Urban Gradient Research Articles

Reconstructing urban vegetation evolution in China using multimodal deep learning and 30-years Landsat archive

To retrospect the impact of urbanization on vegetation, consistent and reliable maps that provide urban vegetation estimates are required. In this study, we make the first attempt to employ deep learning for urban vegetation mapping of 2120 cities in China using a 30-years Landsat archive (UV-30). We present a multimodal deep learning (MDL) model to combine features from 5 categories, namely reflective bands, remote sensing indices, texture variables, topographical variables, and time labels. We normalized elevation data locally to remove the inter-city differences, while retaining topographic details. We used time labels to account for spectral variability over time and Landsat sensors. The performance of the MDL models was compared with a vanilla deep neural network, random forest, and support vector regression. Results indicated that the fusion of different categories of features improved the prediction accuracy. The MDL performed best in most validation cities, and our results were superior to the fractional maps aggregated from high-resolution datasets in homogeneous urban landscapes. We further analyzed urban vegetation dynamics across the urban core-new town-outskirt gradients of different geographical regions and city sizes. We found a gradually diminishing de-greening trend in urban China, especially in urban cores and new towns. Nevertheless, we observed a more pronounced degradation of urban vegetation in the south regions of China compared to the north, and smaller cities show no evident urban vegetation increase. The suggested framework is valuable for urban vegetation assessments and facilitates a thorough understanding and management of urban ecosystems.

Lead levels and abundance of microplastics in surface water and sediment along a rural–urban river gradient

Microplastics are commonly found in aquatic ecosystems and can pose environmental threats to aquatic organisms. While the threats of microplastic ubiquity are recognized, few studies have concomitantly quantified microplastic abundance and heavy metals along a rural–urban river continuum. In the current study, we studied changes in microplastics and heavy metals (using lead as a proxy) by collecting sediment and water samples along a rural–urban river over two seasons (temperate spring and summer) and across five sites in a North American River. Our results revealed that microplastics decreased in a downstream direction in surface water but did not change predictably in sediment samples collected along the river continuum. Regarding the relationship between microplastic abundance and lead concentrations, we found a positive relationship between microplastics in sediment samples and lead concentrations. Contrariwise, we found no discernible correlation between microplastics in surface water and lead concentrations along the river continuum. Given the presence of microplastics at every site and moderate lead pollution documented in the Wolf River, our results provide baseline data that can aid in the concurrent assessment of microplastics and heavy metals in river systems. These findings can inform environmental managers in planning pollution management strategies for waterways flowing through rural–urban areas.

Plant responses to urban gradients: Extinction, plasticity, adaptation

Abstract Biodiversity‐oriented urban management and planning require information on the drivers of wildlife composition and ecosystem function within cities. Urban landscapes impose environmental gradients along which species may be filtered away, or respond by showing adaptive variation in functional trait values. Such trait variation may in turn be due to a species' phenotypic plasticity, or a consequence of microevolution leading to local adaptation. This study investigates three possible plant responses to urban environmental gradients, with different evolutionary consequences: extinction, plasticity and adaptation. We assessed whether individual functional traits (LMA—leaf mass per area, plant height and flower length), population performance traits (seed mass and germination rate), as well as species frequency in the plant community, responded to gradients in mowing frequency, soil fertility and structure, temperature and surrounding mean building height, among four herbaceous plant species present in the metropolitan area of Strasbourg. Using a common garden experiment, we tested whether the observed trait variation was hereditary, and may thus constitute evidence for local adaptation. Our results detected the three types of expected responses. Plantago lanceolata is plastic to urban gradients, and Trifolium pratense showed both plastic and hereditary responses. Dactylis glomerata and Medicago lupulina showed all three responses: they both declined under increasing mowing frequency, were plastic to surrounding mean building height, and showed hereditary responses to different urban gradients. Urban management and planning therefore impact on the evolutionary capabilities of plants in cities. In the case of management this is highlighted by the detected trends in species' traits and frequency in response to mowing. The consequences of urban planning are evidenced by mean building height eliciting most often plastic and adaptive responses. Synthesis. Herbaceous plants often change their morphology in response to urban conditions: grass cutting, altered soils, warmer temperatures and being surrounded by tightly packed buildings. These changes are sometimes hereditary, which suggests that city management and planning affect the ability of plants to survive and evolve in urban environments.

Variation in species-specific responses to habitat fragmentation and land cover structure in urban small mammal communities

Abstract Urbanization is a key driver of habitat loss and fragmentation worldwide, yet many urban ecosystems contain vegetated habitat patches that support diverse wildlife communities. Managing urban systems to support robust wildlife communities requires us to understand the mechanisms that drive the response of species to the urban environment. Small mammals are key components of terrestrial ecosystems (e.g., seed predators, prey) and likely also carry out these roles in urban ecosystems; however, the effects of urbanization on small mammal communities are understudied. To identify how species-specific responses to urban environments shape community composition, we quantified both overall community and species-specific changes in small mammal abundance across an urbanization gradient in a Midwestern US metropolitan area. We combined small mammal trapping and land cover data to generate a hierarchical community abundance model. Species diversity increased with increasing proportional cover of human-modified land cover (i.e., impervious surfaces and turfgrass). This finding is driven by high species diversity on sites bordering streams in mowed parks and low diversity on sites with high tree canopy closure. Additionally, modeling results indicated that species responded differently to landscape attributes, leading to variation in small mammal community composition across the urbanization gradient: prairie-associated species tended to be more abundant in tall vegetation bordering mowed parks while habitat generalists tended to be more abundant on sites with greater canopy closure and shrub cover. Our results suggest that studies that focus on community-level responses (e.g., species richness) to urbanization may miss important species-specific responses. It may be particularly important to assess both species-specific and community-level responses in cities at ecotones (e.g., between forest and grassland) where species with different habitat requirements may replace one another in different types of green spaces, thereby changing community composition without affecting species diversity or richness. Our findings also indicate that vegetated urban patches, especially patches with tall vegetation cover and low canopy cover, are important habitat for prairie-associated small mammal communities, providing conservation options in heavily altered landscapes.

Biodiversity loss in a gradient of urbanization: rodent community structure in a subtropical area of Northern Argentina

Abstract Urbanization promotes habitat degradation because it involves irreversible processes that homogenize habitats and favor the exclusion of native species. This research evaluates rodent community structure at different levels of urbanization in Misiones, Argentina. We expect that rodent communities are less diverse in more highly urbanized areas and that communities differ between each level of urbanization. To assess these hypotheses, rodent capture sessions were carried out from July 2017 to March 2020, totaling 21,985 trap-nights. Alpha and beta diversity were calculated for each level of urbanization. We captured a total of 684 individuals belonging to 8 sylvan-native and 2 commensal-exotic species. Species richness was greatest and evenness was lowest in natural protected areas. The native species Akodon montensis was the most abundant, while the remaining 7 native species represented less than 23% of the total of captures. The rural area showed the second-highest richness, and the community was principally represented by 2 native and 2 exotic species. The periurban area was ranked third in richness and with the highest evenness, dominated by A. montensis followed by Mus musculus and Rattus rattus. The urban area exhibited the lowest richness represented only by the 2 commensal-exotic species. In agreement with our expectations, these results show a negative association between urbanization level and small rodent diversity, evidenced by a reduction in the number of native species in highly urbanized areas.

Intraspecific diversity of multiple plant species shows no change across an urbanization gradient

Intraspecific diversity of multiple plant species shows no change across an urbanization gradient

Genetic lineages of <i>Parisotoma notabilis</i> sensu lato (Hexapoda, Collembola) and their use in biological monitoring

Widespread species of small soil arthropods are being traditionally used in the biological monitoring of the environment. A promising development in this direction could be the usage of genetic methods, namely the composition of genetic lineages in populations of polytypic species. These species include the widespread springtail, Parisotoma notabilis sensu lato, which is especially abundant in Europe. At present, six lineages of this complex are known, the genetic distances between which are sufficiently close to the species. Previously, we showed the differentiation of genetic lineages in an urbanization gradient (natural forest – forest park – urban lawn) using the Moscow region as an example. In this work, the divergence of genetic lineages in these habitats was confirmed for various natural zones. The least disturbed habitats are marked by lineages L2, L4-Hebert and L0, the most disturbed ones by L1. Monitoring changes in the soil layer of ecosystems is possible only in zones of sympatry of different P. notabilis genetic lineages, i.e. the areas where they co-occur. Such areas seem to include the entire European part of Russia.

Soil animal communities demonstrate simplification without homogenization along an urban gradient.

Urbanization profoundly impacts biodiversity and ecosystem function, exerting an immense ecological filter on the flora and fauna that inhabit it, oftentimes leading to simplistic and homogenous ecological communities. However, the response of soil animal communities to urbanization remains underexplored, and it is unknown whether their response to urbanization is like that of aboveground organisms. This study investigated the influence of urbanization on soil animal communities in 40 public parks along an urbanization gradient. We evaluated soil animal abundance, diversity, and community composition and related these measures to urban and soil characteristics at each park. The most urbanized parks exhibited reduced animal abundance, richness, and Shannon diversity. These changes were influenced by many variables underscoring the multifaceted influence of urbanization on ecological communities. Notably, contrary to our expectation, urbanization did not lead to community homogenization; instead, it acted stochastically, creating unique soil animal assemblages. This suggests that urban soil animal communities are concomitantly shaped by deterministic and stochastic ecological processes in urban areas. Our study highlights the intricate interplay between urbanization and soil animal ecology, challenging the notion of urban homogenization in belowground ecosystems and providing insight for managing and preserving belowground communities in urban areas.

Understanding Ixodes ricinus occurrence in private yards: influence of yard and landscape features

BackgroundLyme borreliosis is the most frequent zoonotic disease in the northern hemisphere and is transmitted by ticks of the genus Ixodes. Although many people are bitten by ticks in private yards, our understanding of the factors associated with their presence in these areas remains limited. To address this gap, we used a citizen science approach to identify the local and landscape features associated with tick presence in yards.MethodsThis study was conducted near Nancy, a city in northeastern France, from 2020 to 2022. Citizen scientists collected ticks in their yard on a single event (n = 185) and measured 13 yard features. Additionally, we computed 11 features related to the landscape composition and spatial configuration surrounding these yards. Using generalized linear mixed models, we determined the yard and landscape features associated with the presence of ticks and nymphal Ixodes ricinus (hereafter nymphs), the life stage, and species that mostly bite humans.ResultsDespite a low density, ticks were found in 32% of the yards, including yards in urbanized areas. At the transect level, the likelihood of finding a nymph was nearly three times higher in transects shaded by vegetation compared to those in open areas, with no relationship between nymph occurrence and transect location or grass height. At the yard level, the occurrence of ticks and nymphs was related to both yard and landscape characteristics. Nymph and tick occurrence were more than twice as high in yards with signs of deer and a wood/brush pile compared to those without these characteristics, and increased with the connectivity of vegetation areas and the percentage of forest areas in the landscape.ConclusionsOur study reveals that private yards across an urbanization gradient are locations of tick exposure with tick presence linked to both yard and landscape factors. These findings emphasize the importance of public awareness regarding tick exposure in yards and provide crucial insights for future public health prevention campaigns.

Occupancy dynamics of the mottled owl Strix virgata using object-based image analysis along an urbanized Neotropical gradient

Urbanization has profound effects on wildlife. Although some species benefit or even thrive in urban environments, most species respond differently to the varying degrees of disturbance that can be found across an urbanized landscape. Quantifying the effects of urbanization in wildlife distributions, however, is complicated: species vary in their patterns of presence/absence, abundance, and detectability across spatial and temporal scales, e.g., daily, seasonal, or throughout the annual cycle. Here, we use occupancy models to offer a realistic approach to the study of populations of urban owls. Most studies on owl population dynamics have not considered temporal variation in occupancy between seasons or assess the uneven effects of urbanization along a habitat gradient. We investigated the seasonal habitat associations of mottled owls along an urban gradient in the Neotropical city of Xalapa, Veracruz, Mexico. Using high-resolution satellite images and object-based image classification techniques, were analyzed the relationship between different vegetation and environmental characteristics with the occupancy of mottled owls. We employed different sampling techniques, including playback surveys and silent listening periods, to detect the presence or absence of owls along a gradient from highest to lowest urbanization. Environmental data and different vegetation types were used to analyze the habitat associations of mottled owls during January (late non-breeding season) and May (late breeding season) of 2023. In total, we detected 68 mottled owls during the non-breeding season and 102 during the breeding season, with higher detection rates in areas with >28 % forest surface. Our results revealed that the best occupancy model included forest and forest division (occupancy), ambient noise and moonlight (detection) for the non-breeding season, as well as urban, forest, grass, and forest division (occupancy), and noise (detection) for the breeding season. The percentage of forested and grass areas positively influenced mottled owl occupancy while the percentage of urbanization and forest division influenced it negatively. Moonlight was positively related to mottled owl detection, while ambient noise had a negative effect on detection probabilities of mottled owls during both seasons. Forested areas emerged as pivotal for owl occupancy, indicating their sensitivity to forest changes along the urban gradient. With urban areas increasing, the interplay between forest division, ambient noise, and moonlight unveils critical insights into mottled owl behavior and habitat dynamics, underscoring the necessity for informed conservation strategies amidst urban expansion. Future research should survey different years to provide a more robust assessment of the dynamic occupancy of mottled owls in Neotropical urban gradients.

Unveiling riverine N2O dynamics along urbanization gradients by integrating hydrological, biogeochemical and microbial processes

Human-disturbed rivers are globally significant sources of atmospheric nitrous oxide (N2O). Yet, the underlying mechanisms of urbanization impact on riverine N2O dynamics are not well understood. This study unveiled the effects of urbanization on N2O dynamics by integrating hydrological, biogeochemical and microbial processes in a river with various urbanization intensities. Riverine NO3− concentration enhanced with increasing urban land percentage, primarily because of the increased proportional contribution of sewage & manure source. The 15N site preference and relevant isotopic evidences revealed that the proportion of denitrification derived N2O increased from 60% to 76%, with the urban land percentage increasing from < 5% to > 22%, which was caused by decreases in flow velocity and dissolved oxygen saturation, increases in NO3− concentration and N2O-denitrifying genes. The non-negligible contribution of nitrification to N2O production (∼ 40%) in lower-urbanized river stretches may be attributed to aerobic conditions and lower impermeable riparian zone facilitating the occurrence of in-river nitrification and the access of in-soil nitrification to river. Urbanization-mediated decreases in flow velocity and dissolved oxygen and increases in nitrogen availability and denitrification process resulted in an increase in N2O concentration and flux, with N2O concentration approximately four times higher in higher-urbanized river reaches (50.7 ± 26.3 nmol/L) than in lower-urbanized river reaches (14.4 ± 2.5 nmol/L). In addition, increased proportional contribution of sewage & manure source also provides the possibility for exogenous N2O inputs with urban expansion. These findings contribute to deepening our understanding of how urbanization drives N2O dynamics in river systems.

Patterns and causes of soil heavy metals and carbon stock in green spaces along an urbanization gradient

The surge in urbanization has correspondingly given rise to exacerbated carbon footprint and burgeoning heavy metal (HM) contamination, constituting a critical impediment to the realization of environmentally sustainable urban development pathways. Therefore, it is highly essential to investigate the impacts of urbanization process on soil carbon, heavy metals (HMs), as well as their interrelationships. Employing remote sensing and land use data within a 45 km radius in Chongqing, this study selected 31 sites to assess the variation in urban green spaces (UGSs) carbon sequestration capabilities and associated HM pollution risks across differing urbanization levels. Results showed that urbanization dynamics and land use history play a more decisive role than current anthropogenic management in shaping the distribution of soil carbon and HMs within urban environments. The average soil organic carbon (SOC) distribution of UGSs is 8.47 mg ha−1 (1.50–24.20 mg ha−1), concurrent with moderate HM pollution showing Ni: 32.03–33.50 mg kg−1, Pb: 27.93–29.65 mg kg−1, Cu: 26.97–41.20 mg kg−1, while Cd exhibits the most severe pollution range of 0.23–0.30 mg kg−1. The rate of urbanization significantly influences SOC stocks, exhibiting an increase when the urbanization rate is below 70.79 % and a decrease upon surpassing this threshold. The concentration of HMs is predominantly determined by the historical usage of the land, with a marked escalation correlating with the duration of land utilization history. These relationships were quantitatively modeled through the application of fitted linear functions. The structural equation model demonstrated that UGSs operating without anthropogenic disturbance tend towards degradation, indicating that temporary homeostasis might be sustained via the addition of N and P nutrients and pH modulation. In conclusion, we formulate an Urban Green Spaces Development Hypothesis that aims to shed light on the multifaceted challenges encountered by cities amidst varying degrees of urbanization and, concurrently, to probe potential ameliorative strategies.

Metal concentration in honeybees along an urbanization gradient in Central Mexico

Urbanization is rapidly increasing worldwide, leading to rising levels of pollution, one of the major drivers of environmental change; yet little is known about the relationship between urbanization intensity and pollution levels in pollinator taxa. Toxic metals are among the most common contaminants in urban environments, but few data exist on their presence in the flora and fauna of cities in Latin America, one of the world's most urbanized and biologically diverse regions. In this study, we used an urban-rural gradient approach to analyze the relationship between the concentrations of eleven metals present in adult honeybees (Apis mellifera) and the degree of urbanization within twelve landscapes in the metropolitan area of Pachuca, Hidalgo, which forms part of the megalopolis of Mexico City. Metal concentrations were compared with previously reported values contrasting honeybees from urban and rural areas after standardizing urbanization levels among published reports. The concentrations of Ag, Cr, Cu, and Zn in honeybees increased significantly with the degree of urbanization. Urbanization was not found to influence the levels of Al, Ba, Cd, Mn, and Sr in honeybees. The maximum concentrations of six metals in our urban sites (Al, Ba, Cd, Cu, Mn, and Sr) were higher than the maximum values reported for bees in other urban areas. The concentrations of two metals measured in our study (Cr and Zn) were within the range of values previously published for urban areas. Compared to other studies, we did not detect Pb in the body of honeybees. We conclude that the concentrations of Ag, Cr, Cu, and Zn present in honeybees are a quantitative reflection of the degree of urbanization in central Mexico. Our results highlight the need to monitor metal emission sources in this and other areas and investigate their effects on bees and other pollinator taxa.

Urbanization alters sandy beach scavenging assemblages and dogs suppress ecosystem function

AbstractUrbanization is rapidly transforming coastal landscapes around the world, altering the structure and function of marine, intertidal, and terrestrial ecosystems. In tandem, coastal areas are hotspots for human recreation, leading to shifts in wildlife behavior and activity patterns. Together, urban development and recreational use of wildlife habitats can shape wildlife behavior, abundance, and ecosystem dynamics at different spatial and temporal scales. In this study, we explore the impact of urbanization and human and domestic dog activity on the structure of vertebrate scavenging assemblages and the ecosystem functions they provide in sandy beach ecosystems across 40 km of the central California coast, USA. We surveyed vertebrate scavenging assemblages using baited camera traps on 17 beaches spanning a gradient of coastal urbanization. We found that urbanization extent within small spatial scales (i.e., 1 or 3 km radii of each site) and the rate of beach visitation by domestic dogs or humans were the best additive predictors of assemblage structure. We identified pronounced urbanization‐associated shifts in the composition of vertebrate scavenger guilds but found that the rate of carrion processing was more strongly influenced by domestic dog habitat use and diel period. Scavenging activity was substantially lower on beaches with more domestic dogs, suggesting that dogs interfere with critical scavenging ecosystem functions on sandy beaches. Our results underscore the pervasive and nuanced effects of urbanization and recreation on the dynamics of land–sea connectivity and suggest a need for comprehensive consideration of cross‐ecosystem linkages in ongoing shoreline conservation and development efforts.

Effects of urbanization on orchid bee diversity and orchid pollination: From neotropical cloud forests to urban cores

Urbanization is a significant driver of land use change, profoundly impacting biodiversity and ecosystem services worldwide. However, its effects in the tropics, which host some of the planet's highest biodiversity, remain inadequately understood. Orchid bees (Apidae: Euglossini) are key pollinators in Neotropical ecosystems, playing crucial roles in maintaining floral diversity and reproductive success of orchids and other plant families. Yet, little is known about how urbanization influences their diversity and pollination. In this study, we analyzed the diversity and composition or orchid bee communities along an urbanization gradient which extends from the city center to the surrounding cloud forests, which bear high orchid endemism while being highly threatened. Along the same gradient, we further evaluated pollination of a model native orchid, Gongora galeata, which is exclusively pollinated by the bee Euglossa obrima. As expected, increasing urbanization led to a decrease in orchid bee diversity, as well as a clear separation in species composition between urban and non-urban sites and a reduction in G. galeata pollination (i.e. fruit production). However, contrary to our expectations, orchid pollination also decreased with environmental heterogeneity and the abundance of its specific pollinator. Despite urban areas still hosting orchid bee species, our results reveal clear negative effects of urbanization not only on diversity, but also on the ecosystem function of a highly threatened group of bees. This study highlights the importance of considering local factors of urban landscapes for preserving not only biodiversity, but also fundamental ecological processes in cities.

Influence of livelihood assets on biodiversity and household food security in tropical homegardens along urbanisation gradients

Abstract By 2050, 70% of the global population will reside in urban areas, raising concerns about food security and biodiversity loss. Tropical homegardens, a form of agroforestry, may have the potential to align concurrent demands for biodiversity conservation and food security in urban environments. Nevertheless, this depends on land-use decision-making strategies that are enabled by household livelihood assets. We examined which livelihood assets are associated with homegarden agrobiodiversity and food availability and accessibility in Kerala, India, the nature of these associations, and whether they vary along urbanisation gradients using data from 304 homegardens. We observed higher plant species richness closer to the urban centre and in smaller homegardens. Meanwhile, yields and share of household food consumption from homegardens tend to be higher farther away from urban centres. Assets like fertilizer use, irrigation and kinship affiliation are positively associated with both homegarden agrobiodiversity and food outcomes. Conversely, homegarden size is negatively associated with biodiversity outcomes across urbanisation gradients and positively associated with yield outcomes furthest away from urban centre. Some assets like family labour and farming association membership were only positively associated with food outcomes, while others like external labour availability were positively associated only with plant diversity in the urban centre. Overall, synergies between homegarden agrobiodiversity and household food security requires inputs to natural processes, such as irrigation and soil fertility, and social processes like knowledge sharing and social cohesion, especially in urban peripheries. We emphasize the relevance of homegardens and enhancing livelihood assets for food-secure households in biodiverse urban environments.

Constitutive innate immune defenses in relation to urbanization and population density in an urban bird, the feral pigeon Columba livia domestica.

Urbanization processes modulate the immunological challenges faced by animals. Urban habitat transformations reshape pathogen diversity and abundance, while high population density-common in urban exploiter species-promotes disease transmission. Responses to urbanization may include adaptive adjustments of constitutive innate immune defenses (e.g. complement system and natural antibodies [NAbs]), which serve as first-line protection against infections. Here, we investigated associations of habitat urbanization and host population density with complement and NAbs in an urban bird, the feral pigeon Columba livia domestica. To do so, we employed the hemolysis-hemagglutination assay to analyze nearly 200 plasma samples collected across urbanization and pigeon population density gradients in five major cities in Poland. We found a negative association between urbanization score and hemagglutination (i.e. NAbs activity), but not hemolysis (i.e. complement activity), indicating either immunosuppression or adaptive downregulation of this immune defense in highly transformed urban landscape. Population density was not significantly related to either immune parameter, providing no evidence for density-dependent modulation of immune defenses. At the same time, there was a negative association of hemolysis with condition (scaled mass index), suggesting resource allocation trade-offs or contrasting effects of the urban environment on immune defenses and body condition. The results demonstrate that habitat structure can be an important factor shaping the immune defenses of the feral pigeon, although these associations were not mediated by variation in population density. Our study highlights the complexity of the links between immune defenses in wildlife and urbanization and reinforces the need for comprehensive ecoimmunological studies on urban animals.

Diversity and Activity of Soil N2O-Reducing Bacteria Shaped by Urbanization.

Nitrous oxide (N2O) is a potent greenhouse gas with various production pathways. N2O reductase (N2OR) is the primary N2O sink, but the distribution of its gene clades, typically nosZI and atypically nosZII, along urbanization gradients remains poorly understood. Here we sampled soils from forests, parks, and farmland across eight provinces in eastern China, using high-throughput sequencing to distinguish between two N2O-reducing bacteria clades. A deterministic process mainly determined assemblies of the nosZI communities. Homogeneous selection drove nosZI deterministic processes, and both homogeneous and heterogeneous selection influenced nosZII. This suggests nosZII is more sensitive to environmental changes than nosZI, with significant changes in community structure over time or space. Ecosystems with stronger anthropogenic disturbance, such as urban areas, provide diverse ecological niches for N2O-reducing bacteria (especially nosZII) to adapt to environmental fluctuations. Structural equation modeling (SEM) and correlation analyses revealed that pH significantly influences the community composition of both N2O-reducing bacteria clades. This study underscores urbanization's impact on N2O-reducing bacteria in urban soils, highlighting the importance of nosZII and survival strategies. It offers novel insights into the role of atypical denitrifiers among N2O-reducing bacteria, underscoring their potential ecological importance in mitigating N2O emissions from urban soils.

Impact of urbanization on gut microbiome mosaics across geographic and dietary contexts.

The study examined gut microbiome composition across diverse geographical locations in Kazakhstan, spanning urban centers and rural settlements. This allows for thoroughly investigating how urbanization gradients and geographic factors shape the gut microbiome. The study's examination of the gut resistome and prevalence of virulence-associated genes provide essential insights into the public health implications of urbanization-driven microbiome alterations. Collecting comprehensive demographic, dietary, and stool sample data enables the researchers to better understand the relationships between urbanization, nutritional patterns, and gut microbiome composition. The findings have important implications for understanding how urbanization-driven microbiome changes may impact human health and well-being, paving the way for tailored interventions to restore a balanced gut microbial ecology.

Amphibian diversity across an urban gradient in southern South America

Amphibian diversity across an urban gradient in southern South America