Development of any area often leads to more intensive land use and increase in the generation of pollutants. Modeling these changes is critical to evaluate emerging changes in land use and their effect on stream water quality. The objective of this study was to assess the impact of spatial patterns in land use and population density on the water quality of streams, in case of data scarcity, in the Chugoku district of Japan. The study employed artificial neural network (ANN) technique to assess the relationship between the total phosphorous (TP) in river water and the land use in 21 river basins in the district, and the model was able to reasonably estimate the TP in the stream water. Uncertainty analysis of ANN estimates was performed using the Monte Carlo framework, and the results indicated that the ANN model predictions are statistically similar to the characteristics of the measured TP values. It was observed that any reduction in forested area or increase in agricultural land in the watersheds may cause the increase of TP concentration in the stream. Therefore, appropriate watershed management practices should be followed before making any land use change in the Chugoku district. and Rozvoj územia často súvisí so zintenzívnením využívania krajiny a produkciou znečistenia. Dôležité je modelovanie týchto zmien a ich vplyvu na kvalitu vody v tokoch. Cieľom štúdie je určiť vplyv priestorových zmien pri využívaní krajiny a zmeny hustoty osídlenia na kvalitu vody v tokoch v čase nedostatku vody v oblasti Chugoku, Japonsko. Pri riešení sa využívajú umelé neurónové siete (artificial neural network -ANN), prostredníctvom ktorých sa určuje vzťah medzi celkovým obsahom fosforu (TP) v toku a využívaním kajiny v 21 povodiach oblasti; tento model je schopný vypočítať TP v tokoch. Analýza neurčitosti výsledkov dosiahnutých pomocou ANN bola vykonaná metódou Monte Carlo; výsledky analýzy naznačujú, že predpovede pomocou metódy ANN sú štatisticky podobné meraným hodnotám TP. Bolo zistené, že redukcia lesnatosti a zvýšenie plochy poľnohospodársky využívanej pôdy v povodí môže viesť k zvýšeniu koncentrrácie TP v toku. Je preto potrebné pred zmenou vo využívaní krajiny prijať zodpovedajúce opatrenia v manažmente krajiny, ktoré budú minimalizovať negatívne dôsledky zmien využívania krajiny.
Since 1978, the abundance of Coccinella septempunctata L. has been recorded at a hibernation site in the western Czech Republic. Over the years, abundance varied by two orders of magnitude and a long-term trend for decrease in C. septempunctata abundance was observed beginning in the early 1990s. This recession was correlated with the decreasing abundance of its dominant prey, cereal aphids. The acreage of small grain cereals and other crops suitable for breeding C. septempunctata populations also decreased. The change in abundance of cereal aphids may be associated with a dramatic decrease in fertilizer input after 1990. Decreasing fertilizer use has changed the quality of small grain cereal crops and is reflected in lower yields.
The impacts of land use and land cover on the transformation of the rainfall-runoff episodes were studied and analyzed with the utilization of HYDROG and HEC-HMS rainfall-runoff models in the Olše basin. Two episodes were selected - common regional rainfall with low antecedent watershed saturation and convective flash rainfall with higher watershed saturation. Watershed response was studied and modeled on separate levels of the forestation - actual forestation state, 50 % of forest land cover and 100 % of forest land cover. Results which were achieved with the utilization of the various methods of the hydrologic transformation in the watershed scale (Horton, SCS-CN) confirm the influence of forest land cover on the rainfall-runoff relations. Further research with the support of another methods and the continuous models such as GSSHA and MIKE SHE will allow the comparison of achieved results and possible generalization of them. and Pomocí srážkoodtokového modelování v modelovacím software HYDROG a HEC-HMS byla řešena otázka vlivu krajinného pokryvu na transformaci srážkové epizody v povodí Olše. Byly vybrány dvě srážkové epizody - regionální srážka v kombinaci s málo nasyceným povodím a přívalová srážka v kombinaci s nasyceným povodím - a byla zkoumána odezva povodí při simulované změně zalesnění povodí z aktuálního stavu na 50 a 100%. Dosavadní výsledky událostních simulací tento uvažovaný vliv potvrzují, a to i za použití různých metod hydrologické transformace na povodí (Horton, SCS-CN). Další výzkum a s pomocí jiných metod a kontinuálních modelů HEC-HMS, GSSHA a MIKE SHE umožní srovnání výsledků a jejich případné zobecnění.
Photosynthetic pathways (C3, C4, and CAM) and morphological functional types were identified for the species from vegetation in agro-pastoral ecotone, North Beijing. 792 vascular plant species (nearly half of the total species in the ecotone), in 66 families and 317 genera, were identified with C3, C4, and CAM photosynthesis (Table 1). 710 species (90 % of the identified species in Table 1) in 268 genera and 64 families were found with C3 photosynthesis, 68 species (9 % of the total identified species) in 40 genera and 7 families with C4 photosynthesis, and 14 species in 4 genera and 1 family with CAM photosynthesis. Gramineae is the leading family with C4 photosynthesis (43 species), Cyperaceae ranks the second (16 species) followed by Chenopodiaceae (5 species). The significant increase of C4 proportion (C4/total species) with land deterioration suggested the plants of this type are remarkably responsive to land use in the ecotone. 792 species were classified into nine morphological functional types and the changes of most of these types (e.g. perennial forbs (PEF), annual grasses (ANG), and annual forbs (ANF)) were consistent with habitats and vegetation dynamics in the agro-pastoral ecotone. Hence the photosynthetic pathways, combined with the morphological functional types, are efficient indications for studying the linkage between species and ecosystems in the ecotone. and X. Q. Liu, R. Z. Wang.
The objective of the study was to evaluate the spatial distribution of peakflow pre-event water contributions and streamwater residence times with emphasis on land use patterns in 38 subcatchments within the 687 km2 large mesoscale transboundary catchment Lužická Nisa. Mean residence times between 8 and 27 months and portions of pre-event water between 10 and 97% on a storm event peakflow were determined, using 18O data in precipitation and streamwater from a weekly monitoring of nearly two years. Only a small tracer variation buffering effect of the lowland tributaries on the main stem was observed, indicating the dominant impact on the mountainous headwaters on the runoff generation. Longest mean streamwater residence times of 27 months were identified in the nearly natural headwaters of the Jizera Mountains, revealing no ambiguous correlation between the catchment area and altitude and the mean resi-dence time of streamwater. Land use control on the pre-event water portions were determined for three land use catego-ries with percentage of urban areas from 0 to 10%, 10 to 20% and more than 20%. The fraction of pre-event water in the first category decreases from 97% to 65% with the increasing percentage of forest from 76% to 100%, revealing that for-ests may provide only a limited infiltration of precipitation due to leaf interception and soil water use for transpiration. Fractions of pre-event water of 39–87% in the second (agricultural catchments) and of 10–35% in the third (urbanized catchments) category increase with percentage of non-urban areas.
The Loess Plateau is the main source of water in Yellow River, China. After 1980s, the Yellow river water presented a significant reduction, what caused the decrease of the Yellow river discharge had been debated in academic circles. We proceeded with runoff generation mechanisms to explain this phenomenon. We built saturation excess runoff and infiltration excess runoff generation mechanisms for rainfall–runoff simulation in Jingle sub-basin of Fen River basin on the Loess Plateau, to reveal the influence of land use change on flood processes and studied the changes of model parameters under different underlying conditions. The results showed that the runoff generation mechanism was mainly infiltration-excess overland flow, but the flood events of saturation-excess overland flow had an increasing trend because of land use cover change (the increase of forestland and grassland areas and the reduction of cultivated land). Some of the model parameters had physical significances，such as water storage capacity (WM), infiltration capacity (f), evapotranspiration (CKE), soil permeability coefficient (k) and index of storage capacity distribution curve (n) showed increasing trends, and index of infiltration capacity distribution curve (m) showed a decreasing trend. The above results proved the changes of runoff generation mechanism from the perspective of model parameters in Jingle sub-basin, which can provide a new perspective for understanding the discharge reduction in the Yellow River basin.
Changes in Functions of the Czech Landscape and their Influence on Land use, Model Areas of Košťálkov, Abertamy-Hřebečná, Rudná, Živohošť, the Moravské Slovácko Region.