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Urban Ecosystems 

Latest Results for Urban Ecosystems
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Development of urban behaviour is associated with time since urbanization in a reed-nesting waterbird
23. Juni 2018
Abstract Behavioural adaptations are recognized as crucial determinants for successful establishment and persistence of animal populations in a novel urban environment. Here, we examined mechanisms responsible for the development of urban behavioural type in a common waterbird, the Eurasian coot Fulica atra. We compared the behaviour of coots from a rural population and two urban populations that differed in the timing of colonization event (1960s vs. 2000s). We found that some behavioural characters associated with urban life (aggression during nest defence and boldness...
Vertical segregation by breeding ring-necked parakeets Psittacula krameri in northern Italy
22. Juni 2018
Abstract Cavities represent a limiting resource for breeding birds, thus triggering potential competition, mostly in urban ecosystems. The ring-necked parakeet Psittacula krameri is one of the main alien invasive bird species of the world. Introduced populations are reported for over 35 countries, Italy included. This parakeet mainly depends on trunk cavities for reproduction but, occasionally, it may nest within building holes. A growing population of this species is present in the urban area of Pavia (northern Italy). Differently, from what has been observed in other...
Components of landscape pattern and urban biodiversity in an era of climate change: a global survey of expert knowledge
22. Juni 2018
Abstract There is sufficient evidence to show that both humans and fauna are profoundly affected by landscape pattern composition and configuration in relation to adaptation to climate change impacts in urban landscapes. Despite this, global-scale research that ranks which components of landscape pattern play the most pivotal roles in this process is absent. Also lacking is in-depth examination of the potential areas of conflict between biodiversity conservation targets and those that pertain to human dimensions of climate change adaptation goals in relation to landscape...
Reduction by half: the impact on bees of 34 years of urbanization
20. Juni 2018
Abstract Urban ecosystems are growing rapidly and urbanization is an important cause of the loss of biodiversity. Bees are declining in abundance worldwide, including urban areas, and this decline is alarming because of their global importance as plant pollinators. Here we examine that decline by comparing a bee assemblage sampled in the 1980s and again in 2015, in an urban area of the city of Curitiba. Both studies sampled assemblages with hand-nets every two weeks during one year of study. Bee species richness has declined by 45% (112 species then, 63 today). Two...
Coming in like a wrecking-ball: are native Eurasian red squirrels displacing invasive Siberian chipmunks? A study from an urban park
17. Juni 2018
Abstract Alien squirrels may seriously threaten native species by means of interspecific competition. In our work, we analysed whether the distribution of alien Siberian chipmunks within the Sigurtà Garden urban park (north-eastern Italy) changed after the natural spread of native Eurasian red squirrels in a 20-year period. Distribution of both squirrels was estimated through a citizen-science approach, in the first 10-year after red squirrel arrival 1 (i.e. Decade 1: 1997–2006) and in the second 10-year interval (i.e. Decade 2: 2007–2017). We compared habitat use of...
Decay patterns of invasive plants and plastic trash in urban streams
16. Juni 2018
Abstract Urban streams are impacted by invasion of exotic riparian plants and the accumulation of plastic trash, which alter in-stream litter subsidies, and cause changes that cascade up the aquatic food web. The impacts of these factors on urban streams is poorly understood. We compared decay rates and invertebrate colonizers of 5 litter pack types in 4 urban streams in Victoria, British Columbia, Canada: Native Red alder (Alnus rubra) and Sitka willow (Salix sitchensis), invasive English ivy (Hedera sp.), Himalayan blackberry (Rubus armeniacus) and plastic trash (i.e...
A comparative study of urban fragmentation patterns in small and mid-sized cities of Idaho
16. Juni 2018
Abstract Urbanization has a massive impact on ecological function and impedes the provisioning of environmental services. The interaction between urbanization and the environment has been researched extensively. However, the existing research focused on the urbanization characteristics of large metropolitan areas. In this paper, we investigate the urban fragmentation patterns of small and mid-sized cities in Idaho, USA. To capture the urban morphology for each site within the study we use both concentric ring and transect analysis as well as several spatial/landscape...
Nesting patterns among Neotropical species assemblages: can reserves in urban areas be failing to protect anurans?
16. Juni 2018
Abstract Nestedness among species assemblages implies that sites of lower species richness are subsets of richer sites in a regional species pool. This nestedness is a reflection of a non-random process of species loss as a consequence of factors that promote the disaggregation of assemblages. The impoverishment of assemblage diversity is more often observed in fragmented landscapes. This non-random process has important implications for conservation. We recorded 95 species of anurans across 22 protected areas, of which 11 sites were in an urban matrix and 11 were in a...
Rainfall interception by six urban trees in San Juan, Puerto Rico
12. Juni 2018
Abstract Rainfall interception is an important part of the urban hydrological cycle. Understanding is limited about the role of urban trees and other vegetation in the interception process. This study quantified interception losses by six trees in the Caribbean coastal city of San Juan, Puerto Rico, three representing a broadleaf evergreen, and three representing a broadleaf deciduous species. Rainfall was partitioned into throughfall for 13 storms to compare the results between tree types. Total rainfall ranged from 2.9 to 72.4 mm, and storm duration spanned 1 h to...
Gross primary productivity of a large metropolitan region in midsummer using high spatial resolution satellite imagery
11. Juni 2018
Abstract Although gross primary productivity (GPP) is estimated with remote sensing over large regions of Earth, urban areas are usually excluded due to the lack of light use efficiency (LUE) parameters for urban vegetation and the spatial heterogeneity of urban land cover. Here, we estimated midsummer GPP, both within and among vegetation and land-use types, across the Minneapolis-Saint Paul, Minnesota metropolitan region. We derived LUE parameters for urban vegetation types using estimates of GPP from tree sap flow and eddy covariance CO2 flux observations, and from...
Evaluating the distribution of invasive woody vegetation around riparian corridors in relation to land use
01. Juni 2018
Abstract Invasive species have been causing important and irreversible impacts to native species and communities of ecosystems. They distort ecosystem functions by degrading forest lands, wetlands, and agricultural habitats and replace the native vegetation and reduce biodiversity, forest productivity, and suitable wildlife habitat. To address disturbances caused by invasive species occurrence, further information is needed regarding the occurrence, extent, and dispersal of invasive species and how land use may increase the spread of these species. The objective of this...
Rural land use bifurcation in the urban-rural gradient
01. Juni 2018
Abstract The classic urban-rural gradient concept assumes a decline in land use intensity from an intensively developed urban core outward to residential suburbs, culminating in lightly developed rural areas. The concept provides a common framework directing urban socio-ecological research. Given that rural land use includes woodlands and croplands, and croplands appear as ecologically depauperate as urban lands, we investigated land-use patterns along urban-rural gradients for 30 large metropolitan areas in the eastern United States. We predicted a bifurcation at the...
Buzzing on top: Linking wild bee diversity, abundance and traits with green roof qualities
01. Juni 2018
Abstract Green roofs are potentially valuable habitats for plants and animals in urban areas. Wild bees are important pollinators for crops and wild plants and may be enhanced by anthropogenic structures, but little is known about wild bees on green roofs in cities. This study investigates the effects of green roof qualities (floral resources, substrate character and depth, roof height and age) on wild bee diversity, abundance and traits (nesting type, sociality, pollen specialisation, body size) on green roofs in Vienna. Nine green roofs were sampled monthly between...
Wild bee abundance declines with urban warming, regardless of floral density
01. Juni 2018
Abstract As cities expand, conservation of beneficial insects is essential to maintaining robust urban ecosystem services such as pollination. Urban warming alters insect physiology, fitness, and abundance, but the effect of urban warming on pollinator communities has not been investigated. We sampled bees at 18 sites encompassing an urban warming mosaic within Raleigh, NC, USA. We quantified habitat variables at all sites by measuring air temperature, percent impervious surface (on local and landscape scales), floral density, and floral diversity. We tested the...
Invasive weeds in urban riparian zones: the influence of catchment imperviousness and soil chemistry across an urbanization gradient
01. Juni 2018
Abstract The riparian zones of urban waterways are frequently degraded by weed invasions. This study examined the effects of different levels of catchment imperviousness, as a surrogate for the extent and intensity of urbanisation, on invasive weeds and soil physical and chemical attributes. The study was conducted adjacent to waterways in the partly urbanised Georges River catchment in south western Sydney. Vegetation and soil sampling was undertaken in the riparian zone of 10 freshwater streams in non-urban (low imperviousness), peri-urban (moderate imperviousness...
Ecohydrological model for the quantification of ecosystem services provided by urban street trees
01. Juni 2018
Abstract Urban green spaces have been recognized as an important source of ecosystem services, whose quantification requires the determination of quantities related to energy, water, carbon and soil nutrient content. In this paper we propose a stochastic ecohydrological model that couples two existing models for water and nutrients in urban soil at the single street-tree scale. The model input are rainfall and irrigation, for water, and deposition and fertilization, for nitrogen, while the output are evapotranspiration, runoff and deep percolation, for water, and plant...
Does urbanization explain differences in interactions between an insect herbivore and its natural enemies and mutualists?
01. Juni 2018
Abstract Urbanization can alter the composition of arthropod communities. However, little is known about how urbanization affects ecological interactions. Using experimental colonies of the black bean aphid Aphis fabae Scopoli reared on Vicia faba L, we asked if patterns of predator-prey, host-parasitoid and ant-aphid mutualisms varied along an urbanization gradient across a large town in southern England. We recorded the presence of naturally occurring predators, parasitoid wasps and mutualistic ants together with aphid abundance. We examined how biotic (green areas...
The state and use of municipal tree inventories in Swedish municipalities – results from a national survey
01. Juni 2018
Abstract Urban trees are an essential component of urban ecosystems, and management of this resource constitutes an essential element of urban open space management. However, municipal tree inventories in Sweden and elsewhere have received limited attention. It is unknown how common municipal tree inventories are in Sweden, factors governing whether a municipality has an inventory and what the inventories are used for. This study therefore sought to: Create an overview of the state of Swedish municipal tree inventories and determine how municipality size, green space...
Determining species specific nightly bat activity in sites with varying urban intensity
01. Juni 2018
Abstract Time of peak bat activity during the night differs among bat species due to temperature, prey availability, habitat availability, and/or interactions between species. Habitat availability is altered in urban areas, which may affect insect prey availability and interspecies interactions. Our objectives were to use mobile acoustic monitoring to determine when bat species were active in a single night in urban and nonurban sites and if nightly bat activity patterns differed in urban versus nonurban sites. Bat echolocation call sequences were recorded using Anabat...
Comparison of water-use characteristics of landscape tree ( Tabebuia argentea ) and palm ( Ptychosperma macarthurii ) species in a tropical roof garden with implications for urban water management
01. Juni 2018
Abstract In cities, landscape palms and trees are planted for scenic views and normally maintained with frequent irrigation. With similar water input, their morphological difference may lead to different water-use that varies seasonally. Thus, evaluating their water-use patterns is necessary to achieve proper urban water management. Here, we examined water-use characteristics of Tabebuia argentea and Ptychosperma macarthurii, a tree and a palm species, in a roof garden in Bangkok, Thailand. Self-constructed Granier’s probes were used for sap flux measurement and...