Urban Principles for Ecological Landscape Design and Maintenance: Scientific Fundamentals

Urban ecology is a rapidly developing scientific discipline with great relevance to sustainable city design and management. Though several frameworks have been proposed in the last 10 years, urban ecology, as yet, has no complete, mature theory. There are, however, general principles emerging that may facilitate the development of such a theory. In the meantime, these principles can serve as useful guides for ecological landscape design and maintenance. This paper aims to use the principles to conceptually frame a series of papers to follow in this special issue. The main ecological principles concerning cities are that: 1) Cities are ecosystems; 2) Cities are spatially heterogeneous; 3) Cities are dynamic; 4) Human and natural processes interact in cities; and 5) Ecological processes are still at work and are important in cities. The first three principles address the structure of cities and the change in structure through time. The remaining two principles focus on ecological processes in cities. We briefly summarize each of these principles and their roots in the ecological and design fields. Each principle points to ecological functions that can be translated into ecosystem services. Application of these principles to ecological landscape design and maintenance is discussed

Introduction to the Baltimore Ecosystem Study, Long-Term Ecological Research Project, Phase III

The Baltimore Ecosystem Study (BES) is one of two urban Long-Term Ecological Research (LTER) projects in the United States. It began its third funding cycle in 2011. Although the project continues key measurements that were started in 1997 at the inception of the research, the third phase is characterized by a new conceptual framework. Phase III of BES focuses on metropolitan Baltimore, Maryland, as a system poised for transition from a "sanitary city" -- characterized by engineered environmental solutions, management via discrete disciplines, and government control to a "sustainable city" -- which would be characterized by additional biological solutions, collaborative management, and polycentric and multi-level governance. In such a situation, the guiding research question becomes, "What are the effects of adaptive processes aimed at sustainability in the Baltimore socio-ecological system?" Adaptive processes are those social and biophysical features and actions which allow a complex system to adjust to changing internal and external drivers. The full proposal and other details of BES can be discovered on the project website: www.beslter.or

An optimum city size? The scaling relationship for urban population and fine particulate (PM2.5) concentration

We utilize the distribution of PM2.5 concentration and population in large cities at the global scale to illustrate the relationship between urbanization and urban air quality. We found: 1) The relationship varies greatly among continents and countries. Large cities in North America, Europe, and Latin America have better air quality than those in other continents, while those in China and India have the worst air quality. 2) The relationships between urban population size and PM2.5 concentration in large cities of different continents or countries were different. PM2.5 concentration in large cities in North America, Europe, and Latin America showed little fluctuation or a small increasing trend, but those in Africa and India represent a "U" type relationship and in China represent an inverse "U" type relationship. 3) The potential contribution of population to PM2.5 concentration was higher in the large cities in China and India, but lower in other large cities. (C) 2015 Elsevier Ltd. All rights reserved.Natural Science Foundation of China [NSFC41301199]; Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education MinistrySCI(E)[email protected]; [email protected],SI96-10120

Spatial-Temporal Variations of Water Quality and Its Relationship to Land Use and Land Cover in Beijing, China

Rapid urbanization with intense land use and land cover (LULC) change and explosive population growth has a great impact on water quality. The relationship between LULC characteristics and water quality provides important information for non-point sources (NPS) pollution management. In this study, we first quantified the spatial-temporal patterns of five water quality variables in four watersheds with different levels of urbanization in Beijing, China. We then examined the effects of LULC on water quality across different scales, using Pearson correlation analysis, redundancy analysis, and multiple regressions. The results showed that water quality was improved over the sampled years but with no significant difference (p > 0.05). However, water quality was significantly different among nonurban and both exurban and urban sites (p < 0.05). Forest land was positively correlated with water quality and affected water quality significantly (p < 0.05) within a 200 m buffer zone. Impervious surfaces, water, and crop land were negatively correlated with water quality. Crop land and impervious surfaces, however, affected water quality significantly (p < 0.05) for buffer sizes greater than 800 m. Grass land had different effects on water quality with the scales. The results provide important insights into the relationship between LULC and water quality, and thus for controlling NPS pollution in urban areas

An Ecology for Cities: A Transformational Nexus of Design and Ecology to Advance Climate Change Resilience and Urban Sustainability

Cities around the world are facing an ever-increasing variety of challenges that seem to make more sustainable urban futures elusive. Many of these challenges are being driven by, and exacerbated by, increases in urban populations and climate change. Novel solutions are needed today if our cities are to have any hope of more sustainable and resilient futures. Because most of the environmental impacts of any project are manifest at the point of design, we posit that this is where a real difference in urban development can be made. To this end, we present a transformative model that merges urban design and ecology into an inclusive, creative, knowledge-to-action process. This design-ecology nexus—an ecology for cities—will redefine both the process and its products. In this paper we: (1) summarize the relationships among design, infrastructure, and urban development, emphasizing the importance of joining the three to achieve urban climate resilience and enhance sustainability; (2) discuss how urban ecology can move from an ecology of cities to an ecology for cities based on a knowledge-to-action agenda; (3) detail our model for a transformational urban design-ecology nexus, and; (4) demonstrate the efficacy of our model with several case studies

An Interdisciplinary and Synthetic Approach to Ecological Boundaries

We introduce a collection of articles that proposes conceptual and methodological tools to advance the integrated study of ecological boundaries. A number of studies are germane to understanding the structure and function of boundaries over a wide array of ecological systems and scales. However, these studies have not been unified in a consistent theoretical framework. To integrate these seemingly disparate studies and to advance future research on boundaries, these articles present a common conceptual framework, a classification of the different types of boundaries and their potential functions, and statistical and modeling approaches that can be applied to a wide range of systems, processes, and scales. We summarize the themes that emerge from these articles and suggest questions to guide future research