of the water body. Chlorophyll-а concentration was estimated based on the surface algal bloom index. The information was obtained about 148 water bodies, 141 of which are water bodies in the floodplain of the Dnipro River. The area of floodplain water bodies within the reserve was 3.28 million m2. The area of floodplain water bodies ranged from 300–232,500 m2. Trophic State Index allows us to estimate the trophic level of Dnipro River waters as mesotrophic, water bodies of first and second order as eutrophic, and water bodies of third and fourth order as hypereutrophic. The dynamics of chlorophyll-a content in water followed the seasonal course of temperatures. The concentration was lowest in the cold period of the year and reached its maximum in the second half of summer. The autumn decrease occurred at the end of September. The seasonal course of air temperature was superimposed on the peculiarities of the temperature regime of a particular water body, which depended on its depth and flow rate. The time, water body area, distance from the Dnipro River channel, connectivity and order of water bodies were the statistically significant predictors of chlorophyll concentration in water and were able to explain 85% of the variation of this indicator. The increase in chlorophyll-a concentration with increasing order of a water body is due to a decrease in the intensity of water exchange and a decrease in the depth of water bodies of higher order. An increase in the order of a water body is accompanied by a branching network of water bodies, the ability of water bodies to clear sediments decreases. Sediment accumulation leads to a decrease in their depth. Warming of shallow ponds and accumulation of organic matter in them are factors of intensive growth of blue-green algae. The evacuation of surplus organic matter, which results from mass vegetation development with excessive nutrient inputs, is a key driver of the eutrophic regime of water bodies. The increasing importance of regulatory processes develops in agreement with an increase in chlorophyll-a concentration in a water body. The importance of the considered factors reaches the highest level in summer time, when simultaneous maximum warming of water bodies and minimum water level in them take place. Accordingly, the differences between deep and relatively cool water bodies and shallow water bodies that warm up quickly, which significantly stimulates the growth of organic mass, reach the greatest contrast. The spatial patterns of variation in chlorophyll-a concentration have a complex multiscale structure, indicating the multiple nature of the acting factors. The spatial variability was represented as a composition of broad-scale and medium-scale spatial processes. The broad-scale process is most dependent on connectivity, whereas for the medium-scale process the leading one is the effect of water body order

    Age estimation of black locust (Robinia pseudoacacia) based on morphometric traits

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    The use of black locust (Robinia pseudoacacia L.) is still controversial, especially in managed forests, due to its invasive nature. The black locust has been proven effective in reclamation of degraded lands when native species are not an alternative in the face of the climate change and desertification. Therefore, the importance of black locust in European ecosystems remains a matter of debate. Of course, it is an adventitious species originating from another continent. However, the ecological characteristics of the species in its natural range are very useful for ensuring the restoration of vegetation cover in areas that have experienced significant anthropogenic pressure. This species has a large number of important and useful features that make it an important agent in the forestry system and provide significant environmental and economic benefits. The status of black locust as an invasive species, i.e. one that is capable of uncontrolled spread, remains speculative. Such a conclusion requires various studies, including those identifying exact age of the plants based on morphometric parameters. In our study, we tested the hypothesis that plant height and trunk diameter will allow for an accurate assessment of black locust age. The plants of black locust were measured in the zone of spontaneous self-seeding of plants from a planted 60-years-old forest. The plants dispersed towards a fallow land, formed in the corner of an agricultural field. The spreading began 15 to 20 years ago. The plants are mainly propagated by seedlings. An expert estimated the age of the plants visually. The measured trees were cut to obtain cross sections to account for the number of annual rings. A total of 68 trees were examined for morphometric characters. Black locust communities during self-dispersal are represented by individuals of different ages. The spatial pattern of distribution of individuals of different ages can reveal the spatial and temporal dynamics of the formation of spontaneous populations of black locust. For this purpose, it is critical to accurately identify the age of a large sample. Expert estimation of age is fast and fairly accurate, but it depends greatly on the qualifications of the expert and oftentimes plant ages are underestimated, especially in the early stages of population development. Plant height is also a good predictor of plant age, but the model gives poor predictions for plants older than 10 years. The tree height ranged 2.3 to 16.0 meters. The diameter at breast height (DBH) ranged 1.0 to 17.5 cm. The diameter at the root collar (DRC) ranged 1.6 to 21.7 cm. The age of the studied trees, determined by the number of annual rings per transect, ranged 6 to 17 years. The age of the trees according to the expert estimates was 8.2 ± 4.8 years. The expert estimates of age and the age according to the number of annual rings were statistically significantly different. The expert estimates of tree age were linearly related to tree size, while estimates of the number of annual rings showed a logarithmic relationship with tree height. Expert estimates also showed a closer relationship with tree height, while the relationship of estimates based on the number of annual rings had a slightly lower dependence on the morphometric traits. Regression analysis showed that there is a linear relationship between morphometric traits of the black locust. The coefficient of determination for the dependence of diameter at breast height on tree height was 0.96, and for the dependence of diameter at the base of the trunk on diameter at breast height was 0.97. This indicates a high level of multicollinearity of these morphometric traits when considering them as predictors of plant age. Taking into account the diameter at breast height and the diameter at the level of the root collar significantly improved the predictive ability of the model for identifying the age of the black locust trees

    Использование модели трансформационного лидерства в управлении полицией

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    The police, as well as other government agencies is a rather conservative mechanism not prone to rapid changes of style, techniques and methods of work and management methods as well. Despite more than a four-year "experience" of police reform in Russia, the police, is still the subject of constant criticism both from policing practitioners and theorists. This article describes the "cooperative" management system. The goal of the proposed material to the reader is the opening for the Russian reader leadership practices of the German police. The authors suggest that familiarity with the data presented below will help the continued practice of reforming of the Russian police, as well as police forces of the Commonwealth of Independent States (CIS). Today, both in Europe and Russia the traditional authoritarian system management and administration of the force dominates the fact that due to authors does not meet modern requirements of a changing and globalizing society and in the Police Science there is almost complete lack of international studies and those present are very scattered and fragmentary. It seems that this material will be useful for the further work of managers in the Russian police and possibly other countries of the so-called the former Soviet Union.La policía, como otros organismos estatales, es un mecanismo bastante conservador, no propenso a cambios rápidos en el estilo, los métodos y los métodos de trabajo, así como los métodos de gestión. A pesar de más de cuatro años de "experiencia" en la reforma de la policía en Rusia, la policía sigue siendo objeto de críticas constantes por parte de la policía y los teóricos. Este artículo describe un sistema de gestión "cooperativo". El propósito del material ofrecido al lector es la divulgación de las prácticas líderes de la policía alemana para el lector ruso. Los autores sugieren que conocer los datos que se presentan a continuación ayudará a continuar la práctica de reformar la policía rusa, así como las fuerzas policiales de los países de la Comunidad de Estados Independientes (CEI). Hoy en día, tanto en Europa como en Rusia, el sistema autoritario tradicional de gestión y administración de fuerzas domina en que, según los autores, no cumple con los requisitos modernos de una sociedad de globalización cambiante, y casi no hay investigación internacional en ciencia policial. Este material será útil para el trabajo posterior de los gerentes de la policía rusa y, posiblemente, de otros países de la llamada antigua Unión Soviética.Полиция, как и другие государственные органы, является довольно консервативным механизмом, не склонным к быстрым изменениям стиля, приемов и методов работы, а также методов управления. Несмотря на более чем четырехлетний «опыт» реформирования полиции в России, полиция по-прежнему подвергается постоянной критике со стороны как полицейских, так и теоретиков. В данной статье описывается «кооперативная» система управления. Целью предлагаемого читателю материала является раскрытие для российского читателя лидерских практик немецкой полиции. Авторы предполагают, что знакомство с данными, представленными ниже, поможет продолжить практику реформирования российской полиции, а также сил полиции стран Содружества Независимых Государств (СНГ). Сегодня как в Европе, так и в России традиционная авторитарная система управления и администрирования сил доминирует в том, что, по мнению авторов, не отвечает современным требованиям изменяющегося общества глобализации, а в науке о полиции почти полностью отсутствуют международные исследования. Этот материал будет полезен для дальнейшей работы менеджеров российской полиции и, возможно, других стран так называемого бывшего Советского Союза

    Urban park layers: Spatial variation in plant community structure

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    Horizontal structure of natural plant communities attracted the attention of researchers for a long time, while the problem of horizontal structure of urban park plantations was not studied sufficiently. Species richness of different tiers of park plantation in the large industrial city of Dnipro (Ukraine) was revealed in this study. Also features of variation in the structure of plant communities at different spatial levels were revealed, the influence of park plantation canopy on the understory and herbaceous layer of the park. There were 30 plant species in the tree layer of the park plantation. The most common species were Robinia pseudoacacia L., Acer platanoides L., A. negundo L., Gleditsia triacanthos L., Aesculus hippocastanum L., Populus carolinensis Moench. The variance-to-mean ratio revealed that 13 tree species were randomly distributed throughout the park, and 14 species were aggregated. The number of occurrences of a given tree species per site and variance-to-mean ratio were positively correlated. The numerous tree species showed a tendency of aggregated distribution within the park. Sixteen plant species were found in the understory. Among them, the most abundant species were Acer platanoides L., A. negundo L., A. pseudoplatanus L., Sambucus nigra L., Robinia pseudoacacia L. Eight species were found to be randomly distributed over the park area, and eight species showed an aggregate distribution. The number of species encountered in the understory and variance-to-mean ratio were positively correlated. In the herbaceous stand, 99 plant species were found, of which Chelidonium majus L., Viola odorata L., Impatiens parviflora DC., Parthenocissus quinquefolia (L.) Planch., Geum urbanum L. predominated. The variance-to-mean ratio of all species was significantly less than unity, indicating regular spatial distribution. The values of alpha- and gamma-diversity of the plant community in separate layers are very different. The highest gamma diversity was found for the herbaceous stand, while the diversity of the tree stand and understory was significantly lower. Alpha biodiversity of the tree stand and the understory did not practically differ. Beta diversity values between the layers are very close, and beta diversity is practically equal for tree stand and herbaceous layer. Thus, we can assume that the mechanisms of species turnover for the plant communities of different layers are determined by the common causes. The spatial broad-scale component was able to explain 8.2% of community variation, the medium-scale component was able to explain 4.2% of community variation, and the fine-scale component was able to explain 0.7% of community variation. The understory is the most sensitive to the environmental factors, the herbaceous stand is somewhat less sensitive, and the tree stand is the least sensitive to the environmental factors. The environmental factors in this study are represented by a set of variables. The spatial variation of the stand is predominantly influenced by the factors of trophicity and moisture of the edaphotope. These same factors also act on the herbaceous stand and understory, but along with them are included the environmental variables, which are determined by the architectonics of the crown space and thus the light regime, which is regulated by the tree stand. It is important to note that the variation of the communities of the different layers of the park plantation is subject to spatial patterns. The herbaceous and understory variation is more spatially structured than the tree stand variation. The spatial patterns can arise as a result of the influence of spatially structured environmental factors and as a result of factors of a neutral nature. The latter aspect of variation is best described by the pure spatial component of community variation
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