Proportion Of Built-up Area Research Articles

Indicators on the ecosystem service “regulation service of floodplains”

The capacity to absorb and retain surface waters in the floodplain in case of floods and thus prevent or reduce threats to settlement areas through flooding is an important aspect among others within the ecosystem service “Regulation service of floodplains”. Two simplified indicators for measuring the potential flood retention in Germany are proposed here: the “Area for flood retention” on the one hand and the “Proportion of built-up areas in the current floodplain” on the other. The results for the 79 largest rivers of Germany, which are also presented in the form of a map, show among other things that only around 35% of the morphological floodplain in Germany still serve for natural flood retention. In the short period between 2010 and 2015 alone, the area for flood retention decreased by 7.3 km2 (0.13%) nationwide due to the increase in the settlement and traffic area.Capturing the ecosystem service of floodplains also for smaller rivers would make sense from a flood protection perspective. It is also necessary to regularly capture any change of the current floodplain due to embankments and dyke relocations that currently cannot be deduced from available geodata. A political aim in Germany is to significantly increase the retention areas within the next few years. Our results show that huge efforts are necessary in order to reach this aim, which would directly contribute to the prevention of flood damage.

Evolution of runoff and groundwater recharge in the Gaza Strip over the last four decades

Gaza Strip is experiencing a severe water crisis caused mainly by overexploitation of the groundwater source. Rainfall is the only source of freshwater replenishment for the Gaza coastal aquifer. Groundwater level has dropped to more than 10 m below mean sea level as a result of aquifer exploitation and imbalance between recharge and abstraction in the past decades, which exposes the groundwater to seawater intrusion. As the only fresh water source recharging the aquifer is from rainfall, it is essential to estimate the annual recharge volume from rainfall. This paper is focusing on recharge estimation based on historical daily rainfall data for the past 41 years (1973–2014). An estimation of surface runoff was made using soil conservation services curve number method. An estimation of groundwater recharge has been calculated using two different methods: Thornthwaite and Mather soil moisture balance approach and chloride mass balance. Four land use maps and data have been used for the entire calculation period, three of them based on actual surveys carried out in 1994, 2004 and 2010, while the fourth map was developed based on the population expansion trend to cover the period before 1993. It was found that the proportion of built-up area has expanded from 8.25% in 1982 to 25.23% in 2010, while the sand dune area has shrunk from 31.46% in 1982 to 8.64% in 2010. Runoff has doubled from 6.9 million m3 in 1982 to 13.7 million m3 in 2010, while groundwater recharge was reduced from 24.4 million m3 in 1982 to 18.1 million m3 in 2010.

Responses of aerial insectivorous bats to local and landscape-level features of coffee agroforestry systems in Western Ghats, India.

Shade coffee has shown great promise in providing crucial habitats for biodiversity outside formal protected areas. Insectivorous bats have been understudied in coffee, although they may provide pest control services. We investigated the influence of local and landscape-level features of coffee farms on aerial insectivorous bats in Chikmagalur district in the Western Ghats biodiversity hotspot, India. Bats were monitored in 20 farm sites using ultrasound detectors, and the response of bat species richness and activity to changes in tree density, proportion of built-up area in the neighborhood, and distance of farm from forest areas quantified. We examined if models built to explain the species richness and activity could also predict them in nine additional sites. We detected nine phonic types/species in the study area. The quantified predictors had no effect on assemblage-level species richness and activity of bats. Responses of edge-space and cluttered-space forager guilds mirrored those of the overall assemblage, but some species vulnerable to forest conversion like Rhinolophus beddomei were detected rarely. Best models explained up to 20% and 15% variation in assemblage-level species richness and activity respectively, and were poor predictors of both response variables. We conclude that coffee farms in our study area offer an important commuting space for insectivorous bats across a gradient of shade management. Further research should include species-specific responses to management decisions for at-risk species and quantification of ecosystem services like natural pest control to inform biodiversity conservation initiatives in the Western Ghats coffee landscapes.

Urban core areas are important for species conservation: A European-level analysis of breeding bird species

Natural habitats and species richness have decreased due to the urbanization. The main aim of this study was to determine whether heavily urbanized town centers can also harbor threatened bird species. Twenty-six threatened species nested in the most urbanized areas of European towns. Species-rich areas had a high number of threatened species, indicating that overall species richness could be used as a surrogate for the large number of threatened bird species. Threatened species were more likely to be found in town centers as their distribution range increased. Neither landscape nor plot-level variables explained the species richness of threatened species, which was likely due to the homogeneous habitat structure of urban core zone areas in Europe. The occurrence of Falco tinnunculus increased with increases in human density within a built-up area. The occurrence of Hirundo rustica and Muscicapa striata decreased with increases in the proportion of built-up areas in the surrounding landscape. The occurrence of Delichon urbica and Muscicapa striata decreased with increases in habitat diversity and the proportion of buildings in the study plot. The most common threatened bird species nested in cavities or buildings. The availability of suitable nesting sites or protection from predators can support the occurrence of cavity nesters in towns. We suggest that modern architecture should account for the breeding habitat needs of cavity-nesting species in building design and that urban green management must consider the occurrence of old trees with cavities or alternatively use nest boxes to support the occurrence of threatened, cavity-nesting bird species.

The effect of site- and landscape-scale factors on lead contamination of leafy vegetables grown in urban gardens

Urban environments are exposed to various toxic substances that may contaminate agricultural products grown in urban areas. We examined the site- and landscape-scale factors that affected the lead (Pb) contents of leafy vegetables grown in urban gardens. We measured the Pb contents of 84 leafy vegetables from eight different species collected near industrial complexes in the city of Daejeon, Korea, and found that 25% of the sampled vegetables exceeded the Korean standard for maximum Pb content in leafy vegetables of 300 μg/kg, with a mean and median of 254 μg/kg and 165 μg/kg, respectively. In spite of the non-negligible levels of Pb contamination of the sampled vegetables, almost all (94%) of the urban gardeners who participated in the survey felt that their vegetables were safe. A regression analysis with lettuce only samples showed that landscape-scale variables (the proportion of built-up areas within 100-m buffers and the proportion of industrial areas within 200-m buffer) had greater impacts on the Pb contents of the vegetables than site-scale variables, suggesting that managing Pb emission sources spread on urban landscape would be needed to mitigate Pb contamination of urban vegetables.

Dynamics of Urbanization Levels in China from 1992 to 2012: Perspective from DMSP/OLS Nighttime Light Data

The authenticity and reliability of urbanization levels measured by different indicators in China have not reached a consensus, which may impede our understanding of the process of urbanization and its impacts on the environment. The objective of this study was to describe a reliable method of estimating urbanization level based on the Operational Line-scan System (OLS) on the Defense Meteorological Satellite Program (DMSP) nighttime light data and to analyze the dynamics of urbanization levels in China from 1992 to 2012. We calculated the comprehensive urbanization level at the national, provincial, and county scales using a compounded night light index (CNLI) and compared the change rate of CNLI with those of the other two conventional urbanization level indicators, proportion of the nonagricultural population and proportion of built-up area. Our results showed that CNLI derived from the DMSP/OLS data set provided a relatively reliable and accurate measure of the comprehensive urbanization level in China. During the last two decades, China has experienced continued and rapid urbanization with large regional variations. The CNLI increased 3.12 times, from 1.72 × 10−3 to 7.09 × 10−3. The annual increases of CNLI in eastern provinces were much faster than those in western provinces. In addition, we found that the rates of change in these three indicators were consistent for most provinces with the exception of the four municipalities (Beijing, Tianjin, Shanghai, and Chongqing) and a few eastern coastal provinces (Jiangsu, Zhejiang, Fujian, and Guangdong). Because the imbalance among population growth, urban expansion and socioeconomic development may affect cities’ sustainable development, we should pay more attention to these regions with large disparities between different indicators.

Urban social vulnerability assessment with physical proxies and spatial metrics derived from air- and spaceborne imagery and GIS data

Risk management in urban planning is of increasing importance to mitigate the growing amount of damage and the increasing number of casualties caused by natural disasters. Risk assessment to support management requires knowledge about present and future hazards, elements at risk and different types of vulnerability. This article deals with the assessment of social vulnerability (SV). In the past this has frequently been neglected due to lack of data and assessment difficulties. Existing approaches for SV assessment, primarily based on community-based methods or on census data, have limited efficiency and transferability. In this article a new method based on contextual analysis of image and GIS data is presented. An approach based on proxy variables that were derived from high-resolution optical and laser scanning data was applied, in combination with elevation information and existing hazard data. Object-oriented image analysis was applied for the definition and estimation of those variables, focusing on SV indicators with physical characteristics. A reference Social Vulnerability Index (SVI) was created from census data available for the study area on a neighbourhood level and tested for parts of Tegucigalpa, Honduras. For the evaluation of the proxy-variables, a stepwise regression model to select the best explanatory variables for changes in the SVI was applied. Eight out of 47 variables explained almost 60% of the variance, whereby the slope position and the proportion of built-up area in a neighbourhood were found to be the most valuable proxies. This work shows that contextual segmentation-based analysis of geospatial data can substantially aid in SV assessment and, when combined with field-based information, leads to optimization in terms of assessment frequency and cost.

Napovedi sprememb rabe tal v Sloveniji do leta 2012

Po podatkih iz zemljiškega katastra smo izdelali analizo sprememb rabe tal med letoma 1994 in 1999. Ta je bila osnova za napoved sprememb rabe tal do leta 2012. Na podlagi linearnega trenda sprememb deležev površin do leta 2012 smo prikazali napovedi sprememb deležev površine za osnovne zemljiške kategorije. Najbolj naj bi se zmanjšal delež sadovnjakov, povečal pa delež pozidanih površin.

Density fluctuations in an urban population of Tawny Owl Strix aluco: a long-term study in Rome, Italy

The population of Tawny Owls Strix aluco breeding in urban Rome, Italy, was studied from 1992 to 2001. Yearly density (range: 0.9–1.1 territories km-2) was rather stable compared with data from central Europe, likely due to mild weather conditions and abundant food supply. The rate of territory occupation, regarded as estimator of density fluctuations, was non-linearly correlated with density and proportion of wooded and farmland areas, and not correlated with the proportion of built-up areas. In plots with owl density ranging from 2–4 territories km-2 all the breeding territories were stable over ten years. At decreasing density the lower rate of territory occupation was attributable to the large proportion of unsuitable habitat. Competition with neighbours and the consequent reduction of mean territory size may account for the lower territory stability at high densities, where the proportion of wooded areas is high. The proportion of farmland areas, which is a poor habitat for breeding but represent a suitable hunting ground, explains additional variance of the density fluctuations.

Utilization of data bank on grid square basis for regional planning

This paper deals with results of case studies using actual magnetic tape records of “Statistics on Grid Square Basis” and “Digital National Land Information” which have been compiled since 1965 by governmental agencies on the same grid square basis from census and map reading covering the whole country. The number of items on the records has been increasing, including land information and socio-economic statistics which seem to be useful for land development/conservation planning and regional planning. However, in reality a majority of local governments have not used to date these records enough. In this study the combination analysis of two or more items is made in order to make more effective use of the records for these plannings. The number of grid squares under fixed conditions are calculated and the distribution maps are drawn by means of line printer or X-Y plotter. The themes are as follows: 1. Population distribution and population growth and land use type by landform classification, 2. Proportion of built-up area in city planning area, 3. Selection of possible space for housing development, 4. Division of a given area based on natural conditions for daily life into three areas, namely suitable areas, possible but rather difficult areas, and unsuitable areas. 5. Selection of suitable areas for sightseeing and recreation. The items used for combination analysis are 1970 and 1975 Population Census, ground elevation, angle of inclination, value of relief, landform classification, surface geology classification, soil classification, land use classification, and city planning area. The data of land value and distance from nearest station are produced by map reading for the test area in this study. From these combinations an objective and detailed distribution can be determined. Finally, several examples of the studies are shown.