scholarly journals The role of invasion and urbanization gradients in shaping avian community composition

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Andrew M Rogers ◽  
Andrea S Griffin ◽  
Françoise Lermite ◽  
Berndt van Rensburg ◽  
Carla Archibald ◽  
...  
Keyword(s):  
Urban Areas ◽  
Native Species ◽  
Urban Environments ◽  
Avian Community ◽  
Remnant Vegetation ◽  
Common Myna ◽  
South Wales ◽  
Large Numbers ◽  
Gradual Loss ◽  
A Site

Abstract The extent to which native species utilize urban environments depends on species responses to multiple threatening processes. Here, we aimed to quantify changes in bird communities in response to changing habitat structure, invasive species and aggressive native species. We conducted surveys in two independently invaded regions with similar patterns of urban development. The study regions were New South Wales (NSW) and Queensland (QLD), Australia. We observed 127 species in NSW and 144 species in QLD. Most species (NSW 83 and QLD 84) are urban adapters making use of some or all urban sub-environments. Urban avoiders, species only found in remnant vegetation, were the second largest group (urban avoiders: NSW 23 and QLD 31). We found the lowest richness in the most urban sites (urban exploiters: NSW 10 and QLD 15). Using generalized linear mixed models, we found a non-significant relationship between species richness and the abundance of aggressive species like the common myna and noisy miners, Manorina melanocephala, but a significant positive correlation with the percentage of shrub cover at a site. As there is a gradual loss of species with increasing urbanization, retaining higher complexity in vegetation structure in urban areas will support large numbers of species and could help mitigate the potential impacts of aggressive urban-adapted species and habitat loss.

Diversity of organisms

2018 ◽  
Author(s):  
Philip James
Keyword(s):  
Life Cycle ◽  
Urban Areas ◽  
Native Species ◽  
New Technologies ◽  
Urban Environments ◽  
Green Spaces ◽  
The Common ◽  
Living Organisms ◽  
Micro Organisms ◽  
Diversity Of Life

The focus of this chapter is an examination of the diversity of living organisms found within urban environments, both inside and outside buildings. The discussion commences with prions and viruses before moving on to consider micro-organisms, plants, and animals. Prions and viruses cause disease in plants and animals, including humans. Micro-organisms are ubiquitous and are found in great numbers throughout urban environments. New technologies are providing new insights into their diversity. Plants may be found inside buildings as well as in gardens and other green spaces. The final sections of the chapter offer a discussion of the diversity of animals that live in urban areas for part or all of their life cycle. Examples of the diversity of life in urban environments are presented throughout, including native and non-native species, those that are benign and deadly, and the common and the rare.

The analysis and standardisation of light-trap catches of Heliothis armiger (Hübner) and H. punctiger Wallengren (Lepidoptera: Noctuidae)

1981 ◽  
Vol 71 (2) ◽  
pp. 207-225 ◽  
Author(s):  
R. Morton ◽  
L. D. Tuart ◽  
K. G. Wardhaugh
Keyword(s):  
Wind Speed ◽  
Light Trap ◽  
Adult Emergence ◽  
Wind Speeds ◽  
South Wales ◽  
Large Numbers ◽  
Successive Generations ◽  
Hourly Distribution ◽  
A Site ◽  
Trap Catches

AbstractHourly and nightly catches of Heliothis armiger (Hb.) and H. punctiger Wllgr. at a site adjacent to 2000 ha of commercial cotton in the Namoi Valley of New South Wales, were analysed in relation to various environmental factors and showed that wind speed, temperature, night-length and (H. armiger only) moonlight exerted a significant influence on trap-catch. For H. punctiger and H. armiger respectively, these factors accounted for 80 and 60% of the deviance in hourly catches but only 70 and 40% of the variation in nightly catches. Wind speeds of more than 1·7 m/s suppressed the catch of both species but had a greater effect on H. punctiger than H. armiger. Whereas with both species, the optimum temperature for trapping was about 27°C, temperature had a greater influence on the catch of H. punctiger than of H. armiger. Bright moonlight was estimated to reduce the catch of H. armiger by 49%, but no significant effect was detected for H. punctiger. The analysis revealed a number of occasions for both species in which the hourly distribution of catch and/or the change in catch between successive nights was aberrant. With H. armiger, these inconsistencies appeared to be associated with changes in population due to adult emergence, whereas for H. punctiger the most likely cause seemed to be changes due to movement. The combined effects of wind speed, temperature, night-length and moonlight were used to adjust the nightly catches of each species according to the environmental conditions prevailing on a ‘ standard’ night. This was defined as a typical summer's night with temperatures decreasing from 28·8°C at dusk to 20·6°C at dawn and ideal catching conditions, i.e. no moon and wind speed never exceeding 1·7 m/s. As such, the adjusted catches could be taken as indices of moth abundance. These showed that H. armiger had three discrete periods of abundance, characterised by the presence of large numbers of young moths and spaced at intervals suggesting successive generations. A similar pattern was lacking in H. punctiger, which was abundant only during the first half of the season. Except during periods of emergence (H.armiger), or once when spraying occured during daylight, the aerial application of insecticides to the cotton adjecent to the light-trap resulted in marked reductions in the populations of both species.

scholarly journals Quantifying the attractiveness of garden flowers for pollinators

2019 ◽  
Vol 23 (5-6) ◽  
pp. 803-817 ◽  
Author(s):  
Rosi Rollings ◽  
Dave Goulson
Keyword(s):  
Urban Areas ◽  
Native Species ◽  
Early Spring ◽  
Solitary Bees ◽  
Insect Communities ◽  
Insect Visitation ◽  
Pollinating Insects ◽  
Flower Visiting ◽  
Myosotis Arvensis ◽  
A Site

Abstract There is great interest in planting urban areas to benefit pollinating insects, with the potential that urban areas and gardens could act as an extensive network of pollinator-friendly habitats. However, there are a great many different plant cultivars available to the gardener, and a paucity of evidence-based advice as to which plants are truly most attractive to flower-visiting insects. Here, we report insect visitation to metre square plots of 111 different ornamental plant cultivars at a site in central UK. Data were collected over 5 years, and comprise over 9000 insect observations, which were identified to species (for honeybees and bumblebees) or as ‘solitary bees’, Syrphidae, Lepidoptera and ‘others’. Unlike some previous studies, we found no difference in numbers of insects attracted to native or non-native species, or according to whether plants were annuals, biennials or perennials, but we did find that native plants attracted a significantly higher diversity of flower-visiting insects. Overall, the most-visited plants were Calamintha nepeta, Helenium autumnale and Geranium rozanne. However, patterns of visitation were quite different for every insect taxa examined. For example, different species of short-tongued bumblebees showed little overlap in their most-preferred plant cultivars. Interestingly, very similar plant cultivars often attracted different insect communities; for example, 72% of visitors to Aster novi belgii were honeybees or bumblebees, while the related Anthemis tinctoria, which also has daisy-like flowers, did not attract a single honeybee or bumblebee but was popular with solitary bees, hoverflies, and ‘other’ pollinators. Some plant cultivars such as Eryngium planum and Myosotis arvensis were attractive to a broad range of insects, while others attracted only a few species but sometimes in large numbers, such as Veronicastrum virginicum and Helenium autumnale which were both visited predominantly by honey bees. It is clear that we do not yet fully understand what factors drive insect flower preferences. Recommendations are made as to which flower cultivars could be combined to provide forage for a diversity of pollinator groups over the season from early spring to autumn, though it must be born in mind that some plants are likely to perform differently when grown in different environmental conditions.

scholarly journals Propagation models for high sites in urban areas

2006 ◽  
Vol 4 ◽  
pp. 345-349 ◽  
Author(s):  
A. Hecker ◽  
M. Neuland ◽  
T. Kuerner
Keyword(s):  
Urban Areas ◽  
Mobile Station ◽  
Base Station ◽  
Urban Environments ◽  
Angle Of Incidence ◽  
Propagation Models ◽  
Validity Range ◽  
A Site

Abstract. Analyses of results from commonly used propagation models applied to UMTS Ultra High Sites in urban environments are presented. Differences between predicted and measured values for a site in Nuernberg are calculated as a function of the distance between base station and mobile station and as a function of the angle of incidence. An assessment of the validity range of the different propagation models is done. Furthermore, an analysis of the accuracy of the classification of building data is presented.

scholarly journals Guided by the light: Roost choice and behaviour of urban Rainbow Lorikeets (Trichoglossus haematodus)

2016 ◽  
Vol 2 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Savannah Daoud-Opit ◽  
Darryl N. Jones
Keyword(s):  
Urban Areas ◽  
Positive Impact ◽  
Bird Species ◽  
Urban Environments ◽  
Artificial Light ◽  
Large Numbers ◽  
Wide Range ◽  
Rainbow Lorikeet ◽  
Individual Trees ◽  
Selection Of

Abstract 1. The formation of large communal roosts is a conspicuous phenomenon associated with a wide range of bird species successfully exploiting urban environments. In many Australian cities, the abundance of the Rainbow Lorikeet (Trichoglossus haematodus), a native parrot, has increased markedly in recent decades, with the species roosting in very large numbers within suburban sites. These roosting locations are noisy and cause significant fouling of the land beneath, resulting in conflict with humans. 2. We investigated the selection of roosting sites in this species in Brisbane, Australia, by comparing characteristics of both the general sites of these roosts as well as individual trees used within roosting sites and trees that were avoided. 3. Lorikeets used a wide variety of tree types for roosting but demonstrated a clear preference for clumped trees within sparsely treed areas that received significantly more artificial light at night than otherwise suitable sites and trees nearby. 4. These features of roosting sites may enhance the detection of nocturnal predators by Rainbow Lorikeets, suggesting a potential positive impact of anthropogenic lighting. Our findings provide valuable insights into the management of roost-related conflicts in urban areas. We encourage further investigations into the possible benefits of artificial light.

Habitat use by grey-crowned babbler, Pomatostomus temporalis, in urban and peri-urban environments

2017 ◽  
Vol 23 (1) ◽  
pp. 88
Author(s):  
Kathryn Teare Ada Lambert ◽  
Hugh Ford
Keyword(s):  
Habitat Use ◽  
Urban Areas ◽  
Native Species ◽  
Woody Debris ◽  
Bird Species ◽  
Ground Cover ◽  
Urban Environments ◽  
High Rate ◽  
Habitat Requirements ◽  
Urban Landscapes

Habitat loss in the urban environment leads to a high rate of local extinction of native fauna. In contrast, where key habitat structures, such as woody debris, shrubs and trees, are maintained, urban landscapes can retain many native species. To manage urban habitats successfully for urban bird communities, it is, therefore, necessary to understand the habitat requirements of the species using them. We have previously shown that the grey-crowned babbler, Pomatostomus temporalis, exhibits similar mean weight, sex ratio and group size in natural and altered habitat in and around Dubbo, New South Wales. In the present study, we detail the movements and habitat use of the groups that inhabit urban areas. We found that groups behaved similarly in urban and peri-urban areas, but showed small differences in the frequency of behaviours, based on the habitat feature that was available. The results suggested that, despite the decline of the grey-crowned babbler in the southern parts of its range, this species is able to survive in altered habitats, if nesting habitat and ground cover remain available and neighbouring groups persist nearby. Because other woodland bird species have shown similar responses to urban environments, managers of urban parkland should provide foraging substrates for a variety of woodland bird species, including vulnerable species, to ameliorate threatening processes and protect key habitat requirements.

scholarly journals Immigration and establishment of urban Trypanosoma cruzi populations

2019 ◽  
Author(s):  
Alexander S.F. Berry ◽  
Renzo Salazar-Sánchez ◽  
Ricardo Castillo-Neyra ◽  
Katty Borrini-Mayorí ◽  
Claudia Chipana-Ramos ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Causative Agent ◽  
Human Activities ◽  
Urban Areas ◽  
Native Species ◽  
Phylogenetic Analyses ◽  
Urban Environments ◽  
South American ◽  
Environment Impact

AbstractChanging environmental conditions, including those caused by human activities, reshape biological communities through both loss of native species and establishment of non-native species in the altered habitats. Dynamic interactions with the abiotic environment impact both immigration and initial establishment of non-native species into these altered habitats. The repeated emergence of disease systems in urban areas worldwide highlights the importance of understanding how dynamic migratory processes affect the current and future distribution and abundance of pathogens in urban environments. In this study, we examine the pattern of invasion of Trypanosoma cruzi—the causative agent of human Chagas disease—in the city of Arequipa, Peru. Phylogenetic analyses of 136 T. cruzi isolates from Arequipa and other South American locations suggest that only one T. cruzi immigrant established a population in Arequipa as all T. cruzi isolated from vectors in Arequipa form a recent monophyletic group within the broader South American phylogeny. We discuss several hypotheses that may explain the limited number of established T. cruzi lineages despite multiple introductions of the parasite.Author SummaryHuman-associated pests and pathogens, who benefit from the abundance of humans and human-associated hosts or vectors, commonly invade environments altered by human activities. As the number and size of human-disturbed environments increase, so does the importance of identifying ecological and environmental factors that affect the probability that disease systems immigrate to, subsequently establish populations in, urban environments. We examined the number and timing of immigration and establishment events of Trypanosoma cruzi, the causative agent of Chagas disease, in a currently endemic area. Phylogenetic analyses of 136 T. cruzi isolates suggests that the current population descended from a single, recent immigration event. We discuss historical and ecological hypotheses that can explain the limited T. cruzi diversity in this region.

scholarly journals Quantifying the Characteristics of the Local Urban Environment through Geotagged Flickr Photographs and Image Recognition

2020 ◽  
Vol 9 (4) ◽  
pp. 264 ◽  
Author(s):  
Meixu Chen ◽  
Dani Arribas-Bel ◽  
Alex Singleton
Keyword(s):  
Urban Environment ◽  
Image Recognition ◽  
Urban Areas ◽  
Urban Population ◽  
Daily Life ◽  
Urban Environments ◽  
Population Densities ◽  
Recognition Method ◽  
Dynamic Distribution ◽  
Large Numbers

Urban environments play a crucial role in the design, planning, and management of cities. Recently, as the urban population expands, the ways in which humans interact with their surroundings has evolved, presenting a dynamic distribution in space and time locally and frequently. Therefore, how to better understand the local urban environment and differentiate varying preferences for urban areas has been a big challenge for policymakers. This study leverages geotagged Flickr photographs to quantify characteristics of varying urban areas and exploit the dynamics of areas where more people assemble. An advanced image recognition model is used to extract features from large numbers of images in Inner London within the period 2013–2015. After the integration of characteristics, a series of visualisation techniques are utilised to explore the characteristic differences and their dynamics. We find that urban areas with higher population densities cover more iconic landmarks and leisure zones, while others are more related to daily life scenes. The dynamic results demonstrate that season determines human preferences for travel modes and activity modes. Our study expands the previous literature on the integration of image recognition method and urban perception analytics and provides new insights for stakeholders, who can use these findings as vital evidence for decision making.

scholarly journals Long-term changes of plumage between urban and rural populations of white-crowned sparrows (Zonotrichia leucophrys)

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Shawn H Smith ◽  
Jesi Hessong-Brown ◽  
Sara E Lipshutz ◽  
Jennifer N Phillips ◽  
Catherine Rochefort ◽  
...  
Keyword(s):  
San Francisco ◽  
Rural Areas ◽  
Urban Areas ◽  
Native Species ◽  
Urban Environments ◽  
Rural Populations ◽  
Zonotrichia Leucophrys ◽  
Selection Pressures ◽  
Rural Environments ◽  
Urban And Rural Areas

Abstract Urbanization is one of the most extreme forms of land transformation and results in changes to ecosystems and species compositions. As a result, there are strong directional selection pressures compared to nearby rural areas. Despite a surge in research on the different selection pressures on acoustic communication in urban and rural areas, there has been comparatively little investigation into traits involved with visual communication. We measured the plumage of museum specimens of white-crowned sparrows (Zonotrichia leucophrys) from urban and adjacent rural habitats in San Francisco, CA, to assess the effects of divergent habitats on plumage. We found significant differences in dorsal plumage, but not crown plumage, between urban and rural populations that have been diverging over the past 100 years. Urban birds have increasingly darker and duller dorsal plumage, whereas rural birds in adjacent areas have plumage with richer hues and more color complexity. Our findings suggest a newly observed adaptation to urban environments by native species and suggest that many traits, in addition to acoustic signals, may be changing in response to urban selection pressures. Additional collections in urban areas are needed to explore likely divergences in plumage coloration between urban and rural environments.

Ice-free area expansion compounds the non-native species threat to Antarctic terrestrial biodiversity

2019 ◽  
Author(s):  
Grant Duffy ◽  
Jasmine R Lee
Keyword(s):  
Human Activity ◽  
Native Species ◽  
Climate Scenario ◽  
Climatic Environment ◽  
Species Establishment ◽  
Suitable Habitats ◽  
Terrestrial Biodiversity ◽  
A Site ◽  
Area Expansion ◽  
Free Area

Warming across ice-covered regions will result in changes to both the physical and climatic environment, revealing new ice-free habitat and new climatically suitable habitats for non-native species establishment. Recent studies have independently quantified each of these aspects in Antarctica, where ice-free areas form crucial habitat for the majority of terrestrial biodiversity. Here we synthesise projections of Antarctic ice-free area expansion, recent spatial predictions of non-native species risk, and the frequency of human activities to quantify how these facets of anthropogenic change may interact now and in the future. Under a high-emissions future climate scenario, over a quarter of ice-free area and over 80 % of the ~14 thousand km2 of newly uncovered ice-free area could be vulnerable to invasion by one or more of the modelled non-native species by the end of the century. Ice-free areas identified as vulnerable to non-native species establishment were significantly closer to human activity than unsuitable areas were. Furthermore, almost half of the new vulnerable ice-free area is within 20 km of a site of current human activity. The Antarctic Peninsula, where human activity is heavily concentrated, will be at particular risk. The implications of this for conservation values of Antarctica and the management efforts required to mitigate against it are in need of urgent consideration.

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