Abstract: Both the native Pascopyrum smithii and introduced Poa pratensis are dominant plants in the mixed-grass prairie. Knowledge of leaf-water relations and water use strategies in these two grasses under animal grazing and drought is needed for understanding responses of the prairie to future climate change. We studied leaf-water relations traits of Pascopyrum and Poa by combined use of information from the pressure-volume analysis, leaf structural characteristics and leaf stomatal conductance as a function of leaf water status. Fieldwork was done in three grazed pastures and three exclosures in 2002 and 2003. With growing season drought, available soil water became lower in the grazed pastures than in the nongrazing exclosures. This had a more negative impact on leaf water status of the shallow-rooted Poa than the deep-rooted Pascopyrum. In both grasses, a significant decrease in leaf stomatal conductance occurred near the turgor loss water potentials of -2.42 MPa for Poa and -3.5 MPa for Pascopyrum, respectively. Both Poa and Pascopyrum responded to grazing with more negative osmotic potentials (and thus more concentrated cell solution) in months of peak growth. Specific leaf area and its two components, i.e., leaf density and thickness, had minimum responses to grazing for Pascopyrum, while in Poa, less dense leaves accompanied by a higher specific leaf area was observed, suggesting that long-term grazing encourages a higher potential growth rate but also a higher susceptibility to drought stress in Poa than in Pascopyrum.

Keywords: leaf density, leaf osmotic potential, Pascopyrum smithii, Poa pratensis, specific leaf area

Abstract: Biogas may be produced from communal sewage sludges by anaerobic decomposition. To follow up the decomposition processes enzyme activity tests have been applied. It is advantageous to use these activity tests if there are frequent substrate-, or specific organic matter load changes in the digesting towers. For describing the total activity of the cells, dehydrogenase-, while for following up the frequent substrate changes protease-, lipase- and cellulase enzyme activity analyses have been carried out. No internationally accepted standards are available for testing the enzyme activity of sewage sludges. Thus, in our experimental work we modified the enzyme activity analyses described earlier in the special literature for the tests of other than sewage sludge samples. Our enzyme activity tests can be completed quickly and at a relative low cost, thus it is possible to use them in generally equipped wastewater treatment laboratories also.

Keywords: sludge, dehydrogenase, lipase, protease, cellulase

Abstract: A numerical simulation study is carried out to assess the possible reject water circulation pattern around the Lekki coast, Nigeria. Critical decision like selection of suitable location for intake and outfall systems are decided based on the simulation results. The tide and wave induced flow pattern and the advection-dispersion of disposed thermal plume in the vicinity of the Lekki coast are established using hydrodynamic model (HD) and advection-dispersion (AD) model of Mike-21 suite of programs respectively. The modeling and simulation experiment is performed using the field measurements and the end results for critical scenarios are presented in this paper. The performance of the model is encouraging and it is a reliable tool for marine environmental monitoring.

Keywords: advection-dispersion, wastewater disposal, thermal plume

Abstract: Oribatid mites are one of the most abundant and species rich group in soil mesofauna. In spite of this, we have limited knowledge on the role they play in ecological processes. Since they are small like other mesofauna members and live a hidden life, their observation is difficult. Their life style, interactions with other organisms and role in soil decomposition processes can be investigated with laboratory experiments more exactly and effectively. While the literature of microcosm studies is very extensive, relatively few review papers have been written about the methodology of microcosm studies. The present review summarizes details of techniques that have been applied laboratory microcosms involving oribatid mites. It is shown what one should keep in mind in planning, composing and setting up a microcosm. Our comparative evaluation reveals how the laboratory experiments were maintained and manipulated and what kind of information was extracted. This methodological review can be useful in preparing microcosm experiments applied to other animal groups as well.

Keywords: ecosystem, community ecology, microcosms, mesofauna, soil ecology, methodology

Abstract: Carbon sequestration potentials of 8 woody species were assessed on an ecosystem level, using the CO2FIXV.2 model, for two scenarios. Net carbon sequestration potentials ranged from 246.23 to 306.22 Mg C ha-1 with complete rotation every 40 years, and 292 to 359.3 Mg C ha-1 with partial cut. Ricinodendron heudelotii had the highest net carbon sequestration potential (306.22 and 359.3 Mg C ha-1 for the complete and partial cuts respectively), while Cola lepidota had the least under both scenarios. There were higher carbon stocks in plant biomass than soil for all agroforests under both management regimes. Fine litter had the highest soil carbon fraction and soluble compounds had the least in all the agroforests. Under complete rotation, the agroforests had potential carbon credit values ranging from US$2756 to $3264/ha/rotation, and $ 3114 to $3678/ha/rotation with partial cut. Partial cuts allowed for higher rates of carbon accumulation, and the farmer always has a standing crop. Economic prioritization showed that Irvingia wombulu was the best (US$6.67/Kg), followed by Ricinodendron heudelotii and Afrostyrax lepidophyllus ($5.55/Kg) and the least was Trycocypha abut ($0.33/Kg). These results would aid policy makers in mitigating climate change, improving rural livelihoods, and contributing to sustainable development.

Keywords: carbon stocks, CO2FIXV.2 model, sustainability, climate change and carbon trade

Abstract: In order to estimate the future regional climate change for the Carpathian Basin located in Central/Eastern Europe, outputs from several RCMs (from the completed European project ENSEMBLES) are summarized and analyzed using the SRES A1B scenario. Composite maps of the projected annual and seasonal temperature and precipitation changes are generated using RCM simulations (with 25 km spatial resolution) for the reference period 1961-1990, and the target periods 2021-2050, 2071-2100. Overall, the results suggest significant warming in Hungary. Projected seasonal warming is 1-3 °C, and 2-6 °C for 2021-2050, and 2071-2100, respectively. The largest temperature increase is likely to occur in summer. In case of precipitation, the annual sum is not likely to change significantly in the region. However, the summer precipitation is projected to decrease significantly during the 21st century, autumn and winter precipitation amounts are projected to increase.

Keywords: regional climate modeling, climate change, ENSEMBLES project, temperature, precipitation

Abstract: This paper studies a transboundary economy with two countries located in a lake basin. Each country withdraws water from the lake for irrigation purposes, which in turn causes the lake to desiccate. The receding lake leaves surfaces covered with salt dust, which is transported by wind to the surrounding area, increasing the salinity of the two countries’ lands. This paper examines whether a partially cooperative water – allocation scheme, where a central authority chooses the two countries’ respective abatement levels (of salt dust) after the countries individually choose per–unit taxes on water withdrawal, induces the countries to withdraw water at the socially efficient level. We find that the partial scheme works, i.e. it induces both countries to optimally choose to withdraw at the socially efficient level.

Keywords: interbasin water resources allocation, water quality, benefit reallocation, optimization, game theory

Abstract: Street trees provide a number of environmental and social benefits, including contributing to climate change adaptation and mitigation and providing urban green space. In all settlements is important to know the quantity and quality of the trees and develop up-to-date tree cadastres. Frequently there is a need to place a monetary value on amenity trees, therefore several methods with different approaches have been developed. In our paper we discuss and compare some widely applied international and Hungarian methods taken into consideration their benefits and disadvantages. A tree survey was done in the year 2010, in one of the greenest districts of Budapest. Based on the survey species composition, distribution by age of the trees, condition of the trees, proportion of the fruit and ornamental trees were analysed and calculations were done regarding the tree values. Results show that good judgement through experience is important in selecting the method to use, for no one method can be used under every condition.

Keywords: tree appraisal, Budapest, tree value calculation, Radó method, Párkányi method

Abstract: Use of sampling techniques is of paramount importance since the precision of estimates greatly depend on it. Different methods of sampling have to be investigated to find out the best sampling technique for a given situation. This study was conducted to determine the best sampling technique to estimate tree diversity and aboveground biomass in Sinharaja forest. Three sampling techniques, namely; Quadrat method, Transect method, and Point centered quarter method (PCQ) were evaluated in this study. Sampling techniques were compared for tree density, basal area, aboveground biomass and diversity indices estimated by each technique. According to the results, PCQ method gave the highest precision for most of the parameters estimated. The non-linear functions fitted for the species – area (Quadrat method) and species – point (PCQ method) relationships estimated that the minimum total sampling area required to assess the number of tree species (in an area of 50 ha) of Singharaja forest as 6000 m2 for Quadrat method and 160 sampling points for PCQ method. It was difficult to estimate the minimum sampling area required to estimate the above ground biomass in Sinharaja since there was no clear cut relationship between biomass and number of sampling units. The results of the study emphasized that the PCQ method is a precise sampling technique that can be used to estimate the tree density, tree diversity and above ground biomass in natural forests. The random distribution of individuals is not necessary for tree diversity and biomass estimation by PCQ method if site stratification and random placement of sampling points in the study area are performed. Considering the higher precision of estimates and the saving of time and cost, the PCQ method can be recommended as an effective sampling technique for tree diversity and biomass studies.

Keywords: sampling techniques, point centered quarter method, rain forests, aboveground biomass, bio diversity

Abstract: Setting out from the database of Operophtera brumata, L. in between 1973 and 2000 due to the Light Trap Network in Hungary, we introduce a simple theta-logistic population dynamical model based on endogenous and exogenous factors, only. We create an indicator set from which we can choose some elements with which we can improve the fitting results the most effectively. Than we extend the basic simple model with additive climatic factors. The parameter optimization is based on the minimized root mean square error. The best model is chosen according to the Akaike Information Criterion. Finally we run the calibrated extended model with daily outputs of the regional climate model RegCM3.1, regarding 1961-1990 as reference period and 2021-2050 with 2071-2100 as future predictions. The results of the three time intervals are fitted with Beta distributions and compared statistically. The expected changes are discussed.

Keywords: Operophtera brumata, L., population dynamical model, climatic indicators, climate change, RegCM