Urban Edge Research Articles

Population density, survival, and rabies in raccoons in an urban national park

Density and survival of a raccoon (Procyon lotor) population in Rock Creek Park, an urban national park inWashington, D.C., were estimated using mark–recapture and radio-tracking over an 8-year period following the appearance ofthe mid-Atlantic States (Mid-Atlantic) rabies epizootic. Raccoon density ranged from 333.3 to 66.7/km2 , with an overall parkestimate of 125/km2 . This density places the Rock Creek population within the range of other urban and suburban populationsand is many times greater than raccoon densities reported from other habitats. Density was particularly high in one thin spur ofparkland with the smallest ratio of area to urban edge. Raccoon survival rates were high except among juveniles during therabies epizootic. Data on rabies prevalence from Washington, D.C., indicate a cycle with peaks in 1983 during the initialepizootic and again in 1987 and 1991, a pattern similar to that seen in other carnivores and in rabies models. We found evidenceof decreased raccoon density during and after the 1987 rabies resurgence relative to the years following the original epizootic,when rabies prevalence was low. While hunting and trapping represent a major mortality factor for many rural raccoonpopulations, urban and suburban populations and protected populations may frequently be subject to epizootics of diseasessuch as canine distemper and rabies, even years after initial contact with a disease.

Conflicts arise on the urban fringe

The frequent expansion of urban edges presents a challenge for California agriculture as the state's rich farmland base is consumed by nonfarm development. Some issues of conflict emerge as a part of the struggle for limited resources while others are related to the proximity of urban development and agriculture. Other conflicts reflect the urban resident's and farmer's different perspectives on the purpose or value of farmland. Local governments need to establish firm urban-growth boundaries, create buffers between agriculture and urban land uses, and zone to eliminate incompatible land uses in agricultural areas. For its part, the agricultural community needs to educate the urban public to help them understand why particular farm management practices are necessary.

On the Urban Edge: A New and Enhanced Role for Foresters

On the Urban Edge: A New and Enhanced Role for Foresters

Egg and seed removal at urban and suburban forest edges

Predation rates of natural and artificial bird nests in rural landscapes have been the subject of numerous studies, often in the context of proximity to edge. Similar studies in urban and suburban landscapes are lacking. We carried out a study of egg and seed removal at forest reserve edges in three urban and two suburban forests in and near New York City in 1994-1995. Few significant edge effects were found, but this may have been because of the extraordinarily high rates of egg and seed removal. Daily removal rates were higher in suburban sites (eggs, 86%; seeds, 95%) than in urban sites (eggs, 64%; seeds, 88%). Exposed seeds and eggs suffered higher rates of removal than seeds and eggs covered by leaf litter. Despite statistically significant differences among treatments, all of these rates would be prohibitively high if experienced by ground-nesting birds or large-seeded trees (if removal was associated with predation). A survey of the literature suggests that egg predation rates are prohibitively high in cities and peak in suburban sites (at least in this study), then drop rapidly in ex-urban and rural sites, perhaps because of a similar pattern in the abundance of corvid bird predators.

Gis-aided land evaluation and decision-making for regulating urban expansion: A South African case study

A computerised aid to the land use planning process is demonstrated on the urban edge of Cape Town, South Africa. Multi-criteria analysis is performed in the IDRISI GIS package to evaluate development suitability for four land use categories according to appropriately measured and weighted criteria. The four suitability images are then subjected to multi-objective land allocation to demarcate optimum locations for each land use type. The decision-making process entails execution of seven consecutive steps which are discussed in detail and applied in the case study. Technical decisions are rationalised and results displayed. The paper concludes with a call for the development of applications which can incorporate public participation in this type of decision-making process to ensure the wider acceptance of advanced GIS technology as ‘appropriate technology’.

The suburban public realm I: Its emergence, growth and transformation in the American metropolis

Abstract This two‐part essay analyses the changing nature of the public realm in the evolving edge of the American metropolis and the implications for urban design and planning. Many forces are changing the form and use of public space in cities—concerns for safety and liveability, increasing dependence on telecommunications, decline in public revenues, the privatization of many amenities, and an increasingly pluralist society. The essay specifically focuses on the historical influence of planning and design practices on suburban form: density levels, land use and zoning patterns, suburban layouts and streetscapes. Field surveys and morphological analyses of urban edge patterns from the San Francisco Bay area document the current state of the suburban public realm. The second part of the essay will examine how physical planning can contribute to restoring a more vibrant public realm amidst raging debates over its changing nature and relevance.

Fire regimes and biodiversity: the effects of fragmentation of southeastern Australian eucalypt forests by urbanisation, agriculture and pine plantations

Fragmentation of eucalypt forests has been common in southeastern Australia. Urbanisation, agriculture and the establishment of plantations of the exotic tree Pinus radiata are major agencies of fragmentation. The study of the effects of these agencies on adjacent forested land has lacked a suitable framework. By constructing generalized trophic-level diagrams for each fragmenting system—farm, urban area and pine plantation—the major potential impacts on adjacent forested land can be examined. Urban areas, for example, have a relatively large non-native predator biomass (especially cats and dogs) compared with the original forest, whilst farms support a relatively large biomass of exotic herbivores. In pine plantations, by way of contrast, the biomass of native or exotic herbivores and predators is relatively small. Landscape fires are an integral part of the ecology of native eucalypt forests but are kept out of suburban areas, farms with improved pastures and standing plantations as much as possible. To explore the potential impacts on biodiversity of fire regimes in forests at the edges of urban areas, farms and plantations, we constructed and sought evidence for, a series of scenarios (each a compound hypothesis). Urban interface scenario: ‘There is a low frequency of unplanned fire in forest remnants. To prevent losses of life and property in adjacent urban areas, regular frequent prescribed burning is practiced. Regular frequent prescribed burning reduces biodiversity’. Support for the first two parts of this scenario was strong although the frequency of fires, prescribed or unplanned, may be a function of distance from the urban edge, the size of management unit and the nature of the tuels. Urban predators may be expected to reduce vertebrate biodiversity, especially after fires. Agricultural interface scenario: ‘Clearing for agriculture leaves only small forest remnants with become fire free. Fire-free fragments eventually decline in plant species biodiversity’. Forest fragments in rural areas vary widely in size and occur as roadside remnants, farm woodlots, Travelling Stock Reserves, State Forests and designated conservation reserves. The circumstances of burning vary widely. Grazing from domestic stock, especially combined with fire, may negatively affect biodiversity. Absence of fire may also reduce biodiversity. Pine interface scenario: ‘Pines spread from plantations to neighbouring forest areas, reducing native plant and animal species diversity. This situation can be reversed by a prescribed burning regime that has fires intense enough to cause pine death and frequent enough to prevent pine seed set’. There was considerable support for this scenario although at this stage the spread of pines may be only in areas peripheral to plantations. Because fires have effects on biodiversity, crops, lives and property in fragmented forests and adjacent areas, integrated management—across landuses and jurisdictions—is recommended.

The Evolving Metropolis: Studies of Community, Neighborhood, and Street Form at the Urban Edge

Abstract This paper examines the form of the evolving metropolitan fringe by means of comparative case studies of fringe development in the San Francisco Bay area at three scales —the community, the neighborhood, and the street and house lot. The study identifies underlying organizing principles and spatial typologies and analyzes patterns of growth, land use, and street layouts for several periods of suburban development beginning early in the twentieth century and continuing into the 1990s. As the scale of development has grown, there has been a parallel growth of self-contained, single-use developments and an erosion of the public street framework. This shift has serious implications for the character, convenience, and adaptability of new urban environments.

Urban edges and the public realm

The physical disintegration of the US city has led not only to the disintegration of downtown areas but also the destruction of coherent districts and neighbourhoods. Cincinnati is no exception; the historic districts on the edge of the central city are in a state of terminal decline. This study of Cincinnati attempts to identify the basic structure and urban morphology of the neighbourhood which acts as a gateway to the city centre in one direction. Instead of merely addressing the housing problems and needs, the urban design framework investigates ways in which the public realm, through landscape design, can begin to reunify a previously semi-derelict district.

Urban planning in the developing world: Lessons from experience

In planning literature, there are ample examples of well-documented cases of plan-making and formal decision-making, and an equally substantial amount of literature devoted to implementation. However, limited case analyses exist from the perspective of political decision-making, currently perceived as “a black box to planners” (Albrechts, 2003: 250). The City of Cape Town (CoCT), South Africa, have employed an urban edge as a growth management instrument in its Spatial Development Framework (CTSDF) since 2001 (City of Cape Town, 2009), however, the latest CTSDF (2017) retracted this instrument. Instead, the latest spatial strategy to manage growth centres on encouraging dense development that supports transit-oriented development in the urban core, whilst discouraging peripheral expansion by stating intent not to extend services towards the urban periphery in the short-term. This paper contributes to inquiry that tests the implementation of planning instruments in post-colonial urban settings (Fekade, 2000; Barredo and Demicheli, 2003; and Kombe, 2005) by firstly, evaluating the physical extent of urban sprawl in the CoCT and secondly, by analysing the decision-making process that resulted in two large-scale amendments to the original urban edge, and ultimately the final termination of the urban edge policy.

Women in the informal house-building industry in Nigeria

House-building is of national importance in view of its contribution to the economic and physical investment of the nation. The house-building industry comprises skilled, semi-skilled and unskilled labour (usually women). Women, according to Conable ( Urban Edge, 12, 1988), built the foundations of stable growing communities, but development efforts have not lent enough strength to women, and have not entrusted enough resources to them. Women in the housing construction industry have tended to be relegated to secondary chores like fetching and carrying water. Thus, this paper examines the involvement of the unskilled labour, women usually referred to as Birisopes (in the local language) in the informal house-building industry in Nigeria.

History as a Design Mode: The New Bibliotheca Alexandrina

The design of the new Alexandria library requires a consideration of the many cultural and historical layers of the site, the city, and the country. Our design process began with our vision of the role of the library within its historical and cultural setting, the library as myth and metaphor. We then proceeded to analyze the site in its various contexts: the site in history; within its urban fabric; and in its position as link between the University of Alexandria and the sea. Program elements were then overlaid onto this. The concept that emerged marries the symbolic axis toward the site of the ancient lighthouse Pharos and the functional axis toward the University of Alexandria campus, allowing the building mass to act as an urban edge.

Shakespeare at the Odessa Globe

The Shakespeare festival at the Globe of the Great Southwest in Odessa, Texas, founded in i969, is about to transcend civic promotion and regional pride to become an event of national stature. The promising academic relationship recently worked out between the Globe and the new University of Texas of the Permian Basin, the quality of the Shakespearean actors being trained in its own Academy, and the high degree of sophistication in the 1973 summer productions of The Comedy of Errors and The Tempest all suggest that the Odessa Globe is to be taken very seriously indeed. Director Charles David McCally still speaks of educating an audience, but his productions are inventive and physically alive-full of subtle and effective stage business and paced well (though both Errors and The Tempest moved better before intermission than after); it is clear that a regional audience has not made McCally tentative. How much of the achievement of the past five years at the Globe should be credited to this fine director was suggested by the Cyrano which completed the 1973 summer repertory; McCally played the title role with the right panache, but under Arthur Nations' direction the company were largely colorless in a production that dragged badly. The Globe is the right theater for McCally's talents; the stage thrusts into a 400-seat house, offering great flexibility and good intimacy. The sight lines are excellent and the acoustics near perfect. The 'tiring-house facade is Adams/ Globe, and McCally used it well-nowhere better than in mounting Tempest I.i on the balcony as ship's deck with the lookout in the chamber window high above, while Ariel danced with a ship model on his head among gauze waves in the half-light on the main stage below. The exterior of: the building, beams and swirled concrete, gives the sense of adobe architecture as well as of Tudor, and one feels that the Globe belongs in its setting. The urban location-the edge of a warehouse district, in fact-is more suggestive of the Bankside than the spacious lawns and swans one associates with Shakespeare festivals. Marjorie Morris, the designer of the building and first mover of the project, may not have 'intended this effect, but it is real and appealing. The conjunction of Errors and The Tempest is interesting for several reasons. Both plays can be done uncut as the two shortest in the canon; what a director has in each of them is probably close to what Shakespeare's company actually mounted. If he cuts a massive scenario like Hamlet or Troilus and Cressida to a two-hours' traffic, he has the satisfaction of going through the selective process that Shakespeare and his fellows went through in preparing a script for the playhouse, but he has little likelihood of emerging with what was actually staged-it is worth remembering that the cuts in Hamlet on the late seventeenth-century stage included the soliloquies. A second affinity between Errors and The Tempest is thematic: both plays