Ecosystem services and urban heat riskscape moderation: water, green spaces, and social inequality in Phoenix, USA

Urban ecosystems are subjected to high temperatures--extreme heat events, chronically hot weather, or both-through interactions between local and global climate processes. Urban vegetation may provide a cooling ecosystem service, although many knowledge gaps exist in the biophysical and social dynamics of using this service to reduce climate extremes. To better understand patterns of urban vegetated cooling, the potential water requirements to supply these services, and differential access to these services between residential neighborhoods, we evaluated three decades (1970-2000) of land surface characteristics and residential segregation by income in the Phoenix, Arizona, USA metropolitan region. We developed an ecosystem service trade-offs approach to assess the urban heat riskscape, defined as the spatial variation in risk exposure and potential human vulnerability to extreme heat. In this region, vegetation provided nearly a 25 degrees C surface cooling compared to bare soil on low-humidity summer days; the magnitude of this service was strongly coupled to air temperature and vapor pressure deficits. To estimate the water loss associated with land-surface cooling, we applied a surface energy balance model. Our initial estimates suggest 2.7 mm/d of water may be used in supplying cooling ecosystem services in the Phoenix region on a summer day. The availability and corresponding resource use requirements of these ecosystem services had a strongly positive relationship with neighborhood income in the year 2000. However, economic stratification in access to services is a recent development: no vegetation-income relationship was observed in 1970, and a clear trend of increasing correlation was evident through 2000. To alleviate neighborhood inequality in risks from extreme heat through increased vegetation and evaporative cooling, large increases in regional water use would be required. Together, these results suggest the need for a systems evaluation of the benefits, costs, spatial structure, and temporal trajectory for the use of ecosystem services to moderate climate extremes. Increasing vegetation is one strategy for moderating regional climate changes in urban areas and simultaneously providing multiple ecosystem services. However, vegetation has economic, water, and social equity implications that vary dramatically across neighborhoods and need to be managed through informed environmental policies.     

Hierarchical Bayesian scaling of soil properties across urban, agricultural, and desert ecosystems.

Ecologists increasingly use plot-scale data to inform research and policy related to regional and global environmental change. For soil chemistry research, scaling from the plot to the region is especially difficult due to high spatial variability at all scales. We used a hierarchical Bayesian model of plot-scale soil nutrient pools to predict storage of soil organic carbon (oC), inorganic carbon (iC), total nitrogen (N), and available phosphorus (avP) in a 7962-km2 area including the Phoenix, Arizona, USA, metropolitan area and its desert and agricultural surroundings. The Bayesian approach was compared to a traditional approach that multiplied mean values for urban mesic residential, urban xeric residential, nonresidential urban, agricultural, and desert areas by the aerial coverage of each land-use type. Both approaches suggest that oC, N, and avP are correlated with each other and are higher (in g/m2) in mesic residential and agricultural areas than in deserts or xeric residential areas. In addition to traditional biophysical variables, cultural variables related to impervious surface cover, tree cover, and turfgrass cover were significant in regression models predicting the regional distribution of soil properties. We estimate that 1140 Gg of oC have accumulated in human-dominated soils of this region, but a significant portion of this new C has a very short mean residence time in mesic yards and agricultural soils. For N, we estimate that 130 Gg have accumulated in soils, which explains a significant portion of "missing N" observed in the regional N budget. Predictions for iC differed between the approaches because the Bayesian approach predicted iC as a function of elevation while the traditional approach employed only land use. We suggest that Bayesian scaling enables models that are flexible enough to accommodate the diverse factors controlling soil chemistry in desert, urban, and agricultural ecosystems and, thus, may represent an important tool for ecological scaling that spans land-use types. Urban planners and city managers attempting to reduce C emissions and N pollution should consider ways that landscape choices and impervious surface cover affect city-wide soil C, N, and P storage.     

人类活动对上海市生物多样性空间格局的影响

为了揭示人类活动对城市化地区生物多样性空间格局的影响及其景观生态学机制,文章将上海市作为研究对象,选择3个人类活动指标、3个主要类型生态系统的4个景观特征指标与8个生物多样性指标,探讨人类活动强度、野生动植物生境景观特征及生物多样性三者之间的相互关系。结果显示,人口增长和城市扩张对上海市生物多样性的空间格局产生了显著影响。在上海地区,人口密度较高、交通较为发达的区域,湿地和农田的景观连续性较低,生物多样性也较低,外来入侵物种丰度较高。这表明在快速城市化过程中,人类活动通过改变野生动植物栖息地景观质量来对区域生物多样性产生影响。本研究还显示,经济发展并非一定对生物多样性具有负面影响。因此,在保持经济发展的同时,通过优化产业结构与加强生物多样性管理,可实现对生物多样性有效保护。     

Landscape spatial changes associated with rapid urbanization in Shenzhen,China

Rapid urbanization and a building boom in Chinese cities, together with the increase in human disturbances in ecosystems, have resulted in a range of ecological and land-use problems. The formulation of policies relating to urban land use requires adequate understanding of the landscape dynamics. The objective of the study was to describe spatial patterns and dynamic changes of the regional landscape of Shenzhen in the past 20 years. Based on MSS & TM images from 1978, 1986, 1990, 1995 and 1999, a landscape classification map of Shenzhen was constructed. Three kinds of spatial pattern indices, including landscape diversity, spatial configuration and characteristics of patches, as well as a human disturbance index, were examined using models and GIS. In the past two decades, the regional landscape in Shenzhen has changed dramatically, from a typical agricultural landscape to a rapidly urbanizing landscape. The gradual reduction in the cultivated land area and the dramatic increase in the built-up areas illustrate this progress clearly. Indices for the landscape spatial pattern have changed substantially. Some of the changes, reflecting the reasonable control of urban planning on the regional landscape, are the consequence of careful planning, but many of them are the result of disordered human disturbances that have occurred during the rapid urbanization process. These findings are helpful to future landscape development and land-use planning.     

A GIS-based moving window analysis of landscape pattern in the Beijing metropolitan area,China

Quantifying landscape pattern and its change is essential for monitoring and assessment of ecological consequences of urbanization. Using the GIS-based land-use data for 2002, we combined moving window analysis along an urban-rural gradient and around the urban centre with landscape metrics to quantify the spatial pattern of urbanization in Beijing. The results of moving window analysis along the urban-rural gradient indicated that, for class-level metrics, the spatial pattern of urbanization could be quantified using landscape metrics, different land-use types exhibited distinctive spatial signatures, and, for landscape-level metrics, the increase in urbanization in the metropolitan Beijing region has resulted in dramatic increases in patch density (PD), edge density (ED), and patch and landscape shape complexity, and sharp decreases in the largest and mean patch size (MPS), agriculture land-use type, and landscape connectivity. The results of moving window analysis around the urban centre showed that the direction of urbanization could be quantified using the class-level metrics, and landscape-level metrics indicated similar results to gradient analysis. In general, moving window analysis showed that the increasingly urbanized landscape became compositionally more diverse, geometrically more complex, and ecologically more fragmented.     

A multi-agent simulation to assess the risk of malaria re-emergence in southern France

A multi-agent simulation (MAS) was developed to assess the risk of malaria re-emergence in the Camargue in southern France, a non-endemic area where mosquitoes of the genus Anopheles (Culicidae) live. The contact rate between people and potential malaria vectors, or the human biting rate, is one of the key factor to predict the risk of re-emergence of malaria, would the parasite be introduced in the region. Our model (called MALCAM) represents the different agents that could influence malaria transmission in the Camargue – people, mosquitoes, animal hosts and the landscape – in a spatially explicit environment. The model simulates spatial and temporal variations in human biting rate at the landscape scale. These variations depend on the distribution of people and potential vectors, their behaviour and their interactions. A land use/cover map was used as a cellular-spatial support for the movements of and interactions between mobile agents. The model was tested for its sensitivity to variations in parameter values, and for the agreement between field observations and model predictions. The MALCAM model provides a tool to better understand the interactions between the multiple agents of the disease transmission system, and the land use and land cover factors that control the spatial heterogeneity in these interactions. It allows testing hypotheses and scenarios related to disease dynamics by varying the value of exogenous biological, geographical, or human factors. This application of agent-based modelling to a human vector-borne disease can be adapted to different diseases and regions.     

城市热力景观格局季节变化特征分析及其应用

热岛效应是城市发展过程中所产生的特有的环境问题,已经成为一种城市环境公害,对其形成和演变规律的研究有助于人们提出有效的应对措施。热力景观是分析城市热岛空间格局的一种新方法。以厦门为研究对象,利用2002年1、2、3、8、12月的Landsat ETM＋影像数据进行地表温度反演,在此基础上使用景观格局指数分析厦门城市热力景观格局的季节变化特征。结果表明：厦门城市热岛在夏季（8月）最强,春秋次之,冬季（1月）最弱。该变化特征是城市地表吸收太阳辐射和人为废热排放随季节变化的共同结果。应用该方法对2002年厦门热污染源进行调查,发现当年共有热污染源26个,其中工业热污染源18个。该研究可为环保、能源等部门乃至于整个城市的规划管理提供有力的决策依据。     

Local disturbance cycles and the maintenance of heterogeneity across scales in marine metapopulations

In marine systems, the occurrence and implications of disturbance-recovery cycles have been revealed at the landscape level, but only in demographically open or closed systems where landscape-level dynamics are assumed to have no feedback effect on regional dynamics. We present a mussel metapopulation model to elucidate the role of landscape-level disturbance cycles for regional response of mussel populations to onshore productivity and larval transport. Landscape dynamics are generated through spatially explicit rules, and each landscape is connected to its neighbor through unidirectional larval dispersal. The role of landscape disturbance cycles in the regional system behavior is elucidated (1) in demographically open vs. demographically coupled systems, in relation to (2) onshore reproductive output and (3) the temporal scale of landscape disturbance dynamics. By controlling for spatial structure at the landscape and metapopulation levels, we first demonstrate the interaction between landscape and oceanographic connectivity. The temporal scale of disturbance cycles, as controlled by mussel colonization rate, plays a critical role in the regional behavior of the system. Indeed, fast disturbance cycles are responsible for regional synchrony in relation to onshore reproductive output. Slow disturbance cycles, however, lead to increased robustness to changes in productivity and to demographic coupling. These testable predictions indicate that the occurrence and temporal scale of local disturbance-recovery dynamics can drive large-scale variability in demographically open systems, and the response of metapopulations to changes in nearshore productivity.     

Distributional analysis of regional benefits and cost of air quality control

The methodology and results of an analysis of benefits and costs of air quality control for an urban region in Florida are given. The machinery used considers the spatial distribution of (a) emission sources, (b) the ambient levels resulting from local meteorological conditions and geographic features, and (c) the socioeconomic characteristics of the impacted population groups. This facilitates an examination of the distributional aspects of costs and benefits associated with various control scenarios. With appropriate adaptation and inputs the steps in our analysis should apply to a distributional benefit/cost analyses for any region.     

Rainfall-human-spatial interactions in a salinity-prone agricultural region of the Western Australian wheat-belt

To explore the complexity of temporal and spatial dynamics of an agricultural landscape under various external and internal driven scenarios, SimKat, an agent-based model, has been developed with the simulation computer program CORMAS. This model combines simplified bio-physical processes of land cover, regional dry-land salinity changes, rainfall impact on productivity, farm profitability and the complexity of land-use decisions of individual farmers in a dry-land agricultural catchment (no irrigation). In this model, simulated farmers formulate individual decisions dealing with land-use changes based on the combined performance of their past land cover productivity and market returns. The willingness to adapt to market drivers and the ability to maximize returns vary between farmers. In addition, farmers in the model can demonstrate various attitudes towards dry-land salinity mitigation as a consequence of experiencing and perceiving salinity on their farm, in the neighborhood or across the entire region. Consequently, farmers can adopt land cover strategies aimed at reducing dry-land salinity. Aggregating the simulated individual behavior of farmers combined with historical rainfall and market price records, reproduced similar aggregated trends of land-cover changes, regional salinity change and farm number decline as observed in the last 20 years in the subject region (Katanning, Western Australia). Using the model in an initial exploratory study on the impact of rainfall variability and change highlighted the importance of average rainfall decline and the widespread willingness of farmers to adapt perennial vegetation in their farming systems to combat regional dry-land salinity. Rainfall decline, as one of the observed consequences of climate change in this region, can also lead to prolonged sequences of dry seasons in the future. Adaptation by farmers to sequences of dry and wet seasons, rather than an average trend in rainfall, seems to be critical for farm survival in this region. Intensifying cropping during wet seasons to maximize farm returns can increase vulnerability in subsequent periods of dry seasons, in particular where alternative income from pasture and sheep production has been lost in the adaptation process.     

Addressing transboundary conservation challenges through marine spatial prioritization

The Adriatic and Ionian Region is an important area for both strategic maritime development and biodiversity conservation in the European Union (EU). However, given that both EU and non‐EU countries border the sea, multiple legal and regulatory frameworks operate at different scales, which can hinder the coordinated long‐term sustainable development of the region. Transboundary marine spatial planning can help overcome these challenges by building consensus on planning objectives and making the trade‐offs between biodiversity conservation and its influence on economically important sectors more explicit. We address this challenge by developing and testing 4 spatial prioritization strategies with the decision‐support tool Marxan, which meets targets for biodiversity conservation while minimizing impacts to users. We evaluated these strategies in terms of how priority areas shift under different scales of target setting (e.g., regional vs. country level). We also examined the trade‐off between cost‐efficiency and how equally solutions represent countries and maritime industries (n = 14) operating in the region with the protection‐equality metric. We found negligible differences in where priority conservation areas were located when we set targets for biodiversity at the regional versus country scale. Conversely, the prospective impacts on industries, when considered as costs to be minimized, were highly divergent across scenarios and biased the placement of protection toward industries located in isolation or where there were few other industries. We recommend underpinning future marine spatial planning efforts in the region through identification of areas of national significance, transboundary areas requiring cooperation between countries, and areas where impacts on maritime industries require careful consideration of the trade‐off between biodiversity conservation and socioeconomic objectives.     

城市生态系统的格局和过程

城市生态系统是人类活动影响下的复合生态系统。人为的开发利用活动和局地的生物物理条件形成了城市特有的景观格局。城市发展改变了自然的生物栖息环境,从根本上改变了生态系统的结构、过程、功能,以及所提供的各种服务。这种改变最终又会影响人类自身的健康生存。文章综述了国内外有关城市景观格局和和重要生态过程之间相互作用机制的研究进展。通过研究发现,在大尺度上,净初级生产力是衡量城市发展对区域物流、能流影响的有效指标;在小尺度上,城市物流、能流过程和城市内部的景观结构、格局有很强的相关性。城市发展显著的改变了自然的栖息地及生物生长过程,本地植被种类减少,外来种增加,外来种的数量和人口数量有显著的相关性;而城市动物群落主要由一些小型哺乳动物、无脊椎动物、鸟类、两栖爬行类动物组成,其中,鸟类是研究城市化过程的有效指示物种。城市生态系统特有的景观格局及生态等过程显著的改了局部区域的微气候和水文过程,城市气温增加,风速降低,云、雾量增加,地表径流增加,流速加大,污染负荷增强等。因此,控制人类活动,优化土地利用的结构和空间格局,是改善城市生态系统结构和过程,保证可持续发展的基本出发点。但是,目前有关城市-格局-过程之间的影响机制还不十分清楚,尤其是定量研究较少。因此,结合传统的城市生态学,景观生态学的理论和其他相关学科领域的发展,为深入分析城市格局-过程之间的关系提供了重要的研究前景。     

Assessing landscape values: a proposal for a multidimensional conceptual model

To evaluate a specific form of resource management, for example, the maintenance of valuable cultural landscapes, the contributions of many different viewpoints must be considered. In this paper, a model for assessing and integrating the different aspects contributing to landscape evaluation is proposed. Some results of its use in landscape assessment in the Madrid region (central Spain) are discussed.The model takes into account five assessment dimensions which are considered to be independent—the ecological, productive, economic, social and cultural evaluative systems and it recognises and assumes conflicts and trade-offs between these components. The inclusion of the production system as an independent assessment dimension is original and is justified because it is the link that connects the ecological and economic systems. Since this dimension acts most directly on the ecosystem, the production system includes the attribute of ecological or strong (in the sense of [For the Common Good, Beacon Press, Boston, 1994]) sustainability.The evaluation method places special emphasis on defining a conceptual framework, and from this defines scenarios in comparison with which particular development models (landscape planning, resources management) can be evaluated. Seven scenarios, coming from a hypothetical, traditional sustainable scenario of resources management, are defined. One of these, the sound sustainable scenario, is defended as the only one viable in the long term, particularly in developing countries.This method was employed to evaluate the agricultural and natural landscape of the Madrid region municipalities. The multivariate approach adopted was based on the selection of indicator sets for each evaluative dimension. The structure of relationships among indicators was then analysed separately for each dimension and values assigned to the municipalities according to their position on the main axes of the multivariate analyses. Each municipality was assigned to one of the seven development scenarios by means of discriminant analysis. The approach’s greatest assets are its flexibility in the selection of the indicators and the efficacy in its monitoring and comparison of the different analysed cases once a rigorous conceptual framework was established.The paper discusses the conditions for the sustainability of the human activities and provides a method for evaluating and comparing scenarios of resources management.     

Need for multiscale planning for conservation of urban bats

For over a century there have been continual efforts to incorporate nature into urban planning. These efforts (i.e., urban reconciliation) aim to manage and create habitats that support biodiversity within cities. Given that species select habitat at different spatial scales, understanding the scale at which urban species respond to their environment is critical to the success of urban reconciliation efforts. We assessed species–habitat relationships for common bat species at 50‐m, 500‐m, and 1 km spatial scales in the Chicago (U.S.A.) metropolitan area and predicted bat activity across the greater Chicago region. Habitat characteristics across all measured scales were important predictors of silver‐haired bat (Lasionycteris noctivagans) and eastern red bat (Lasiurus borealis) activity, and big brown bat (Eptesicus fuscus) activity was significantly lower at urban sites relative to rural sites. Open vegetation had a negative effect on silver‐haired bat activity at the 50‐m scale but a positive effect at the 500‐m scale, indicating potential shifts in the relative importance of some habitat characteristics at different scales. These results demonstrate that localized effects may be constrained by broader spatial patterns. Our findings highlight the importance of considering scale in urban reconciliation efforts and our landscape predictions provide information that can help prioritize urban conservation work.     

Emergy analysis of the urban metabolism of Beijing

Cities can be modeled as if they were superorganisms with a range of metabolic processes. Research on this urban metabolism can contribute to solving urban environmental problems by revealing details of the metabolic throughput of the system. A key issue is how to find a common basis for measuring the environmental and economic values. By providing a single unified unit, emergy theory integrates the natural and socioeconomic systems and thoroughly evaluates a system's metabolism. We analyzed Beijing's urban metabolic system using emergy synthesis to evaluate its environmental resources, economy, and environmental and economic relations with the regions outside the city during 14 years of development. We compared Beijing's emergy indices with those of five other Chinese cities and of China as a whole to assess Beijing's relative development status. These indices are the emergy self-support ratio (metabolic dependence), the environmental load ratio (metabolic loading), empower density (metabolic pressure), emergy used per person (metabolic intensity per capita), and the monetary equivalent of emergy (emdollars; metabolic intensity). Based on our emergy analysis, Beijing's socioeconomic system is not self-sufficient, and depends greatly on external environmental resources. Its GDP is supported by a high percentage of emergy purchased from outside the city. During the study period, Beijing's urban system showed an increasing dependence on external resources for its economic development. Beijing's loading and pressure on the ecological environment is continuously increasing, accompanied by continuously increasing human emergy consumption. In the future, it will become increasingly necessary to improve Beijing's metabolic efficiency.     

The urban growth, size distribution and spatio-temporal dynamic pattern of the Yangtze River Delta megalopolitan region, China

As one of the six megalopolitan regions in the world, the Yangtze River Delta is one of the most populated and developed regions of China. The spatial and temporal dynamic pattern of the urbanization process of the megalopolitan region is investigated. This work compared the spatial and temporal dynamic pattern of the urban growth for the five urban areas (Shanghai, Nanjing, Suzhou, Wuxi and Changzhou) in this region. During the 15 years, urban growth patterns were dramatically uneven over three 5-year periods. The size distribution of the five urban areas became more even with the rapid urbanization process. The patterns of urban expansion reflected policy adjustment and economic development throughout the time. Landscape metric analysis across concentric buffer zones was conducted to elucidate the area, shape, size, complexity and configuration of urban expansion. The study indicates the coalescence process occurred during the rapid urban growth from 1990 to 1995 and the moderate growth period from 2000 to 2005, but different urban growth period between 1995 and 2000. The urban growth pattern was coalesced for the Nanjing and Wuxi metropolitan areas and diffused for Shanghai, Suzhou and Changzhou. This approach indicates that the coalescence process was the major growth model for this region in the recent 15 years despite their different size, economic growth and population growth. The diffusion-coalesce dichotomy represent endpoints rather than alternate states of urban growth. This work will be beneficial in understanding the size distribution and urbanization process of the megalopolitan region in China.     

大都市群的环境问题及其环境保护战略

从实现新时期统筹发展的国家战略需求出发,剖析了大都市群跨区域交叉污染、复合污染、累计污染的特点,指出这些区域已成为环境资源“漏斗区”和突发性环境危机的风险区。认为只有采取主动引导发展的国家环境战略才能有效地解决大都市群和环境的协调可持续发展问题。阐述了主动环保战略的重大措施包括引导调整发展布局、转变经济增长方式、转变生活方式、创新国家环境管理体制、创新环境科技体系和系统、人工提高环境承载能力等。     

Current situation and development of Chinese urban forestry

This paper introduces Chinese urban forestry research in terms of the concept, forest types, ecosystem services, spatial structure, planning and construction, assessment and management. Modern Chinese urban forest had a close relationship with traditional landscape architecture. Urban forest services had been quantified in some case cities, and determined by urban forest spatial patterns and internal structures. Based on landscape ecology and urban planning, urban forest spatial patterns have been analysed and planned rationally in some cities. However, studies on urban forestry generally lack long-term, continuous and systemic observations, as well as in-depth research on ecological processes and mechanisms. The development trends in urban forestry in China might include extensive application of '3S' technology, research on the relationship between urban forest landscape spatial patterns and their ecological effects, economic assessment, ecological and economic benefits and studies on the negative effects of pollutants.     

Impacts of Citrus Development on Habitats of Southwest Florida

Examining resource management needs at the landscape level has become critical for the conservation of ecosystems and the preservation of species. Geographic information systems (GIS) that allow for the integration of spatially referenced databases are a powerful tool that can be used by resource managers to examine potential impacts and develop strategies for regional planning. We applied a landscape-level approach to examine the potential impacts of citrus development on habitats and species in southwest Florida. We developed GIS models for panthers, Sandhill Cranes, and wading birds that reflect changes in potential habitats under a series of development scenarios. The models indicate that, under the maximum development scenario, 63% of potential panther habitat, 66% of potential Sandhill Crane habitat, and 67% and 33% of potential wading bird nesting and foraging habitats could be lost. In addition, the habitat that would remain would be severely fragmented. Several key areas were identified that will be critical to the continued existence of these species and to maintenance of regional biodiversity. The areas identified are habitats not represented on the existing public lands concentrated in the southern portion of the study area and/or that provide connections among existing natural areas.