Urban Ecosystems最新文献

Rapid urbanization has caused a series of environmental problems, but its influences on animal-related ecological functions (e.g., seed dispersal) have not been fully studied. Mammals are ideal models for studying the functional consequences of urbanization because they are sensitive to environmental changes. It is well known that large- and medium-sized mammals are vulnerable in fragmentation ecosystem. However, little is known about the functional responses of small mammals (e.g., rodents) to the rapid urbanization. Using infrared cameras and tagged seeds, here, we quantified mammals and mammal-mediated seed dispersal (i.e., Quercus variabilis) in 11 forest patches along city-suburb-exurban gradient in a rapidly urbanizing megacity, central China. We wanted to determine the effects of defaunation on seed dispersal in the isolated urban forests. The results showed that abundance of seed dispersers was higher in the natural exurban forests than in the city forests, while abundance of seed predators did not vary significantly along the city-suburb-exurban gradient. The percentage of seed dispersal was positively associated with the abundance seed dispersers, while the percentage of seed predation increased with the abundance of seed predators. Seed dispersers loss (e.g., small rodents) disrupted the mammal-mediated seed dispersal, possibly contributing to the degradation of urbanized forests. These results suggest that defaunation effects are obvious in the rapidly urbanizing cities, in that abundance of seed dispersers, and mammal-mediated seed dispersal are undergoing decline in the urbanized forests. In order to maintain seed dispersal and natural regeneration of urban forests, diversity of small mammals (e.g., rodents) and their ecological services should be considered in ecological-based urban planning and management.

Urban watercourses are an essential part of blue-green infrastructure (BGI) that can mitigate the negative impact of habitat loss resulting from urbanization. Many studies on temperate urban bats activity did not concern its seasonal variations. Our work evaluated the bats’ activity and occurrence in different urban riverside environments throughout the vegetation period. Our results showed that long-range echolocators were represented mainly by Nyctalus noctula. Their activity peak occurred in late summer in open habitats of high anthropogenic pressure levels, and at least part of the population was present year-round in the city. Recently reported from Cracow: Hypsugo savii and Pipistrellus kuhlii were confirmed in the medium-range echolocators. The high occurrence of P. pygmeus with a relatively low P. pipistrellus was noteworthy and is probably a result of the low competitiveness of the latter in the presence of P. kuhlii. Two spring and late summer activity peaks on different rivers suggest different migration corridors from and to hibernacula. However, the autumn activity in the city center may also indicate partial hibernation in the old town. The activity peak of short-range echolocators occurred in spring, as expected - mainly in a narrow riverbed and low anthropogenic pressure environments. However, ambiguous spring and late summer activity in the open with the highest anthropogenic pressure environment may result from the rapidly progressing synurbization of M. daubentonii. Our results indicate the need to monitor the bat adaptation process to the cities in the context of dynamic climatic and environmental changes.

Coastal oak meadows are fragmented across an increasingly urbanized landscape in Greater Victoria with implications for common camas (qʷɫəɫ/KȽO,EL/Camassia quamash) fitness. Common camas, frequently present in coastal oak meadows, is an ecologically important cultural keystone species that forms the foundation of one of the most important Indigenous food systems in the region. Previous research has examined how the pressures associated with urbanization shape plant community composition and structure, but how these pressures influence individual plant fitness remains unclear. To improve our understanding, we assessed environmental conditions and common camas growth and reproductive traits across an urban-rural gradient in Greater Victoria. We found that urbanization on this landscape alters several key environmental variables (namely increased trampling and soil compaction, and decreased soil depth, canopy cover, and soil phosphorus) and that common camas appears to be responding to these altered conditions with a reduction in growth and reproductive trait values. By targeting the identified pressures, management can work towards supporting more successful urban camas populations into the future.

Efforts to create sustainable cities and urban climate-resilience depend on understanding how wildlife use the urban matrix to guide urban planning and design. Urban environments combine natural elements like topography and waterways, with various intensities of urban development. These combinations shape the spatial environment of cities and influence the diversity and persistence of urban wildlife. Insectivorous bats occur in urban areas, with urban tolerant species correlated with greater mobility and flexible roosting strategies, such as trawling bats. To understand how trawling bats use urban space, we studied patterns of land use selection in an urban population of a trawling bat, the large-footed myotis (Myotis macropus) in a subtropical city. We quantified fine-scale space use using radio telemetry over two seasons using land use categories applied in urban planning and design. Bats used urban land use types in a non-random manner, displaying a preference for green and blue space associated with the recreation land use type at both the landscape and home range scale. Tracked bats used waterways and riparian areas, as well as parkland, sportsgrounds and other green space adjacent to waterways. Trawling bats are dependent on riparian habitats, and these complex habitats are particularly vulnerable to changes to the availability of water resources associated with climate change. Maintaining spatial heterogeneity in urban planning and design by retaining and providing green space along, and adjacent to waterways, will provide a landscape mosaic for urban trawling bats to persist, facilitating climate change resilience in a specialist urban species.

Cities are expanding at fast rates across the world, representing one of the main drivers of biodiversity loss due to habitat replacement. Nonetheless, urban and peri-urban areas often feature green spaces that may offer opportunities to wildlife and even represent safe havens for endangered species. Nonetheless, the key drivers that shape wildlife responses to urban landscapes, and in turn their ability to persist within cities, are far from being fully understood. Here we focus on an ecologically specialized butterfly, the endemic Italian festoon Zerynthia cassandra, as a model to assess how endangered species may survive in highly modified urban landscapes. The relatively low mobility and high host plant specialization make Z. cassandra an excellent target for studies in urban ecology, as they make the species able to exploit small suitable patches while at the same time potentially sensitive to habitat fragmentation and loss due to urbanization and land reclamation. We thus first document the relatively widespread occurrence of potentially suitable sites within two highly modified landscapes of central and southern Italy, with 25 and 35% of sites actually occupied by Z. cassandra. By modeling the probability of butterfly occurrence as a function of environmental characteristics, we found that Z. cassandra is strongly influenced by functional connectivity among suitable sites in urban landscapes, as well as by the abundance of Aristolochia host plants, and by the availability of profitable land cover classes in the immediate surroundings of potential oviposition sites. Our results indicate not only that networks of urban and peri-urban green spaces may host populations of protected and endangered species, but that management should also focus on the urban matrix in order to provide connecting corridors, as key assets to guarantee species persistence in cities.

Preserving biodiversity is a paramount global concern and, in this regard, monitoring urban biodiversity has increasingly taken on a significant role. Citizen science has emerged as a resource for addressing this challenge, offering a cost-effective approach capable of producing extensive data while promoting public engagement. In this work, a Lisbon university campus was used to determine the effectiveness of a citizen science project launched on the BioDiversity4All/iNaturalist platform to monitor urban biodiversity and analyse the influence of different engagement actions on biodiversity observations. The data analysis was based on biodiversity observations, including the temporal evolution of observations, the most frequently observed taxonomic groups, and the impact of promotional actions on project data. Additionally, the profiles of the observers were analyzed to assess their level of engagement and continued involvement in citizen science. The project had an effect on the increase in the number of observers and observations, and it was also possible to see a positive effect of the organized activities. The two indices used showed that Researchers and Students were the observer categories responding the most to the project, followed by Naturalists and Others. The results highlighted the capacity of citizen science to increase interest in biodiversity among both the university community and the general public. Furthermore, this work underlines the role of different strategies such as BioBlitzes, social media campaigns, and formal education activities to reduce the impact of relevant limitations associated with citizen science, namely taxonomic, aesthetic, and temporal biases.

Background: Fractures of the distal humerus are a common fragility fracture in older adults. The purpose of this study was to systematically review the literature to produce pooled estimates of the outcomes of treatment using total elbow arthroplasty (TEA), open reduction and locking plate fixation (ORIF), hemiarthroplasty or with conservative management.

Methods: A systematic review of PUBMED and EMBASE databases was conducted for studies reporting outcomes of intra-articular fractures in older adults. Data extracted included patient-reported outcome measures as well as clinical outcomes including ROM, adverse events and all-cause reoperation rates.

Results: Forty-eight studies met the inclusion criteria and included 1838 acute, intra-articular distal humeral fractures. There was no clinically important difference in patient-reported pain and function measured on the Mayo Elbow Performance Score (TEA = 89.3 (SD 20.0), Hemi = 88.4 (SD 10.6), internal fixation = 85.0 (SD 14.7), non-operative = 85.1 (SD 11.0)).

Discussion: Each of the treatment modalities studies resulted in a reasonable level of elbow function. The included studies were largely non-comparative and at considerable risk of bias. As elbow replacement surgery becomes centralised in the UK, there is a real need for high-quality comparative research studies to inform practice.

Anthropogenic disturbances have drastic negative effects on the biodiversity, thereby also compromising the ecosystem service it provides. Bees are one of the key players since they provide essential pollination services for both natural and agriculture ecosystems. Nevertheless, these insects are facing an increasing threat due to expansion of urban areas and inappropriate land use practices. Therefore, understanding the impact of different anthropogenic disturbances on bee communities is essential to assure the ecosystem functioning and human well-being. In this study, we made use of a well-known bee group, i.e., euglossine bees (Euglossine: Apidae), and of a fast-growing city to investigate the impact of anthropogenic disturbance on bee community. Using scent traps, we monthly collected male euglossine bees in seven sampling areas, differing in terms of the anthropogenic use/disturbance. Land use in each area was characterized through pre-georeferenced images and mapping software and from these data we calculated an Anthropogenic Transformation Index. Our results reveal that anthropogenic disturbance negatively impacts the euglossine bee community, in contrast to the positive effect of the proximity to the river. However, and perhaps the most alarming aspect of our findings, is the interaction effect between these two conditions, demonstrating that as we approach the river, parameters such as abundance, species richness, and diversity of these bee communities become more compromised by disturbance. Our study shows the urgent need to implement effective conservation strategies and sustainable management practices to protect and restore riparian forests in Caatinga urban areas, aiming to safeguard its associated biota and the valuable ecosystem services they provide.

In the cities, remnants of the vegetation that originally occupied these areas can be found. Exotic species have established in these relicts, and therefore these spaces require management aimed at recovering native vegetation. In this study, we evaluated the impact of the removing exotic species on the floristic composition of the remnants of an oak forest. We compared the abundance/cover and composition of exotic plants in a forest that has been managed through citizen participation with that of reference forests (both with remnants, but the former without protection and the latter with protection). We established 48 sampling sites to characterize the vegetation in three strata (upper, middle, and low) and monitored changes in composition in managed forest sites for a period of 3 years. The results indicate that the managed forest hosts different species than those found in the reference forests, with lower abundance and cover of exotic plants in the upper and lower strata. Regarding temporal changes, we observed shifts in floristic composition before and after management activities, and a reduction in the cover of exotic species before and after management, with consistently low cover three years later. This underscores the effectiveness of citizen-led management activities, offering a viable alternative for restoring native vegetation in urban environments.

Few studies have evaluated the invasive effects on soil properties in urban ecosystems. In this study, population density and impervious surface area were used to divide the two river wetlands of Qingdao City, China— River Zhangcun and River Wenquan—into urban and periurban types. Sediments were sampled from plots colonized by the invasive Alternanthera philoxeroides and the native Typha angustifolia in these two river wetlands. The sediment properties, including fertility, stoichiometry, microbial diversity indices (observed species, Chao1, Shannon’s diversity index and Simpson’s diversity index) and species composition, were evaluated and compared. We found similar fertility and stoichiometry between sediments derived from invasive and native species. A greater bacterial diversity was found in the sediment derived from A. philoxeroides in the periurban river, while a greater fungal diversity was merely shown for the Shannon’s diversity index of A. philoxeroides regardless of river types. In addition, more microbes relevant to nutrient cycling processes, such as denitrification, accumulated in response to invasion, which may have decreased the habitat quality and impeded the invasion of T. angustifolia into A. philoxeroides populations. The discrepancy in urbanization status affected the impact of plant colonization on sediment properties, and the opposite results were shown for the comparisons of sediment nitrogen availability and bacterial diversity between the two species. Urbanization discriminated the impact of invasion to some degree. The invasion of A. philoxeroides altered the sediment microbiome, and the potential plant‒soil feedback needs further investigation.