Urbanization impacts the taxonomic and functional structure of aquatic macroinvertebrate communities in a small Neotropical city

Due to habitat fragmentation, resource disruption and pollution, urbanization is one of the most destructive forms of anthropization affecting ecosystems worldwide. Generally, human-mediated perturbations dramatically alter species diversity in urban sites compared to the surroundings, thus influencing the functioning of the entire ecosystem. We investigated the taxonomic and functional diversity patterns of the aquatic macroinvertebrate communities in tank bromeliads by comparing those found in a small Neotropical city with those from an adjacent rural site. Changes in the quality of detrital inputs in relation to lower tree diversity and the presence of synanthropic species are likely important driving forces behind the observed structural changes in the urban site. Leaf-litter processors (i.e., shredders, scrapers) were positively affected in the urban site, while filter-feeders that process smaller particles produced by the activity of the shredders were negatively affected. Because we cannot ascertain whether the decline in filter-feeders is related to food web-mediated effects or to competitive exclusion (Aedes aegypti mosquitoes were present in urban bromeliads only), further studies are necessary to account for the effects of intra-guild competition or inter-guild facilitation.     

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

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

     

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

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

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

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

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

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

Energy crop production in an urban area: a comparison of habitat types and land use forms targeting economic benefits and impact on species diversity

In urban areas, the potential of biomass production is rarely utilized, although many biomass sources are located in cities, ranging from road margins to public parks. There is, however, increasing interest in these potential biomass sources, as they are close to consumers and provide options to reduce maintenance costs of urban green areas. We analyzed the costs and benefits of utilizing biomass, and compared it to the biodiversity maintained on 17 urban land use forms the Ruhr Metropolitan Area (Germany). Economic costs and benefits were reflected by contribution margins, while biodiversity was measured by species numbers of plants, birds and butterflies. For the 17 land use types, there is a weak overall correlation between contribution margins and species numbers. However, this is mainly due to the two land use forms with the highest contribution margins (cultivation of energy maize and fertilized grassland), which are characterized by the lowest species numbers. For the remaining cases, there is no relationship between contribution margins and species numbers. Comparatively high contribution margins and high mean species numbers were observed for road margins, industrial fallows with wood cutting for biogas production and water-influenced grassland mown traditionally. We conclude that biomass production and the maintenance of urban biodiversity is not necessarily a contradiction.     

Similar effects of residential and non-residential vegetation on bird diversity in suburban neighbourhoods

Estimating the relative importance of vegetation on residential land (gardens, yards, and street-trees) and vegetation on non-residential land (parks and other large green spaces) is important so that competing options for urban conservation planning can be prioritized. We used data from an urban breeding-bird monitoring program to compare the relative effects vegetation on residential land and vegetation on non-residential land (both the amount and type of vegetation at local and landscape scales) on bird species richness and an index of conservation value for the bird community. We then estimated the realised relative benefit of managing the amount of vegetation on these two types of land (i.e., as alternative management options for promoting biodiversity), which might be achieved within the practical limits imposed by human population density. The local effects of increasing residential and non-residential vegetation amount were similar and positive on all measures of bird species richness and conservation value. Non-residential vegetation had an additional landscape-scale influence on bird diversity that residential vegetation did not. Options for managing the amount of non-residential vegetation appear to be more limited by high human population density than for managing the amount of residential vegetation. This suggests that there may be greater realised benefits to bird diversity from managing the amount of vegetation on residential land than from the more common focus of urban planning of managing vegetation on non-residential land.     

Influence of a parking area on soils and vegetation in an urban nature reserve

We studied the influence of a car park on soil and vegetation within Richmond Park, UK, before and after imposition of fenced boundaries restricted public access. Soil and vegetation samples were taken before (once) and after (twice) access restrictions were enforced. The over-riding trend in all the data was for soil adjacent to the car park to be less acidic and more fertile than pristine local soils, accompanied by a more eutrophic grassland community (Lolium perenne/Trifolium repens, compared with Agrostis/Festuca grassland away from the car park). The chemical influence of the car park extended at least 50 m from its boundary. A common acidophilic collembole Folsomia quadrioculata was replaced by Cryptopygus thermophilus adjacent to the car park. There was little evidence from the vegetation data that car park closure benefitted the ecosystem, but chemical data showed signs of progressive recovery in the 2 years following restrictions. Possible explanations for the car park's influence on the local landscape are suggested to include calcareous chippings and canine faecal deposits.     

Frugivory and habitat use by thrushes (Turdus spp.) in a suburban area in south Brazil

Thrushes (Turdus spp., Turdidae) are among the most common frugivorous birds in urban areas around the world, where they disperse the seeds of a variety of plant species. We studied the abundance, habitat use, foraging behavior and diet of four thrush species (Turdus rufiventris, T. amaurochalinus, T. leucomelas, and T. albicollis) in a suburban area in south Brazil. Abundance, habitat use and foraging behavior were based on birds surveyed along a 3,240 m transect crossing open (formed by lawns, streets, and buildings) and forested areas. Diet was based on fecal samples collected from mist-netted birds. Turdus rufiventris was the most abundant species, followed by T. amaurochalinus, T. leucomelas, and T. albicollis. All species used forest fragments more frequently than expected by chance. A total of 91.8% (n = 147) of the fecal samples contained fruit remains, while 42.2% contained only animal matter. Most of the foraging records were on the ground, where birds got mainly invertebrates. Fruits and invertebrates were eaten more frequently in open than in forested areas. A total of 25 seed morfospecies were found in the droppings, including five exotic plant species. Thrushes overlapped widely in the fruit composition of their diets. The high abundance and degree of frugivory, coupled with the frequent use of forest patches, indicate that thrushes are among the great bird contributors to the seed dispersal occurring in urban forest patches, potentially influencing the vegetation dynamics of such habitats so important for the maintenance of the biodiversity in urban areas.     

Seasonal patterns of urban bird diversity in a Mediterranean coastal city: the positive role of open green spaces

Urban Ecosystems - Urbanization causes rapid changes in the landscape and land use, exerting a significant pressure on bird communities. The effect of urbanization on bird diversity has been widely...     

Value of park reserves to migrating and breeding landbirds in an urban important bird area

Increasing urban development threatens not only breeding habitat for migratory landbirds but also critical stopover habitat. The purpose of this study was to investigate the relationship between landbird community composition and land cover in and surrounding urban park reserves in the Mississippi River Twin Cities Important Bird Area (IBA) in order to evaluate this area’s value during both spring migration and summer breeding seasons. This IBA includes a mosaic of residential, commercial, and park reserve land running along the Mississippi River between Minneapolis and Hastings, Minnesota. Using citizen-science data collected at 8 park reserve sites in the IBA between 2007 and 2010, we calculated species richness, diversity, and evenness for the migrating and breeding landbird community at each site and categorized species into three conservation statuses (species of greatest conservation need, native and exotic) and four migratory behavior classes (permanent residents, short-distance migrants, resident neotropical migrants, and en-route neotropical migrants). We used AIC to rank multiple regression models to evaluate how these groupings vary across sites in comparison to the land cover in and surrounding each site. We found that most measures of both the spring migration and breeding communities were negatively related to increased impervious cover. Exotic species and permanent residents were less affected by surrounding land use, while breeding season resident and transitory neotropical migrants were greatly affected. Patterns of landbird richness and density suggest that removing impervious cover within lower quality sites can improve habitat supporting migrating birds.     

In-stream habitat predicts salamander occupancy and abundance better than landscape-scale factors within exurban watersheds in a global diversity hotspot

Urban Ecosystems - The southern Appalachian Mountains have experienced rapid human population growth rates since the 1980s. Land used practices are shifting from rural to residential. The majority...     

Educational guidance for functional visual diversity in Nicaragua. Design and evaluation of a teacher-training program

The article exposes the process of design and implementation of a training program for teachers that teach people with Visual Functional Diversity (VFD), taking into account their needs both in training and in the provision of resources in Nicaragua. To verify the effectiveness of the program, a quasi-experimental design was carried out with a non-equivalent pretest and posttest control group. The experimental group received training while the control group did not receive training. The evaluation of the results obtained after the application of the program was carried out through two instruments: an efficacy questionnaire and a satisfaction questionnaire. The results showed significant differences between the experimental and control group after the application of the program (Z = −4,383; p = 0.000) in favor of the experimental group. It is confirmed that the program is effective in training teachers on inclusive education for the visually impaired as the teachers who took part in the training program significantly increased their knowledge in that issue.     

Effects of dog leash laws and habitat type on avian and small mammal communities in urban parks

Remnant natural areas within urban settings can act as important refuges for wildlife, substantially increasing local biodiversity. However, habitat suitability for these species is potentially affected by human recreational activities including the presence of free-running dogs. To compare the diversity and abundance of songbird and small mammal communities between areas with bylaws that require, or do not require, dogs to be leashed, point counts and live-trapping surveys were conducted in three habitat types (deciduous, coniferous, and meadow) in the river valley parks of Edmonton, Alberta. Among birds, there was no difference between areas with different leashing bylaws in species diversity for any of the three habitat types. Similarly, there was no difference in bird diversity for a subset of species that were plausibly breeding at these sites. However, higher bird diversity was recorded in deciduous and coniferous sites than in meadow sites, regardless of leash designation, probably as a function of the horticultural practice of mowing meadows. Among both birds and small mammals, there was no difference in the abundance of individuals as a function of leashing bylaws. Our results suggest that off-leash dogs have no effect on the diversity or abundance of birds and small mammals in urban parks, but it is also possible that other factors, such as leash law compliance, reduced or obscured the effects of off-leash dogs in this study.     

Influence of testosterone substitution on glycemic control and endothelial markers in men with newly diagnosed functional hypogonadism and type 2 diabetes mellitus: a randomized controlled trial

Abstract

Effects of testosterone (T) on the cardiovascular system of men remain controversial. The impact of T-replacement therapy (TRT) in men with functional hypogonadism and type 2 diabetes mellitus (T2DM) has to be elucidated. This study included 80 men (mean age 51.5?±?6.3 years) with newly diagnosed T2DM (according to ADA criteria) and functional hypogonadism (according to EAU criteria). Randomization: Group1 (n?=?40): TRT using 1%-transdermal T-gel (50?mg/day), Group2 (n?=?40) no TRT (controls). Dietary treatment applied to both. Parameters at baseline/after 9?months: anthropometric parameters, lipids and indicators of carbohydrate metabolism (fasting glucose, insulin, HbA1c, HOMA-IR), markers of adipose tissue and EnD (leptin, resistin, p- and e-selectin, ICAM- 1, VCAM- 1 and CRP). ANCOVA for repeated measurements revealed TRT to cause a significant decrease in waist circumference (WC), HOMA-IR and HbA1c vs controls (p?<?.001, p?=?.002, p?=?.004, respectively). Leptin declined in subjects receiving TRT vs controls (p?=?.04). Concentrations of resistin, ICAM-1, p-selectin and CRP decreased significantly vs controls (all p?<?.001); no effects for e-selectin and VCAM-1. Advanced age attenuated effects, higher delta testosterone levels augmented effects. Decrement of WC was related to decreasing markers of adipose tissue secretion/EnD. TRT in men with functional hypogonadism and T2DM improved carbohydrate metabolism and markers of endothelial dysfunction.     

Influence of seasonality and vegetation type on suburban microclimates

Urbanization is responsible for some of the fastest rates of land-use change around the world, with important consequences for local, regional, and global climate. Vegetation, which represents a significant proportion of many urban and suburban landscapes, can modify climate by altering local exchanges of heat, water vapor, and CO₂. To determine how distinct urban forest communities vary in their microclimate effects over time, we measured stand-level leaf area index, soil temperature, infrared surface temperature, and soil water content over a complete growing season at 29 sites representing the five most common vegetation types in a suburban neighborhood of Minneapolis–Saint Paul, Minnesota. We found that seasonal patterns of soil and surface temperatures were controlled more by differences in stand-level leaf area index and tree cover than by plant functional type. Across the growing season, sites with high leaf area index had soil temperatures that were 7°C lower and surface temperatures that were 6°C lower than sites with low leaf area index. Site differences in mid-season soil temperature and turfgrass ground cover were best explained by leaf area index, whereas differences in mid-season surface temperature were best explained by percent tree cover. The significant cooling effects of urban tree canopies on soil temperature imply that seasonal changes in leaf area index may also modulate CO₂ efflux from urban soils, a highly temperature-dependent process, and that this should be considered in calculations of total CO₂ efflux for urban carbon budgets. Field-based estimates of percent tree cover were found to better predict mid-season leaf area index than satellite-derived estimates and consequently offer an approach to scale up urban biophysical properties.     

Influence of water quality and habitat conditions on amphibian community metrics in rivers affected by urban activity

Urban Ecosystems - Anuran amphibians are highly dependent on aquatic ecosystems. Many amphibian species are exhibiting population declines primarily due to habitat destruction and water quality...     

Influence of urban landscape structure on bird fauna: a case study across seasons in the city of Valencia (Spain)

Studies on bird fauna of urban environments have had a long history, but the potential of studies mapping the distribution of birds in cities probably has not fully developed. The bird fauna of the municipality of Valencia (Spain) was studied to determine the influence of urbanization on bird species richness and abundance. Birds were censused during winter and the breeding season of years 1997–1998 in 197 squares measuring 49 ha each from a rural and an urbanized area. Across seasons the number of species decreased around 40% in the city compared with the rural landscape surrounding it. Such pattern could be attributed to the low number of farmland species capable to use the habitats inside the city, and the limited ability of urban parks in attracting woodland species. In the urban landscape, the influence of the dimensions and spatial arrangement of habitat patches was outweighed by the amount of each habitat per square. Bird richness and the abundance of most species were negatively related with the amount of built-up habitat per square and positively with the amount of urban parks, and of habitat diversity. Conversely, bird fauna was largely independent of mean park size per square especially during winter, indicating that at the landscape scale even small patches of habitat could play an ecological role. Conservation of urban bird diversity could benefit of two complementary strategies: (i) the protection of the surrounding rural landscape from urban development; (ii) habitat enhancement within the city. Particularly, a proper design and habitat management of urban parks could improve their suitability for urban bird fauna.