Effects of dog leash laws and habitat type on avian and small mammal communities in urban parks

Remnant natural areas within urban settings can act as important refuges for wildlife, substantially increasing local biodiversity. However, habitat suitability for these species is potentially affected by human recreational activities including the presence of free-running dogs. To compare the diversity and abundance of songbird and small mammal communities between areas with bylaws that require, or do not require, dogs to be leashed, point counts and live-trapping surveys were conducted in three habitat types (deciduous, coniferous, and meadow) in the river valley parks of Edmonton, Alberta. Among birds, there was no difference between areas with different leashing bylaws in species diversity for any of the three habitat types. Similarly, there was no difference in bird diversity for a subset of species that were plausibly breeding at these sites. However, higher bird diversity was recorded in deciduous and coniferous sites than in meadow sites, regardless of leash designation, probably as a function of the horticultural practice of mowing meadows. Among both birds and small mammals, there was no difference in the abundance of individuals as a function of leashing bylaws. Our results suggest that off-leash dogs have no effect on the diversity or abundance of birds and small mammals in urban parks, but it is also possible that other factors, such as leash law compliance, reduced or obscured the effects of off-leash dogs in this study.     

Animal behavior in urban ecosystems: Modifications due to human-induced stress

Wildlife-human interactions are increasing in prevalence as urban sprawl continues to encroach into rural areas. Once considered to be unsuitable habitat for most wildlife species, urban/suburban areas now host an array of wildlife populations, many of which were previously restricted to rural or pristine habitats. The presence of some wildlife species in close proximity to dense human populations can create conflict, forcing resource managers to address issues relating to urban wildlife. However, evidence suggests that wildlife residing in urban areas may not exhibit the same life history traits as their rural counterparts because of adaptation to human-induced stresses. This creates difficulty for biologists or managers that must address problems associated with urban wildlife. Population control or mitigation efforts aimed at urban wildlife require detailed knowledge of the habits of wildlife populations in urban areas. This paper describes the history of wildlife in urban areas, provides examples of wildlife populations that have modified their behavior as an adaptation to urban stresses, and discusses the challenges that resource managers face when dealing with urban wildlife.     

Assessing the effect of developed habitat on waterbird behaviour in an urban riparian system in Ottawa,Canada

Waterbird species were used to assess the consequences of developed habitat on wildlife behaviour in an urban riparian system along the Rideau River in Ottawa, Canada. Fourteen developed sites and 14 undeveloped sites were surveyed from October 2004 to February 2005. Each site was approached on foot and the first observed behaviour (i.e., fleeing, foraging, resting or swimming) of each individual was recorded. A total of 10,604 behavioural observations were made across 12 taxa. Overall, the fleeing behaviour was observed more often at undeveloped sites. Foraging, resting and swimming behaviours were observed more often at developed sites. We found that seven species fled more often at undeveloped sites, including hooded merganser. This species was also more abundant at undeveloped sites, suggesting that hooded merganser may be more sensitive to anthropogenic disturbance in urban environments than other species that are habituated toward humans. For sensitive species, undeveloped shoreline may serve as a refuge from human disturbance in urban ecosystems.     

Exotic plant invasions in forested wetlands: effects of adjacent urban land use type

There are a variety of land use types in urbanized areas that may have different effects on the ecological characteristics of patches of natural vegetation. In particular, residential housing and industrial land-use may have different effects on adjacent forest communities. We tested this hypothesis by examining the vegetation of forested wetlands in a densely urban region, northeastern New Jersey. Wetlands embedded in industrial areas were much less invaded by exotic plant species than were wetlands embedded in residential areas, as reflected in the number of exotic species, the fraction of the total flora that was exotic, and their frequencies of occurrence. Few other structural characteristics of the vegetation differed between the two types of urban areas. We suggest that the management of land adjacent to forest edges may explain this surprising result. The low rate of invasion of wetlands within industrial areas suggests they could have high conservation value in urban ecosystems.     

Developing habitat models for waterbirds in urban wetlands: a log-linear approach

Up to 95% of wetlands in southwestern Ontario, Canada, have been drained and converted to other land uses since the mid-1800s. Remaining wetlands now exist within a mosaic of urban and agriculture land cover and may resemble “islands” from the point of view of species that need this habitat. We investigated the relationships between waterbirds and wetland size, isolation, and adjacent forest cover and roads in 19 wetlands within and adjacent to London, Ontario. Waterbirds were grouped into resource-based guilds: Dabblers, Divers, Waders, and Gulls and Terns (because of small samples, the Passerine and Raptor guilds were dropped from the statistical analyses). Because of the high degree of multicollinearity between variables, we used log-linear analysis to develop models that explained variations in species richness in the waterbird guilds. The log-linear technique provided quantification of environmental effects in a richer way than previous research as the interplay between biophysical factors found in reality are partially captured by the inclusion of interaction in the habitat models. All of the models incorporated the biophysical variables of wetland size and adjacent wetland area, forest cover, and roads. Waterbirds in these urban and near-urban landscapes appear to be using all wetlands available to them, no matter how small or how disjunct the wetland. This has implications for wetland evaluations that may not rate wetlands in human-dominated landscapes highly enough to be protected from development.     

The behavioral response of emerging pine snakes (<Emphasis Type="Italic">Pituophis melanoleucus</Emphasis>) to people: implications for survival and protection

Considerable attention has been devoted to the effects of people on birds and mammals, usually in wilderness areas. In contrast, human disturbance of reptiles has largely been ignored. Many reptiles, such as snakes, are hard to conserve because they are difficult to locate and protect. The young are especially vulnerable to predators when they first hatch and must emerge from nest sites. In this paper, the response of pine snake (Pituophis melanoleucus) hatchlings to the presence and handling by people was observed in the laboratory and in the field. Pine snakes lay their eggs in underground burrows in open sandy pine barrens, and the hatchlings push their way to the surface to emerge. Hatchlings that were visually-disturbed or touched as they emerged returned immediately to their tunnels and nests, and required more time to re-emerge than did their siblings that were not visually-disturbed or touched during their initial disturbance. In nature, undisturbed pine snakes showed similar re-emergence times to those from the laboratory, and disturbed snakes required longer to re-emerge. These data suggest that in nature even the presence of people in nesting areas of pine snakes would lengthen the time the young are in burrows, exposing them to additional threats from predators. This suggests that parks or nature reserves with vulnerable snake populations should restrict human disturbance during the period when young snakes are emerging from their nests. Field observations indicate that a set-back distance of more than 12 m from known nesting areas is essential to protect emerging hatchlings.     

Nesting ecology of mourning doves in an urban landscape

The expansion of urban areas into native habitat can have profound effects on avian populations and communities, yet little is known regarding the effects of urban features on avian reproductive success. The objective of this study was to examine the reproduction of an urban-enhanced species, the mourning dove, to determine how tree and urban landscape features affect nest-site selection and nest success. Mourning dove nests were located by systematically searching potential nest sites on a weekly basis from late-March through mid-September in 2003 and 2004. A total of 1,288 mourning dove nests were located and monitored on the Texas A&M University Campus. Of these nests, 337 (26.6%) were successful (fledged, ≥1). An equal number of potential nest sites were randomly generated in ArcGIS and assigned to non-nest trees to evaluate habitat variables associated with nest-site selection. Mourning dove nests were located in trees with a larger canopy diameter and diameter at breast height (DBH) than the computer generated potential nests and nest trees were located closer to roads and farther from buildings than non-nest trees. Within the study area, nest success was predominately influenced by the proximity of urban features with successful nests being located closer to roads and farther from buildings than unsuccessful nests.     

Five new towns in the Seoul metropolitan area and their attractions in non-working trips: Implications on self-containment of new towns

In the late 1980s, the Korean government initiated the “Two Million Home Construction Plan” to tackle severe shortages in housing and soaring housing prices. Five new towns (Bundang, Ilsan, Pyeongchon, Sanbon, and Joongdong) were planned around the city of Seoul. By the mid-1990s the residential areas in the five new towns were mostly developed. However, their commercial areas have remained underdeveloped and as a consequence, the new towns are believed to have become bedroom communities.This paper assesses self-containment status of the new towns by analyzing non-working trip patterns in the five new town areas. A survey conducted on non-working trip patterns of the residents in the five new towns and the nearby areas (to shop for groceries, clothing, electronics/jewelry, leisure/entertainment, and to access medical services) reveals that Bundang's commercial dependency upon the city of Seoul has been reduced significantly over the past 5 years (from 1995 to 2000). The survey results on non-working trip patterns of the residents in the five new towns and nearby residential areas in the Seoul Metropolitan Area indicate that the five new towns have been growing as suburban centers in the region in terms of retail attractions, even though they are still maintaining a high dependency on Seoul in terms of working commutes.These observations provide some new indications about self-containment arguments relevant to new town planning. The new towns are currently maintaining a decent degree of self-containment in terms of non-working trip, which has been an important aspect absent in self-containment arguments. In addition, the appeal of self-containment in non-working activities is growing in a dynamic sense. Observations on the dynamic process of the new town developments in Korea demonstrate that the self-containment can be established but through a long taking cumulative and stepwise process rather than immediately by planning.     

Examination of the relationship between urban form and urban eco-efficiency in china

The present study aims at exploring whether aspects of urban form are associated with urban eco-efficiency in China. Quantitative indicators relating to urban form (form, compactness ratio, elongation ratio and population density) and urban eco-efficiency (resource efficiency, environmental efficiency and overall eco-efficiency) were selected and quantified using remote sensing and data envelopment analysis methods. The urban form aspects of form and compactness ratios were positively correlated with urban eco-efficiency and resource efficiency. Conversely, the urban elongation ratio exhibited negative correlations with urban eco-efficiency and resource efficiency. Regarding environmental efficiency, no significant correlation is found with compactness though a negative correlation is found with population density. These results indicate that, within China, designing cities to be compact may be lead to increases in eco-efficiency and resource efficiency, but if the population density is too high the increased pollution costs will result in a decrease in environmental efficiency.     

Urban cultivation in Accra: an examination of the nature, practices, problems, potentials and urban planning implications

The literature on urban farming in Sub-Saharan African cities reveals that most studies have been conducted in Eastern, Southern and Central African cities. A few have focused on West Africa, including Sierra Leone, Guinea Bissau, and Cameroon. In Ghana there is a paucity of information on urban farming. The purpose of this paper is to examine the status of urban cultivation in Accra, Ghana's capital, reviewing existing research, and to present new empirical findings on urban cultivation emphasizing on its history, nature, practices, problems, potentials and urban planning implications.     

Changing American home life: trends in domestic leisure and storage among middle-class families

This study of middle-class American families draws on ethnography and urban economic history, focusing on patterns of leisure time and household consumption and clutter. We trace how residential life evolved historically from cramped urban quarters into contemporary middle-class residences and examine how busy working families use house spaces. Our ethnographic sample consists of 24 Los Angeles families in which both parents work full time, have young children, and own their homes. Formal datasets include systematically timed family uses of home spaces, a large digital archive of photographs, and family-narrated video home tours. This analysis highlights a salient home-storage crisis, a marked shift in the uses of yards and garages, and the dissolution of outdoor leisure for busy working parents. The UCLA Center on Everyday Lives of Families (CELF) is generously supported by the Alfred P. Sloan Foundation program on the Workplace, Workforce, and Working Families. Anthony Graesch assisted with the tables. Additional information about CELF can be found at www.celf.ucla.edu.     

生态湿地在改善盐碱土壤及景观中的应用

一、总论 湿地是指一年中至少有部分时间为潮湿或水涝的地区,如沼泽、沼地、泥炭地和沼泽群落。它与人类生存、繁衍、发展息息相关,是自然界最富生物多样性的生态景观和人类最重要的生存环境之一,与农业、海洋并称全球三大生态系统。湿地具有丰富的资源,以及巨大的环境调节功能和生态、社会、经济效益。     

Managing urban growth and development in the Riyadh metropolitan area, Saudi Arabia

The paper examines public sector management of urban growth and development in the Riyadh Metropolitan Area, Saudi Arabia. The focus of the paper is on institutional capacity building and development intervention. The paper traces changes in public sector management structures and development activities over the history of the city with the aim of assessing development impact and identifying forces that have shaped the evolving state of urban management. The paper notes that urban management has significantly improved with time but the persistence of urban problems coupled with projections of future growth point to the need for further improvements. The paper, in conclusion, while acknowledging the utility of the metropolitan development strategy (MEDSTAR) being formulated for the city, points to the need for broader administrative reform to improve the ability to cope with long-term challenges of growth in the city. Some issues that reform could address are suggested.     

Techniques of neutralising wildlife crime in rural England and Wales

Within rural studies there have been few attempts to critically analyse crimes against nature. This paper addresses this gap by providing an analysis of farmers’ reasons for illegally culling badgers in the United Kingdom. Drawing on Sykes and Matza’s (1957) concepts of neutralisation and drift, the paper shows how farmers rationalise this activity. Using in-depth interviews with 61 farmers in the England and Wales, the paper shows how they justify badger culling through discursive strategies that claim the activity is necessary, deny the necessity of the law, condemning the condemners, and appealing to community loyalties The paper also shows that neutralisation helps identify contextual factors that allow farmers to drift ambiguously between deviant values and social norms. In the case of badger culling, drift is attributable to an attack on a particular rural identity and way of living that has left farmers perceiving their selves as an effect. As much as they are attempts to rationalise criminal behaviour, neutralisation techniques can also be seen as spatial discourses demarcating the boundaries of cultural and spatial identities. In conclusion, the paper discusses the implications for resolving the problems of wildlife crime.     

Amphibian use of constructed and remnant wetlands in an urban landscape

Urban areas are increasing in number, extent, and human population density worldwide. There is potential to mitigate negative impacts of urbanization to native pond-breeding amphibians by providing habitat in both remnant natural and constructed wetlands. This study examines amphibian use of potential breeding sites in natural and constructed ponds in a large metropolitan area to investigate habitat characteristics that are associated with successful breeding. I surveyed 62 ponds over three breeding seasons in Portland, Oregon, measuring eleven habitat characteristics that may influence their successful breeding: pond depth, nitrate level, aquatic refugia, aquatic vegetation, surrounding vegetation, pond permanence, presence of fish and of introduced bullfrogs, surrounding road density and forest cover, and whether they were constructed or remnant natural ponds. Five of the six native pond-breeding species that occur in the region were regularly found breeding in city ponds. Surrounding forest cover and amount of aquatic vegetation were highly associated with breeding, indicating that preserving and planting vegetation likely benefits urban amphibians. Non-native bullfrogs were not associated with native species richness. Surprisingly, whether a pond was natural or constructed was also only weakly associated with native species breeding, and the trend was towards higher presence for all species in constructed ponds. This indicates that novel, human-dominated areas can provide habitat for these species. Consideration of habitat characteristics associated with breeding success in urban pond management will likely benefit native amphibians in these rapidly expanding landscapes.     

The importance of habitat design and aquatic connectivity in amphibian use of urban stormwater retention ponds

Stormwater retention ponds in urbanizing catchments are constructed to collect and treat runoff from impervious surfaces. Amphibians often inhabit retention ponds, which may partly offset the loss of natural wetlands resulting from urbanization. We investigated the use of retention ponds by frogs in a rapidly-urbanizing region of south-eastern Australia to (1) determine the habitat attributes associated with individual species, and (2) recommend specific wetland design criteria to enhance populations of frog species in the region and in other urbanizing areas throughout their distribution. We detected nine species of frogs during calling surveys at 30 retention pond sites in Greater Melbourne, 2008?C2010. There were contrasting differences in habitat associations among five species for which we produced regression models of abundance or occurrence. The mean abundance of Crinia signifera increased with site area, whereas Limnodynastes dumerilii was associated with smaller sites. The occurrence of L. dumerilii was positively associated with waterbody shore depth, whereas L. peronii and L. tasmaniensis were associated with shallow shores. Two species were positively associated with time since construction or since dredging of a site, whereas the occurrence of L. dumerilii decreased with site age. Aquatic vegetation at a site was important for the occurrence of L. peronii and Litoria ewingii. There was evidence for a positive effect of aquatic connectivity on the occurrence of Limnodynastes peronii, which emphasizes the importance of riparian corridors in urban settings. These results highlight the contrasting differences in habitat associations among species in the region. We recommend that retention ponds in our region and elsewhere be constructed or enhanced to include specific habitat attributes that were found to be associated with different amphibian species. We recommend long-term monitoring at sites to determine whether retention ponds augment existing frog populations or contribute to declines.     

Assessing the abundance of freshwater turtles in an Australian urban landscape

Although interest in the ecological impacts of urbanisation has increased, very little is known about its impacts on freshwater turtles in Australia. This study investigated the abundance and diversity of turtles in lakes in an urbanised subtropical landscape, Brisbane, Australia. It was found that turtles were abundant throughout the lakes surveyed, with four native species and one introduced species being detected. A total of 371 individuals were captured, 77.7% of which were Brisbane River turtle (Emydura macquarii signata). The lakes surveyed were estimated to support a population of 63–269 individuals for all species combined with most lake populations containing less than 100. Turtle demographics may be classed into three stages of population growth: recovery or nascent; intermediate; and climax. Turtle reproductive success is a major concern for the survival of turtles in urban areas. Continued monitoring is needed to establish if population declines are occurring. This study suggests that while turtles are persisting in this urban environment of Australia the pressures of urbanisation, such as habitat loss, increased predation on both nests and juveniles and pollution of waterways may pose on-going risks to their survival.     

Urbanization impacts on the structure and function of forested wetlands

The exponential increase in population has fueled a significant demographic shift: 60% of the Earth's population will live in urban areas by 2030. While this population growth is significant in its magnitude, the ecological footprint of natural resource consumption and use required to sustain urban populations is even greater. The land use and cover changes accompanying urbanization (increasing human habitation coupled with resource consumption and extensive landscape modification) impacts natural ecosystems at multiple spatial scales. Because they generally occupy lower landscape positions and are linked to other ecosystems through hydrologic connections, the cascading effects of habitat alteration on watershed hydrology and nutrient cycling are particularly detrimental to wetland ecosystems. I reviewed literature relevant to these effects of urbanization on the structure and function of forested wetlands. Hydrologic changes caused by habitat fragmentation generally reduce species richness and abundance of plants, macroinvertebrates, amphibians, and birds with greater numbers of invasives and exotics. Reduction in soil saturation and lowered water tables result in greater nitrogen mineralization and nitrification in urban wetlands with higher probability of NO^– ₃ export from the watershed. Depressional forested wetlands in urban areas can function as important sinks for sediments, nutrients, and metals. As urban ecosystems become the predominant human condition, there is a critical need for data specific to urban forested wetlands in order to better understand the role of these ecosystems on the landscape.     

Variability of water quality,metals and phytoplankton community structure in urban stormwater ponds along a vegetation gradient

Stormwater Ponds (SPs) are common throughout urbanizing environments, yet their ecological role has not been well established. SPs are primarily designed for hydrological control of stormwater, but many are also designed to attenuate the quality of runoff prior to discharge. Thus, SPs likely serve as an important land-water linkage between terrestrial and aquatic systems in urban areas. In this study, we characterized 22 SPs and 3 natural reference ponds from Durham Region, Ontario, Canada representing a gradient in emergent plant cover. There was high variability and wide ranges in water quality parameters among SPs. The percentage of impervious surface served as a measure of urbanization intensity, and was a significant driver of conductivity, chloride and total suspended solids regardless of emergent vegetation cover. In fact, only water temperature (r?=??0.61) was found to significantly correlate with vegetation cover. This suggests a minimal role for emergent vegetation in mediating SP water quality. SPs had notably higher conductivity and runoff-metals (Cu, Zn, Pb, and Cr) than reference ponds, but nutrients (Total P and Total N) and algal biomass did not significantly differ between SPs and reference ponds. Dominant phytoplankton groups included blue-green and euglenid algae, both of which are indicators of eutrophic and high organic systems, respectively. The blue-green genus Microcystis was detected in all ponds, and was the dominant taxon in most SPs. This raises concern that SPs may serve as reservoirs of toxin-producing algae. Multivariate analyses of metals, water quality variables and algal species composition showed considerable dissimilarity among SPs, yet comparably high similarity among reference ponds. This indicates that SPs are dynamic and diverse systems despite their engineered origins. Such broad gradients in water quality characteristics also imply variable impacts to receiving waters in the same region.     

The changing morphology of the gulf cities in the age of globalisation: the case of Bahrain

Cities in the Gulf region have been witnessing dramatic changes in their morphology and internal structures during the last three decades due to the successive shifts from endogenous to exogenous types of urban growth. In the past, the urban space was mainly shaped by the tribal structure and the economy of subsistence that is based on fishing, pearl trading and/or farming. After the discovery of oil, a first shift towards an exogenous form occurred. Due to the accumulation of wealth, the kingdom adopted a distributive and comprehensive welfare policy, and became a major and unique actor in shaping the city. At present, a second stage of “exogeneity” is occurring due to globalisation. The installation of large multi-national companies, the liberalisation of the economy and the integration with the world banking system are having a direct impact on the socio-economic, cultural and thus, urban morphology. Bahrain seems to reflect the three stages through the changing urban morphology of its two main cities; Muharraq and Manama. Analysed in the light of the endogenous–exogenous model, it opens a debate on the conditions for the survival of the old cities and defines a theoretical framework for the approach to management and planning to be adopted.