Showing papers in "Urban Ecosystems in 2016"

Urban forest structure, ecosystem services and change in Syracuse, NY

Abstract: The tree population within the City of Syracuse was assessed using a random sampling of plots in 1999, 2001 and 2009 to determine how the population and the ecosystem services these trees provide have changed over time. Ecosystem services and values for carbon sequestration, air pollution removal and changes in building energy use were derived using the i-Tree Eco model. In addition, photo interpretation of aerial images was used to determine changes in tree cover between the mid-1990s and 2009. Between the mid-1990s and 2003, tree cover in Syracuse exhibited a decline from 27.5 to 25.9 %, but subsequently increased to 26.9 % by 2009. The total tree population exhibited a similar pattern, dropping from 881,000 trees in 1999 to 862,000 in 2001, and then increasing to 1,087,000 trees in 2009. Most of this increase in the urban tree population is due to invasive or pioneer trees species, particularly Rhamnus cathartica, which has more than tripled in population between 2001 and 2009. Insects such as gypsy moth and emerald ash borer pose a substantial risk to altering future urban forest composition. The annual ecosystem services provided by the urban forest in relation to carbon sequestration, air pollution removal and reduction in building energy use are estimated at about $2.4 million per year. An improved understanding of urban forests and how they are changing can facilitate better management plans to sustain ecosystem services and desired forest structure for future generations.

Ecosystem services in managing residential landscapes: priorities, value dimensions, and cross-regional patterns

Abstract: Although ecosystem services have been intensively examined in certain domains (eg, forests and wetlands), little research has assessed ecosystem services for the most dominant landscape type in urban ecosystems—namely, residential yards In this paper, we report findings of a cross-site survey of homeowners in six US cities to 1) examine how residents subjectively value various ecosystem services, 2) explore distinctive dimensions of those values, and 3) test the urban homogenization hypothesis This hypothesis posits that urbanization leads to similarities in the social-ecological dynamics across cities in diverse biomes By extension, the thesis suggests that residents’ ecosystem service priorities for residential landscapes will be similar regardless of whether residents live in the humid East or the arid West, or the warm South or the cold North Results underscored that cultural services were of utmost importance, particularly anthropocentric values including aesthetics, low-maintenance, and personal enjoyment Using factor analyses, distinctive dimensions of residents’ values were found to partially align with the Millennium Ecosystem Assessment’s categories (provisioning, regulating, supporting, and cultural) Finally, residents’ ecosystem service priorities exhibited significant homogenization across regions In particular, the traditional lawn aesthetic (neat, green, weed-free yards) was similarly important across residents of diverse US cities Only a few exceptions were found across different environmental and social contexts; for example, cooling effects were more important in the warm South, where residents also valued aesthetics more than those in the North, where low-maintenance yards were a greater priority

Adaptive governance to promote ecosystem services in urban green spaces

Abstract: Managing urban green space as part of an ongoing social-ecological transformation poses novel governance issues, particularly in post-industrial settings. Urban green spaces operate as small-scale nodes in larger networks of ecological reserves that provide and maintain key ecosystem services such as pollination, water retention and infiltration, and sustainable food production. In an urban mosaic, a myriad of social and ecological components factor into aggregating and managing land to maintain or increase the flow of ecosystem services associated with green spaces. Vacant lots (a form of urban green space) are being repurposed for multiple functions, such as habitat for biodiversity, including arthropods that provide pollination services to other green areas; to capture urban runoff that eases the burden on ageing wastewater systems and other civic infrastructure; and to reduce urban heat island effects. Because of the uncertainty and complexities of managing for ecosystem services in urban settings, we advocate for a governance approach that is adaptive and iterative in nature—adaptive governance—to address the ever changing social order underlying post-industrial cities and offer the rise of land banks as an example of governance innovation.

Effects of urbanization on breeding birds in European towns: Impacts of species traits

Abstract: Urbanization acts as a filter on bird species behavioral traits so that only few species can tolerate urban constraints. We analyzed how behavioral traits (nesting, feeding, and migratory habits) of breeding bird species affect their frequency of occurrence in the urban centers of 38 European towns. We used binary logistic regression analysis to predict the bird species traits belonging to each trait group. A total of 108 species (21% of the European breeding bird species) were found to breed in the European town centers. According to our broad-scale analyses the bird species most frequently breeding in town centers nest in buildings and/or buildings have diverse diets, in trees (40%) and are resident omnivores, or relied on seeds or fruits as their sources of food. However, almost all bird species also fed on arthropods (92%) during the breeding season. Only a few urban bird species bred on the ground. Four out of the studied 108 species were non-native and five species were predators. Our broad-scale results from Europe indicate that bird species with different behavioral traits can respond differently to urbanization. Bird species that nest in cavities/buildings have diverse diets, that benefit a resident way-of-life, may have an advantage in living and settling in European town centers. Our results from Europe may provide insights related to the development of bird assemblages in the urban core areas of the New World.

Food in a row: urban trees offer valuable floral resources to pollinating insects

Abstract: Urbanization affects the availability and diversity of floral resources (pollen and/or nectar) for wild pollinating insects. For example, urban green areas are characterized by an abundance of ornamental plant species. Increasingly, trees are planted to improve the aesthetics of urban streets and parks. These urban trees might offer important floral resources to pollinating insects. To examine the suitability of urban trees as resources for pollinating insects, we investigated the chemical composition of pollen and nectar as well as the amount of nectar produced by the nine major insect-pollinated tree species planted in cities of Western Europe, namely Acer pseudoplatanus, Aesculus carnea, A. hippocastanum, Robinia pseudoacacia, Tilia cordata, T. x euchlora, T. x europaea, T. platyphyllos and T. tomentosa. The analyses revealed that globally the Tilia trees provide pollen with lower contents of polypeptides, amino acids and phytosterols compared with the other species. Urban tree flowers offer abundant nectar with relatively high sugar contents (0.16–1.28 mg/flower); sucrose was the predominant sugar in all nectars. The investigated tree species could therefore be considered in future city plantings.

Impacts of urban sprawl on species richness of plants, butterflies, gastropods and birds: not only built-up area matters

Abstract: Urban growth is a major factor of global environmental change and has important impacts on biodiversity, such as changes in species composition and biotic homogenization. Most previous studies have focused on effects of urban area as a general measure of urbanization, and on few or single taxa. Here, we analyzed the impacts of the different components of urban sprawl (i.e., scattered and widespread urban growth) on species richness of a variety of taxonomic groups covering mosses, vascular plants, gastropods, butterflies, and birds at the habitat and landscape scales. Besides urban area, we considered the average age, imperviousness, and dispersion degree of urban area, along with human population density, to disentangle the effects of the different components of urban sprawl on biodiversity. The study was carried out in the Swiss Plateau that has undergone substantial urban sprawl in recent decades. Vascular plants and birds showed the strongest responses to urban sprawl, especially at the landscape scale, with non-native and ruderal plants proliferating and common generalist birds increasing at the expense of specialist birds as urban sprawl grew. Overall, urban area had the greatest contribution on such impacts, but additional effects of urban dispersion (i.e., increase of non-native plants) and human population density (i.e., increases of ruderal plants and common generalist birds) were found. Our findings support the hypothesis that negative impacts of urban sprawl on biodiversity can be reduced by compacting urban growth while still avoiding the formation of very densely populated areas.

Agroecological and social characteristics of New York city community gardens: contributions to urban food security, ecosystem services, and environmental education

Abstract: There is growing public interest and participation in food-producing urban community gardens in North America, yet little research has examined agricultural production and ecological processes in these spaces. We describe the agroecological and social characteristics of 61 food-producing gardens in New York City, drawing on gardener interviews, land-use maps, plant species inventories, arthropod scouting, and soil sampling and analysis. Gardens contained agricultural crops, food production infrastructure, ornamental plants, and recreational areas in varying proportions, indicating that gardens serve multiple and distinct purposes depending on community needs and interests. On average, gardeners devoted the greatest proportion of garden area (44 %) to food production, and supplied a large share of their households’ produce needs from their community gardens. Solanaceae, Brassicaceae, and Cucurbitaceae crops dominated food crop areas, hindering effective crop rotation to prevent disease and pest problems. Most gardeners grew crops in raised beds constructed with clean fill and compost. These soils generally had sandy textures, low water-holding capacity, high organic matter levels (with a large proportion from recent inputs) and excessive nutrient levels. Soil water content at field capacity increased exponentially with total soil carbon, suggesting that organic matter enhances water-holding capacity. Insect pest densities greatly exceeded action thresholds in nearly all gardens for aphids and whiteflies on Brassica crops, aphids on Cucurbit crops, and two-spotted spider mites on tomatoes. Predator and parasitoid densities were generally low (less than one per plant on average), perhaps partially due to low floral and woody perennial cover in most gardens (12 % and 9 % on average, respectively). Dominant groups of natural enemies were minute pirate bugs, spiders, and parasitoid wasps. A wide variety of people of differing experience levels, incomes, and ethnicities participate in community gardening in NYC, and most gardens host multiple languages. Promising directions for urban gardening research, education, and practice include: 1) Cover cropping to improve soil quality and nutrient management, and diversify crop rotations; 2) Improving access to soil testing and guidance on appropriate use of soil amendments, 3) Enhancing habitat for arthropod natural enemies that provide biological control of insect pests with floral and woody perennial plantings; and 4) Incorporating ecological knowledge and inquiry-based approaches into gardening workshops, educational materials, and technical support, and offering these resources in multiple languages.

Urban high-resolution fossil fuel CO2 emissions quantification and exploration of emission drivers for potential policy applications

Abstract: Fossil fuel carbon dioxide (FFCO2) emissions are the largest driver of anthropogenic climate change. Approximately three-quarters of the world’s fossil fuels carbon dioxide emissions are generated in urban areas. We used the Hestia high resolution approach to quantify FFCO2 for Salt Lake County, Utah, USA and demonstrate the importance of high resolution quantification to urban emissions mitigation policymaking. We focus on the residential and onroad sectors across both urbanized and urbanizing parts of the valley. Stochastic Impact by Regression on Population, Affluence, and Technology (STIRPAT) regression models using sociodemographic data at the census block group level shows that population, per capita income, and building age exhibit positive relationships while household size shows a negative relationship with FFCO2 emissions. Compact development shows little effect on FFCO2 emissions in this domain. FFCO2 emissions in high income block groups is twice as sensitive to income than low income block groups. Emissions are four times as sensitive to household size in low-income versus high-income block groups. These results suggest that policy options targeting personal responsibility or knowledge feedback loops may be the most effective strategies. Examples include utility bill performance comparison or publicly available energy maps identifying high-emitting areas. Within the onroad sector, high emissions density (FFCO2/km) is associated with primary roads, while high emissions intensity (FFCO2/VMT) is associated with secondary roads. Opportunities exist for alignment of public transportation extension with remaining high emission road segments, offering a prioritization of new onroad transportation policy in Salt Lake County.

Mangrove forests store high densities of carbon across the tropical urban landscape of Singapore

Abstract: Tropical forested ecosystems provide multiple ecosystem services to rural and urban landscapes, with carbon storage gaining particular attention. Deforestation due to rural-urban transitions may lead to a reduction in carbon storage ability. Coastal mangrove forests are particularly at risk from deforestation due to their location in the rapidly urbanizing coastal zone, and the city state of Singapore is an extreme example, losing as much as 90 % of its original mangrove cover due to land reclamation and reservoir construction. Knowledge of mangrove ecosystem services may allow better conservation, restoration and incorporation of remaining mangrove patches into the urban landscape. Focusing on the regulating ecosystem service of carbon storage, mangrove carbon stocks have been estimated for Singapore using a combination of field and remote sensing techniques. Biomass carbon showed substantial spatial variation, with old, contiguous mangrove patches containing a higher density of biomass carbon than fragmented, river-fringing or restored mangroves. In total, national biomass carbon equated to 116,117.1 megagrams of carbon (Mg C), and a coarse estimate of the total carbon stock (including soil carbon) suggests that Singapore’s mangroves may store 450,571.7 Mg C. While lower than other regional estimates focused on natural, oceanic mangroves, this is a significant carbon stock for a disturbed, urban mangrove system, and may be equivalent to the average annual carbon emissions of 621,000 residents. This analysis, alongside a review of other urban forest studies, highlights the importance of forested ecosystems such as mangroves in providing a carbon storage ecosystem service to urban areas.

Diet of the crowned eagle ( Stephanoaetus coronatus ) in an urban landscape: potential for human-wildlife conflict?

Abstract: The study of diet is pivotal in understanding a species, particularly for quantifying a predatory raptors’ economic niche and potential for human-wildlife conflict The crowned eagle (Stephanoaetus coronatus) is one of Africa’s apex predators and a population is present within the urban greenspace mosaic of Durban and Pietermaritzburg, KwaZulu-Natal, South Africa In close association with urban development, the local population of crowned eagles has the potential to be a concern to the safety of domestic stock and pets Time-lapse cameras were positioned at urban nest sites (n = 11) to identify the prey composition during breeding, particularly in regards to taxa with human associations The numerical proportion of avian prey, particularly hadeda ibis (Bostricia hagedash) pulli, was several times greater than any previous diet description The methodology used and the abundance of hadeda ibis in these urban environments are potential contributing factors Rock hyrax (Procavia capensis) was the primary prey and where hyrax were unavailable, the diet composition was broader and included more vervet monkeys (Chlorocebus pygerythrus) It was found that domestic stock comprised 6 % of the identifiable prey Contrary to popular belief, no dogs (Canis familiaris) and few cats (Felis domesticus) were delivered to the nest by breeding eagles in this study The negative consequences of small proportions of pet losses should be considered against the majority of wildlife prey consumed, which also have various wildlife conflict interactions Juvenile and sub-adult eagles are most frequently identified at in situ attacks of pets, particularly toy dog breeds Further research on juvenile dispersal and winter diet will provide insights on the ecological impacts of eagle management strategies in the region

Resilient food systems: a qualitative tool for measuring food resilience

Abstract: This paper is dedicated to the topic of food resilience in the context of urban environments and aims at developing a qualitative tool for measuring it The emphasis is laid on urban food security with a significant global relevance due to the interconnectedness of our urban and global food systems We argue that food and agriculture have to be understood as integral components of contemporary urban and peri-urban landscapes as urban agriculture supports in many cases also ecosystems, biodiversity, urban ecology and urban landscape architecture The topic is introduced through contemporary urban food system models and definitions followed by characteristics of a resilient urban food system, including consumer, producer, food processing, distribution and market resilience Based on the review of food system models and assessment tools, a new food system model for resilience analysis has been developed This is then applied to worked examples and further developed on the Christchurch case study, where the tool is applied to existing intra-urban and peri-urban landscape components of Christchurch, New Zealand

Vegetation type alters water and nitrogen budgets in a controlled, replicated experiment on residential-sized rain gardens planted with prairie, shrub, and turfgrass

Abstract: Vegetation type alters surface hydrology and nitrogen (N) cycling by partitioning evapotranspiration (ET) and drainage, but has not been fully utilized for this purpose in the design of urban rain gardens. Replicated treatments of three vegetation types (prairie, shrub, and turfgrass) commonly planted in rain gardens, as well as bare soil (control), were evaluated 1 year after establishment in 12, free-drainage bioretention cells designed to specifications for residential rain gardens in the Midwestern United States. Water and N budgets were calculated to assess differences in ET, drainage, soil moisture, and N transport following three stormwater applications in July, August, and October of 2006. Evaporative demand was also estimated as potential or reference ET during the study period using Hamon, Priestley-Taylor, and FAO Penman-Monteith models. Results show that after 1 year of establishment, vegetation type changed the water budgets of rain gardens thus altering their provisioning of ecosystem services via observed tradeoffs between daytime evaporative cooling (ET), stormwater storage, N-load reduction, soil and plant N retention, and groundwater recharge (drainage). Vegetation effects on hydrology and N transport were most significant when evaporative demand was high during the middle of the growing season. Observed changes in ET, drainage, soil moisture, and N transport support the incorporation of different vegetation types into conceptual and numerical models of rain gardens to assess ecological outcomes and tradeoffs at a variety of spatiotemporal scales.

Does urbanization affect the seasonal dynamics of bird communities in urban parks

Abstract: The environmental factors affecting the spatial dynamics of bird communities in urban parks are well understood, but much less attention has been paid to the seasonal dynamics of bird communities. Since migrant and resident human commensal birds might have contrasting responses to environmental factors of urban parks, we expected different seasonal dynamics among parks. On the other hand, because bird species can have different habitat relationships throughout the year, we also expected different responses of bird richness to environmental variables between breeding and non-breeding seasons. Bird surveys were conducted in 14 small urban parks (1–4 Ha) of Mar del Plata city (Argentina) for one full annual cycle. Bird richness changed between seasons, but bird abundance remained constant. Bird community composition did not vary between seasons, but urban parks near the urban center, with the highest pedestrian traffic and isolation to other green areas had the least seasonal change of composition. During the breeding season, bird richness was negatively affected by the percentage cover of high buildings surrounding the immediate limits of parks, whereas during the non-breeding season bird richness was not related with any environmental variable. Bird composition variation among parks was affected by the distance to the urban center during both seasons. Results showed that urbanization promotes a seasonal homogenization of bird communities in urban parks, probably by affecting the presence of migrant species and promoting the temporal stability of human commensal species.

Exotic trees can sustain native birds in urban woodlands

Abstract: Native landscaping has been proposed as a means of increasing native bird diversity and abundance in urban landscapes. However residents’ preferences for vegetation are such that exotic plants are often preferred over natives. We investigated the extent to which native birds foraged in three common native and three exotic tree species in mixed urban woodland during four seasons. We predicted that native birds would spend more time foraging in native trees, and that food resources provided by deciduous exotic trees would be more seasonal than those provided by non-deciduous natives. Native birds spent a lot of time foraging in two of the native tree species, but very little time in native red beech (Nothofagus fusca). They used exotic oak (Quercus robur) throughout the year, and sycamore (Acer pseudoplatanus) seasonally. Oak and European beech (Fagus sylvatica) were used by the largest number of species overall, because they attracted both native and exotic birds. With the exception of tree fuchsia (Fuschia excorticata), which produces large volumes of nectar followed by fruits, all tree species were sources of invertebrates for insectivorous feeding. Seasonality of use was high only in sycamore, indicating limited support for our second prediction. We show that being native doesn’t necessarily entail being a good food source for native birds, and popular landscaping exotic species, such as oak, provide foraging opportunities across all seasons.

Urbanization is not associated with increased abundance or decreased richness of terrestrial animals - dissecting the literature through meta-analysis

Abstract: The widely accepted consensus is that urbanization increases abundance but reduces species richness of animals. This assumption is the premise for empirical tests and theoretical explanations. We studied the association of urbanization with abundance and species richness of different animal taxa in 20 and 26 published articles reporting abundances and richness, respectively via meta-analysis. Because some articles had multiple estimates, we analyzed 40 and 58 estimates of abundance and richness, respectively. Contrary to conventional wisdom, the overall abundance of terrestrial animals was not higher in urban areas, but instead actually lower, while we failed to confirm the conventional thinking of lower species richness with urbanization. These findings cannot, however, be generalized across all cities and animal species, as conflicting differences were reported among geographical regions, animal taxa. Our results question the conventional wisdom that urbanization generally increases abundances while reducing species richness, and highlights the variability of urbanization effects on diversity among taxa and geographic regions.

Drivers of biodiversity patterns in parks of a growing South American megacity

Abstract: How urban habitats contribute to biodiversity conservation is a key challenge in a rapidly urbanising world. Urban parks can provide important habitats for native species, but previous studies are geographically biased; fast growing megacities, in particular in South America, are clearly understudied. To assess habitat functions and underlying drivers in parks of Santiago de Chile, we analysed the assemblages of wild growing plant species in two ubiquitous park habitat types (grasslands, wooded areas) in 15 parks (150 plots) along an urban-rural gradient. We first used linear contrasts to compare species richness, beta diversity and the proportion of introduced species. We then tested for the explanatory value of environmental variables operating at different spatial scales (plot, park, urban matrix). Unlike in most previous studies, biodiversity patterns were not related to the position of the parks on the urban-rural gradient. Introduced species, mostly from Europe, generally dominated both habitat types (>90 %). Socio-economic (population growth or density), but not spatial, variables were retained in most models. Maintenance intensity was most influential in predicting species assemblages, complemented by park age in wooded areas. A high proportion of European grassland species indicates a trend of homogenisation in park grassland at a cross-continental scale. We conclude that habitat functions of urban parks for native species that have been mainly demonstrated for Europe cannot be generalised to South American megacities. This highlights the need for innovative and locally appropriate conservation approaches (e.g., re-introduction of native species) to foster biodiversity functions in urban parks of South American megacities.

Diversity in flowering plants and their characteristics: integrating humans as a driver of urban floral resources

Abstract: Urban neighborhoods vary in development intensity and in the life style and demographics of their residents. Decisions made by urban residents affect plant communities, their functional characteristics, and the floral resources they provide. We recorded flowers in front-facing yards in 58 neighborhoods in Chicago, IL (USA) and examined patterns in community composition and species turnover between neighborhoods. We investigated how species richness and plant characteristics, including origin, cultivation intent, and life cycle, are affected by neighborhood socioeconomic factors. Urban plant species tended to be perennial, ornamental, and non-native. White clover had the broadest distribution and the highest floral abundance but was not present in several of the highest-income neighborhoods. Although we found 144 morpho-species across neighborhoods, most occurred infrequently. Species turnover was highest for ornamental species and lowest for weedy species, suggesting that intentional plantings are driving beta diversity across the landscape. We found the highest species richness in neighborhoods with intermediate numbers of Hispanic and white residents and with intermediate number of residential lots; neighborhoods with racially or ethnically homogenous populations had fewer plant species. The high frequency of weeds in low-income neighborhoods, the occurrence of certain ornamental plant species in whiter, wealthier communities, and high turnover of species from one neighborhood to another, all suggest a disparity in plant-related ecosystem services across cities. Complexity in urban plantings may be influenced by the suite of perspectives that residents bring towards habitat management. Cultivation sustains a diversity of plants and creates a disparity in plant traits by neighborhood socioeconomics.

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

Abstract: Urban forest is considered as the most important component of urban green infrastructure and can make vital contributions to urban biodiversity. Understanding the species composition and diversity of urban forest is important for urban biodiversity enrichment. In this study, we evaluated the urban forest woody plant diversity and spatial pattern in Changchun, northeast China. The differentiations in species composition and diversity among types of urban forests and gradients of urbanization were then explored. Principal Component Analysis (PCA) was performed to characterize the species distribution. Similarity Percentage (SIMPER) analysis was adopted to determine the species differentiation and the main contributed species among different urban forest types and different urbanization gradients. The results showed that urban forest species in Changchun were abundant with 88 species that belonged to 50 genera and 24 families. The three major species were Salix matsudana, Populus davidiana, and Pinus sylvestris var. mongolica. Native species were preferred in urban forest of Changchun. Significant differentiations in species composition were observed among different types of urban forests. Attached forest (AF) had the highest species richness and biodiversity, whereas production and management forest (PF) had the lowest ones. SIMPER results showed the highest species dissimilarity between AF and PF and lowest species dissimilarity between AF and landscape and relaxation forest (LF). For different urbanization gradients, species richness and diversity in the third ring were the highest and in the first ring were the lowest. SIMPER results showed the lowest species dissimilarity between the third ring and the fourth ring and highest species dissimilarity between the first ring and the fourth ring. Based on the 10/20/30 “rule of thumb”, the diversity must be urgently increased at the species, genus, and family levels for EF and PF. For different urbanization gradients, diversity should be increased at the species level in the first ring and the fifth ring, and should be increased at the family level in the second ring and the fifth ring.

Urban bird conservation : presenting stakeholder-specific arguments for the development of bird-friendly cities

Abstract: Following the call from the United Nations Convention on Biological Diversity “Cities & Biodiversity Outlook” project to better preserve urban biodiversity, this paper presents stakeholder-specific statements for bird conservation in city environments. Based upon the current urban bird literature we focus upon habitat fragmentation, limited habitat availability, lack of the native vegetation and vegetation structure as the most important challenges facing bird conservation in cities. We follow with an overview of the stakeholders in cities, and identify six main groups having the greatest potential to improve bird survival in cities: i) urban planners, urban designers and (landscape) architects, ii) urban developers and engineers, iii) homeowners and tenants, iv) companies and industries, v) landscaping and gardening firms, vi) education professionals. Given that motivation to act positively for urban birds is linked to stakeholder-specific advice, we present ten statements for bird-friendly cities that are guided by an action perspective and argument for each stakeholder group. We conclude with a discussion on how the use of stakeholder-specific arguments can enhance and rapidly advance urban bird conservation action.

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

Abstract: 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.

Urban parks: refuges for tropical butterflies in Southeast Asia?

Abstract: Rapid economic development has accelerated urbanisation and biodiversity loss in Southeast Asia. Studies of urban ecology have suggested urban parks can be effective refuges for wildlife in temperate regions, but their effectiveness as refuges in rapidly urbanising tropical regions is understudied. We examined the species diversity of butterflies in urban parks in the Federal Territory of Kuala Lumpur and investigated the relationships between butterfly species richness and three park variables: i) park size, ii) distance from the central business district and iii) park age. Standardised butterfly sampling was conducted across different microhabitat types at each park: i) groves, ii) hedges, iii) flowerbeds and iv) unmanaged areas. We recorded 572 butterflies belonging to 60 species (97 % considered common) from five families. Although species richness was positively correlated with park size and age and negatively correlated with distance from the central business district; the correlations were weak and not statistically significant. However, species richness of host-specialist species was significantly positively correlated with park size and age. The highest species richness (65 % of observed species) was recorded in the unmanaged microhabitat. It is likely that both park planting scheme and the presence of early successional plants in unmanaged microhabitat led to highest butterfly species richness in parks that contained all four microhabitat types. Whether a diverse planting scheme and increased size and number of unmanaged areas in urban parks can improve the ability of parks to sustain populations of rare butterflies in the face of future urbanisation remains to be seen.

A Comparative Assessment of Track Plates to Quantify Fine Scale Variations in the Relative Abundance of Norway Rats in Urban Slums.

Abstract: Norway rats (Rattus norvegicus) living in urban environments are a critical public health and economic problem, particularly in urban slums where residents are at a higher risk for rat borne diseases, yet convenient methods to quantitatively assess population sizes are lacking. We evaluated track plates as a method to determine rat distribution and relative abundance in a complex urban slum environment by correlating the presence and intensity of rat-specific marks on track plates with findings from rat infestation surveys and trapping of rats to population exhaustion. To integrate the zero-inflated track plate data we developed a two-component mixture model with one binary and one censored continuous component. Track plate mark-intensity was highly correlated with signs of rodent infestation (all coefficients between 0.61 and 0.79 and all p-values < 0.05). Moreover, the mean level of pre-trapping rat-mark intensity on plates was significantly associated with the number of rats captured subsequently (Odds ratio1.38; 95% CI 1.19-1.61) and declined significantly following trapping (Odds ratio 0.86; 95% CI 0.78-0.95). Track plates provided robust proxy measurements of rat abundance and distribution and detected rat presence even when populations appeared 'trapped out'. Tracking plates are relatively easy and inexpensive methods that can be used to intensively sample settings such as urban slums, where traditional trapping or mark-recapture studies are impossible to implement, and therefore the results can inform and assess the impact of targeted urban rodent control campaigns.

Using high-resolution LiDAR data to quantify the three-dimensional structure of vegetation in urban green space

Abstract: The spatial arrangement and vertical structure of vegetation in urban green spaces are key factors in determining the types of benefits that urban parks provide to people. This includes opportunities for recreation, spiritual fulfilment and biodiversity conservation. However, there has been little consideration of how the fine-scale spatial and vertical structure of vegetation is distributed in urban parks, primarily due to limitations in methods for doing so. We addressed this gap by developing a method using Light Detection and Ranging (LiDAR) data to map, at a fine resolution, tree cover, vegetation spatial arrangement, and vegetation vertical structure. We then applied this method to urban parks in Brisbane, Australia. We found that parks varied mainly in their amount of tree cover and its spatial arrangement, but also in vegetation vertical structure. Interestingly, the vertical structure of vegetation was largely independent of its cover and spatial arrangement. This suggests that vertical structure may be being managed independently to tree cover to provide different benefits across urban parks with different levels of tree cover. Finally, we were able to classify parks into three distinct classes that explicitly account for both the spatial and vertical structure of tree cover. Our approach for mapping the three-dimensional vegetation structure of urban green space provides a much more nuanced and functional description of urban parks than has previously been possible. Future research is now needed to quantify the relationships between vegetation structure and the actual benefits people derive from urban green space.

Coexisting with coyotes (Canis latrans) in an urban environment

Abstract: The global spread of urban development and concomitant reduction in wilderness areas can both pressure and entice wild animals to adapt to the urban environment. As wildlife moves into metropolitan areas, however, they come into contact with residents who have become increasingly disconnected from natural environments and have little to no experience in dealing with wild animals. While many large carnivores actively avoid urban areas, North America’s coyote (Canis latrans) has proved remarkably adept at utilizing the highly altered habitat of the modern city. Yet while the coyote’s behavioural adaptations to urban areas have been relatively well researched, fewer studies have focused on human-coyote interactions in cities. Given that human attitudes, fears, knowledge and resulting behaviours often underpin human-wildlife conflicts, the following study investigates and compares the human aspects of coyote conflict in two cities with large populations of both people and coyotes: Chicago and Los Angeles. Data were collected via email surveys sent to residents of Cook and Los Angeles Counties. The survey instrument included questions on residents’ opinions, fears, knowledge, personal experiences with urban coyotes and behaviours affecting them. The general goal of the study was to investigate the potential for human-coyote coexistence in urban environments. The following research revealed great variation in attitudes towards coyotes, with animal lovers being as much a part of the problem as those with a paralyzing fear of wildlife. Consequently, finding acceptable solutions may pose a significant challenge to urban wildlife managers and reconciliation ecologists.

Defining urban, suburban, and rural: a method to link perceptual definitions with geospatial measures of urbanization in central and eastern Massachusetts

Abstract: Developing greater understandings of socio-ecological relationships across urbanizing areas is increasingly recognized as important for the conservation and management of natural resources in a variety of development contexts. Efforts to do so have been hindered by a lack of consistent measures of urbanization and the challenge of integrating socio-cultural characteristics into definitions of urban. We present a novel method for linking perceptual definitions of urban, suburban, and rural to geospatial characteristics and demonstrate how the method can be used to map urban, suburban, and rural areas at multiple scales in central and eastern Massachusetts. Our method can facilitate comparative approaches to urban ecology, be used to scale up socio-ecological studies, and inform conservation research and practice in urbanizing areas.

Influence of soil properties on street tree attributes in Singapore

Abstract: Soil quality is thought to be a primary driver of street tree performance and thus a major concern for urban forest growth, health and longevity. This research was conducted to evaluate the influence of soil physical, chemical and biological properties on Singapore’s street trees. In total, 338 plots, 1014 trees and 32 species across Singapore’s five regions were sampled. Singapore’s street trees are skewed towards smaller diameters (<50 cm) and largely represented (61 %) by five species, four of which are non-native. Most soil properties in Singapore’s streetscapes are likely not limiting for trees: verge (5 to 7 m), bulk density (1.05 to 1.45 Mg m−3), P (1.52 to 2.87 mg kg−1), organic C (7.8 to 11.4 %), Ca (924 to 1772 mg kg−1), Mg (313 to 631 mg kg−1), Na (130 to 208 mg kg−1), Cr (143 to 212 mg kg−1), Pb (55 to 74 mg kg−1), Ni (15 to 30 mg kg−1) and microbial biomass C (265 to 457 mg kg−1). Soil pH (6.04 to 7.63) is not as acidic as the humid-tropical soil commonly found in Singapore. Soil K (23 to 130 mg kg−1) was found to be relatively low and potentially limiting. Individual soil properties and multi-factor models were poor predictors of urban tree attributes across Singapore, but models improved when examined at regional scales. Relatively high soil quality, uniformity of streetscape soils and fast growth rates of these trees are proposed as explanations for why soil properties appear to poorly predict street tree attributes in Singapore.

Social-ecological innovation: adaptive responses to urban environmental conditions

Abstract: Novel approaches to natural resource management, particularly those which promote stakeholder participation, have been put forward as fundamental ingredients for establishing resilient, polycentric forms of environmental governance. This is nowhere more pertinent than in the case of the complex adaptive systems associated with urban areas. Decentralisation of urban green space management has been posited as an element thereof which, according to resilience thinking, should contribute to the adaptive capacity of cities and the ecosystem services upon which they rely. Implicit in this move towards increased adaptive capacity is the ability to manage through innovation. Although the importance of innovation towards system adaptability has been acknowledged, little work has thus far been carried out which demonstrates that innovative use of urban green space represents a form of adaptive response to environmental conditions. The current paper reports on research which maps examples of organised social-ecological innovation (OSEI) in an urban study area and evaluates them as adaptive responses to local environmental conditions which may contribute to system resilience. The results present OSEI as a coherent body of responses to local social and environmental deprivation, exhibiting diversity and adaptability according to individual contexts. The study therefore provides evidence for the importance of local stakeholder-led innovation as in the building of adaptive capacity in urban social-ecological systems.

Avian haemosporidian parasites in an urban forest and their relationship to bird size and abundance

Abstract: Urbanization has been identified as a threat to biodiversity due to landscape modifications Studies of parasite ecology in urbanized areas lagged behind those made on macro organisms Here we studied infection prevalence of haemosporidian parasites in an avian community of an urban forest from Germany, and its relationship with bird abundance and body mass We used PCR to amplify a fragment of the mtDNA cyt b gene to determine the infection status of birds, and bird point counts to determine bird relative abundances The avifauna was dominated by two small sized insectivore passerines (Parus major, Cyanistes caeruleus), representing ~40 % of the total bird records The highest haemosporidian prevalence was recorded for Turdus philomelos (100 %) and for Fringilla coelebs (75 %) Bird abundance and body mass were positively associated with infection status for two haemosporidian genera: Plasmodium and Leucocytozoon Infection rate was lower in juveniles compared to adult birds We recorded a total of 7 Plasmodium, 26 Haemoproteus, and 10 Leucocytozoon lineages Avian malaria (P relictum) was detected infecting 5 individuals of P major, the most abundant species in the community These results, together with those of previous studies at the same site, suggest that potentially any of the genetic haemosporidian lineages detected in this urban forest can be transmitted across native and pet bird species, and to species of conservation concern housed at aviaries

Effects of human-related disturbance on breeding success of urban and non-urban blue tits (Cyanistes caeruleus)

Abstract: There is a need to study the effects of urbanization on wildlife in order to understand the ecological implications of increasing urbanization and find out how to reduce its threats to biodiversity. The blue tit evolved as a forest species and prefers deciduous and mixed forests, whereas its nesting in urban habitats is a more recent phenomenon. Our long-term study of blue tit populations has been conducted in two habitats: an urban parkland (frequently visited by people) and a deciduous forest outside of the city. Using linear mixed modeling, we revealed that a relationship of blue tit breeding success (and the number of fledglings) with thermal conditions in May differed between the urban parkland and the forest. While the relationship was positive in the forest, it was negative in the parkland. In addition, breeding success in the parkland increased with increasing number of rainy days in May. We argue that the main possible reason for such patterns is human activity in the parkland, which interferes with tit parental care, especially the regular feeding of nestlings, whereas it is evidently associated with weather conditions. Human disturbance in the forest is likely to be negligible.

The causal response of avian communities to suburban development: a quasi-experimental, longitudinal study

Abstract: Correlations between urbanization and biodiversity are well known, but the causes driving such associations are lacking. We used a long-term, quasi-experimental approach to study the responses of avian communities to suburban and exurban development around Seattle, WA, USA. We measured indices of bird abundance, reproduction, and survival for 12 years at many locations, including 5 forest ‘reserves,’ 10 existing ‘developments,’ and 11 ‘changing’ sites where ongoing development converted forests to single-family residential neighborhoods. In the first few years of clearing, building, and occupation of new neighborhoods by humans avian communities shifted from those typical of second-growth forest to those more characteristic of developments. During this time avian diversity increased and numerical dominance by abundant birds declined. Species that adapted and exploited development reproduced more successfully there than did forest-dependent species that avoided development. Adults of species that thrived in developments attained equal annual survival across reserved to developed landscapes, while species that avoided neighborhoods tended to survive poorly outside of reserves. The humans living in our study areas frequently fed birds and provided nest boxes. These actions were positively correlated with increases in secondary cavity nesting and seed eating birds. Humans also maintained outdoor cats and 11 % of humans both fed birds and let their cats outside. These actions were negatively correlated with the abundance of birds regularly using feeders. We suggest that a key management goal in urban ecosystems is the maintenance of avian diversity because a diverse avifauna engages a diversity of humans.