Approaches to the study of urban ecosystems: The case of Central Arizona—Phoenix

CAP LTER focuses on an arid-land ecosystem profoundly influenced, even defined, by the presence and activities of humans and is one of only two LTER sites that specifically studies the ecology of an urban system. In this large-scale project, biological, physical, and social scientists are working together to study the structure and function of the urban ecosystem, to assess the effects of urban development on surrounding agricultural and desert lands, and to study the relationship and feedbacks between human decisions and ecological processes.Our interdisciplinary investigations into the relationship between land-use decisions and ecological consequences in the rapidly growing urban environment of Phoenix are of broad relevance for the study of social ecological systems and cites in particular. Refinements in our conceptual model of social ecological systems focuses our attention on recognizing the scales and periodicities of ecological and human phenomena, understanding the means and impacts of human control of variability in space and time, and finally an evaluation of the resilience of various aspects of socio-ecological systems especially their vulnerabilities and their potential for adaptive learning.     

Methods for spatial and temporal land use and land cover assessment for urban ecosystems and application in the greater Baltimore-Chesapeake region

Understanding contemporary urban landscapes requires multiple sets of spatially and temporally compatible data that can integrate historical land use patterns and disturbances to land cover. This paper presents three principal methods: (1) core analysis; (2) historic mapping; and (3) gradient analysis, to link spatial and temporal data for urban ecosystems and applies their use in the Baltimore-Chesapeake region. Paleoecological evidence derived from the geochronology of sediment cores provides data on long-term as well as recent changes in vegetative land cover. This information, combined with contemporary vegetation maps, provides a baseline for conducting trend analyses to evaluate urbanization of the landscape. A 200-year historical land use database created from historical maps, census data, and remotely sensed data provides a spatial framework for investigating human impacts on the region. A geographic information system (GIS) integrates core analyses with historic data on land use change to yield a comprehensive land use and land cover framework and rates of change. These data resources establish the regional foundation for investigating the ecological components of an urban ecosystem. Urban-rural gradient analyses and patch analyses are proposed as the most appropriate methods for studying the urban ecosystem as they link ecological and social patterns and processes for varying degrees of urbanization.     

Terrestrial vertebrates in urban ecosystems: developing hypotheses for the Gwynns Falls Watershed in Baltimore,Maryland

We review the literature on terrestrial vertebrates in urban and urbanizing areas in terms of the new paradigm in ecology that focuses on the origin, spatial pattern, and current influences of habitat patches. Studies of terrestrial vertebrates have documented differences in species composition along an urban-rural gradient and have identified some of the key land use features associated with these differences. We use information from a database developed for the Gwynns Falls Watershed in Baltimore City and County, Maryland to demonstrate how a study of forest-dependent breeding birds could be used to identify mechanisms that account for differences in the bird communities of forest patches in urban areas, and to provide useful information to planners and managers involved in wildlife conservation and management.     

Modeling urban landscape dynamics: A case study in Phoenix,USA

Urbanization has profoundly transformed many landscapes throughout the world, and the ecological consequences of this transformation are yet to be fully understood. To understand the ecology of urban systems, it is necessary to quantify the spatial and temporal patterns of urbanization, which often requires dynamic modeling and spatial analysis. In this paper, we describe an urban growth model, the Phoenix Urban Growth Model (PHX-UGM), illustrate a series of model calibration and evaluation methods, and present scenario-based simulation analyses of the future development patterns of the Phoenix metropolitan region. PHX-UGM is a spatially explicit urban landscape model and is a modified version of the Human-Induced Land Transformations (HILT) model originally developed for the San Francisco Bay Area. Using land use and other data collected for the Phoenix area, existing growth rules were selectively modified and new rules were added to help examine key ecological and social factors. We used multiple methods and a multi-scale approach for model calibration and evaluation. The results of the different evaluation methods showed that the model performed reasonably well at a certain range of spatial resolutions (120–480 m). When fine-scale data are available and when landscape structural details are desirable, the 120-m grain size should be used. However, at finer levels the noise and uncertainty in input data and the exponentially increased computational requirements would considerably reduce the usefulness and accuracy of the model. At the other extreme, model projections with too coarse a spatial resolution would be of little use at the local and regional scales. A series of scenario analyses suggest that the Metropolitan Phoenix area will soon be densely populated demographically and highly fragmented ecologically unless dramatic actions are to be taken soon to significantly slow down the population growth. Also, there will be an urban morphological threshold over which drastic changes in certain aspects of landscape pattern occur. Specifically, the scenarios indicate that, as large patches of open lands (including protected lands, parks and available desert lands) begin to break up, patch diversity declines due partly to the loss of agricultural lands, and the overall landscape shape complexity also decreases because of the predominance of urban lands. It seems that reaching such a threshold can be delayed, but not avoided, if the population in the Phoenix metropolitan region continues to grow. PHX-UGM can be used as a tool for exploring the outcome of different urban planning strategies, and the methods illustrated in this paper can be used for evaluating other urban models.     

Patterns of human disturbance and response by small mammals and birds in chaparral near urban development

We report on the extent of disturbance (including habitat alteration and road and trail proliferation) in chaparral near urban development and analyze the effects of disturbance on small mammal and resident bird species. Disturbance patterns were evaluated in a 6700 ha study area in southern California: effects on mammals and birds were investigated by analyzing relationships between vegetation structure and animal species richness and abundance. Disturbance was prevalent throughout the study area and included extensive human-altered habitat (from past human activities such as vegetation clearing, human-caused fires, refuse dumping, and vegetation trampling) and 157 km of roads and trails. A nonsignificant trend was found between human-altered habitat and proximity to development, but human-altered habitat was significantly associated with roadway proximity. Trails were also more frequent near urban development and roads. Small mammals responded strongly to disturbance-related vegetation changes, while birds showed little or no response. Mammals endemic to chaparral vegetation were less diverse and abundant in disturbed sites, whereas disturbance-associated species increased in abundance. Close proximity of urban development to natural areas resulted in alteration of natural habitat and proliferation of roads and trails. Variation in life history traits between birds and mammals may affect response to disturbance and influence persistence if disturbance continues. Conservation efforts must recognize the potential for habitat damage and associated declines in native animal species caused by disturbance near urbanization and implement strategies to reduce these threats.     

Silphids in urban forests: Diversity and function

Many ecologists have examined the process of how urbanization reduces biological diversity but rarely have its ecological consequences been assessed. We studied forest-dwelling burying beetles (Coleoptera: Silphidae)—a guild of insects that requires carrion to complete their life cycles—along an urban-rural gradient of land use in Maryland. Our objective was to determine how forest fragmentation associated with urbanization affects (1) beetle community diversity and structure and (2) the ecological function provided by these insects, that is, decomposition of vertebrate carcasses. Forest fragmentation strongly reduced burying beetle diversity and abundance, and did so far more pervasively than urbanization of the surrounding landscape. The likelihood that beetles interred experimental baits was a direct, positive function of burying beetle diversity. We conclude that loss of burying beetle diversity resulting from forest fragmentation could have important ecological consequences in urban forests.     

Occurrence of breeding bird species in urban parks: Effects of park structure and broad-scale variables

Occurrences of breeding bird species in 54 urban parks were investigated in the city of Oulu in northern Finland. Park area, human activity, habitat, and landscape structure within a 9-ha square surrounding the study park were related to the bird species richness and occurrence of individual bird species. A total of 22 species was observed. The area of the park explained 39% of the variance of species richness. Seven species (wheatear [Oenanthe oenanthe], common rosefinch [Carpodacus erythrinus], garden warbler [Sylvia borin], lesser whitethroat [Sylvia curruca], linnet [Acanthis cannabina], redpoll [Carduelis flammea], and yellowhammer [Emberiza citrinella]) were not detected in parks of >0.75 ha. Species with lower area demands occurred closer to the town center than species with greater area requirements. Ground-nesting species were poor colonizers of urban parks, whereas high numbers of nest boxes in urban parks attracted many cavity-nesting species. The willow warbler (Phylloscopus trochilus) and the magpie (Pica pica) bred more often in unmanaged than in managed parks, probably because of the greater vegetation cover in unmanaged parks. Park structure variables were entered into models for 7 of the 12 most common bird species, whereas broad scale variables were entered into models for 6 of the 12 species. The number of adjacent buildings had a negative affect on three bird species (the willow warbler, hooded crow [Corvus corone cornix], and spotted flycatcher [Muscicapa striata]). The occurrence of breeding species in urban parks depends on the size of the park, park structure, and landscape structure outside the park.     

Reinvigorating resilience: violence against women,land rights,and the women's peace movement in Myanmar

In Myanmar, movements for gender justice strive to foster personal and collective security, vibrant livelihoods, and political engagement during a period of rapid and uncertain transition. This article draws from the experience of the Gender Equality Network (GEN), a coalition of over 100 organisations in Myanmar. It examines three cases in which GEN sought to document existing forms of resilience and expand these mechanisms through national-level advocacy. The first describes current attempts to publicise, and eventually eliminate, violence against women (VAW). VAW is a fundamental threat to personal safety, but also to the principle of societal accountability – that is, the extent to which society upholds the interests and rights of women and girls. The second focuses on women's (lack of) access to natural resources and economic decision-making, drawing on gender-focused input into the National Land Use Policy. Finally, we examine the impacts of conflict on women's resilience, and women's increasing participation in the peace process. In all three cases, effective mobilisation and networking not only increased female political voice, but also enabled creation of a more resilient democracy by modelling effective policy, research, advocacy, and communication strategies.     

Bridging the divide in urban sustainability: from human exemptionalism to the new ecological paradigm

This paper reviews the main bodies of contemporary urban sustainability theory. From this analysis, two underpinning paradigms of urban sustainability are identified: (1) The ‘Human Exemptionalism Paradigm’ (HEP), which emphasizes the ability of humans to overcome environmental problems—see Urban Sociology, Urban Ecology, Urban Geography, Urban Psychology and Political Economy; and (2) The ‘New Ecological Paradigm’ (NEP), which emphasizes the criticality of ecological limits to human progress—see Urban Metabolism, Energy/Emergy Analysis and Ecological Footprinting. Each of these approaches is critically reviewed, highlighting their main assumptions, theoretical and practical foci. It is argued in the paper that if the related issues of urban sustainability and development are to be progressed, there needs to be: (1) a greater maturation of the NEP approaches, which are ‘relative newcomers’ to the area of urban theory; and (2) greater integration and dialogue between the HEP and NEP approaches to urban sustainability than has hitherto been the case.

Connecting local environmental knowledge and land use practices: A human ecosystem approach to urbanization in West Georgia

Issues of urban sprawl and migration of exurban residents into the surrounding countryside of metropolitan areas have generated considerable debate across the US. These debates often revolve around the ecological footprint of urban areas and the erosion of quality of life indicators associated with rapid expansion of urban and residential areas. Although there has been much research done on the environmental and socioeconomic impacts of urbanization, little attention has been given to cultural impacts. This paper focuses specifically on the role of local environmental knowledge as an important resource in human ecosystems, and looks at the implications of environmental knowledge loss associated with urbanization and its related demographic changes. We compared environmental knowledge among rural, urban, and developing watersheds in western Georgia, and also look at relationships between local environmental knowledge and variables such as gender, education, income, and participation in outdoor recreational activities. We then explored how variations in environmental knowledge affected land use practices at the household level. The mean knowledge scores of residents in all three classifications of rural watersheds were higher than those living in developing and urban watersheds. We found residents of managed pine watersheds possessed the highest mean scores (p = 0.006), while urban watershed residents were the lowest. We also found that local environmental knowledge was influenced by active participation in outdoor recreation, with active bird-watchers having the highest environmental knowledge scores. However, we found less influence of factors such as education and income on environmental knowledge. We also found a clear connection between local environmental knowledge and land management practices. Timber owners scored higher than non-timber owners (p = 0.099), and landowners who constructed streamside management zones (SMZs) scored higher than those who did not (p = 0.034).