Value of an urban habitat for the native Mediterranean avifauna

Mediterranean landscapes resulted from complex land uses that produced a mosaic of extensive crops, grasslands, scrublands and scattered woodlands. During the twentieth century the decrease in traditional agriculture triggered a decrease in open habitats and an increase in forests. In the meantime urban centres grew dramatically. Both spread of forest and urban areas have been suspected to participate in the decline of typical Mediterranean bird species and, in general, to cause faunal loss. However, modern cities offer a variety of landscape types and, in the Mediterranean, their value for native bird species has been little assessed. We compared the bird communities from an urban landscape, including built up and natural or semi natural units within the limits of the city of Montpellier, to the bird communities from non-urban habitats (cropland, grassland and woodland) located nearby but away from direct urban influence. Fifty four percent of the bird species recorded in the non-urban habitats also occurred in the urban landscape. On average, estimated species richness in the urban landscape was similar to values obtained for non-urban habitats. Within the urban landscape species richness was lowest in the dense historical centre and highest in the residential areas. The residential areas and urban woods were suitable habitats for most generalist species but also for several more specialized species recorded in the non-urban habitats. Some species actually reached their highest observation frequency in the urban landscape. Urban landscape was least favourable to the same farmland and open-habitat specialists that have been negatively affected by agricultural abandonment in the region. Finally, five of the species common in the urban landscape had an unfavorable conservation status in 2004 in the EU. This study emphasizes that Mediterranean urban areas have the potential to host a diverse native bird community. Finding ways to improve their carrying capacity for the local avifauna might be a worthwhile objective for animal conservation.     

The pattern of distribution and diversity of avifauna over an urbanizing tropical landscape

An investigation was done to determine the occurrence and composition of avian fauna community in the urbanizing city of Nairobi, Kenya. We conducted bird counts in sample sites randomly distributed over the Nairobi landscape within a two-year period. The proportion of seven different land cover types derived from within a 500 m radius of classified satellite image described the habitat condition of each sample site. Multivariate analysis of the site and species data indicated that savannah vegetation, forest and agriculture land cover types were the main environmental gradients that differentiated the sample sites. Four clusters of sample sites occurred on the ordination plane according to canonical correspondence analysis (CCA). From 50 families of birds observed, species related to bush and scrub habitats occurred at a rate of about 31 %, followed by grassland species at 20 % and forest species at about 16 % rate. Out of CCA, five functional groups of birds were distinguishable. The proportion of sites occupied by birds per functional group and mean count of individual birds declined significantly, p?<?0.0001, as groups of birds changed from being urban-related to savannah and then to forest-related species. One cluster comprised birds marked as having conservation concern status and related mainly to savannah vegetation of scrub and grasslands. In this landscape context, features such as native savannah vegetation and woodland accompanied by a process of controlled land use, could greatly mitigate negative impacts of ecosystem degradation on the sensitive tropical urban bird biodiversity.     

Human mobility in functional urban regions: understanding the diversity of mobilities

This paper brings together three contrasting strands of conceptualization relating to human mobility in metropolitan regions. First, the well-established literature on functional urban regions which focuses above all on the role of journey to work in defining these, and on patterns of relative population centralization versus decentralization in urban regions. Other than in terms of defining metropolitan zones, this literature is mostly based on analyses of ‘permanent’ population flows. Therefore, the second theme of this paper is a focus more on fluidity, on the importance of various forms of temporary population movements which can either confirm or challenge the trajectories of centralization versus decentralization that are suggested by permanent population shifts. These themes are explored through an empirical analysis of Portsmouth, UK, a mature metropolitan area which has been subject to absolute population centralization in recent years. Finally, we explore how diverse mobilities are interwoven – a process that can be understood in terms of Urry's notions of scapes and flows, and also of enfolded mobilities.     

Effects of area size,heterogeneity, isolation,and disturbances on urban park avifauna in a highly populated tropical city

We assessed bird diversity and nesting activity in 54 urban parks in the core of a highly populated East-Asian tropical city to investigate the effects of area, isolation, habitat heterogeneity, and human disturbances on avifauna. Tree density and heterogeneity were lower while isolation was greater in small than in large or medium-sized parks. Yet, park features were often interrelated, with isolation variables negatively correlated to each other, heterogeneity positively correlated to area, and habitat variables mostly positively correlated with one another but variously to disturbances; whereas pedestrian densities wee positively correlated with green area proportions (ISO3) but negatively with the distances to large green areas (ISO2). Park size played a primary role by positively affecting species richness and numbers of nesting species, thus contributing to higher total and nesting species heterogeneity, and determining the occurrence of a greatest number of species. Pedestrian density, canopy cover, and ground heterogeneity played secondary roles, whereas isolation appeared less influential at the community level. Omnivores, granivores, and aerial insectivores appeared more abundant but were dominated by several common species. Nesting was restricted to even fewer species. While species varied in the occupancy responses to these factors, tree heterogeneity positively affected the nesting of Zosterops japonicus and cavity-nesting birds, and predator density negatively affected those of Lonchura punctulata and Streptopelia doves. Improved urban land use planning and park management incorporating these effects should be implemented to enhance breeding and avoid compositional homogenization for long-term sustainability of urban avian diversity.     

Correction to: Influence of environmental factors on bird diversity in greenspaces in an Amazonian city

Urban Ecosystems - The original version of this article unfortunately contained errors.     

Contrasting effects of urban habitat complexity on metabolic functional diversity and composition of litter and soil bacterial communities

Functional diversity and composition of soil bacterial communities affect important soil biogeochemical processes. In natural and semi-natural ecosystems, variations in habitat complexity have been shown to significantly impact both litter and soil bacterial communities. However, this remains largely untested in urban ecosystems, where human management can lead to habitat complexity combinations unobserved in rural ecosystems. We established 10 research plots in low-complexity park, high-complexity park, and high-complexity remnant habitat types (n = 30) in Melbourne, Australia. The use of organic carbon substrates by soil and litter bacteria was measured using EcoPlates to investigate the effects of habitat complexity upon metabolic functional diversity and functional composition of bacterial communities of i) soil and ii) one-year old litter. Direct and indirect effects of habitat complexity, microclimate and decomposition status upon litter microbial functional diversity and composition were also modelled using path analysis. Soil bacterial communities had significantly higher functional diversity compared to litter bacterial communities, but no significant effect of habitat complexity was apparent. The functional composition of soil bacterial communities was not affected by habitat complexity. In contrast, the functional composition of litter bacterial communities in high complexity parks and remnants was significantly different from that in low-complexity parks. The functional composition of litter bacterial communities, but not their diversity, was directly affected by habitat complexity and microclimate as well as their indirect effects upon the decomposition status of litter. Human management of urban habitat complexity can alter the functional composition of litter and soil bacterial communities without affecting their functional diversity. While this can have significant impacts on bacteria-regulated processes and ecosystem services, it also suggests that urban bacterial communities might be able to adjust to further environmental and climatic changes affecting urban ecosystems.     

Habitat- and matrix-related differences in species diversity and trait richness of vascular plants,Orthoptera and Lepidoptera in an urban landscape

Urban growth is considered to be a major driver of environmental change. Urbanisation can affect urban biodiversity in different ways. So far, most studies focused on the impact of urbanisation on single taxa in one habitat type. In this study, we used data of species inventories and GIS-based landscape elements to examine the effects of habitat size and landscape composition on the species diversity of three taxonomic groups (vascular plants, Orthoptera and Lepidoptera) in meadows and ruderal sites in the urban region of Basel, Switzerland. We also related the responses of three species traits (body size, dispersal ability and food specialisation) to habitat size in Orthoptera and Lepidoptera. We found that species of the different taxonomic groups differed in their response to habitat size and landscape composition both in meadows and ruderal sites depending on the traits examined. The species richness of Orthoptera and Lepidoptera was positively related to meadow size but not to the size of ruderal sites, while the opposite was true for plants. For Lepidoptera in ruderal sites, the percentage cover of ruderal area in the closer surroundings was a better predictor of species richness than habitat size per se. To sustain high levels of urban biodiversity, we recommend that urban planners develop adequate management strategies to satisfy the different requirements of various taxonomic groups and to increase the quality of green sites surrounding the target habitat.     

Butterfly diversity,habitat and vegetation usage in Hong Kong urban parks

The conservation value of urban parks for butterfly communities remains poorly understood, particularly for tropical butterflies in Asia. We conducted point count and route transect butterfly surveys, and used them to sample four habitats located within 13 urban parks across Hong Kong. We found 1054 individuals and 58 species of butterflies recorded in 60 survey hours over 6 months. This represents approximately one quarter of the entire known Hong Kong butterfly species list. Over 30 % of the individuals counted were Catospilia sp. but six of the species identified are classified locally as rare or very rare. Tree-covered habitats and grasslands showed higher butterfly diversity than open areas. The most common butterfly behavior was “directed flight,” which we also found to be habitat-dependent and most common in ponds and open areas. We additionally observed the use of vegetation in urban parks, which included 40 species of nectar plant and four records of butterfly oviposition. The high butterfly diversity, presence of rare species and usage of vegetation (especially as a nectar resource) we documented in this study suggests that urban parks have some conservation value for Hong Kong. However, the use of pesticides and heavy vegetation clearing may limit significant butterfly reproduction and population growth. Altogether these results emphasize the diversity of uses of urban parks for butterflies in Hong Kong while also providing possible directions for improvement in habitat and vegetation management that could increase urban park value for biodiversity.     

Tree diversity,distribution, history and change in urban parks: studies in Bangalore,India

Urban parks constitute critical biodiversity hotspots in crowded, concrete-dominated city environments. Despite the importance, they remain little researched. This paper assesses the biodiversity and distribution of trees in urban parks in the southern Indian city of Bangalore. 127 plots were used to survey tree distribution in parks across the city. The distribution is largely dominated by a few common species. The proportion of exotic species was very high, with 77% of trees belonging to introduced species. Park history had an impact on distribution. Old parks had fewer but larger trees, and greater species diversity compared to recently established parks. Old parks also differed in species composition, having a greater proportion of large canopy trees compared to young parks. Examination of size distributions revealed that large canopied species were gradually being phased out, and replaced by narrow and medium sized tree species which are easier to maintain, but which may not provide the same environmental and ecological benefits. Greater attention requires to be paid to the selection of trees in cities, not just with a view to easy maintenance as is currently the case, but to select an appropriate mix of trees that supports biodiversity and maximizes environmental and ecosystem services.     

Effects of urban infrastructure on aquatic invertebrate diversity

Urban Ecosystems - Wetlands are one of the world’s most important, economically valuable, and diverse ecosystems. A major proportion of wetland biodiversity is composed of aquatic...     

Relationships between urban parks and bird diversity in the Bangkok metropolitan area,Thailand

An analysis of the birds in Bangkok’s urban parks and landscapes provided guidance in designing healthy urban ecosystems. This research studied the relationships between bird diversity, park size, distance to the nearest main park, and habitat compositions in 10 urban parks in the Bangkok metropolitan area between January and August in 2013. Thirty sampling points per park were used to observe the number and species of birds in each urban park. A total of 50 bird species were found. Phutthamonthon, the largest urban park (400 ha), contained the greatest number of species (39 species), followed by Suan Luang Rama IX (80 ha and 34 species) and Wachirabenchatat (60 ha and 29 species). Moreover, the diversity index (H′) was highest in Phuttamonthon (1.17), followed by Thawiwanarom (1.08), and Wachirabenchatat (1.04). Larger urban parks and parks closer to the largest urban park had higher species richness than smaller parks and parks further from the largest urban park. The large parks contain higher habitat compositions than small parks. These findings can be applied to future urban ecosystem planning to combine the importance of park size (island size, and its proximity to a large park) and its arrangement, including features such as wetland, forest, buildings and grassland; and provide basic advice for future urban park design, as well as re-design of current urban parks.

     

Impact of urban structure on avian diversity along the Truckee River, USA

Urban riparian habitats are potentially important resources for native birds in arid ecosystems. Most studies have assessed the value of urban riparian habitat in terms of vegetation and natural resources; however, the surrounding land use and infrastructure may determine the viability of urban habitat. We studied the impact of urban structure, the combination of land use, infrastructure and vegetation variables that work together to shape the urban environment, on avian riparian habitat in the Truckee Meadows, Nevada, USA. Land use and infrastructure explained avian species richness and abundance better than local vegetation alone, but community resemblance was more strongly correlated to vegetation. Avian species guilds responded differentially to surrounding land use, suggesting there may be a functional difference between land use types. The best models for bird diversity used urban structure (both land use and vegetation) to describe potential habitat. Urban structure describes urban habitat in ways that vegetation variables alone cannot. Studies that ignore land use and infrastructure and other socioeconomic variables are likely missing key functional differences within urban ecosystems, and may miss the potential for compatible development that encourages both biodiversity and urban growth.     

Impacts of urbanisation on the native avifauna of Perth, Western Australia

Urban development either eliminates, or severely fragments, native vegetation, and therefore alters the distribution and abundance of species that depend on it for habitat. We assessed the impact of urban development on bird communities at 121 sites in and around Perth, Western Australia. Based on data from community surveys, at least 83 % of 65 landbirds were found to be dependent, in some way, on the presence of native vegetation. For three groups of species defined by specific patterns of habitat use (bushland birds), there were sufficient data to show that species occurrences declined as the landscape changed from variegated to fragmented to relictual, according to the percentage of vegetation cover remaining. For three other groups (urban birds) species occurrences were either unrelated to the amount of vegetation cover, or increased as vegetation cover declined. In order to maximise the chances of retaining avian diversity when planning for broad-scale changes in land-use (i.e. clearing native vegetation for housing or industrial development), land planners should aim for a mosaic of variegated urban landscapes (>60 % vegetation retention) set amongst the fragmented and relictual urban landscapes (<60 % vegetation retention) that are characteristic of most cities and their suburbs. Management actions for conserving remnant biota within fragmented urban landscapes should concentrate on maintaining the integrity and quality of remnant native vegetation, and aim at building awareness among the general public of the conservation value of remnant native vegetation.     

Patterns of pollinator turnover and increasing diversity associated with urban habitats

The role of urban expansion on bee diversity is poorly understood, but it may play an important role in restructuring pollinator diversity observed in rural regions at the urban perimeter. We studied bee communities in two habitats essential for pollinators (residential gardens and semi-natural areas) at 42 sites situated at the edge of greater Montreal, Canada. Bee species richness, abundance and functional diversity all increased with urbanization in both habitat types, but gardens and semi-natural areas supported distinct bee communities with unique responses to urbanization in terms of species turnover. Compared to semi-natural sites, residential gardens supported bees that foraged from a greater number but a lower proportion of available plant species. Bees did not discriminate between exotic and indigenous plant species in either gardens or semi-natural sites and were attracted to flowers in either habitat irrespective of their origins. Protecting semi-natural ruderal areas and providing residential garden habitats for pollinators are both effective means of promoting regional bee diversity in urbanizing regions.     

Assessing the diversity of the benthic oligochaete communities in urban and woodland ponds in an industrial landscape (Upper Silesia,southern Poland)

Studies were carried out in two mining pond complexes in an industrial landscape. The first complex (consisting of six ponds) was located in an urban area and the second one (consisting of six ponds) in a woodland area. The aims of the study were to assess the diversity of benthic oligochaetes and to evaluate which environmental variables are most important in determining variations in the community structure in ponds of varying location. In total, 21 oligochaete species were recorded (7–11 in the urban ponds, 11–15 in the woodland ponds). Aulodrilus pluriseta, Aulodrilus japonicus and Ophidonais serpentina were only found in the woodland ponds, while Potamothrix bavaricus only occurred in the urban ponds. Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Chaetogaster diaphanus and Ophidonais serpentina dominated in the woodland ponds, whereas Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Potamothrix bavaricus and Tubifex tubifex prevailed in the urban ponds. The total density of oligochaetes was higher in the urban ponds thought the values of the diversity indices were higher in the woodland ponds. The local diversity of the ponds was high, while the among-site diversity made only a small contribution to the regional diversity. Nonetheless, a cluster analysis divided all of the ponds into two distinct groups depending on their location. CCA analysis showed that conductivity, pH, total hardness, alkalinity, the concentration of chlorides and the content of organic matter in the bottom sediments were most associated with the distribution of some oligochaete species among the ponds studied.     

Greenspace sites conserve taxonomic and functional diversity of dung beetles in an urbanized landscape in the Brazilian Cerrado

Urban Ecosystems - Urbanization transforms natural ecosystems, creating an environmental mosaic, characterized by native vegetation sites mixed with constructed sites. In this study, we compared...     

Species richness,phylogenetic and functional structure of bird communities in Chinese university campuses are associated with divergent variables

University campus is an important component of urban landscapes for biodiversity conservation. However, to our knowledge no study has quantitatively assessed the diversity and structure of bird communities in Chinese university campuses, especially from phylogenetic and functional perspectives. Here, for the first time we linked species richness, phylogenetic structure and body mass structure of campus bird communities with contemporary climate, glacial-interglacial climate change, altitudinal range, population density around campus, area and age of campus to test their associations. We found 393 bird species in 38 university campuses (29% of all Chinese bird species, two species are endangered, four species are vulnerable, and 33 species are near threatened). The variables significantly correlated with campus bird species richness, phylogenetic structure and body mass structure were altitudinal range and mean annual precipitation, glacial-interglacial anomaly in temperature, and altitudinal range, respectively. In particular, there were more species in steeper and wetter campuses, more young species clustered in campuses with stable glacial-interglacial climate, and more species with smaller body size in steeper campuses. Our study highlights the importance of considering both phylogenetic and functional information for biodiversity conservation in urban ecosystems.     

Network diversity,contact diversity,and status attainment

We propose that diversity in social relations measured by network diversity and cross-race/cross-gender contacts affords job seekers higher contact status that in turn brings better status attainment outcomes. Controlling for traditional strength of tie measures and other confounders, the empirical study confirms that (1) network diversity in race and gender are significantly associated with actual utilization of cross-race/cross-gender contacts in job search, (2) use of cross-race/cross-gender contacts is significantly related to higher contact status for nonwhite and female job seekers, but (3) contact status (activated social capital) partially provides jobs of higher SEI scores for white job seekers. Similarly, male job seekers obtain better jobs through female contacts, but the same does not apply to female job seekers. These findings show relative return deficits of social capital experienced by racial minorities and females even when they exert extra effort to obtain heterogeneous social relations and contacts.     

Effects of forest type and urbanization on species composition and diversity of urban forest in Changchun,Northeast China

Urban Ecosystems - Urban forest is considered as the most important component of urban green infrastructure and can make vital contributions to urban biodiversity. Understanding the species...