Revisiting the stability of spatially heterogeneous predator-prey systems under eutrophication

We employ partial integro-differential equations to model trophic interaction in a spatially extended heterogeneous environment. Compared to classical reaction-diffusion models, this framework allows us to more realistically describe the situation where movement of individuals occurs on a faster time scale than the demographic (population) time scale, and we cannot determine population growth based on local density. However, most of the results reported so far for such systems have only been verified numerically and for a particular choice of model functions, which obviously casts doubts about these findings. In this paper, we analyse a class of integro-differential predator-prey models with a highly mobile predator in a heterogeneous environment, and we reveal the main factors stabilizing such systems. In particular, we explore an ecologically relevant case of interactions in a highly eutrophic environment, where the prey carrying capacity can be formally set to 'infinity'. We investigate two main scenarios: (i) the spatial gradient of the growth rate is due to abiotic factors only, and (ii) the local growth rate depends on the global density distribution across the environment (e.g. due to non-local self-shading). For an arbitrary spatial gradient of the prey growth rate, we analytically investigate the possibility of the predator-prey equilibrium in such systems and we explore the conditions of stability of this equilibrium. In particular, we demonstrate that for a Holling type I (linear) functional response, the predator can stabilize the system at low prey density even for an 'unlimited' carrying capacity. We conclude that the interplay between spatial heterogeneity in the prey growth and fast displacement of the predator across the habitat works as an efficient stabilizing mechanism.Comment: 2 figures; appendices available on request. To appear in the Bulletin of Mathematical Biolog

Расширение спектра межкультурного взаимодействия в сфере туризма (на примере Республики Беларусь и Ливана)

Статья посвящена изучению вопроса взаимодействия Республики Беларусь и Ливанской Республики в сфере туризма, и дана оценка перспективам стратегического развития сотрудничества между государствами. Автором выявлены проблемы и резервы межкультурного взаимодействия стран и основные факторы, определяющие этот процесс, включая интерес к культурному наследию (в том числе историко-кульурное наследие и святыни христиан), желание получить образование в Беларуси и возможность посещения туров в рамках экотуризма. Утверждается, что, несмотря на существующие трудности, стратегическое сотрудничество является перспективным и соглашения в сфере туризма и смежных отраслях в настоящее время подписаны. Подчеркивается, что увеличение культурного разнообразия современного человечества требует создания новых подходов к сохранению и развитию их целостности и культурного облика. Это актуально как для Беларуси, так и для Ливана в 2022 году, поскольку обе страны сталкиваются с одинаковой проблемой неполноты или недооценки своего имиджа в мире. Были предложены идеи для улучшения развития туризма в странах. Полученные результаты могут использоваться организациями и предприятиями, задействованными в туристическо-экскурсионной сфере при разработке новых экскурсионных маршрутов и туров, выборе стратегии расширения целевой аудитории туристов и экскурсантов.The article is devoted to the study of interaction between the Republic of Belarus and the Lebanese Republic in the field of tourism. It assesses the prospects for the strategic development of cooperation between the states. The author identifies the problems and reserves of interrelationship. Main factors that determine the conditions of potential intercultural interaction, such as interest in cultural heritage (including Christian religious sights and shrines), desire to get education in Belarus and chances to be engaged in ecotourism are highlighted. It is stated that despite existing difficulties, there are still chances for strategic cooperation as counties concluded agreements in fields connected with tourism. It is outlined that the increase in cultural diversity of modern humanity requires the creation of new approaches to preservation and development of their integrity and cultural appearance. It is relevant for both Belarus and Lebanon in 2022 as far as both countries face the same struggle of their image being undervalued around the globe. New ideas were proposed to improve the development of tourism in the countries. The results obtained can be used by organizations and enterprises involved in the tourist and excursion sphere when developing new sightseeing routes and tours or choosing a strategy for expanding the target audience of tourists

Intercomparison of five nets used for mesozooplankton sampling

Intercomparison of nets commonly used for mesozooplankton sampling in the Black and Mediterranean seas was attempted within SESAME (Southern European Seas: Assessing and Modelling Ecosystem Changes) project. Five nets were compared: three Juday nets equipped with 150 μm, 180 μm and 200 μm mesh size, Nansen net (100 μm mesh size) and WP2 (200 μm mesh size). Replicated samples were collected at one station in the western Black Sea offshore waters in April 2009. Collected samples were analyzed at species level (except for meroplankton), stages (for copepods) and size length. A decrease of total abundance values was observed with increasing mesh size, due to the significantly higher numbers of animals smaller than 1 mm in the samples obtained by fine mesh size than with coarser nets. Few comparisons were revealed significant for the abundance of animals with 1-2 mm length, while no significance was detected for specimens larger than 2 mm. The above differences resulted in discripancies between nets regarding species and stages composition. Biomass values did not differ significantly between nets, due to the strong contribution to total biomass of the large animals fraction (Calanus euxinus). The smallest and the largest animals revealed high variability between replicates collected by Nansen, Juday- 200 μm and WP2 nets. Correction factors were calculated for the conversion of abundance values between each couple of nets. The detected differences between nets regarding the abundance and biomass, the community taxonomic composition and size structure, as well as the estimated correction factors, provide useful information for the harmonization of data obtained by the above nets in the Black Sea

Comparative Assessment of Climate Change Scenarios Based on Aquatic Food Web Modeling

In the years 2004 and 2005, we collected samples of phytoplankton, zooplankton, and macroinvertebrates in an artificial small pond in Budapest (Hungary). We set up a simulation model predicting the abundances of the cyclopoids, Eudiaptomus zachariasi, and Ischnura pumilio by considering only temperature and the abundance of population of the previous day. Phytoplankton abundance was simulated by considering not only temperature but the abundances of the three mentioned groups. When we ran the model with the data series of internationally accepted climate change scenarios, the different outcomes were discussed. Comparative assessment of the alternative climate change scenarios was also carried out with statistical methods

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas : the PERSEUS experience

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES. 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license.peer-reviewe

Expanding the spectrum of intercultural interaction in the field of tourism (on the example of the Republic of Belarus and Lebanon)

Статья посвящена изучению вопроса взаимодействия Республики Беларусь и Ливанской Республики в сфере туризма, и дана оценка перспективам стратегического развития сотрудничества между государствами. Автором выявлены проблемы и резервы межкультурного взаимодействия стран и основные факторы, определяющие этот процесс, включая интерес к культурному наследию (в том числе историко-кульурное наследие и святыни христиан), желание получить образование в Беларуси и возможность посещения туров в рамках экотуризма. Утверждается, что, несмотря на существующие трудности, стратегическое сотрудничество является перспективным и соглашения в сфере туризма и смежных отраслях в настоящее время подписаны. Подчеркивается, что увеличение культурного разнообразия современного человечества требует создания новых подходов к сохранению и развитию их целостности и культурного облика. Это актуально как для Беларуси, так и для Ливана в 2022 году, поскольку обе страны сталкиваются с одинаковой проблемой неполноты или недооценки своего имиджа в мире. Были предложены идеи для улучшения развития туризма в странах. Полученные результаты могут использоваться организациями и предприятиями, задействованными в туристическо-экскурсионной сфере при разработке новых экскурсионных маршрутов и туров, выборе стратегии расширения целевой аудитории туристов и экскурсантов.The article is devoted to the study of interaction between the Republic of Belarus and the Lebanese Republic in the field of tourism. It assesses the prospects for the strategic development of cooperation between the states. The author identifies the problems and reserves of interrelationship. Main factors that determine the conditions of potential intercultural interaction, such as interest in cultural heritage (including Christian religious sights and shrines), desire to get education in Belarus and chances to be engaged in ecotourism are highlighted. It is stated that despite existing difficulties, there are still chances for strategic cooperation as counties concluded agreements in fields connected with tourism. It is outlined that the increase in cultural diversity of modern humanity requires the creation of new approaches to preservation and development of their integrity and cultural appearance. It is relevant for both Belarus and Lebanon in 2022 as far as both countries face the same struggle of their image being undervalued around the globe. New ideas were proposed to improve the development of tourism in the countries. The results obtained can be used by organizations and enterprises involved in the tourist and excursion sphere when developing new sightseeing routes and tours or choosing a strategy for expanding the target audience of tourists