Ecological resilience in urban ecosystems: Linking urban patterns to human and ecological functions

Urban ecosystems evolve over time and space as the outcome of dynamic interactions between socio-economic and biophysical processes operating over multiple scales. The ecological resilience of urban ecosystems—the degree to which they tolerate alteration before reorganizing around a new set of structures and processes—is influenced by these interactions. In cities and urbanizing areas fragmentation of natural habitats, simplification and homogenization of species composition, disruption of hydrological systems, and alteration of energy flow and nutrient cycling reduce cross-scale resilience, leaving systems increasingly vulnerable to shifts in system control and structure. Because varied urban development patterns affect the amount and interspersion of built and natural land cover, as well as the human demands on ecosystems differently, we argue that alternative urban patterns (i.e., urban form, land use distribution, and connectivity) generate varied effects on ecosystem dynamics and their ecological resilience. We build on urban economics, landscape ecology, population dynamics, and complex system science to propose a conceptual model and a set of hypotheses that explicitly link urban pattern to human and ecosystem functions in urban ecosystems. Drawing on preliminary results from an empirical study of the relationships between urban pattern and bird and aquatic macroinvertebrate diversity in the Puget Sound region, we propose that resilience in urban ecosystems is a function of the patterns of human activities and natural habitats that control and are controlled by both socio-economic and biophysical processes operating at various scales. We discuss the implications of this conceptual model for urban planning and design.     

Assessing the effects of land use and land cover patterns on thermal conditions using landscape metrics in city of Indianapolis,United States

Direct applications of remote sensing thermal infrared (TIR) data in landscape ecological research are rare due to limitations in the sensors, calibration, and difficulty in interpretation. Currently there is a general lack of methodology for examining the relationship between land surface temperatures (LST) derived from TIR data and landscape patterns extracted from optical sensors. A separation of landscapes into values directly related to their scale and signature is a key step. In this study, a Landsat ETM+ image of Indianapolis, Unites States, acquired on June 22, 2000, was spectrally unmixed (using spectral mixture analysis, SMA) into fraction endmembers of green vegetation, soil, high albedo, and low albedo. Impervious surface was then computed from the high and low albedo images. A hybrid classification procedure was developed to classify the fraction images into seven land use and land cover (LULC) classes. Using the fractional images, the landscape composition and pattern were examined. Next, pixel-based LST measurements were correlated with the landscape fractional components to investigate LULC based relationships between LST and impervious surface and green vegetation fractions. An examination of the relationship between the LULC and LST maps with landscape metrics was finally conducted to deepen understanding of their interactions. Results indicate that SMA-derived fraction images were effective for quantifying the urban morphology and for providing reliable measurements of biophysical variables. LST was found to be positively correlated with impervious surface fraction but negatively correlated with green vegetation fraction. Each temperature zone was associated with a dominant LULC category. Further research should be directed to the theoretical and applied implications of describing such relationships between LULC patterns and urban thermal conditions.

略论实现长三角地区城市化与土地供应之间的平衡

本文立足于长江三角洲在全国的重要经济地位和城市化的必要性,针对长三角地区城市化所产生的问题,指出其对长三角和全国经济发展的影响,并根据中央经济工作会议提出的城市化新思路、新战略,对城市化与土地供应的关系进行研究,分析城市化布局错位的现状及产生的问题,重点从大城市与中小城市及小城镇的协调发展、投资人的去向、农民工的流动、农家居的分布等四个方面进行详细解析,指出解决城市化与土地供应平衡的具体措施,从而为下一步更好的推进城市化发展提供思路及建议。     

The role of private corporations in regional planning and development: Opportunities and challenges for the governance of housing and land use

There is a broad consensus that the corporate sector has an active role in facilitating community development through corporate-community investment. However, there remains uncertainty as to how much the sector should invest without taking on responsibilities and influencing decisions which are traditionally within the realm of the state. This paper explores the contemporary role of mining companies in regional governance through a case study of housing and residential land use planning and supply within the Bowen Basin coal mining and coal seam gas extraction region in Queensland, Australia. Mining companies were found to have a broad role in planning and development with far-reaching implications for land use and the wider regional community. These arrangements have emerged in response to corporate sensibilities, some recent policy requirements and most importantly, in pragmatic response to the institutional void apparent in many regional communities. In the absence of an effective regional framework with a clear and defined role for governments and corporations, powerful corporate interests risk effectively ‘capturing’ the regional development agenda within a framework that works on short-term paternalism rather than long-term regional partnerships. This also has implications for the efficiency of governance. Stronger institutional arrangements need to be developed to strengthen the capacity of the state to oversee these relationships. Regional governance and planning theory also needs to address this deficit.