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Combler le fossé entre les prévisions des modèles climatiques à échelle grossière et la réalité climatique à échelle fine des espèces est un enjeu clé de la recherche en biologie du changement climatique. Bien qu'il soit maintenant bien connu que la plupart des organismes ne connaissent pas les conditions climatiques enregistrées dans les stations météorologiques, il existe peu d'informations sur les écarts entre les microclimats et les températures interpolées mondiales utilisées dans les modèles de répartition des espèces, et leurs conséquences sur les performances des organismes. Pour résoudre ce problème, nous avons examiné l'hétérogénéité spatio-temporelle à échelle fine des températures de l'air, du couvert végétal et du sol des paysages agricoles des Andes équatoriennes et les avons comparés aux prévisions des grilles climatiques interpolées mondiales. Des séries temporelles de températures ont été mesurées dans l'air, la canopée et le sol pour 108 localités à trois altitudes et analysées à l'aide de la transformée de Fourier. Les écarts entre les températures locales et les grilles interpolées mondiales et leurs implications pour la performance des ravageurs ont ensuite été cartographiés et analysés à l'aide de la boîte à outils statistique SIG. Nos résultats ont montré que les prévisions globales interpolées surestiment de 77,5±10 % et sous-estiment de 82,1±12 % les températures locales minimales et maximales de l'air enregistrées dans la grille étudiée. Des modifications supplémentaires de la température de l'air local étaient dues au tamponnage thermique du couvert végétal (de − 2,7°K pendant la journée à 1,3°K pendant la nuit) et des sols (de −4,9°K pendant la journée à 6,7°K pendant la nuit) avec un effet significatif de la phénologie des cultures sur l'effet tampon. Ces écarts entre les températures interpolées et locales ont fortement affecté les prévisions de la performance d'un ravageur ectothermique des cultures, car les températures interpolées prédisaient des taux de croissance des ravageurs 2,3 à 4,3 fois inférieurs à ceux prédits par les températures locales. Cette étude fournit des informations quantitatives sur la limitation des données climatiques à échelle grossière pour capturer la réalité de l'environnement climatique vécu par les organismes vivants. Dans les régions très hétérogènes telles que les montagnes tropicales, il convient donc de faire preuve de prudence lors de l'utilisation de modèles mondiaux pour déduire des processus biologiques à l'échelle locale. Cerrar la brecha entre las predicciones de los modelos climáticos a escala gruesa y la realidad climática a escala fina de las especies es un tema clave de la investigación en biología del cambio climático. Si bien ahora es bien sabido que la mayoría de los organismos no experimentan las condiciones climáticas registradas en las estaciones meteorológicas, hay poca información sobre las discrepancias entre los microclimas y las temperaturas globales interpoladas utilizadas en los modelos de distribución de especies, y sus consecuencias para el rendimiento de los organismos. Para abordar este problema, examinamos la heterogeneidad espaciotemporal a escala fina en las temperaturas del aire, el dosel de los cultivos y el suelo de los paisajes agrícolas en los Andes ecuatorianos y los comparamos con las predicciones de las redes climáticas interpoladas globales. Las series temporales de temperatura se midieron en aire, dosel y suelo para 108 localidades a tres altitudes y se analizaron mediante la transformada de Fourier. Las discrepancias entre las temperaturas locales frente a las redes interpoladas globales y sus implicaciones para el rendimiento de las plagas se mapearon y analizaron utilizando una caja de herramientas estadísticas SIG. Nuestros resultados mostraron que las predicciones interpoladas globales sobreestiman en un 77.5±10% y subestiman en un 82.1±12% las temperaturas mínimas y máximas locales del aire registradas en la cuadrícula estudiada. Las modificaciones adicionales de las temperaturas locales del aire se debieron al amortiguamiento térmico de las copas de las plantas (de -2,7 ° K durante el día a 1,3 ° K durante la noche) y los suelos (de -4,9 ° K durante el día a 6,7 ° K durante la noche) con un efecto significativo de la fenología de los cultivos en el efecto amortiguador. Estas discrepancias entre las temperaturas interpoladas y locales afectaron fuertemente las predicciones del rendimiento de una plaga de cultivo ectotérmico, ya que las temperaturas interpoladas predijeron tasas de crecimiento de plagas 2.3–4.3 veces más bajas que las predichas por las temperaturas locales. Este estudio proporciona información cuantitativa sobre la limitación de los datos climáticos a escala aproximada para capturar la realidad del entorno climático experimentado por los organismos vivos. Por lo tanto, en regiones altamente heterogéneas como las montañas tropicales, se debe tener precaución al utilizar modelos globales para inferir procesos biológicos a escala local. Bridging the gap between the predictions of coarse-scale climate models and the fine-scale climatic reality of species is a key issue of climate change biology research. While it is now well known that most organisms do not experience the climatic conditions recorded at weather stations, there is little information on the discrepancies between microclimates and global interpolated temperatures used in species distribution models, and their consequences for organisms' performance. To address this issue, we examined the fine-scale spatiotemporal heterogeneity in air, crop canopy and soil temperatures of agricultural landscapes in the Ecuadorian Andes and compared them to predictions of global interpolated climatic grids. Temperature time-series were measured in air, canopy and soil for 108 localities at three altitudes and analysed using Fourier transform. Discrepancies between local temperatures vs. global interpolated grids and their implications for pest performance were then mapped and analysed using GIS statistical toolbox. Our results showed that global interpolated predictions over-estimate by 77.5±10% and under-estimate by 82.1±12% local minimum and maximum air temperatures recorded in the studied grid. Additional modifications of local air temperatures were due to the thermal buffering of plant canopies (from −2.7°K during daytime to 1.3°K during night-time) and soils (from −4.9°K during daytime to 6.7°K during night-time) with a significant effect of crop phenology on the buffer effect. This discrepancies between interpolated and local temperatures strongly affected predictions of the performance of an ectothermic crop pest as interpolated temperatures predicted pest growth rates 2.3–4.3 times lower than those predicted by local temperatures. This study provides quantitative information on the limitation of coarse-scale climate data to capture the reality of the climatic environment experienced by living organisms. In highly heterogeneous region such as tropical mountains, caution should therefore be taken when using global models to infer local-scale biological processes. يعد سد الفجوة بين تنبؤات النماذج المناخية ذات النطاق الخشن والواقع المناخي الدقيق للأنواع قضية رئيسية في أبحاث البيولوجيا المتعلقة بتغير المناخ. في حين أنه من المعروف الآن أن معظم الكائنات الحية لا تعاني من الظروف المناخية المسجلة في محطات الطقس، إلا أن هناك القليل من المعلومات حول التناقضات بين المناخات الدقيقة ودرجات الحرارة العالمية المستكملة المستخدمة في نماذج توزيع الأنواع، وعواقبها على أداء الكائنات الحية. لمعالجة هذه المشكلة، قمنا بفحص عدم التجانس الزماني المكاني الدقيق في الهواء ومظلة المحاصيل ودرجات حرارة التربة للمناظر الطبيعية الزراعية في جبال الأنديز الإكوادورية وقارناها بتنبؤات الشبكات المناخية العالمية المستكملة. تم قياس السلاسل الزمنية لدرجة الحرارة في الهواء والمظلة والتربة لـ 108 موقعًا على ثلاثة ارتفاعات وتم تحليلها باستخدام تحويل فورييه. ثم تم رسم خرائط التناقضات بين درجات الحرارة المحلية مقابل الشبكات العالمية المستكملة وآثارها على أداء الآفات وتحليلها باستخدام مجموعة الأدوات الإحصائية لنظم المعلومات الجغرافية. أظهرت نتائجنا أن التنبؤات العالمية المستكملة تزيد عن التقديرات بنسبة 77.5±10 ٪ وتقل عن التقديرات بنسبة 82.1±12 ٪ من الحد الأدنى المحلي والحد الأقصى لدرجات حرارة الهواء المسجلة في الشبكة المدروسة. كانت التعديلات الإضافية في درجات حرارة الهواء المحلية بسبب التخزين المؤقت الحراري لمظلات النباتات (من - 2.7 درجة كلفن خلال النهار إلى 1.3 درجة كلفن خلال الليل) والتربة (من - 4.9 درجة كلفن خلال النهار إلى 6.7 درجة كلفن خلال الليل) مع تأثير كبير لظاهرة المحاصيل على تأثير العازل. أثرت هذه التناقضات بين درجات الحرارة المستكملة والمحلية بشدة على التنبؤات بأداء آفة المحاصيل خارجة الحرارة حيث تنبأت درجات الحرارة المستكملة بمعدلات نمو الآفات 2.3–4.3 مرة أقل من تلك التي تنبأت بها درجات الحرارة المحلية. توفر هذه الدراسة معلومات كمية عن محدودية البيانات المناخية ذات النطاق الخشن لالتقاط واقع البيئة المناخية التي تعاني منها الكائنات الحية. في المناطق غير المتجانسة للغاية مثل الجبال الاستوائية، يجب توخي الحذر عند استخدام النماذج العالمية لاستنتاج العمليات البيولوجية على المستوى المحلي.

Actual importance of research theme: Combating hunger and providing the Earth’s population with sufficient amount of products is considered one of the strategic priorities of human civilization sustainable development by the UN up to 2030. The rapid growth of this planet’s human population in the 21st century, estimated at 7.6. billion people, leads to the global demand for production and foodstuff. Simultaneously, traditional strategies of extensive development conventional in the 20th century and “target” intensification of agriculture do not take expected positive effect nowadays. World economy requires for new strategies of agricultural production, as well as promoting ‘green revolution’ based on the ground of IT technology advances and “Industry 4.0.”. The generalization of world experience concerning development and implementing agricultural production strategies in the 21st century is of greater theoretical and practical importance for all countries which export agricultural production in mass scales, including Ukraine which focuses on the leadership in the world agricultural business. Thus, the urgency of the issue confirms the actual importance of this article. The problem statement. Foodstuff output in world economy is growing slowly and does not meet the increasing demand for food and agricultural products in industry in global scales. Under these conditions the manufacturers of agricultural products like farmers, agro-businesses and agro-holdings, as well as transnational corporation alter and modify agricultural strategies that were conventional in the 20th century. Among the new strategies transition to precision farming and innovational agriculture based on implementing IT technologies takes the leading role. The core and socio-economic consequences of such strategy implementation require further study. Analysis of latest studies and publication. The important contribution to the study of the core and dimensions of agricultural production strategies linked to innovation and investment development as well as to improvement property relations is made by such Ukrainian scholars as P. Makarenko, V. Pilyavskiy [1] and O. Shul’ga [2]. Foreign scientists like Smaller, C., andW. Speller, withH. Mirza, N. Bernasconi-Osterwalder, andG. Dixie [3] paid the specific attention to the study of strategic priorities concerning risks minimization and profit maximization by agro-businesses and TNC within the realization of agricultural contracts at world markets. Overseas researchers KeatingB., HerreroM., CarberryP. [4] emphasized on actual importance of compliance with strategy of foodstuff security in global environment in their studies. However, the issue of developing the strategy of precise agricultural production based on widespread use of innovation and IT technologies, research into socio-economic consequences accompanying their implementation in the 21st century remains poorly studied. Research challenge of general issue. The issue of studies the core and elements of agricultural production development process in world economy is highlighted in world economic literature pretty well. Nevertheless, the study of TNCs and agricultural businesses strategies and strategies concerning transition of TNCs to the development of precise agriculture is really meaningful. Besides, at present time the trends of direct foreign investments as for agricultural lands purchase and priorities analysis of their use by TNCs in developed and developing world countries are uncertain. Socio economic consequences of mass precise agriculture introduction for national economy in countries with agrarian specialization also require detailed researching. Problem statement, objective of research. The objective of research is to highlight the core and define the regularity of formation, as well as emphasize the basic expected socio-economic consequences of precise agriculture development strategy implementing on the grounds of generalization the world experience of agricultural TNC sactivity. To achieve the objective set the article aimed at solution the following tasks: to note the main ‘players’ at the world agricultural market and study the priorities of their economic activity; to study the core and the elements of ‘green revolution’ strategy, as well as strategy of transition to precise agricultural production based on implementing innovations and IT technologies; to define strategic goals of TNCs as for the use of acquiring land ( at the cost of direct foreign investments) on the grounds of generalization developed and developing countries experience; to point out the expected socio-economic consequences of mass implementation of precise agricultural production strategies by TNCs and national agro-businesses for the economy of the countries specialized in agriculture. Method and methodology of the study. While studying the world experience of implementation the precise agricultural production development strategies theoretical and empirical methods of scientific research were employed. Historical and logical methods, abstract and specific methods, methods of analysis and synthesis, as well as causal (cause-and-effect) method were applied in the article to define strategic priorities of agricultural business and agricultural TNC specialization, to point out expected socio-economic consequences of mass transition to precise agricultural production in the countries with agrarian specialization. Synergetic approach, method of expert estimates and casual methods were applied to ground “green revolution” strategy, as well as strategy of TNCs as for transition to precise agriculture based on innovations and IT technologies. The results of study. Agricultural production is presented by farmers, households, state agricultural sector, national agro-businesses and agro-holdings, international TNCs. As a rule, farms are focused on domestic market; they specialize in production of minor parties of manual crop production and horticulture, grow vegetables, fruit and berries, as well as they are engaged in poultry farming, beekeeping, dairy production, stockbreeding in rather small scales. The farmers in developed world countries, particularly EU countries, concentrate on organic production which is of high demand among middle-class representatives. In EU countries farming is traditionally supported by the state, as it bears both economic and social valuable functions, i.e. assists in rural development and creates workplaces in countryside. The main stakeholders at the mass agricultural market in the world are considered large national and international agro-holdings an TNCs specialized in agricultural production and its industrial processing. TNCs shaped the closed loop – from selection to agricultural production, from its processing to its manufacturing. At the cost of large production scales, as well as capital concentration and centralization it is the agricultural TNCs which leads in production and export of foodstuffs at world markets. TNCs ‘ leadership at world agriculture markets is grounded on ‘green revolution’ strategy implementing, which consists of such elements as innovations, bio-selection to produce performance breed, intensive growth in crop productivity, including the one using GMO which makes cropping insensitive to water shortage, high temperatures and droughts. Agrarian TNCs in the 21st century actively implement the strategies of transition to precise agriculture based on the use of innovations and IT technologies. As the world experience confirms, strategies of transition to precise agriculture combine the following innovations: astronaut and aviation technologies, unmanned technologies, unmanned aerial vehicles; mass transition to the use of apparatus to analyze the ground online; spreading of “agro-scouting” innovation technologies as for field information gathering concerning the condition and development of agriculture; implementation intellectual system of managerial decision-making support; introduction of monitoring and control auto-system and implementation of IT-system as for account of agriculture process elements. The development of precise agriculture for national world economies which are agriculture-based offers a lot of benefits, such as: increase in labor productivity in agriculture; the decrease in employment that saves working capital of agro-businesses; industrialization and technical renovation of agrarian sector which promotes the market for IT products, precise machine building; increase in commerce and export potential of the country, mainly, in the sphere of monostructural crop production (grain, corn, soya, raps, oilseeds etc.). Such strategies also provide revitalization of direct foreign investment processes by TNCsconcerning purchasing farmland in the developing countries with their further listing as raw materials supplier for TNCs. The latter shape and control international links of production value added to all kinds of agricultural products. Among the risks which implementation of precise agriculture strategies bear for national developing country’s economy which are agriculture-based the following should be mentioned: risks concerning decrease in farms and decline in production of labor-intensive small-scale agriculture products (vegetables, fruit, honey etc.); risks of jobs recession and, respectively, the number of rural population and others. There are also other risks linked to these processes like risks of growing volumes of ready foodstuffs import, chronic scarcity of state budget and increase in internal debt, enhancing migration processes etc. In case of falling world prices for foodstuffs and worsening global conditions for agriculture products, including agrarian raw materials, in particular, due to another world economic crisis, the abandonment of occasional farmland purchased by TNCs in developing agrarian countries, their further freezing and ceasing the processing for better times should not be excluded. Under such circumstances the risks of famine for countries which could lose the managerial control over own land resources are also a threatening exercise as for implementing such TNC strategy. The field of results application. International economic relations and world economy, development of agriculture competitive strategies in world countries and agrarian TNCs in world economy. Conclusions. Farms, agro-businesses, agro-holdings and agrarian TNCs are the economic centres of mass agriculture production in all world countries. Farms are mainly specialized in labour-intensive small-scale agriculture production like horticulture, gardening, bee-keeping etc. Large agro-businesses and agrarian TNCs choose the strategy of specializing in mass monostructural agriculture production such as crop production (grain, corn, soya beans and industrial crops). In developed world countries TNCs apply the strategy of farmlands multi-purpose use, including the goals aimed at development and processing livestock and crop production; at development of renewable energy and bio-energy. In developed world countries TNCs focus on processing all kinds of agriculture products and foodstuffs production with high value added. Purchasing of farmlands by TNCs in developing countries, in particular, at the cost of direct foreign investment, provides for implementation the strategy of purchased lands engagement, mainly, to develop crop production as a raw basis for their further processing in the native countries for TNCs. The general world trend of agrarian TNCs development is use of innovation technologies, transition to precise agriculture based on IT technologies, aviation and astronautic technologies, unmanned aerial vehicles and other innovations which positively impact labor productivity and mass industrial production profitability, as well as choose transition to monostructural agrarian specialization as a priority, but bear a set of social risks for developing countries’ economies. Transition of Ukrainian agro-businesses and agro-holdings to the strategy of precise agriculture development based on innovations and IT technologies provides Ukraine’s competitiveness at the world agrarian markets. This process should go hand-in-hand with land reform taking into account Ukrainian farming interests. Establishing industrial processing of agriculture raw products and production of ready foodstuffs with high value added should be strategic for Ukraine.

Introduction. The problem of Ukraine's economic development in modern conditions is directly related to the implementation of the Ukraine–European Union Association Agreement, so the national economy is facing new opportunities and challenges, including the lack of effective mechanisms to restrict timber exports. The research aimed at assessing the effectiveness of the export bans to the EU. Aim and tasks. The aim of the paper is to study the mechanisms of regulation of the timber market and their export to the EU. Results. The impact of the imposed moratorium on the declared goals is analyzed in the paper. Analyzed statistics show no effect moratorium on the reduction of deforestation and halt exports of unprocessed timber. It is also impossible to make a clear conclusion about the positive impact of the moratorium on the supply of raw materials of domestic enterprises woodworking and furniture industries. However, within the structure of Ukrainian exports, the share of products of woodworking and furniture industries has increased. This was due to the reduction of Ukrainian export volumes against the background of increasing the share of exports of timber and wood products, as well as the resumption of sales of the furniture industry. Conclusions. A study of the ban on raw wood showed that in general, the effect of the moratorium imposed is not obvious, since the number of woodworking enterprises has increased and the level of employment in these sectors has increased. Ukraine requires the adoption of a comprehensive targeted program that would combine measures to develop both the woodworking and forest industries. The national interest of Ukraine is the preservation and restoration of forests, and the moratorium introduced is an example of how partial, fragmentary unsystematic decisions are made. The practical significance of the results allows to analyze existing and find new alternative export balance, ensuring equal opportunities and non-discrimination between domestic and European Union market.

Although traditional agriculture carried out by ethnic groups is considered for its high biodiversity and important for food security and sovereignty, few studies have investigated the potential of these systems in the interest of promoting a sustainable agricultural development policy according to United Nations Sustainable Development Goals. Using the FAO's Sustainability Assessment of Food and Agriculture (SAFA) methodology, this study analyzed the sustainability of four traditional agricultural systems, three indigenous (Waorani, Shuar, and Kichwa) and one migrant settler populations in the Yasuní Biosphere Reserve (YBR) and identified synergies and trade-offs among the dimensions of sustainability. The results showed different dynamics in all dimensions of sustainability-specifically, trade-offs in the dimensions of good governance with environmental integrity and social well-being, economic resilience, and social well-being. It was identified that the differences in terms of sustainability are narrowing between the indigenous Shuar people's traditional agricultural systems and those of migrant settlers, which provides policymakers with specific information to design sustainable development policies and rescue traditional agricultural systems in the Amazon region.

Information about decadal to millennial variability of El Nino Southern Oscillation (ENSO) is fundamental for the assessment of ENSO responses to natural and anthropogenic forcings. Despite a growing number of ENSO reconstructions, the overall picture of Holocene ENSO variability is inconsistent. Here, we revisit the iconic Holocene ENSO sediment record of Lake Pallcacocha, Ecuador (Rodbell et al., 1999). We asked: (i) How coherent are the records of clastic layers (flood layers) in the sediments of Lake Pallcacocha and adjacent Lake Fondococha? (ii) What are the synoptic-scale atmospheric conditions that lead to intense precipitation and, potentially, to alluvial activity promoting the deposition of clastic layers in these lakes? (iii) Is intense precipitation in this area associated with El Nino, or not? We analyzed clastic layers in Late-Holocene sediments from multiple cores in Lakes Pallcacocha and Fondococha from Cajas National Park, southern Ecuadorian Andes. Additionally, we investigated precipitation data from 13 nearby meteorological stations to test if intense precipitation (percentiles P0.95, P0.99, P0.995) is predominantly related to El Nino conditions or not (based on 15 different ENSO indices). Our results show that the absolute flood frequencies (clastic layers per 100 years) differ substantially from lake to lake. This indicates that the frequency of clastic layers reflects different sensitivities (thresholds of precipitation) of the catchments to alluvial activity. 210Pb ages suggest that neither the 1982/83 nor the 1997/98 very strong El Ninos produced clastic layers comparable to those found in the late Holocene. Daily precipitation records from meteorological stations close to Lake Pallcacocha including a high-altitude station from the western slope of the Andes did not show unusually high precipitation during the super El Nino 2015/16. We further find that intense precipitation in this area occurs at roughly equal probability under El Nino, La Nina and neutral conditions. Although the spectral properties of the late Holocene clastic layers in Lake Pallcacocha fall into the typical ENSO frequency band, we do not find evidence in the recent sediments and the meteorological data that would support a diagnostic link between alluvial activity in Lake Pallcacocha and strong El Nino events. Our data do not support the idea that the (late) Holocene flood record of Lake Pallcacocha is a conclusive paleo-El Nino record

Abstract Páramo peatlands are a regional reservoir of biodiversity and ecosystem services, accumulating large amounts of carbon and buffering water flows. Despite their importance, they have a long history of use and impacts including drainage for agriculture and grazing, and water withdrawal for human uses. Here we present a preliminary assessment of the conservation status of páramo peatlands in Ecuador and, using a case study, discuss peatland restoration as a tool for mitigation and adaptation to the impacts of current climate change. Through a simple index assessing the cumulative presence of signs of human activities on 163 peatland sites, we found that the level of impact was higher for peatlands located in the Western branch of the cordillera, whereas current human population density, precipitation, and elevation were not significant predictors of the levels of impact. Also, starting in 2017, we implemented a pilot restoration initiative on a 21-ha peatland which had been drained and converted into pasture for at least 150 years. The restoration consisted of two ditch blocking techniques implemented to stop fast-moving water and promote the rewetting of the peatland. During the next 3 years, water table increased from 27 ± 3 cm below the soil surface to 7 ± 1 cm by 2021, while wetland plant communities are colonizing and closing the pools in the blocked ditches. Re-wetting of the peatland has led to an increase in the abundance of native species. This case study suggests that restoration initiatives are an efficient and cost-effective approach to a better management of páramo peatlands, with high potential as a tool for mitigation and adaptation to climate change.

Residual biomass from guava (Psidium guajava L.), a common and widespread fruit tree native to Latin America, has been analyzed in the present research in order to determine the biomass quality and its potential use for energy purposes. Obtained biomass was grinded and compacted into the form of fuel briquettes. Determinations of solid biofuel parameters, i.e., physical, mechanical and chemical properties such as calorific value, moisture, ash content, volatile matter, mechanical durability, contents of the main chemical elements and heavy metals were performed according to international standards. As a result, not inconsiderable traces of heavy metals were found, with a concentration of zinc 4.57 mg kg−1 as the highest. Guava’s moisture content (9.8%) comfortably fulfilled the minimum standard requirements and the net calorific value as received (17.11 MJ kg−1) met the average value of a wood. However, measured sulphur content (0.063%) as well as ash content (3.74%) exceeded the maximum allowed limits for the graded wood briquettes and, therefore, guava wood briquettes should be rather categorized as non-woody A class briquettes. The results of the study can contribute significantly to the knowledge of guava wood properties and its potential as renewable solid fuel since there is little published data about it.

During 2009–2011, 50 points of the Daube River Basin were surveyed. In 23 of them, seven species of Unionidae were recorded: U. pictorum, U. tumidus, U. crassus sensu lato, A. anatina, A. cygnea, P. сomplanatа and S. woodiana, which is an invasive species. Th e index of occurrence of freshwater mussels in general was 100 % in the Lower Danube River (5 study areas), 42 % in Tisa River (31 study areas), 33.3 % in Seret River (3 study areas), 36 % in Prut River (11 study areas). Th e index of occurrence of species was rather low: 24 % of A. anatina, 22 % of U. tumidus, 22 % of U. crassus, 16 % of U. pictorum, 14 % of P. complanata, 14 % of S. woodiana, and 2 % of A. cygnea. U. crassus was not found in the Lower Danube river, while A. cygnea was found only there outside the main watercourse. Th e invasive species S. woodiana occurred in the Lower Danube River and in the sub-basin of Tisa River (with 83 % and 20 % frequency, respectively. Th e mean values of population densities ranged from 1.00 (A. cygnea) to 6.14 ind./m2 (S. woodiana), and the mean biomass varied from 1.14 (P. сomplanatа) to 797.54 g/m2 (S. woodiana).