Floral visitors in urban gardens and natural areas: Diversity and interaction networks in a neotropical urban landscape

Because cities concentrate 50% of the world’s population, and are experiencing a re-emergence of urban agriculture, we investigated the influences of urban agriculture and surrounding natural areas on floral visitors (bees, wasps, butterflies and flies) and plant species in San Cristóbal de Las Casas, Mexico.Throughout the frost, dry and rainy seasons of 2015, we sampled floral visitors in nine urban gardens and nine natural areas. We found 210 floral visitor species: 78% pollinators, 18% predators, and 4% florivores. Rarefaction curves showed that natural areas harbor significantly more floral visitor species (148) than home gardens (132). However, the differences in species composition between habitats and seasons highlight the need to view natural areas and home gardens as complementary habitats with which floral visitors interact in varying ways, during successive seasons, to meet different needs. Furthermore, mean species richness of floral visitors was influenced mainly by seasonality, and increased as seasons progressed from the dry, frost season to the rainy season. Nonetheless, some taxa were influenced by both season and habitat type. Floral visitor abundance was influenced by both habitat type and season, with home gardens showing higher abundance across seasons. Moreover, interaction networks for each season were more asymmetric in natural areas than in home gardens. Urban cover in the surrounding landscape influenced in a quadratic way the species number of floral visitors, but not their abundance. Thus, our results are evidence that natural areas surrounding cities and urban agriculture contribute to floral visitor communities and their networks.     

A framework towards a composite indicator for urban ecosystem services

This article describes a composite indicator for ecosystem services. This composite is composed of several sub-indices, each representing either land use types or ecosystem services. While the overall composite indicates a general overview of the performance of a system in terms of ecosystem services provision, the sub-indices provide sources of variation. Taking into consideration potential trade-offs between making the framework complex and keeping it simple, the composite was developed on two levels. The first level, a simpler one, requires few indicators and therefore needs less data as inputs. The second level, in contrast, is more complex requiring more indicators, involving more detailed measurements, and therefore can be applied with more confidence.     

Integrating the third dimension into the concept of urban ecosystem services: A review

The spatial configuration of urban environments and its impact on local and global ecological functions were the subject of recent urban ecosystem service (UES) research projects. The outcomes of these projects with respect to the data they used, however, mainly consisted of two dimensions (2D). Studies that assess aspects of the third dimension (3D) of UES – such as height, volume and shadowing effects – were absent. The objective of this paper is to contribute to a better understanding of the local ecological functions based on knowledge of three-dimensional UES. 298 articles were selected for in-depth critical analyses. The technical and computational approaches for extracting urban 3D structures and 3D structures of vegetation were the focus of the reviewed literature. Authors’ affiliations would be a better indicator for assessing the spatial distribution of articles. Uneven distribution of knowledge among countries is related to the technical and scientific advancement of countries. There was a shift in the sub-theme of reviewed publications discussing the concept of ecosystem services in the first few years, while later researchers’ interests moved towards UES and adaptation of cities to the changing climate. Further studies should progress in the development of both 3D data and results. Implementing 3D data and results helps to better understand the coupling of humans and their environs. It will be then a critically important step toward developing ecologically friendly cities.     

Forest and the city: A multivariate analysis of peri-urban forest land cover patterns in 283 European metropolitan areas

Heterogeneous definitions of urban areas and poorly homogenized forest data at the country scale have hampered the comparative assessment of peri-urban forest structure in developed countries. The present study investigates selected landscape characteristics of peri-urban forests in 283 metropolitan areas in Europe controlling for the role of the local context and regional suburbanization trends. Using landscape metrics derived from Urban Atlas maps (a Copernicus/GMES initiative providing a comprehensive land-use assessment of European cities >100,000 inhabitants), significant differences in peri-urban forest structure were detected under five European regions. Specific class metrics (percent forest area, mean patch size, perimeter-to-area ratio) were correlated with urban morphology, landscape and territorial indicators. On average, forest cover is larger in northern and southern European metropolitan areas. Forest patch size increases from western to eastern Europe, with more regular patch shapes in central and eastern regions and less regular shapes in the rest of Europe. Forest class area increases with the area of discontinuous, medium-density settlements. Forest patch size increases with the average patch size of discontinuous dense urban fabric. Our evidence outlines a ‘sprawl model' shaping fringe landscapes characterized by discontinuous urban settlements mixed with fragmented – but possibly well protected – forest patches.     

Evolution of a multidimensional architectural landscape under urban regeneration: A case study of Jinan,China

Urban regeneration is a key to achieving the main goals of China's urbanisation plan. How to analyse the urban landscape of the rapid development in order to meet the challenges of urban planning and build liveable cities is a concern for both government and society. This analysis is based on a case study on downtown Jinan, China, covering the period 2001–2011. It explores urban architectural changes in the horizontal and vertical landscapes after a decade of urban regeneration, focusing on two aspects: construction purpose and number of floors. The study uses the land use transfer matrix method, along with landscape indexes and spatial autocorrelation analysis, based on cadastral data. Results show that the horizontal architectural landscape changed at the city's edges, with no apparent change in the city centre. With changes in urban functions, horizontal landscapes became broken, but patch shapes did not manifest obvious changes. Residential, commercial, and industrial landscapes were the dominant types. Most converted areas became residential landscapes. Vertical landscapes tended to feature upward development. Patch shapes became more complex and broken, landscape richness increased, and building types became less densely aggregated. The dominant landscape type changed from bungalows to multi-layer and low-layer buildings. Vertical space utilisation became increasingly intensive. Urban regeneration was carried out locally. Respective areas marked by horizontal or vertical architectural renewal showed significant positive spatial correlation, implying increasing spatial centralisation. Vertical landscape patches largely changed in line with the horizontal types, but not the other way round. Ramshackle areas and shantytowns were transformed. Urban land use developed intensively, forming vertically dense landscapes. These results will serve as reference source for urban planning, regeneration, land resources management, urban architectural design and layout, optimisation of the ecological environment, and construction of liveable cities.     

Scaling indicator and planning plane: An indicator and a visual tool for exploring the relationship between urban form,energy efficiency and carbon emissions

Ecosystems and other naturally resilient systems exhibit allometric scaling in the distribution of sizes of their elements. In this paper we define an allometry inspired scaling indicator for cities that is a first step toward quantifying the stability borne of a complex systems’ hierarchical structural composition. The scaling indicator is calculated using large census datasets and is analogous to fractal dimension in spatial analysis. Lack of numerical rigor and the resulting variation in scaling indicators – inherent in the use of box counting mechanism for fractal dimension calculation for cities – has been one of the hindrances in the adoption of fractal dimension as an urban indicator of note. The intra-urban indicator of scaling in population density distribution developed here is calculated for 58 US cities using a methodology that produces replicable results, employing large census-block wise population datasets from the 2010 US Census and the 2007 US Economic Census. We show that rising disparity – as measured by the proposed indicator of population density distribution in census blocks in Metropolitan Statistical Areas adversely affects energy consumption efficiency and carbon emissions in cities and leads to a higher urban carbon footprint. We then define a planning plane as a visual and analytic tool for incorporation of scaling indicator analysis into policy and decision-making.     

Prioritizing fuel management in urban interfaces threatened by wildfires

Rapid growth of many cities in Europe in recent decades has resulted in the expansion of human settlements spreading into fire-prone landscapes. Wildfires are increasingly impinging upon human populations because of anthropogenic changes to the global fire cycle. Large investments are therefore required to prevent fires from spreading into urban areas to protect human life and reduce property damage. Naturally, prioritizing fuel management by identifying sites where the greatest number of people are exposed to wildfires is often a challenge for governments because of limited resources. Herein, we offer an approach to quantify management priorities and allocate interventions (i.e., fuel removals from forests) in interfaces between urban and wildland areas threatened by wildfires. For this purpose, an indicator for prioritizing management interventions was developed by integrating social, economic, and ecological factors. This indicator was applied to southern Italy as a case example, where fires have been increasing in both magnitude and frequency. Our results highlight the need to prioritize fuel removals in densely populated landscapes in terms of maximizing the number of people exposed to wildfire suppression per dollar spent on fuel removal. More broadly, we suggest that this approach form the basis for wildfire suppression in urban regions across the globe and be readily applied toward allocating any type of management intervention in landscape management.     

Simulation of urban expansion and encroachment using cellular automata and multi-agent system model—A case study of Tianjin metropolitan region,China

The combination model of cellular automata and multi-agent system were used in this paper for simulating spatio-temporal dynamics of urban expansion and its encroachment on other lands at the regional scale. The human system(contain authorities and residents) and their behavior, the landscape system and its behavior as well as the inter actions between them were all simulated in this paper. The behavior of human system is established based on multi-agent system, the authority agent and the resident agent were both regarded as abstract entities. The cellular automata is embedded into the model for simulating the spontaneous urban growth. The impact of neighbor cells were considered so that the expansion of urban lands can be limited near the existed urban lands. Moreover, the rural residential lands have higher probability to convert to urban lands if they were close to the cities or towns. Simulation of urban expansion is undertaken on the time series from 2000 to 2020 for Tianjin metropolitan region, the largest open coastal city in northern China. The results show that Tianjin’s urban lands focus on the epitaxial expansion around the central city accompanied with the growing exurb expansion distributing in multiple districts and counties. The croplands are taken the most area of the land-use types, 1764.03 km² are converted to urban lands, and more than one fourth of the rural residential lands are changed to urban lands in 2000–2020. The urban development and the cropland protection should be both taken into account to minimize the threats on food security and ecological environment.     

Quantifying urban ecological governance: A suite of indices characterizes the ecological planning implications of rapid coastal urbanization

Urban ecosystems in China have undergone a surge of rapid urbanization leading to phenomenal socio-ecological transformation. To mitigate the regional ecological and environmental impacts, cross-scale ecological governance has not been well established. This paper aims to propose an assessment framework to examine and understand urban ecological governance (UEG), a concept that intertwines multiple aspects such as governance, planning, and urban ecology into an integrated procedure for policy formulation and implementation. To test the assessment framework and thereby derive a quantitative approach to studying socio-ecological couplings within the urban systems, we choose Lianyungang, a rapid urbanizing coastal city in China for an empirical study. We ascertain each subsystem (e.g., urbanization, ecological, governance) presents a fluctuating trend particularly after 2005. Also, the overall trends of UEG increased slightly during the two study periods (1997–2012 and 2005–2012), mainly due to the influences of the Urban Master Plan and Eastern Coastal Regional Development Strategic Planning of Lianyungang. These results imply that the UEG in China’s local governments is unique, and the planning system especially acts a core player to cope with increasing regional ecological risks and uncertainties. It is suggested that China’s UEG needs to enhance experimental governance, ecological redline policy (ERP) and multi-plan integration and combine its current government-dominant top-down system with Western bottom-up decision-making mechanisms.