Urbanization, Biodiversity, and Conservation
We use cookies to enhance your experience on our website. By continuing to use our website, you are agreeing to our use of
cookies. You can change your cookie settings at any time.
The impacts of urbanization on native species are poorly studied, but educating a highly urbanized human population about
these impacts can greatly improve species conservation in all ecosystems
Michael L. McKinney (e-mail: mmckinney{at}utk.edu) is a professor of geological sciences and director of the Environmental Studies Program at the Department of Geological
Sciences, University of Tennessee–Knoxville, Knoxville, TN 37996. His current research interests focus on the impacts of urbanization
on biodiversity. In addition to his professorial responsibilities at the university, he strives to educate the general public
about conservation in all ecosystems.
Among the many human activities that cause habitat loss (), urban development produces some of the greatest local extinction rates and frequently eliminates the large majority of
native species (, , , ). Also, urbanization is often more lasting than other types of habitat loss. Throughout much of New England, for example,
ecological succession is restoring forest habitat lost from farming and logging, whereas most urbanized areas in that region
not only persist but continue to expand and threaten other local ecosystems ().
Another great conservation challenge of urban growth is that it replaces the native species that are lost with widespread
“weedy” nonnative species. This replacement constitutes the process of biotic homogenization that threatens to reduce the
biological uniqueness of local ecosystems (). Urban-gradient studies show that, for many taxa, for example, plants () and birds and butterflies (), the number of nonnative species increases toward centers of urbanization, while the number of native species decreases.
The final conservation challenge of sprawl is its current and growing geographical extent (). A review by
finds that urbanization endangers more species and is more geographically ubiquitous in the mainland United States than any
other human activity. Species threatened by urbanization also tend to be threatened by agriculture, recreation, roads, and
many other human impacts, emphasizing the uniquely far-reaching transformations that accompany urban sprawl.
About 50% of the US population lives in the suburbs, with another 30% living in cities (). Over 5% of the total surface area of the United States is covered by urban and other built-up areas (). This is more land than is covered by the combined total of national and state parks and areas preserved by the Nature Conservancy.
More ominously, the growth rate of urban land use is accelerating faster than land preserved as parks or conservation areas
by the Conservancy . Much of this growth is from the spread of suburban housing. It is estimated, for example, that residential yards occupy
135,000 acres in the state of Missouri (). This residential landscape represents nearly 1% of the total area of Missouri and is nearly three times the area occupied
by Missouri state parks.
View larger version:
Amount of land covered in the lower 48 states, by category. Source: All data are from Statistical Abstract of the United States
for the years shown, except for Nature Conservancy data, which is from .
Here I review the growing literature that documents how urban (and suburban) expansion harms native ecosystems. This knowledge
can aid conservation efforts in two major ways. One is through the use of ecological principles—such as preserving remnant
natural habitat and restoring modified habitats to promote native species conservation—to reduce the impacts of urbanization
on native ecosystems. Rare and endangered species sometimes occur in urbanized habitats (, ) and thus could be conserved there. Managing the large amount of residential vegetation (1% of the state area, as noted above)
in ways that promote native plants and animals could also make a significant contribution to conservation.
A second way in which the study of urban ecology can serve conservation is by helping to develop a more ecologically informed
public. Providing a well-informed public could be the most important application of urban ecology, as a means of promoting
effective conservation of native species (). Because 80% of the American public lives in or near urban areas, there are many opportunities for creating an informed
public that can wield enormous economic and political pressure to promote conservation policies. People who live in urban
environments often have a great appreciation of many urban species, such as birds (). Indeed, residents of suburban and urban areas tend to place a much higher value on species conservation than those living
in rural areas (). This is reflected in voting behavior: Legislators from highly urbanized states and districts tend to be more supportive
of strengthening the Endangered Species Act ().
Unfortunately, these conservation opportunities are hindered by the very poor ecological knowledge of typical American urbanites.
A survey of Texas high school students, for example, showed that 60% of the students misidentified the opossum as a rodent
and that ecological understanding of human effects on b only 2% of the students knew that raccoons tend
to benefit from many human activities ().
The urban–rural gradient: General patterns
Urban-to-rural gradient studies examine changes in plants and animals along a transect from the inner city to surrounding,
less- they also show what happens to surrounding native ecosystems as urban sprawl expands. General patterns
that emerge from these studies are described below.
Physical gradients
Physical changes along the gradient strongly influence available habitat for native species. A number of reviews (, , ) show increases in these physical changes, as one moves toward the urban core, in such metrics as human population density,
road density, air and soil pollution, average ambient temperature (“heat island” effect), average annual rainfall, soil compaction,
soil alkalinity, and other indicators of anthropogenic disturbance. The percentage of area that is impervious surface (pavement,
asphalt, buildings) ranges from well over 50% at the urban core to less than 20% at the fringe of urban expansion . In addition, the amount of subsidized energy and matter imported for use by humans and available to other species increases
toward the urban center (, ).
View larger version:
Urban–rural gradient. This is a very generalized and simplified depiction of changes in surface area, species richness, and
composition, as compiled from a number of sources discussed in the text. Two basic conservation strategies with respect to
urban sprawl are shown at the top.
Habitat-loss gradient
These physical changes produce a gradient of natural habitat loss that steepens from rural areas toward the urban center.
As habitat is lost, it becomes increasingly fragmented into more numerous but smaller remnant patches (, ). The lost natural habitat is then replaced by four types of altered habitat that become progressively more common toward
the urban core. The four types of replacement habitat are listed below, in order of increasing habitability to most native
species and decreasing proportion of coverage toward the urban core. The latter three types are based on .
Built habitat: buildings and sealed surfaces, such as roads
Managed vegetation: residential, commercial, and other regularly maintained green spaces
Ruderal vegetation: empty lots, abandoned farmland, and other green space that is cleared but not managed
Natural remnant vegetation: remaining islands of original vegetation (usually subject to substantial nonnative plant invasion)
Diversity changes along the urban–rural gradient
It is probably intuitive to even the most casual observer that the increasing fragmentation of natural habitat by human disturbances
in the direction toward urban centers will tend to reduce species richness (number of species) in that direction. There are,
however, many variables that can affect the rate and consistency of species loss along the gradient, so empirical studies
are crucial in measuring urban impacts.
Urban core, low diversity
Many studies document that the lowest species diversities along the urban–rural gradient occur in the intensively “built”
environments of the urban core. This has been shown for many taxa, including plants (), birds and butterflies (), many insects (, ), and mammals (). In all these taxa, the number of species at the urban core is reduced to less than half of that found in the rural, more
natural areas at the opposite end of the gradient .
, for example, found just 7 summer resident bird species in the central business district of Palo Alto, California, compared
with 21 species that inhabited a natural area (preserve) outside the city limits. Similar reductions were found for birds
and butterflies in other cities, as shown by , and especially by , comprehensive compilation of studies on urbanization impacts on birds.
Much of the reduction in richness is obviously caused by the loss of vegetation. The number of species of animal taxa, such
as birds () and insects (), tends to correlate with the number of plants in an area. Also, area covered by vegetation is a good predictor of species
numbers for birds (); mammals, amphibians, and reptiles (); and insects ().
As over 80% of most central urban areas is covered by pavement and buildings (, ), less than 20%, therefore, remains as vegetated area. Furthermore, the remaining vegetated habitat often contains low plant
diversity as a result of erosion, trampling, pollution, invasion or cultivation of a few nonnative species, and many other
human disturbances. Also, mowing, pruning, and other common landscaping practices further reduce the volume of the remaining
vegetation (, ).
Suburban diversity: Peak or plunge?
Some studies indicate that species richness tends to be higher in areas with low to moderate levels of human development (such
as outlying suburban developments) than in more natural rural areas such as preserves. This suburban peak in species numbers
is evident in many taxa, such as mammals (), birds and butterflies (), bumblebees (), ants (), lizards (), and plants ().
An explanation often suggested for this suburban peak (e.g., , , ) is the intermediate disturbance hypothesis. The initial human impacts of suburban sprawl are sometimes relatively mild,
with only a few housing subdivisions in a matrix of largely natural or agricultural habitat. This promotes environmental heterogeneity,
because different habitats occur alongside one another. Such habitat diversity is enhanced by the fact that individual homeowners
often make individualistic choices in the plants that they cultivate ().
In addition to providing spatial heterogeneity, these anthropogenic habitats are typically very productive (), being highly subsidized in scarce resources, ranging from water to nutrients (e.g., fertilizers). Cultivated plants include
many ornamentals that often bear fruits and seeds that are utilized by animals, especially birds and bats (, ). Some animals have adapted to the direct consumption of human resources () that are provided accidentally (garbage) or intentionally (bird food).
In contrast to the above, other studies show that suburban areas have reduced species diversity compared to less-altered rural
habitats . For example,
compilation of 51 bird studies found that 31 of the studies (61%) showed lower species richness in suburban and other areas
of human settlement, compared with more natural rural areas. The remaining 20 studies reported either an increase or no change
in diversity with increasing human settlement. The 51 studies covered a wide range of geographic and natural settings, so
it is difficult to identify which variables determine whether a rise or fall of species richness occurs with increasing settlement
and suburban development.
Teasing apart these variables, such as the role of the natural setting, is clearly a priority for further work on urban–rural
gradients. , for example, has suggested that urbanization in a tropical rain forest may have different effects on local species richness
than urbanization in other natural settings, because rain forest birds have exceptional difficulty adapting to human settlements.
Local extinctions during housing development
Areas of active development tend to have low biodiversity because of the devastating impact on native species of most residential
and commercial development methods. Before construction of most residential and commercial buildings, it is common for developers
to remove most vegetation and even topsoil (). This reduces construction costs by allowing equipment ready access to the construction site.
A study of the fate of natural vegetation during urban development in Wisconsin found that only about one-third of the original
vegetation was not destroyed (). The loss of native vegetation (and total vegetated area) has a negative impact on native animal diversity. Bird species
richness declined dramatically in the early stages of housing construction (compared to preconstruction diversity) in California
() and Poland ().
Once construction is finished, some of the area is paved, which removes it as habitat for nearly all species. In Palo Alto,
California, for example, 25% of the area of residential communities is covered by pavement (); another 20% of the area is covered with housing. Of the remaining nonpaved portions, much is replanted with (usually nonnative)
grasses, shrubs, and trees ().
Conservation strategies
Habitat conservation can utilize preservation and restoration . The most effective (and cheapest in the long term) strategy is to preserve as much remnant natural habitat as possible.
Many studies describe how native species richness in a remnant habitat increases with the area of that habitat. This is true
for many taxa, including birds (), mammals (), and plants ().
One way to preserve remnants in housing developments is to retain predevelopment vegetation. A number of recent books, such
as The Landscaping Revolution (), have pointed out the benefits of retaining preexisting vegetation when building new homes. Unfortunately for conservation
goals, this type of construction is rarely undertaken by most residential real estate developers. Although ostensibly related
to cheaper costs of mass construction, retaining more predevelopment vegetation is less expensive in the long term (Dorney
et al. 1986) and is preferred by many homeowners ().
A major influence on natural remnants is the matrix, or the type of habitat, that surrounds them. Remnants are often embedded
in a highly disturbed matrix that also serves as a continuous source of nonnative species. A major challenge is that remnant
habitats are open to colonization by nonnative species of invasive plants () and predatory animals such as housecats and dogs (). These nonnative invaders and predators can greatly reduce the ability of the remnant habitat to support native species,
especially birds. In the language of population biology, these remnants become population “sinks” that are unable to support
self-sustaining populations of the native species.
Restoration strategies: Succession and cultivation
Conservation strategy can also focus on restoring native species in managed and ruderal habitats. In natural ecosystems, biotic
succession increases the number of plant and animal species after a disturbance (). This is also true of ruderal and managed habitats that remain undisturbed long enough for succession to occur. Various
studies have documented how succession increases species diversity in ruderal and managed communities, for example, increased
plant diversity in urban lots (), increased arthropod diversity in restored communities (), and increased bird species richness in residential communities (, , ). As a consequence, older residential areas (usually nearer the urban core) tend to have higher species richness than younger
ones (e.g., ).
The studies cited above show that the accumulation rate of new species during succession is initially very rapid and is substantially
slower after the first few years and especially after the first decades. Aside from increasing total diversity, ecological
succession also often reduces the diversity of non native species in an area (), many of which rely on disturbance to sustain their populations ().
Another restoration strategy to increase native biodiversity in managed habitats is to cultivate a variety of plant species.
Cultivation with native plant species may benefit not only native plant populations but also native animal populations. For
example, native bird species richness in Australia () and North America () tends to positively correlate with the volume and species diversity of native vegetation. Similarly, the percentage of native
insect species in a fauna has been found to correlate with the percentage of native plant species (). Landscaping golf courses with native plants can benefit many local native bird species ().
Compositional changes along the urban–rural gradient
Species vary in their ability to adapt to the often drastic physical changes along the urban–rural gradient (, ). Although there are probably many ways to categorize these changes in species composition, many bird (e.g., , , ) and mammal (e.g., ) studies have concluded that species along the gradient can be classified, for convenience, into three distinct categories
reflecting their reaction to human activities. Using
terms, these categories are “urban avoiders,” “urban adapters,” and “urban exploiters” . While birds are the best-studied taxa for work on urban–rural gradients, these three categories have also been used for
work on butterflies () and lizards ().
These categories show that, even in highly modified environments, species are nonrandomly assembled in ways that approximate
community assembly processes in nature. Each of these assemblages has a distinctive set of ecological characteristics that
reflect the impacts of urban sprawl on native species. One of the most important traits that separates the three categories
is the extent to which species depend on human-subsidized resources to exist in an area (). As subsidized resources increase toward the urban core, there is a concurrent increase in species that utilize them. Urban
exploiters are generally commensals that are almost entirely dependent on human subsidies (i.e., obligate parasites). Urban
adapters are able to utilize subsidies but are facultative in that they also widely use natural (wild-growing) resources.
Urban avoiders tend to rely only on natural resources ().
Characteristics of urban avoiders, adapters, and exploiters
Because birds, mammals, and, to a lesser extent, plants are the best-studied taxa along urban–rural gradients, they will be
the major focus here. Urban avoiders are species that are very sensitive to human persecution and habitat disturbances. The first species to disappear in the
proximity of humans are usually large mammals, especially predators, because they are actively persecuted, relatively rare,
and have low reproductive rates. Thus, cougars, bison, and elk were among the first to disappear after European settlement
began (). Avian urban avoiders include species adapted to the interior of large, old forests, such as tree-foraging insectivores,
neotropical migrants, and many ground-nesting birds that are very sensitive to the presence of humans and pets (, , , ). Plant species that are very sensitive to human activities would include late-successional (old-growth) and wetland plants
(), the loss of which is attributable to our tendency to clear forests and drain wetlands for agricultural and settlement goals.
Urban adapters are often found in the matrix of human land uses that occur in suburban landscapes. For plants, early successional species
are common in managed suburban habitats, such as residential yards and commercial as well as unmanaged ruderal habitats (e.g.,
undeveloped lots). These early successional plants include both cultivated species favored by humans (e.g., turfgrass, fast-growing
ornamental shrubs, and trees), as well as weedy species that are common in both managed and unmanaged suburban habitats. The
most common weedy species are wind-dispersed lawn weeds (e.g., dandelions, crabgrass) and bird-dispersed invasive shrubs (e.g.,
privet, pokeweed) that commonly grow on cleared, untended landscapes (). Botanically, suburban landscapes are often characterized as structurally approximating sparsely forested savanna or grassland
communities (). This is apparently an aesthetically preferred landscape for most suburbanites ().
Among animals, urban adapters typically include many species often referred to as “edge species,” which are adapted to forest
edges and surrounding open areas (, ). These animals exploit many foods, including human-subsidized foods, such as cultivated plants and garbage. The great abundance
of such subsidized foods is one reason why these animal urban adapters often attain an abundance and biomass that is much
greater than in natural areas (, ). Another reason is that natural predators of these animals are usually eliminated by human activities ().
For birds, urban adapters include a high proportion of certain feeding guilds. These include omnivores and ground foragers,
such as the American robin and many corvids (crows, jays); seedea and aerial sweepers such as swifts
(, , , , ). Each of these three guilds seems to be responding to different aspects of human impacts. The highly productive (i.e., fertilized)
lawn and ornamental plant ecosystem provides a rich source of invertebrate and plant foods () for ground gleaners, while seedeaters favor bird feeding stations and many ornamental plants that produce seeds (). Aerial sweepers take advantage of the many open areas, including pavement, over suburban habitats and the high abundance
of many flying insects, especially those that are attracted to artificial lights. Tree, shrub, and cavity nesters are also
common among urban adapters ().
As most mammals lack the high mobility of flight possessed by birds, life in suburban environments poses different challenges.
Nevertheless, mammalian urban adapters are able to find shelter from intensive human activity as well as exploit rich sources
of food provided by humans (, , ). One group of mammalian adapters finds refuge through their burrowing habits. Groundhogs, cottontail rabbits, moles, and
skunks are examples of successful adaptation to human proximity in suburbia. Trophically, these animals derive much food from
the rich subsidies of suburban lawns, including rapidly growing grasses, ornamental plants, and invertebrates ().
Another group of mammal adapters includes species that require adjacent forest fragments (e.g., in cemeteries and parks) for
shelter (). These species typically forage for human-subsidized food supplies in surrounding areas. Some are medium-sized omnivores
(especially raccoons and opossums) that forage in garbage, vegetable gardens, and other resources provided by humans. Others
are medium-sized carnivores, such as foxes and coyotes, that consume a wide variety of prey. As with birds, elimination of
large predators (in addition to subsidized resources) leads to very high population densities of urban adapter mammal species
Urban exploiters, often called synanthropes (e.g., , , ), are very (often totally) dependent on human resources. The abundance of urban exploiters is usually not dependent upon
the amount or types of vegetation (, , , ). The combination of predator release (predator removal, such as the extermination of wolves and cougars) with abundant food
subsidies allows them to attain enormous population densities (, ).
Urban exploiters probably represent the most homogenized of the world's biotas (). Unlike urban adapters, which are largely composed of early successional species from nearby ecosystems, urban exploiters
are composed of a very small subset of the world' these exploiters are well adapted to intensely modified urban
environments wherever humans construct them across the planet (, , ).
Urban environments typically have more in common with other cities than with adjacent natural ecosystems (), so urban exploiters are often not native to a region (, , ), but tend to leapfrog from city to city. Thus, rock doves, starlings, house sparrows, Norway rats, and the house mouse are
found in all cities in Europe () and North America (). This is also true for urban plants ().
Among plants, urban exploiters tend to be ruderal species that can tolerate high levels of disturbance, especially grasses
and annuals (see reviews in , , ). Examples include wind-dispersed weeds that colonize abandoned industrial and commercial properties and plants that can
grow in and around pavement. Adaptive traits that are typical of urban-exploiting plants include tolerance to high levels
of air pollution (especially smog and acidic fog); and alkaline, compacted, and nitrogenous soils.
Avian urban exploiters are often species evolutionarily adapted to cliff-like rocky areas and therefore are preadapted to
the devegetated concrete edifices of very urbanized areas (, ). Common examples include the rock dove and peregrine falcon. Another group of avian exploiters consists of cavity-nesting
species that are able to inhabit human dwellings. Examples include the house sparrow, house finch, and European starling.
Trophically, avian urban exploiters tend to be ground-foraging seedeaters or omnivores (, ).
Mammalian urban exploiters find shelter in human dwellings and exploit the rich food sources in or near them. Trophically,
they are usually omnivorous () and include such familiar species as the house mouse, black or brown rat, and insects, including a variety of cockroach
Increasing nonnative species toward the city.
Many studies have found that the number (and proportion) of nonnative species tends to increase along the urban–rural gradient,
moving toward the urban center. In general, the proportion of species that is nonnative goes from less than a few percent
in rural areas to over 50% at the urban core. These changing proportions apply to plants in the United States () and Europe () and birds in the United States (). The population density of nonnative species—both mammals () and birds ()—also tends to increase the nearer they are to the urban core.
The increase in nonnative species toward the urban core reflects a number of human causes. One is that higher human population
densities nearer the urban core produce increasing importation (“propagule pressure”) of nonnative species, for example, the
cultivation of nonnative plants (, ). Another cause is the increasing amount of “disturbed” habitat toward the urban core, which provides opportunities for nonnative
species of plants (, ) and animals (, ) that can utilize the new resources.
Conservation implications of compositional changes
In their book Urban Nature Conservation,
note that, as highly urbanized areas are generally occupied by species that thrive in the presence of humans, there will
be relatively few rare native species of conservation concern in areas of high human population density. They review some
examples, however, of rare species of insects and plants found in hi habitat conservation and restoration
could be planned for sites that harbor such species. Not surprisingly, most rare species in urbanized areas are found sites
that have escaped high-intensity development (). Sites where rare species most commonly occur include city parks, cemeteries, railroad trackways, vegetated areas under
transmission lines, and other public rights-of-way that are protected from development (, ).
Aside from the conservation of rare native species, knowledge of the species composition of urban biodiversity can be very
useful as an educational tool to better understand the natural world. An enhanced appreciation of nature by the 80% of the
American public that lives in this environment could promote more effective political and economic action. Examples of such
knowledge include better education of the public in the natural history of local species and problems with nonnative species
Conclusions
Urbanization is a rapidly growing cause of many environmental problems (). The impact of urbanization is documented in the growing literature on the urban–rural gradient. These studies show consistent
changes in species richness and species composition along the gradient.
Species richness of many taxa often declines along the gradient, with the lowest richness to be found in the urban core. Urban
planners should find ways to preserve biodiversity as cities expand outward and subsequently modify natural habitat. Such
efforts would most likely focus on preserving as much remnant natural habitat as possible, as opposed to most current land
development techniques, which remove most natural vegetation during construction.
Where intensive land development has already occurred, native animal biodiversity can be increased by revegetation with a
diversity of native plant species. Protecting this revegetated habitat from disturbance to allow ecological succession will
not only enhance plant and animal diversity but also tend to reduce the diversity of nonnative species. Unfortunately, most
current landscaping tends to revegetate with nonnative plant species in unnatural spatial distributions (, ) and arrests succession through the management of those ecosystems (at
Species composition also shows pronounced changes along the urban–rural gradient. Most notable is that nonnative species become
proportionately more common toward the urban core. Urban avoiders include native species such as large predators and forest-interior
(especially insectivorous) birds that disappear quickly in the initial stages of suburban encroachment, unless special effort
is made to retain large tracts of native habitat and reduce human persecution of species.
Urban adapters, mammals and birds that are mainly adapted to forest edges and open areas, flourish in suburban habitats, especially
older subdivisions where ecological succession has advanced and produced extensive revegetation. Urban adapters are very important
for biodiversity education, because half of the American public lives in a suburban environment (). Public biodiversity education would be most effective if we draw on these familiar suburban community assemblages and species
to promote an understanding of concepts such as ecological succession and the role of native plants in promoting native animal
diversity. Because of its enormous size, wealth, and political influence, a more ecologically informed suburban population
could greatly improve the social support for conservation of native species in all ecosystems.
References cited
. . Urban high school students' knowledge of wildlife. Pages. 83-86. in Adams
DL, eds. Integrating Man and Nature in the Metropolitan Environment. Columbia (MD): National Institute for Urban Wildlife.
. . Urban Wildlife Habitats. Minneapolis: University of Minnesota Press.
Beissinger
. . Effects of urbanization on avian community organization. Condor. 84: 75-83.
. . Occupation of Urban Habitats by Birds in Papua New Guinea. Los Angeles: Western Foundation of Vertebrate Zoology.
. . Once There Were Greenfields. New York: National Resource Defense Council.
. . Birds and butterflies along urban gradients in two ecoregions of the U.S. Pages. 33-56. in Lockwood
ML, eds. Biotic Homogenization. Norwell (MA): Kluwer.
. . Butterfly diversity and human land use: Species assemblages along an urban gradient. Biological Conservation. 80: 113-125.
. . Human perception and appreciation of birds: A motivation for wildlife conservation in urban environments of France. Pages. 69-86. in Marzluff
R, eds. Avian Ecology in an Urbanizing World. Norwell (MA): Kluwer.
. . A new urban ecology. American Scientist. 88: 416-425.
. . Does native invertebrate diversity reflect native plant diversity? A case study from New Zealand and implications for conservation. Biological Conservation. 83: 209-220.
. . Mesopredator release and avifaunal extinctions in a fragmented system. Letters to Nature. 563-566.
. . Lots of weeds: Insular phytogeography of vacant urban lots. Journal of Biogeography. 6: 169-181.
. . Economic associations among causes of species endangerment in the United States. BioScience. 50: 593-601.
. . Species density in relation to urban open space. Land Contamination and Reclamation. 3: 114-116.
. . Insect communities on experimental mugwort plots along an urban gradient. Oecologia. 113: 269-277.
. . Habitat fragmentation and vertebrate species richness in an urban environment. Journal of Applied Ecology. 24: 337-351.
Guntenspergen
. . Composition and structure of an urban woody plant community. Urban Ecology. 8: 69-90.
. . Energetics of a suburban lawn ecosystem. Ecology. 57: 141-150.
. . Predation on artificial bird nests along an urban gradient: Predation risk or relaxation in urban environments. Ecography. 22: 532-541.
. . Lizard species distributors and habitat occupation along an urban gradient in Tucson, Arizona, USA. Biological Conservation. 97: 229-237.
. . Eighteen years of herbaceous layer recovery of a recreation area in a mesic forest. Journal of the Torrey Botanical Society. 127: 230-239.
. . The Ecology of Urban Habitats. London: Chapman and Hall.
. . Temporal analysis of the Brussels flora as indicator for changing environmental quality. Landscape and Urban Planning. 52: 203-224.
. . Breeding birds and vegetation: A quantitative assessment. Urban Ecology. 9: 377-385.
. . Residential lawn alternatives: A study of their distribution, form and structure. Landscape and Urban Planning. 42: 135-145.
. . Synanthropic birds of North America. Pages. 49-67. in Marzluff
R, eds. Avian Ecology in an Urbanizing World. Norwell (MA): Kluwer.
. . The Value of Life. Washington (DC): Island Press.
. . Urban Nature Conservation. London: Chapman and Hall.
. . On the role of alien species in urban flora and vegetation. Pages. 85-103. in Pysek
PM, eds. Plant Invasions—General Aspects and Special Problems. Amsterdam (Netherlands): SPB Academic.
. . Bird communities and the structure of urban habitats. Canadian Journal of Zoology. 57: 2358-2368.
. . Conservation in the context of non-indigenous species. Pages. 107-116. in Schwarz
MW, ed. Conservation in Highly Fragmented Landscapes. London: Chapman and Hall.
. . The development of bird communities in new housing estates in Warsaw. Memorabilia Zoologica. 49: 257-267.
Mackin-Rogalska
. . Changes in vegetation, avifauna, and small mammals in a suburban habitat. Polish Ecological Studies. 14: 293-330.
. . Early fall urban bird communities of Hobart, Tasmania. Yamashina Institute of Ornithology. 22: 56-69.
. . Invertebrates assist the restoration process: An Australian perspective. Pages. 212-237. in Urbanska
PJ, eds. Restoration Ecology and Sustainable Development. Cambridge (United Kingdom): Cambridge University Press.
. . Worldwide urbanization and its effects on birds. Pages. 19-47. in Marzluff
R eds. Avian Ecology in an Urbanizing World. Norwell (MA): Kluwer.
. . Mammals in forest islands in southeastern Wisconsin. Pages. 55-66. in Burgess
DM, eds. Forest Island Dynamics in Man-Dominated Landscapes. New York: Springer-Verlag.
. . Ecology of urban arthropods: A review and a call to action. Annals of the Entomological Society of America. 93: 825-835.
. . Forest-landscape structure along an urban-to-rural gradient. Professional Geographer. 47: 159-168.
. . A roll call analysis of the Endangered Species Act amendments. American Journal of Agricultural Economics. 83: 501-512.
[MDC] Missouri Department of Conservation
. . Landscaping for backyard wildlife. (3 September 2002; ).
Munyenyembe
. . Determinants of bird populations in an urban area. Australian Journal of Ecology. 14: 549-557.
. . Analysis of small mammal community data and applications to management of urban greenscapes. Proceedings of the National Symposium on Urban Wildlife. 2: 53-59.
. . An ecological survey of ants in a landscaped suburban habitat. American Midland Naturalist. 102: 353-362.
Pawlikowski
Pokorniecka
. . Observations on the structure of bumblebee communities of the town-forest areas in Torun Basin, North Poland. Acta Universitatis Nicolai Copernici Biologia. 37: 3-22.
. . Urban ecological systems: Linking terrestrial, ecological, physical, and socioeconomic components of metropolitan areas. Annual Review of Ecology and Systematics. 32: 127-157.
. . Small mammal and habitat response to shoreline cottage development in central Ontario, Canada. Canadian Journal of Zoology. 60: 865-880.
. . Correlation between birds and vegetation in Cheyenne, Wyoming. Pages. 75-80. in Adam
KL, eds. Wildlife Conservation in Metropolitan Environments. Columbia (MD): National Institute for Urban Wildlife.
. . Fate of natural vegetation during urban development of rural landscapes in southeastern Wisconsin. Urban Ecology. 9: 267-287.
. . Dominant patterns in bird populations of the eastern deciduous forest birds. Proceedings of the Symposium on Management of Forest and Range Habitats for Nongame Birds. 2: 90-95.
. . Precious Heritage. Oxford (United Kingdom): Oxford University Press.
. . Nature in Cities. Strasbourg (France): Council of Europe.
. . Natural links: Naturalistic golf courses as wildlife habitat. Landscape and Urban Planning. 38: 183-197.
. . Characteristics of urban woodlands affecting breeding bird diversity and abundance. Landscape and Urban Planning. 14: 481-495.
[USCB] US Census Bureau
. . Statistical Abstract of the United States. Washington (DC): Government Printing Office.
. . Suburban bird populations in west-central California. Journal of Biogeography. 3: 157-165.
. . Habitat association of mammals in Syracuse, New York. Urban Ecology. 9: 413-434.
. . The Landscaping Revolution. The Landscaping Revolution: Contemporary Books.
Klimiewica
. . Pages. 125-206. in Burgess
DM, eds. Forest Island Dynamics in Man-Dominated Landscapes. New York: Springer-Verlag.
. . A quantitative analysis of the flora and plant communities of a representative midwestern U.S. town. Urban Ecology. 9: 143-160.
BioScience
10.68(3:UBAC]2.0.CO;2
>> Full Text (HTML)Free
No responses published
The Journal
Published on behalf of
Impact Factor: 4.294
5-Yr impact factor: 6.607
Interim Editor in Chief
Scott Collins
Senior Editor
James Verdier
For Authors
Looking for jobs...
Corporate Services
Alerting Services
Most Cited
Other Oxford University Press sites:
Oxford University Press
Oxford Journals China
Oxford Journals Japan
Academic & Professional books
Children's & Schools Books
Dictionaries & Reference
Dictionary of National Biography
Digital Reference
English Language Teaching
Higher Education Textbooks
International Education Unit
Online Products & Publishing
Oxford Bibliographies Online
Oxford Dictionaries Online
Oxford English Dictionary
Oxford Language Dictionaries Online
Oxford Scholarship Online
Rights and Permissions
Resources for Retailers & Wholesalers
Resources for the Healthcare Industry
Very Short Introductions
World's Classics