Home  About us  Contact
 

Housing Density (housing + density)

Distribution by Scientific Domains
Life Sciences71%

Selected Abstracts

LAND-USE DYNAMICS BEYOND THE AMERICAN URBAN FRINGE,

GEOGRAPHICAL REVIEW, Issue 3 2001
DAVID M. THEOBALD
ABSTRACT. A deficiency common to both the historical debates over loss of agricultural land and the current discussions of urbanization and sprawl is a limited understanding of land-use dynamics beyond the urban fringe. Data aggregated at the county level poorly capture the fine-grained pattern of land-use change beyond the dynamic urban-rural interface. Furthermore, current urban-based definitions are poorly suited to delineate these areas, and low-density, exurban land use is difficult to measure using existing land-cover databases. Urbanization and the conversion of once-agricultural or other natural resource lands to other uses has traditionally been tracked using urban areas, as delimited in the U.S. census. Urban densities are typically defined as areas with more than 1,000 people per square mile, or 1.6 people per acre (U.S. Census Bureau 2000). Assuming an average of 2.5 people per housing unit, this translates to roughly 0.7 units per acre, or approximately 1 unit per 1.6 acres. The analytical units used in the census, however, both overbound and underbound areas with urban densities. About one-third of urban areas in 1990 comprised lower-than-urban housing density, thanks to overbounding. But, then, one-third of locations that had urban-level housing densities failed to be included in urban areas as a result of underbounding, which, if counted, would have constituted another 18 million acres of urban area. An increase over time of the average number of acres required per housing unit in exurban and higher-density locations occurred in roughly one-third of U.S. counties from 1960 to 1990 and persisted from 1990 to 2000. In 2000 roughly 38 million acres were settled at urban densities, and nearly ten times that much land was settled at rates from low, exurban density (as low as one house per 40 acres) to higher rates (up to one per 10 acres). This represents a continuing encroachment on land previously given over to other uses,habitat or agriculture. Practitioners of natural resource management need to recognize the ubiquity of exurban development and better incorporate the fine-scale patterns of land use beyond the urban fringe. [source]

Bird densities are associated with household densities

GLOBAL CHANGE BIOLOGY, Issue 8 2007
JAMIE TRATALOS
Abstract Increasing housing density is an important component of global land transformation, with major impacts on patterns of biodiversity. However, while there have been many studies of the changes in biodiversity across rural,urban gradients, which are influenced in large part by housing densities, how biodiversity changes across the full range of regional variation in housing density remains poorly understood. Here, we explore these relationships for the richness and abundance of breeding birds across Britain. Total richness, and that of 27 urban indicator species, increased from low to moderate household densities and then declined at greater household densities. The richness of all species increased initially faster with household density than did that of the urban indicator species, but nonurban indicator species richness declined consistently after peaking at a very low housing density. Avian abundance showed a rather different pattern. Total abundance and that summed across all urban indicator species increased over a wide range of household densities, and declined only at the highest household densities. The abundance of individual urban indicator species generally exhibited a hump-shaped relationship with housing density. While there was marked intraspecific variation in the form of such relationships, almost invariably avian abundance declined at housing densities below that at which the UK government requires new developments to be built. Our data highlight the difficulties of maintaining biodiversity while minimising land take for new development. High-density housing developments are associated with declines in many of those species otherwise best able to exploit urban environments, and those components of native biodiversity with which human populations are often most familiar. [source]

Housing developments in rural New England: effects on forest birds

ANIMAL CONSERVATION, Issue 1 2000
Daniel A. Kluza
In rural New England, forest fragmentation is caused by housing developments in forested areas. To evaluate the effects of these changes on forest birds, we compared bird assemblages between forests with different housing densities in western Massachusetts. Species occurrences and relative abundances were determined from systematic point count surveys and mist-netting at three plots in forest of low housing density (0,0.05 houses/ha) and of moderate housing density (0.60,6.70 houses/ha) in 1993 and 1994. Among guilds, Neotropical migrants and forest-interior species had significantly lower abundances in forests of moderate housing density. Abundances of ground/shrub nesting birds as a group, and of individual species such as veery (Catharus fuscescens), ovenbird (Seiurus aurocapillus) and wood thrush (Hylocichla mustelina), were greater in forest of low housing density, but blue jays (Cyanocitta cristata) were more abundant in forest of moderate housing density. Although the abundances of ground/shrub nesting birds were positively related to ground cover, this vegetation structure did not differ between forest types. Avian and mammalian nest predators may be responsible for the trends in bird abundance. Avian nest predators may recognize forest of moderate housing density as edge habitat, and this rural development may also support relatively high densities of mammalian nest predators. These trends suggest that birds of New England's relatively extensive forests may be subject to greater fragmentation effects than generally thought, as a result of increasing rural housing development within forests. [source]

LAND-USE DYNAMICS BEYOND THE AMERICAN URBAN FRINGE,

GEOGRAPHICAL REVIEW, Issue 3 2001
DAVID M. THEOBALD
ABSTRACT. A deficiency common to both the historical debates over loss of agricultural land and the current discussions of urbanization and sprawl is a limited understanding of land-use dynamics beyond the urban fringe. Data aggregated at the county level poorly capture the fine-grained pattern of land-use change beyond the dynamic urban-rural interface. Furthermore, current urban-based definitions are poorly suited to delineate these areas, and low-density, exurban land use is difficult to measure using existing land-cover databases. Urbanization and the conversion of once-agricultural or other natural resource lands to other uses has traditionally been tracked using urban areas, as delimited in the U.S. census. Urban densities are typically defined as areas with more than 1,000 people per square mile, or 1.6 people per acre (U.S. Census Bureau 2000). Assuming an average of 2.5 people per housing unit, this translates to roughly 0.7 units per acre, or approximately 1 unit per 1.6 acres. The analytical units used in the census, however, both overbound and underbound areas with urban densities. About one-third of urban areas in 1990 comprised lower-than-urban housing density, thanks to overbounding. But, then, one-third of locations that had urban-level housing densities failed to be included in urban areas as a result of underbounding, which, if counted, would have constituted another 18 million acres of urban area. An increase over time of the average number of acres required per housing unit in exurban and higher-density locations occurred in roughly one-third of U.S. counties from 1960 to 1990 and persisted from 1990 to 2000. In 2000 roughly 38 million acres were settled at urban densities, and nearly ten times that much land was settled at rates from low, exurban density (as low as one house per 40 acres) to higher rates (up to one per 10 acres). This represents a continuing encroachment on land previously given over to other uses,habitat or agriculture. Practitioners of natural resource management need to recognize the ubiquity of exurban development and better incorporate the fine-scale patterns of land use beyond the urban fringe. [source]

Bird densities are associated with household densities

GLOBAL CHANGE BIOLOGY, Issue 8 2007
JAMIE TRATALOS
Abstract Increasing housing density is an important component of global land transformation, with major impacts on patterns of biodiversity. However, while there have been many studies of the changes in biodiversity across rural,urban gradients, which are influenced in large part by housing densities, how biodiversity changes across the full range of regional variation in housing density remains poorly understood. Here, we explore these relationships for the richness and abundance of breeding birds across Britain. Total richness, and that of 27 urban indicator species, increased from low to moderate household densities and then declined at greater household densities. The richness of all species increased initially faster with household density than did that of the urban indicator species, but nonurban indicator species richness declined consistently after peaking at a very low housing density. Avian abundance showed a rather different pattern. Total abundance and that summed across all urban indicator species increased over a wide range of household densities, and declined only at the highest household densities. The abundance of individual urban indicator species generally exhibited a hump-shaped relationship with housing density. While there was marked intraspecific variation in the form of such relationships, almost invariably avian abundance declined at housing densities below that at which the UK government requires new developments to be built. Our data highlight the difficulties of maintaining biodiversity while minimising land take for new development. High-density housing developments are associated with declines in many of those species otherwise best able to exploit urban environments, and those components of native biodiversity with which human populations are often most familiar. [source]

Housing developments in rural New England: effects on forest birds

ANIMAL CONSERVATION, Issue 1 2000
Daniel A. Kluza
In rural New England, forest fragmentation is caused by housing developments in forested areas. To evaluate the effects of these changes on forest birds, we compared bird assemblages between forests with different housing densities in western Massachusetts. Species occurrences and relative abundances were determined from systematic point count surveys and mist-netting at three plots in forest of low housing density (0,0.05 houses/ha) and of moderate housing density (0.60,6.70 houses/ha) in 1993 and 1994. Among guilds, Neotropical migrants and forest-interior species had significantly lower abundances in forests of moderate housing density. Abundances of ground/shrub nesting birds as a group, and of individual species such as veery (Catharus fuscescens), ovenbird (Seiurus aurocapillus) and wood thrush (Hylocichla mustelina), were greater in forest of low housing density, but blue jays (Cyanocitta cristata) were more abundant in forest of moderate housing density. Although the abundances of ground/shrub nesting birds were positively related to ground cover, this vegetation structure did not differ between forest types. Avian and mammalian nest predators may be responsible for the trends in bird abundance. Avian nest predators may recognize forest of moderate housing density as edge habitat, and this rural development may also support relatively high densities of mammalian nest predators. These trends suggest that birds of New England's relatively extensive forests may be subject to greater fragmentation effects than generally thought, as a result of increasing rural housing development within forests. [source]