7 resultados para FOOD-WEB STRUCTURE
em Corvinus Research Archive - The institutional repository for the Corvinus University of Budapest
Resumo:
In the years 2004 and 2005 we collected samples of phytoplankton, zooplankton and macroinvertebrates in an artificial small pond in Budapest. We set up a simulation model predicting the abundance of the cyclopoids, Eudiaptomus zachariasi and Ischnura pumilio by considering only temperature as it affects the abundance of population of the previous day. Phytoplankton abundance was simulated by considering not only temperature, but the abundance of the three mentioned groups. This discrete-deterministic model could generate similar patterns like the observed one and testing it on historical data was successful. However, because the model was overpredicting the abundances of Ischnura pumilio and Cyclopoida at the end of the year, these results were not considered. Running the model with the data series of climate change scenarios, we had an opportunity to predict the individual numbers for the period around 2050. If the model is run with the data series of the two scenarios UKHI and UKLO, which predict drastic global warming, then we can observe a decrease in abundance and shift in the date of the maximum abundance occurring (excluding Ischnura pumilio, where the maximum abundance increases and it occurs later), whereas under unchanged climatic conditions (BASE scenario) the change in abundance is negligible. According to the scenarios GFDL 2535, GFDL 5564 and UKTR, a transition could be noticed.
Resumo:
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.
Resumo:
Egyre többen ismerik fel, hogy az élelmiszer-fogyasztás egészségügyi és környezeti hatása is jelentős. A különböző életstílusú társadalmi csoportok fogyasztási szerkezete eltérő lehet. Jelen tanulmány ezerfős, országos reprezentatív minta alapján vizsgálja az élelmiszer-fogyasztási szerkezet eltéréseit a nemek és különböző iskolázottságú fogyasztók körében. Jellemző fogyasztási klasztereket tár fel a fogyasztás szerkezete alapján. A fogyasztás szerkezeti és mennyiségi értékein túlmenően az ökológiai lábnyom indikátorával a fogyasztás környezetterhelését is számszerűsíti. _____ Concern about both health and environmental impacts of food consumption is increasing. Social groups with various lifestyles can have different food consumption structure. The present study analyses the differences in the food consumption structure among genders and educational groups based on a national, representative survey of 1000 adults. Food consumption clusters are identified based on food consumption structure. Beyond the analysis of food consumption and its structure, its environmental impact is quantified by the ecological footprint indicator.
Resumo:
2004-ben és 2007-ben tizenkét új tagország csatlakozott az Európai Unióhoz, számos változást okozva az európai mezőgazdaságban. Az egyik legfontosabb fordulat az egyes nemzetek mezőgazdasági- és élelmiszer-kereskedelmében következett be. Az eredmények azt mutatják, hogy az új tagországok mezőgazdasági- és élelmiszer-kereskedelmének intenzitása jelentősen nőtt a csatlakozás hatására, ugyanakkor a külkereskedelem mérlege ezen a területen nagymértékben romlott több országnál is. A számítások azt is alátámasztották, hogy jelentős koncentráció ment végbe a kereskedelmi partnerek és a termékek tekintetében egyaránt. Mindemellett egyértelművé vált az is, hogy az új tagországok kereskedelmének struktúrája meglehetősen egyoldalúvá vált: az alapanyagok exportálása mellett az importált javak döntő többsége a feldolgozott termékek köréből került ki. A komparatív előnyök vizsgálata rámutatott, hogy az új tagországok legfontosabb agrártermékei megnyilvánuló komparatív előnnyel bírtak a csatlakozás előtt és után is, habár a legtöbb esetben ezen előnyök komolyan csökkentek.. Döntéshozói szempontból vizsgálva az eredményeket egyértelműen megállapítható, hogy az új tagországokban strukturális változtatások szükségesek a negatív folyamatok megállítása érdekében. A legfontosabb stratégiai cél pedig elsősorban a magas hozzáadott értékű, hazai alapanyagokból készített termékek exportálása. ______ In 2004 and 2007 twelve New Member States (NMS) joined the European Union (EU), causing several changes in the field of agriculture. One of the major changes was the transformation of national agri-food trade. The aim of the paper is to analyse the effects of EU accession on NMS agri-food trade. Results suggest that the intensity of NMS agri-food trade has increased significantly after accession, though there was a serious deterioration in NMS agri-food trade balance in most cases. It has also become evident that NMS agri-food trade was highly concentrated by country and by product. Moreover, our analyses highlight one of the most important characteristics of NMS agri-food trade structure - the focus on agri-food raw materials in export together with agri-food processed products in import. Regarding comparative advantage, results suggest that relevant NMS agri-food products had a revealed comparative advantage before and after accession, though to a weakening extent. From the policy perspective, there is a clear need for structural changes in NMS agriculture and agri-food sector in order to tackle the negative tendencies of national agri-food trade. The most important long-term goal should be the production and export of higher value-added processed products based on domestic raw materials.
Resumo:
In this paper five different models, as five modules of a complex agro-ecosystem are investigated. The water and nutrient flow in soil is simulated by the nutrient-in-soil model while the biomass change according to the seasonal weather aspects, the nutrient content of soil and the biotic interactions amongst the other terms of the food web are simulated by the food web population dynamical model that is constructed for a piece of homogeneous field. The food web model is based on the nutrient-in-soil model and on the activity function evaluator model that expresses the effect of temperature. The numbers of individuals in all phenological phases of the different populations are given by the phenology model. The food web model is extended to an inhomogeneous piece of field by the spatial extension model. Finally, as an additional module, an application of the above models for multivariate state-planes, is given. The modules built into the system are closely connected to each other as they utilize each other’s outputs, nevertheless, they work separately, too. Some case studies are analysed and a summarized outlook is given.
Resumo:
This paper reviews the expected effects of the current financial crisis and subsequent recession on the rural landscape, in particular the agri-food sector in Europe and Central Asia (ECA) on the basis of the structure of the rural economy and of different organisations and institutions. Empirical evidence suggests that the crisis has hit the ECA region the hardest. Agriculture contributes about 9% to gross domestic product (GDP) for the ECA region as a whole with 16% of the population being employed in the agricultural sector. As far as the impact of the financial crisis on the agri-food sector is concerned, there are a few interconnected issues: (1) reduction in income elastic food demand and commodity price decline, (2) loss of employment and earnings of rural people working in urban centres, implying also costly labour reallocation, (3) rising rural poverty originating mainly from lack of opportunities in the non-farm sector and a sizable decline of international remittances, (4) tightening of agricultural credit markets, and the (5) collapse of sectoral government support programs and social safety-net measures in many countries. The paper reveals how the crisis hit farming and broader agri-business differently in general and in the ECA sub-regions.
Resumo:
The role of retail chains is signifi cant, not only in the European but also in the Hungarian market. Major changes can be seen in the food trade, and hypermarkets and supermarkets are becoming more widespread, which has an international tendency. We are able to see the transformation of trade structure and changes in customer behaviour. On the customers’ side, this means newer demands on retail chains, which fact greatly determines the location and shape of stores. In Hungary, the presence of small shops is still signifi cant, in accordance with European and international trends; yet on the basis of turnover, the increasing dominance of larger sales centres can be seen.