scholarly journals Urbanization drives the evolution of parallel clines in plant populations

2016 ◽  
Vol 283 (1845) ◽  
pp. 20162180 ◽  
Author(s):  
Ken A. Thompson ◽  
Marie Renaudin ◽  
Marc T. J. Johnson
Keyword(s):  
Snow Cover ◽  
Urban Areas ◽  
Urban Ecosystems ◽  
Urban Environments ◽  
City Centre ◽  
Freezing Damage ◽  
Urban Centre ◽  
Dominant Feature ◽  
Urbanization Gradients ◽  
The City

Urban ecosystems are an increasingly dominant feature of terrestrial landscapes. While evidence that species can adapt to urban environments is accumulating, the mechanisms through which urbanization imposes natural selection on populations are poorly understood. The identification of adaptive phenotypic changes (i.e. clines) along urbanization gradients would facilitate our understanding of the selective factors driving adaptation in cities. Here, we test for phenotypic clines in urban ecosystems by sampling the frequency of a Mendelian-inherited trait—cyanogenesis—in white clover ( Trifolium repens L.) populations along urbanization gradients in four cities. Cyanogenesis protects plants from herbivores, but reduces tolerance to freezing temperatures. We found that the frequency of cyanogenic plants within populations decreased towards the urban centre in three of four cities. A field experiment indicated that spatial variation in herbivory is unlikely to explain these clines. Rather, colder minimum winter ground temperatures in urban areas compared with non-urban areas, caused by reduced snow cover in cities, may select against cyanogenesis. In the city with no cline, high snow cover might protect plants from freezing damage in the city centre. Our study suggests that populations are adapting to urbanization gradients, but regional climatic patterns may ultimately determine whether adaptation occurs.

scholarly journals Understanding Spatial Variability of NO2 in Urban Areas Using Spatial Modelling and Data Fusion Approaches

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 179
Author(s):  
Said Munir ◽  
Martin Mayfield ◽  
Daniel Coca
Keyword(s):  
Data Fusion ◽  
Spatial Variability ◽  
Urban Areas ◽  
Road Traffic ◽  
Dispersion Model ◽  
Low Cost ◽  
Spatial Modelling ◽  
City Centre ◽  
Small Scale ◽  
The City

Small-scale spatial variability in NO2 concentrations is analysed with the help of pollution maps. Maps of NO2 estimated by the Airviro dispersion model and land use regression (LUR) model are fused with measured NO2 concentrations from low-cost sensors (LCS), reference sensors and diffusion tubes. In this study, geostatistical universal kriging was employed for fusing (integrating) model estimations with measured NO2 concentrations. The results showed that the data fusion approach was capable of estimating realistic NO2 concentration maps that inherited spatial patterns of the pollutant from the model estimations and adjusted the modelled values using the measured concentrations. Maps produced by the fusion of NO2-LCS with NO2-LUR produced better results, with r-value 0.96 and RMSE 9.09. Data fusion adds value to both measured and estimated concentrations: the measured data are improved by predicting spatiotemporal gaps, whereas the modelled data are improved by constraining them with observed data. Hotspots of NO2 were shown in the city centre, eastern parts of the city towards the motorway (M1) and on some major roads. Air quality standards were exceeded at several locations in Sheffield, where annual mean NO2 levels were higher than 40 µg/m3. Road traffic was considered to be the dominant emission source of NO2 in Sheffield.

scholarly journals Green Spaces in Residential Areas of Dar es Salaam City: Types, Coverage and Uses

2021 ◽  
Vol 14 (3) ◽  
pp. 121
Author(s):  
Nicholaus Mwageni ◽  
Robert Kiunsi
Keyword(s):  
Urban Areas ◽  
Green Space ◽  
Dar Es Salaam ◽  
Economic Benefits ◽  
Natural Vegetation ◽  
Green Spaces ◽  
City Centre ◽  
Building Density ◽  
Dar Es Salaam City ◽  
The City

Green spaces in urban areas including in Dar es Salaam City provide multiple ecological, social and economic benefits. Despite their benefits they are inadequately documented in terms types, coverage and uses. This paper attempts to provide information on types, coverage and uses of green space in Dar es Salaam City. A number of methods including literature review, interpretation of remotely sensed image, interviews, focus group discussions and questionnaires were used to document city greenery. The research findings show that residential greenery is made up of greenery found within and external to plots. The dominant green spaces external to residential plots were natural and semi natural vegetation while within plots were woody plants, plots farms vegetable and ornamental gardens. Distribution of greenery varied among the wards due to differences in building density and distance from the city centre. Natural and semi natural vegetation increased with decrease of building density and increase of distance from the city centre, while the number of plots with trees for shade increased with increase of building density. Only Kawe ward that had greenery above Tanzania space planning standards, the other three wards which are informal settlements had green space deficit. Three quarters of the households use green spaces for shade provision and cooling, two thirds as a source of food products and a quarter for recreation and aesthetic purposes. The study reveals that Dar es Salaam City residents invest predominantly on shade trees in their residential plots compared to other green space types.

scholarly journals Activity density of carabid beetles along an urbanisation gradient

2020 ◽  
Vol 66 (Suppl.) ◽  
pp. 21-36
Author(s):  
Simone Fattorini ◽  
Cristina Mantoni ◽  
Davide Bergamaschi ◽  
Lorenzo Fortini ◽  
Francisco J. Sánchez ◽  
...  
Keyword(s):  
Intermediate Disturbance Hypothesis ◽  
Urban Environments ◽  
Carabid Beetles ◽  
City Centre ◽  
Intermediate Disturbance ◽  
Rural Environments ◽  
Activity Density ◽  
Urban Rural ◽  
The Impact ◽  
The City

Several works have investigated the impact of urbanisation on carabid activity density using urban-rural gradients. Such works compared activity density recorded from green spaces located in different parts of a city and assigned to categories of increasing urban intensity, which poses two problems: (1) since the gradient is divided into categories, it is impossible to model continuous variations in biotic responses, and (2) sites representative of different urbanisation levels are not true segments of the same ecological continuum. To surpass these problems, we modelled variations in carabid activity density along an urban-rural transect within a single green space extending from the city centre of Rome to rural environments. Carabids were sampled by pitfall traps from sites distributed along the entire gradient. We used breakpoint regressions to model how (1) carabid activity density, (2) carabids/beetles ratio, (3) carabids/insects ratio and (3) carabids/arthropods ratio varied along the gradient. As already observed for various organisms in urban environments, we found that activity density of carabids and their contribution to the abundance of beetles, insects and arthropods, peaked in the middle of the gradient. This supports the intermediate disturbance hypothesis, according to which moderate urbanisation may favour diversity by increasing habitat heterogeneity.

Urban DAS recording of a vibroseismic campaign with a 21km-long dark fibre in Potsdam, Germany

2021 ◽  
Author(s):  
CharLotte Krawczyk ◽  
Christopher Wollin ◽  
Stefan Lüth ◽  
Martin Lipus ◽  
Christian Cunow ◽  
...  
Keyword(s):  
Urban Areas ◽  
District Heating ◽  
Telecommunication Networks ◽  
Seismic Exploration ◽  
City Centre ◽  
Data Set ◽  
Geothermal Potential ◽  
First Results ◽  
Local Geology ◽  
The City

<p>The de-carbonization strategy of the city of Potsdam, Germany, incorporates the utilization of its geothermal potential.  As a first step of developing a deep geothermal project for district heating, an urban seismic exploration campaign of the Stadtwerke Potsdam took place in December 2020 in the city centre of Potsdam.  Since urban measurements are often difficult to setup and a low-footprint alternative is sought for, we supplemented the contractor-performed Vibroseis survey along three profiles by distributed acoustic sensing (DAS).  In close cooperation with the municipal utilities, we interrogated a 21 km-long dark telecommunication fibre whose trajectory followed the seismic lines as close as possible.  This was accompanied by a network of 15 three-component geophones for further control and research.</p><p>In this contribution we present the data set, the approach for geo-referencing the fibre, and first results regarding DAS recording capabilities of vibroseismic signals in an urban environment.  Following the paradigm that the high density of telecommunication networks in urban areas may facilitate the exploration of the often insufficiently known local geology, we strive to further shed light on the possibilities of their employment for urban exploration.  In this respect we aim at tackling the question of the accuracy of fibre localization, recording sensitivity and range of active stimulation.</p>

scholarly journals Male and female bats differ in their use of a large urban park

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Krista J Patriquin ◽  
Cylita Guy ◽  
Joshua Hinds ◽  
John M Ratcliffe
Keyword(s):  
Urban Areas ◽  
Green Space ◽  
Prey Availability ◽  
Radio Telemetry ◽  
Demographic Data ◽  
Urban Environments ◽  
City Centre ◽  
Adult Males ◽  
Urban Green ◽  
Urban Green Spaces

Abstract Understanding how wildlife respond to ever-encroaching urbanization is of great concern. Bats are the second-most speciose mammalian order and while many appear to be urban adapted, we currently have a limited understanding of their demography and habitat use within urban environments. Using a combination of captures to obtain demographic data, radio-telemetry to examine foraging and roosting behaviour, and data on diet and prey availability, we examined how big brown bats (Eptesicus fuscus), a synurbic species, use an urban green space (High Park) in Canada’s largest city centre, Toronto. We found that adult males outnumbered adult females more than two to one and that males were found throughout the park, while females were concentrated in an area with greater access to water, but lower prey availability. We also found that bats of both sexes were in poorer body condition than reported for other non-urban areas, including a site within southern Ontario. Our data suggest that High Park may not provide adequate resources for reproductive females as they were never found roosting in the park and beetles, their preferred prey, were limited. Although previous studies suggest urban green spaces may offer refuge to bats, most have not considered sex-specific responses to urbanization as they have largely been based on acoustic surveys. Our study therefore highlights the importance of considering demographic differences in response to urbanization to better inform urban management plans and green space development.

scholarly journals Urbanization, environmental stabilization and temporal persistence of bird species: a view from Latin America

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6056 ◽  
Author(s):  
Lucas Matías Leveau
Keyword(s):  
Temporal Variation ◽  
Case Studies ◽  
Urban Areas ◽  
Abiotic Factors ◽  
Bird Species ◽  
Urban Environments ◽  
Temporal Scales ◽  
Urbanization Gradients ◽  
Temporal Stabilization ◽  
Bird Composition

BackgroundA scarcely studied consequence of urbanization is the effect of temporal stabilization of the environment on bird communities. This alteration is thought to dampen environmental variations between day and night, seasons and years, promoting a temporal persistence of bird composition in urban areas. The aim of this study was to review current evidence of temporal stabilization of biotic and abiotic factors in urban environments and the potential effects of such stabilization on temporal variation of bird species presence at different temporal scales.MethodsI selected the literature by searching published articles and book chapters using Scopus and Google scholar. I only included articles that compared the temporal variation of bird composition or resources between different levels of urbanization.ResultsIn general, there is evidence of temporal stabilization of abiotic and biotic factors at the three time scales considered. At the diurnal scale, the main factor considered was artificial light in the context of light pollution. At the seasonal and interannual scales, several case studies found a smaller temporal variation of primary productivity in urban than in natural and rural areas. Bird species composition showed more stabilization in urban environments at the three temporal scales: (1) several case studies reported bird activity at night, associated with artificial light; (2) studies in urban parks and along urbanization gradients showed smaller seasonal variation of bird composition in the more urbanized areas; and (3) in general, case studies along urbanization gradients showed smaller interannual variation of bird composition in the more urbanized areas, although some studies showed no relationships or opposite trends than expected.DiscussionThe published evidence suggests that urban areas dampen the natural cycles at several temporal scales. The stabilization of biotic and abiotic factors, such as light, temperature, food and habitat structure, is desynchronized from natural diurnal, seasonal and interannual cycles. However, there is a dearth of long-term comparisons of bird composition and studies that simultaneously analyze the relationship between resources and bird composition stabilization at the seasonal and interannual scales. More research is needed in the Southern hemisphere, where there is a lack of studies dealing with the seasonal and interannual variations of primary productivity along urbanization gradients and nocturnal activity of bird species. A future research agenda should include differentiation of spatial and temporal homogenization of avifaunas.

scholarly journals The application of selected invasion frameworks to urban ecosystems

NeoBiota ◽  
2020 ◽  
Vol 62 ◽  
pp. 365-386
Author(s):  
Luke J. Potgieter ◽  
Marc W. Cadotte
Keyword(s):  
Urban Areas ◽  
Economic Impacts ◽  
Relative Effectiveness ◽  
Urban Ecosystems ◽  
Urban Environments ◽  
Individual Species ◽  
Urban Effect ◽  
Invasion Stage ◽  
Invasion Impact ◽  
Urban Invasions

Urbanization is a major driver of global change. Profound human-mediated changes to urban environments have provided increased opportunities for species to invade. The desire to understand and manage biological invasions has led to an upsurge in frameworks describing the mechanisms underpinning the invasion process and the ecological and socio-economic impacts of invading taxa. This paper assesses the applicability of three commonly used invasion frameworks to urban ecosystems. The first framework describes the mechanisms leading to invasion; the second and third frameworks assess individual species, and their associated environmental and socio-economic impacts, respectively. In urban areas, the relative effectiveness of the barriers to invasion is diminished (to varying degrees) allowing a greater proportion of species to move through each subsequent invasion stage, i.e. “the urban effect” on invasion. Impact classification schemes inadequately circumscribe the full suite of impacts (negative and positive) associated with invasions in urban areas. We suggest ways of modifying these frameworks to improve their applicability to understanding and managing urban invasions.

Analysis of temperature trends and urban heat island in Madrid

2020 ◽  
Author(s):  
Gregorio Maqueda ◽  
Carlos Yagüe ◽  
Carlos Román-Cascón ◽  
Encarna Serrano ◽  
Jon Ander Arrillaga
Keyword(s):  
Urban Heat Island ◽  
Urban Areas ◽  
Surface Energy Budget ◽  
City Centre ◽  
Synoptic Situation ◽  
Heat Island ◽  
Temperature Trends ◽  
Measuring Period ◽  
Urban Heat ◽  
The City

<p>The temperature in the cities is affected by both global climate change and local changes due to human activities and the different land use compared to rural surroundings. These local changes, which modify the surface energy budget in urban areas, include the replacement of the natural surfaces by buildings and pavements and the heat of anthropogenic origin (heating, air conditioning, traffic). Madrid city (Spain) has a current population of near 3.3 million people and a larger metropolitan area reaching around 6.5 million people. Hence, it is affected by the phenomenon called urban heat island (UHI), which indicates that a higher temperature is found in the city compared with the surrounding rural areas. UHI is defined as the temperature difference between the urban observatory and the rural one and especially affects the minimum temperatures since urban areas cool down to a lesser extent than the neighbouring rural sites. Moreover, the intensity of the UHI is modulated by the meteorological conditions (wind, cloudiness, surface pressure, precipitation), highly associated with different synoptic situations. In this work, we use the Madrid-Retiro meteorological station as the urban one, which has regular and homogeneous data from the beginning of XX century; and the station at Barajas airport (12 km from the city centre) as well as other stations out of Madrid city (but within a range of 20 km from the city centre) as the rural stations. They all have a common measuring period from 1961 until present. The main objectives of the work are: 1) to identify temperature trends in the meteorological stations (both urban and rural); 2) to evaluate the intensity of the UHI for the different rural stations; 3) to apply a systematic and objective algorithm to classify each day in different categories (related to synoptic situation) that produce a different degree of UHI intensity; and, 4) to evaluate possible trends in the UHI intensity.</p>

Living in the urban renaissance? Opportunity and challenge for 21st-century Glasgow

2019 ◽  
pp. 101-120
Author(s):  
Mark Livingston ◽  
Julie Clark
Keyword(s):  
Development Strategy ◽  
Economic Transition ◽  
Radical Change ◽  
City Centre ◽  
Urban Centre ◽  
Short Period ◽  
Economic Forces ◽  
Demographic Shifts ◽  
Post Industrial ◽  
The City

This chapter explores the rebirth of post-industrial Glasgow as a desirable urban centre, which has undergone a radical change in reputation and profile within a relatively short period. Successful urban boosterist strategies have left the imprint of event- and culture-led regeneration clearly legible on the urban fabric and we review city centre revitalisation, safety and neighbourhood change as factors in an apparently growing appetite for urban living. However, the urban environment is shaped by a combination of strategic planning, national and supranational economic forces. Asking who benefits, as Glasgow grapples with the challenge of economic transition, requires consideration of these wider drivers, including tenure structures, demographic shifts and the decentralisation of poverty. Along with Glasgow’s successes, the vulnerabilities of a consumption-based economy and a relatively elite-orientated development strategy mean that the challenge of how the city will support and protect its most vulnerable citizens remains.

scholarly journals In the shadow of the urban regeneration megaproject: Urban transitions in downtown Łódź, Poland

2018 ◽  
Vol 56 (4) ◽  
pp. 41-52
Author(s):  
Jarosław Kazimierczak ◽  
Piotr Kosmowski
Keyword(s):  
Public Space ◽  
Urban Areas ◽  
Large Scale ◽  
Urban Regeneration ◽  
Point Of View ◽  
Business Community ◽  
City Centre ◽  
Functional Changes ◽  
Post Industrial ◽  
The City

Abstract The Nowe Centrum Łodzi project that was completed in 2007 in Łódź, Poland is one of the biggest contemporary large-scale urban (re)development projects in Europe and the largest project of this type in Central Europe. The principal goals of the mega-project in question include the regeneration of degraded post-industrial and post-railway land in the city centre of Łódź and the enhancement of competitiveness and the metropolitan position of the city. The authors seek to identify spatial and functional changes at a mezo-scale, i.e. in the so-called immediate neighbourhood of the urban regeneration megaproject (URMP), which have accompanied the implementation of the Nowe Centrum Łodzi project over the years 2013–2016. The other aim was to classify urban areas neighbouring the URMP based on features of spatial and functional transformation identified in these areas. The studies allowed the researchers to identify three categories of urban area in the immediate neighbourhood of the URMP which revealed differences in spatial and functional transformations. We indicated that the transformation of the immediate neighbourhood of the URMP involved not only the local authorities responsible for the overall improvement of the quality of public space but also other users, inter alia, residents, local urban activists, the business community, public institutions, and NGOs, that in most cases complemented efforts initiated by the Municipality. From the methodological point of view the authors use a case study including desk research, an urban planning inventory, and direct observation.

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