Percentage Of Urban Area Research Articles

Identification of Urban Heat Island Effect on Land Use Land Cover Changes

The effect of urban heat island (UHI), characterized by higher temperatures in urban areas compared to surrounding rural areas, is a significant consequence of rapid urbanization. As cities continue to grow and attract more people, the UHI effect intensifies due to increased heat-absorbing surfaces and reduced green spaces. This can lead to various environmental and health issues, specifically affecting vulnerable populations. This study investigates the phenomenon of UHIs in the Kalutara district of Sri Lanka and examines the relationship between Land Use Land Cover (LULC) changes, urbanization, and the intensity of UHIs. Landsat satellite images from 1991, 2001, 2011, and 2021 were analyzed using Remote Sensing and Geographic Information System (GIS) techniques to create land Surface Temperature (LST) maps and LULC maps. The results show a significant expansion of urban areas and a reduction in green areas within the Kalutara district over the study period, accompanied by an increase in the intensity of UHIs. Regression analysis indicates a negative correlation between the percentage of green areas and LST, highlighting the cooling effect of vegetation. Conversely, a positive correlation is found between LST and the percentage of urban areas. The research demonstrates the spread of UHIs from limited urban centers in 1991 to larger urban areas and adjacent regions in 2021. The findings emphasize the need for sustainable land management practices, preservation of green areas, and effective urban planning strategies to mitigate the adverse effects of UHIs.

Tracking down unknown PFAS pollution – The direct TOP assay in spatial monitoring of surface waters in Germany

PFAS contamination of surface waters in central Europe was investigated in a spatial monitoring using suspended particulate matter and sediment samples. The samples were collected in 2021 at 171 sampling sites in Germany and at five sites in Dutch waters. All samples were analyzed for 41 different PFAS by target analysis to establish a baseline for these compounds. In addition, a sum parameter approach (direct Total Oxidizable Precursor (dTOP) assay) was used to investigate the PFAS load in the samples more comprehensively.PFAS pollution varied widely between water bodies. Target analysis detected ∑PFAS concentrations between <0.5 and 53.1 μg kg−1 dry weight (dw), while levels of <1.0–337 μg kg−1 dw were determined by dTOP assay. Associations were observed for ∑PFSAdTOP and the percentage of urban area in the vicinity of the sampling sites and, less strongly, for distances to industrial sites (i.e. galvanic/paper) and airports. PFAS hotspots were identified by setting the 90th percentile of the data sets for ∑PFAStarget or ∑PFASdTOP as a threshold. Of the 17 hotspots identified by target analysis or dTOP assay, respectively, there were only six overlaps. Thus, 11 highly contaminated sites could not be identified by classical target analysis.The results demonstrate that target analysis captures only a fraction of the actual PFAS load, while unknown precursors remain undetected. Consequently, if only the results of target analysis are considered in assessments, there is a risk that sites heavily polluted with precursors will not be identified delaying mitigation actions and risking prolonged negative impacts on human health and ecosystems. Moreover, effective PFAS management requires establishing a baseline for PFAS using target and sum parameters such as the dTOP assay, and then monitoring this baseline on a regular basis to support emission control and to inform risk management of its effectiveness.

Residential exposure to magnetic fields from high-voltage power lines and risk of childhood leukemia

BackgroundSeveral studies have suggested an excess risk of leukemia among children living close to high-voltage power lines and exposed to magnetic fields. However, not all studies have yielded consistent results, and many studies may have been susceptible to confounding and exposure misclassification. MethodsWe conducted a case-control study to investigate the risk of leukemia associated with magnetic field exposure from high-voltage power lines. Eligible participants were children aged 0–15 years residing in the Northern Italian provinces of Modena and Reggio Emilia. We included all 182 registry-identified childhood leukemia cases diagnosed in 1998–2019, and 726 age-, sex- and province-matched population controls. We assessed exposure by calculating distance from house to nearest power line and magnetic field intensity modelling at the subjects’ residence. We used conditional logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs), with adjustment for potential confounders (distance from nearest petrol station and fuel supply within the 1000 m-buffer, traffic-related particulate and benzene concentrations, presence of indoor transformers, percentage of urban area and arable crops). ResultsIn multivariable analyses, the OR comparing children living <100 m from high-voltage power-lines with children living ≥400 m from power-lines was 2.0 (95% CI 0.8–5.0). Results did not differ substantially by age at disease diagnosis, disease subtype, or when exposure was based on modeled magnetic field intensity, though estimates were imprecise. Spline regression analysis showed an excess risk for both overall leukemia and acute lymphoblastic leukemia among children with residential distances <100 m from power lines, with a monotonic inverse association below this cutpoint. ConclusionsIn this Italian population, close proximity to high-voltage power lines was associated with an excess risk of childhood leukemia.

Economic Growth Does Not Mitigate Its Decoupling Relationship with Urban Greenness in China

Accompanied by China’s rapid economic growth, significant urban greening has occurred in Chinese cities, in particular in the urban core areas. In contrast, rapid urbanization and economic growth also led to a high probability of vegetation degradation in urban fringe regions. However, these significant spatial differences in urban greenness associated with economic growth in Chinese cities are not well understood. This study explored the spatiotemporal characteristics of the nighttime light (NTL) and annual maximum enhanced vegetation index (EVImax) in urban areas from 2001 to 2020. A strong decoupling status between economic growth and urban greenness on the national scale was found. Overall, 49.15% of urban areas showed a decoupling status. Spatially, this percentage of urban areas with a decoupling status would significantly decrease when the long-term average NTL surpasses 51. Moreover, this significant threshold of decoupling status was found in 189 cities out of 344 (54.65%) in China. This threshold in each city showed significant spatial heterogeneity but can mostly be attributed to the gradient in the long-term average precipitation (Pmean) of each city during the period of 2001–2020. Specifically, a spatial increase in Pmean of 100 mm responded to a decrease in the threshold of 0.4 DN (p &lt; 0.01). In contrast, there was no significant correlation between the threshold and the economic growth status of each city. Our results provide valuable insights for coordinating the development of urban greening and economic growth.

Environmental Conditions in Middle Eastern Megacities: A Comparative Spatiotemporal Analysis Using Remote Sensing Time Series

Rapid and timely evaluation and monitoring of the urban environment has gained significant importance in understanding the state of urban sustainability in metropolises. Multi-source remote sensing (RS) data are a valuable source for a comprehensive understanding of urban environmental changes in developing countries. However, in the Middle East, a region with several developing countries, limited study has been conducted to understand urban environmental changes. In this study, to evaluate the changes in the urban environment, 32 metropolises in the Middle East were studied between 2000 and 2019. For this purpose, a comprehensive environmental index (CEI) integrated with Google Earth Engine (GEE) platform for processing and analysis is introduced. The results show degraded environmental conditions in 19 metropolises based on a significant increasing trend in the time series of the CEI index. The highest increasing trend in the value of the CEI was observed in the cities of Makkah, Jeddah, Basra, Riyadh, and Sana’a. The results also show that the percentage of urban areas in all 32 cities that falls into the degraded class varies from 5% to 75% between 2005 and 2018. The results of CEI changes in megacities, such as Ajman, Tehran, Jeddah, Makkah, Riyadh, Karaj, and Sana’a show that these cities have increasingly suffered from the degradation of environmental conditions since 2001. According to the results, it is recommended to pay more attention to environmental issues regarding the future of urban development in these cities. The proposed approach in this study can be implemented for environmental assessment in other regions.

Changes in Reticular River Network under Rapid Urbanization: A Case of Pudong New Area, Shanghai

Large quantity of rivers have disappeared during rapid urbanization in China’s Yangtze River Delta, and it is difficult to define the changes in the river network owing to its high dense and complex reticular structure. Shanghai’s Pudong New Area (SPNA) is a typical area of rapid urbanization in the delta. A Comprehensive River-network Indicator System (CRIS), including quantity and area, geomorphologic structure, and landscape connectivity indicators, was established to characterize the changes in the dense reticular river network in SPNA from 1965 to 2010. The percentage of urban area rapidly increased from 22.52% to 59.49% in SPNA, whereas that of water surface (Wp) decreased from 10.57% to 7.23% during the same period. The changes in river network displayed a clear spatial gradient, and the closer the functional area is to the city center, the earlier and faster the changes in the rivers. CRIS obviously changed when the percentage of built-up area increased from 10% to 30%; however, the CRIS changed more gently when the percentage exceeded 30%. Among the three sub-indicators of CRIS, quantity and area strongly corresponded to urbanization stages, geomorphologic structure was most sensitive to urbanization, and landscape connectivity accurately captured the threshold phenomena in the change in reticular river network.

Urban landscape and infection risk in free-roaming cats.

Despite public concern on the role of free‐roaming cats as reservoirs of zoonotic agents, little is known about the influence of urban and peri‐urban landscapes on the exposure risk. We evaluated the seroprevalence of three zoonotic agents (Chlamydia felis, Coxiella burnetii and Toxoplasma gondii) in domestic cats (Felis catus). Two hundred and ninety‐one free‐roaming cats were trapped in Murcia municipality (Southeast Spain), and their sera were tested for specific antibodies against T. gondii using a modified agglutination test (MAT), and for C. felis, C. burnetii and feline immunodeficiency virus (FIV) antibodies with ELISA technique. Pathogen seroprevalence at 95% CI was calculated for each sex and age category (up to and over 12 months) and compared with a chi‐squared test. The role of human population density and urban landscape characteristics on the risk of pathogen exposure in the cat population was explored using generalized linear models. Seropositivity against a single pathogen was found in 60% of the cats, while 19% was seropositive for two or three pathogens. Seroprevalence of C. felis was 8% (CI95%: 5–11), 37% (CI95%: 31–42) for C. burnetii and 42% (CI95%: 36–47) for T. gondii. In addition to these three pathogens, FIV seropositivity was low (1%, CI95%: −0.1 to 2) and adult cats were more likely to be seropositive to C. burnetii than young individuals (OR: 2.3, CI95%: 1.2–4.2). No sex or age class differences in seroprevalence were observed for the rest of the pathogens. Seropositivity was correlated with water surface areas for C. felis, and not with crop areas. Coxiella burnetii seropositivity was correlated with the percentage of urban areas (continuous with only buildings and discontinuous, that include buildings, parks, and pedestrian and urban green areas), human population size and peri‐urban areas with shrubs, and not correlated with other agricultural landscapes (orchards and crop areas). However, the seroprevalence of T. gondii was only associated with agricultural landscapes such as orchards. The detection of hotspot areas of high pathogen exposure risk is the basis for municipal services to implement surveillance and risk factor control campaigns in specific‐risk areas, including (a) efficient health management of urban cat colonies by geographical location, population census and health status monitoring of the components of each cat colony, (b) improvement of hygiene and sanitary conditions at the feeding points of the cat colony and (c) free‐roaming cat trapping for health monitoring and, in the long term, to know the evolution of the health status of their populations.

The consequences for stream water quality of long-term changes in landscape patterns: Implications for land use management and policies

The preservation of water resources is a worldwide goal that requires continuous research to support the action of decision-makers. The learning about water quality is paramount in that regard to assess the complex interactions between surface waters and pollution sources. To assess the impact of diffuse pressures, many authors established nexus between landscape metrics and surface water quality. The present study used that approach in a Portuguese urban catchment, the Ave River Basin. The relation between landscape metrics and eight surface water quality parameters was studied during 26 hydrological years, based on the Spearman's rank correlation analysis. The correlation analysis exposed strong relationships between water quality and parameters that describe land use composition or configuration. During the studied period, even in recent years, the water quality parameters reached concentrations above the legally recommended limits. The most concerning parameters were ammoniacal nitrogen, chemical oxygen demand and total orthophosphate. Among the analysed metrics, Shannon's diversity index, percentage of urban areas, and the percentage of agricultural edges that are shared with artificial areas were the most preoccupying land use characteristics that indicate degradation of water resources. Besides the correlations, the study calculated the variation rates of land use maps relative to the years of 1995, 2007, 2010, 2015 and 2018. The results of correlation analysis and land use changes identified actions for the short-term that could improve water quality in the Ave River, namely a reduction in agricultural fields and an increase of forest edges density. In the long-term, water quality improvements could be accomplished through the decrease of artificial surfaces, the increase of forested areas and edges surrounding agricultural fields.

The direct and interactive impacts of hydrological factors on bacillary dysentery across different geographical regions in central China

Previous studies found non-linear mutual interactions among hydrometeorological factors on diarrheal disease. However, the complex interactions of the hydrometeorological, topographical and human activity factors need to be further explored. This study aimed to reveal how hydrological and other factors jointly influence bacillary dysentery in different geographical regions. Using Anhui Province in China, consisted of Huaibei plain, Jianghuai hilly and Wannan mountainous regions, we integrated multi-source data (6 meteorological, 3 hydrological, 2 topographic, and 9 socioeconomic variables) to explore the direct and interactive relationship between hydrological factors (quick flow, baseflow and local recharge) and other factors by combining the ecosystem model InVEST with spatial statistical analysis. The results showed hydrological factors had significant impact powers (q = 0.444 (Huaibei plain) for local recharge, 0.412 (Jianghuai hilly region) and 0.891 (Wannan mountainous region) for quick flow, respectively) on bacillary dysentery in different regions, but lost powers at provincial level. Land use and soil properties have created significant interactions with hydrological factors across Anhui province. Particularly, percentage of farmland in Anhui province can influence quick flow across Jianghuai, Wannan regions and the whole province, and it also has significant interactions with the baseflow and local recharge across the plain as well as the whole province. Percentage of urban areas had interactions with baseflow and local recharge in Jianghuai and Wannan regions. Additionally, baseflow and local recharge could be interacted with meteorological factors (e.g. temperature and wind speed), while these interactions varied in different regions. In conclusion, it was evident that hydrological factors had significant impacts on bacillary dysentery, and also interacted significantly with meteorological and socioeconomic factors. This study applying ecosystem model and spatial analysis help reveal the complex and nonlinear transmission of bacillary dysentery in different geographical regions, supporting the development of precise public health interventions with consideration of hydrological factors.

Secondary forest development during urbanization sustains apex carnivore populations of Eurasian otters (Lutra lutra)

Better understanding of the ecological and socioeconomic determinants of land-use change is a key to achieve more sustainable development and conservation objectives. Long-term studies on the ability of regenerated secondary forests to sustain biodiversity compared with primary forests have been little explored. South Korea has experienced rapid urbanization and rapid forest regeneration. In this study, we asked two questions: (1) Does secondary forest development alleviate the negative impacts of urbanization on an apex predator; and (2) Can we elucidate a land use planning balance between urbanization and biodiversity conservation using scenario analysis? We studied the Eurasian otter (Lutra lutra) population in South Korea. We applied generalized linear mixed models to five national otter surveys from 1994 to 2019 with 18 environmental variables. Based on the most parsimonious model, we developed 10 scenarios with three patterns of urbanization (dispersed, clustered, and no further urbanization) with or without forest development or with forest degeneration. The most parsimonious model showed that otter occurrences steadily increased with greater forest density, but were negatively correlated with the percentage of urban areas. The scenarios suggested that diffused urban development had a less negative impact on otter distribution than clustered urban areas. Developed forests considerably alleviated the negative impacts of urbanization. In sample sub-basins, scenarios showed that even without further urbanization, otters will take more than six years to occur with the current forest development trends. Hence, sustainable urban planning should include strategic spatial planning for forest development and preservation.

Associations between socio‐environmental factors and landscape‐scale biodiversity recovery in naturally regenerating tropical and subtropical forests

AbstractNatural regeneration is key for large‐scale forest restoration, yet it may lead to different biodiversity outcomes depending on socio‐environmental context. We combined the results of a global meta‐analysis to quantify how biodiversity recovery in naturally regenerating forests deviates from biodiversity values in reference old‐growth forests, with structural equation modeling, to identify direct and indirect associations between socioeconomic, biophysical and ecological factors and deviation in biodiversity recovery at a landscape scale. Low deviation within a landscape means higher chances of multiple sites in naturally regenerating forests successfully recovering biodiversity compared to reference forests. Deviation in biodiversity recovery was directly negatively associated with the percentage of cropland, forest cover, and positively associated with the percentage of urban areas in the surrounding landscape. These three factors mediated the indirect associations with rural population size, recent gross deforestation, time since natural regeneration started, mean annual temperature, mean annual water deficit, road density, land opportunity cost, percentage cover of strictly protected forest areas, and human population variation in the surrounding landscape. We suggest that natural forest restoration should be prioritized in landscapes with both low socioeconomic pressures on land use conversion to pasturelands and urban areas, and high percentage of forest cover.

Utilization of remote sensing imagery data to determine the priority location of green open space as child-friendly integrated public space in Palembang City

Palembang is a metropolitan city in Indonesia. As the second largest city in Sumatra, the population of Palembang in 2016 was 1,602,071 people, with a population density of 3,999 people / km2. Meanwhile, the area of green open space has been reduced every year. Based on Minister of Public Works Regulation Number: 05/PRT/M/2008 concerning Guidelines for the Supply and Utilization of Green Open Space in Urban Areas, the percentage of urban areas used as green open space is a minimum of 30% of the total urban area, consisting of 20% public green open space and 10% private green open space. The existence of remote sensing imagery and geographic information systems, could help in determining the priority location of green open space as a child-friendly integrated public space in Palembang. The imagery that used in this research is Landsat 8 imagery, analyzed using ArcGIS 10.3. The research method is a quantitative method using a tiered approach. In general, the final result of the study is in the form of a map of priority locations for child-friendly integrated public space. The 5 Ulu urban village is the location that has the greatest potential to be developed into a child-friendly integrated public space.

Urbanization and floods in the Seoul Metropolitan area of South Korea: What old maps tell us

This study examined how land cover change, topographic, and socioeconomic factors affect flood damage in the Seoul metropolitan area of South Korea that has experienced rapid economic growth and urbanization for the last 30 years. We used geographic information system and spatial regression analysis for identifying explanatory factors for each ten years from 1985 to 2014. A unique aspect of this study is how land use history could explain the spatial variation of flood damage using an old map created in the early 20th century. Our results show that high flood damage areas are spatially clustered in the outskirts of the study area where rapid urbanization happened. Population density was the common factor that best explained flood damage in all three periods. The percentage of farmland and the percentage of urban area were positively and negatively associated with flood damage in 1990 and 2000, respectively. Fiscal self-reliance ratio and previous flood damage were negatively and positively related to flood damage in 2010, respectively. In the early stage of urban expansion, the conversion of agricultural land to urban land was associated with increasing flood damage. As urbanization continued and matured, the conversion of forest areas to urban areas better explained the spatial variation of flood damage. This study demonstrates the importance of historical land use for understanding urban floods and shows that factors affecting flood damage have changed over time, suggesting the need for different flood management strategies to minimize flood damage as urbanization progresses.

Assessing flood probability for transportation infrastructure based on catchment characteristics, sediment connectivity and remotely sensed soil moisture

Flooding may damage important transportation infrastructures, such as roads, railways and bridges, which need to be well planned and designed to be able to withstand current and possible future climate-driven increases in flood frequencies and magnitudes. This study develops a novel approach to predictive statistical modelling of the probability of flooding at major road-stream intersection sites, where water, sediment and debris can accumulate and cause failure of drainage facilities and associated road damages. Two areas in south-west Sweden, affected by severe floods in August 2014, are used in representative case studies for this development. A set of physical catchment-descriptors (PCDs), characterizing key aspects of topography, morphology, soil type, land use, hydrology (precipitation and soil moisture) and sediment connectivity in the water- and sediment-contributing catchments, are used for the predictive flood modelling. A main novel contribution to such modelling is to integrate the spatiotemporal characteristics of remotely-sensed soil moisture in indices of sediment connectivity (IC), thereby also allowing for investigation of the role of soil moisture in the flood probability for different road-stream intersections. The results suggest five categories of PCDs as especially important for flood probability quantification and identification of particularly flood-prone intersections along roads (railways, etc.) These include: channel slope at the road-stream intersection and average elevation, soil properties (mainly percentage of till), land use cover (mainly percentage of urban areas), and a sediment connectivity index that considers soil moisture in addition to morphology over the catchment.

Urbanization effects on vegetation cover in major African cities during 2001-2017

Urbanization effects on vegetation cover (VC) have been analyzed in many regions. However, little attention has been paid to Africa, which has undergone rapid urbanization in recent decades. In this study, MODIS land cover and enhanced vegetation index (EVI) data were used to examine urbanization effects on VC in 59 large cities in Africa during 2001–2017. The ΔEVI (urban EVI minus rural EVI) was used to represent urbanization effects on VC. Major findings include: (1) for 59 cities averaged, annual ΔEVI averaged from 2015 to 2017 was -0.116. Negative annual ΔEVI (i.e. urban EVI lower than rural) were observed in 56 of 59 cities. (2) For 59 cities averaged, urban area increased 17.9% from 2001 (262.8 km2) to 2016 (309.8 km2). (3) Annual ΔEVI decreased significantly (p<0.05) in 44 of 59 cities for the period 2001–2017, and annual average area of urbanization effects on VC increased significantly in 40 of 59 cities. For 59 cities averaged, the percentage of urban area with significant decreasing trends of annual ΔEVI was 60.0%. Spatially, cities near the Gulf of Guinea showed more significant decreasing ΔEVI than cities in other regions. In addition, the trends and spatial distributions of urbanization effects on VC differed little by seasons. These results suggested that urbanization and its effects on VC in Africa should arouse more attentions.

A simplified urban-extent algorithm to characterize surface urban heat islands on a global scale and examine vegetation control on their spatiotemporal variability

We develop a new algorithm, the simplified urban-extent (SUE) algorithm, to estimate the surface urban heat island (UHI) intensity at a global scale. We implement the SUE algorithm on the Google Earth Engine platform using Moderate Resolution Imaging Spectroradiometer (MODIS) images to calculate the UHI intensity for over 9500 urban clusters using over 15 years of data, making this one of the most comprehensive characterizations of the surface UHI to date. The results from this algorithm are validated against previous multi-city studies to demonstrate the suitability of the method. The dataset created is then filtered for elevation differentials and percentage of urban area and used to estimate the diurnal, monthly, and long-term variability in the surface UHI in different climate zones. The global mean surface UHI intensity is 0.85 °C during daytime and 0.55 °C at night. Cities in arid climate show distinct diurnal and seasonal patterns, with higher surface UHI during nighttime (compared to daytime) and two peaks throughout the year. The diurnal variability in surface UHI is highest for equatorial climate zone (0.88 °C) and lowest for arid zone (0.53 °C). The seasonality is highest in the snow climate zone and lowest for equatorial climate zone. While investigating the change in the surface UHI over a decade and a half, we find a consistent increase in the daytime surface UHI in the urban clusters of the warm temperate climate zone (0.04 °C/decade) and snow climate zone (0.05 °C/decade). Only arid climate zones show a statistically significant increase in the nighttime surface UHI intensity (0.03 °C/decade). Globally, the change is mainly seen during the daytime (0.03 °C/decade). Finally, the importance of vegetation differential between urban and rural areas on the spatiotemporal variability is examined. Vegetation has a strong control on the seasonal variability of the surface UHI and may also partly control the long-term variability. The complete UHI data are available through this website (https://yceo.yale.edu/research/global-surface-uhi-explorer) and allows the user to query the UHI of urban clusters using a simple interface.

Quantitative Evaluation of the Impact of Climate Change and Human Activity on Runoff Change in the Dongjiang River Basin, China

Climate change and human activity are typically regarded as the two most important factors affecting runoff. Quantitative evaluation of the impact of climate change and human activity on runoff is important for the protection, planning, and management of water resources. This study assesses the contributions of climate change and human activity to runoff change in the Dongjiang River basin from 1960 to 2005 by using linear regression, the Soil and Water Assessment Tool (SWAT) hydrologic model, and the climate elasticity method. Results indicate that the annual temperature in the basin significantly increased, whereas the pan evaporation in the basin significantly decreased (95%). The natural period ranged from 1960 to 1990, and the affected period ranged from 1991 to 2005. The percentage of urban area during the natural period, which was 1.94, increased to 4.79 during the affected period. SWAT modeling of the Dongjiang River basin exhibited a reasonable and reliable performance. The impacts induced by human activity on runoff change were as follows: 39% in the upstream area, 13% in the midstream area, 77% in the downstream area, and 42% in the entire basin. The impacts of human activity on runoff change were greater in the downstream area than in either upstream and midstream areas. However, the contribution of climate change (58%) is slightly larger than that of human activity (42%) in the whole basin.

A partial least squares – Path modeling analysis for the understanding of biodiversity loss in rural and urban watersheds in Portugal

The main purpose of this study was to use Partial Least Squares – Path Modeling (PLS-PM) to quantify the contributions of natural and human-induced threats to biodiversity loss in rural and urban watersheds. The study area comprised the Sabor and Ave river basins, located in northern Portugal. The Sabor is rural and sparsely populated while the Ave is urbanized, industrialized and densely populated. Within PLS-PM, threats are called exogenous latent variables while the ultimate environmental consequence (biodiversity loss) is termed endogenous latent variable. Latent variables are concepts represented by numerical parameters called formative variables. The selected latent variables were given the names “pressures”, “contamination” and “ecological integrity”. The most important “pressures” were the wildfire risk, the percentage of urban area in sub-catchments, the diffuse emissions of livestock nitrogen (N) and agriculture/forest phosphorus (P), and the point source emissions of urban N, P and biochemical oxygen demand, as well as of industrial N. The latent variable called “contamination” was primarily represented by stream water concentrations of phosphate, suspended solids and dissolved oxygen. And finally, the “ecological integrity” was represented by the he North Invertebrate Portuguese Index. The results unequivocally showed that point source emissions in the Sabor (except industrial N) and stream water contamination in the Ave determine biodiversity loss. These contrasting influences suggest that Ave basin has evolved from a catchment where man once produced localized negative effects on stream ecological integrity (a condition still observed in the Sabor basin) to a catchment where the dense human occupation has covered the entire area with urban contaminant sources, somewhat generalizing the local effects. The attribution of local effects to biodiversity loss in the rural catchment and of regional effects in the urban catchment is confirmed by the results of a study covering the entire planet.

The Spatiotemporal Trend of City Parks in Mainland China between 1981 and 2014: Implications for the Promotion of Leisure Time Physical Activity and Planning.

City parks, important environments built for physical activity, play critical roles in preventing chronic diseases and promoting public health. We used five commonly used park indicators to investigate the spatiotemporal trend of city parks in mainland China between 1981 and 2014 at three scales: national, provincial and city class. City parks in China increased significantly with a turning point occurring around the year 2000. Up until the end of 2014, there were 13,074 city parks totaling 367,962 ha with 0.29 parks per 10,000 residents, 8.26 m2 of park per capita and 2.00% of parkland as a percentage of urban area. However, there is still a large gap compared to the established American and Japanese city park systems, and only 5.4% of people aged above 20 access city parks for physical activity. The low number of parks per 10,000 residents brings up the issue of the accessibility to physical activity areas that public parks provide. The concern of spatial disparity, also apparent for all five city park indicators, differed strongly at provincial and city class scales. The southern and eastern coastal provinces of Guangdong, Fujian, Zhejiang and Shandong have abundant city park resources. At the scale of the city classes, mega-city II had the highest of the three ratio indicators and the large city class had the lowest. On one hand, the leading province Guangdong and its mega-cities Shenzhen and Dongguan had park indicators comparable to the United States and Japan. On the other hand, there were still five cities with no city parks and many cities with extremely low park indicators. In China, few cities have realized the importance of city parks for the promotion of leisure time physical activity. It is urgent that state and city park laws or guidelines are passed that can serve as baselines for planning a park system and determining a minimum standard for city parks with free, accessible and safe physical activity areas and sports facilities.

Pre-event water contributions and streamwater residence times in different land use settings of the transboundary mesoscale Lužická Nisa catchment

AbstractThe 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 km2large 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, using18O 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 residence time of streamwater. Land use control on the pre-event water portions were determined for three land use categories 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 forests 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.