Urban Ecosystems最新文献

The vocal behavior of Neotropical birds has received less attention compared to birds in Northern temperate regions. Many bird species rely on acoustic communication to establish and maintain territories and to interact with conspecifics. For this reason, the growing threat of noise pollution in their habitats is a cause for concern. Birds perform behavioral adjustments when confronted with atypical environmental situations (e.g. urban noises, artificial light, human voice or vegetation loss). The aim of this study was to investigate vocal adjustments of Masked Gnatcatcher (Polioptila dumicola) males in environments located near a route with varying level of traffic noise (measured in decibels) and differing percentage of cover vegetation. Linear mixed models (LMMs) were used to analyze the effects of both environmental parameters in P. dumicola song. Results reveal that P. dumicola increases the amplitude of its songs in response to higher levels of traffic noise. Cover vegetation did not show any effect on song parameters. The model with the highest significance demonstrates a positive linear relationship between amplitude and traffic noise. These findings underscore the importance of studying communication alterations in noisy environments and understanding the ecological consequences of such effects on bird populations.

Of 6,012 surveyed trees, 353 hosted mistletoes, but 50 of 96 species did not.

Four tree-related factors affected mistletoe prevalence (3 positively/1 negatively).

Only tree size (positively) affected infection intensity.

Abstract

The floristic richness of Bosnia and Herzegovina has been extensively studied, however urban flora has only recently garnered attention, but no systematic surveys of urban ecosystems have been carried out. To address this problem, a study of the seven urban floras in Bosnia and Herzegovina was conducted to determine the pattern of floristic diversity and correlation with anthropogenic factors: size of the urban area, ratio of green areas in the total urban area, number of inhabitants, and population density. The first finding of the study is that urban floras in Bosnia and Herzegovina are rich in plant species. The results have shown that the urban floristic diversity largely reflects the natural vegetation of the urban environment, compared to urban floras in other parts of Europe. Species structure reflects the geographical location as well, so are the urban areas in the Mediterranean biogeographical region, Mostar and Blagaj, floristically richer, but at the same time species richness correlates with the total urban area, as in Sarajevo and Banja Luka. Moreover, the proportion of alien species is low and there is no pronounced process of floras homogenisation. Of the anthropogenisation factors, population density correlates most strongly with the richness of urban flora. From the results, we have concluded that urban plant diversity correlates with both environmental and anthropogenic factors, in a way that provides a basis for establishment of conservation programs in urban ecosystems.

Urban green cover provides ecosystem services for human well-being and better conditions for biological conservation. Structural analysis and monitoring across space and time at landscape scale can aid better design and management of urban green cover. In this study, we used Sentinel-2 satellite imagery and semiautomatic reclassification methods (i.e., supervised classification) in Google Earth Engine (GEE), to analyze changes in built and urban green cover of Medellín and adjacent municipalities (Colombia) between 2016 and 17 and 2022-23. We used total area, patch number, mean patch area, and patch cohesion index as proxies of landscape structural changes, differentiating grass from trees. Built cover increased its total area from 77.1 to 80.5%, whereas grass and trees decreased it from 6.4 to 5.8%, and 16.6–13.8%, respectively. Built cover decreased in patch number by 1.4% and increased in mean patch area from 7.08 to 7.72 ha, whereas trees decreased in patch number by 7.8% and grass increased by 9.2%. Both green cover categories decreased in mean patch area (trees: 0.27 to 0.23 ha; grass: 0.24 to 0.15 ha). Otherwise, the patch cohesion index decreased in grass and trees, while in built cover it remained constant over time. Urban green cover in Medellín urban area and adjacent municipalities is increasingly reduced and isolated, whereas urbanization sprawls and densifies, suggesting that local development policies need improvement to prevent urban green cover degradation.

Urban expansion is an important cause of biodiversity loss due to habitat destruction involving the replacement of the natural environment with anthropic infrastructure. However, recent studies suggest that the harmonious growth of cities could allow the persistence of biological diversity within them. Thus, some cities, especially those that contain remnant forests that preceded their expansion, could harbor high levels of biodiversity. These remnant forests, i.e., urban natural forests (UNFs), are refuges for native species, providing suitable habitat conditions for population stability. However, traditional ecological studies have focused on natural and planted forests, so our knowledge of ecological dynamics in UNFs is still limited. Here, we explore the suitability of a temperate UNF for saproxylic beetles. These beetles are deadwood-dependent, highly diverse trophic groups that commonly inhabit natural forest ecosystems. However, saproxylic beetle diversity has been understudied in urban forest ecosystems. We analyzed the species richness, abundance, and seasonal variation of saproxylic beetles, including their most important trophic guilds, associated with urban forests. For this purpose, we monitored standing dead trees monthly between December 2019 and December 2022, using trunk window (flight interception) traps in the UNF Arboretum of Valdivia, Chile. Additionally, we measured qualitative and quantitative habitat attributes to evaluate the preferences of these insects in the UNF. We used generalized linear models as statistical methods to estimate saproxylic beetle habitat preferences. We collected 1273 individuals, belonging to 43 families and 195 saproxylic species/morphospecies. We found that diversity and abundance were strongly influenced by seasonality and the degree of decomposition of deadwood, with increased diversity and abundance in warmer months and highly decomposed trees. Our data show that UNF Arboretum harbor a high diversity of saproxylic species and are therefore suitable habitats and that the factors that regulate these assemblages are homologous to those of natural forests. Finally, our research provides evidence useful for the establishment of conservation and management practices to promote high diversity in UNFs, for example increasing the deadwood volume and quality of the habitat for saproxylic diversity.

Ponds are key elements for ecosystem functions in urban areas. However, little is known about pond biodiversity changes over time and the drivers underlying such changes. Here, we tested whether past species assemblages, land cover and pond environmental change influence pond macroinvertebrate species richness and temporal beta diversity. We also compared spatial and temporal beta diversity, and investigated species-specific colonization and extinction rates over time. We sampled for presence of Odonata and Trichoptera (larvae), and Coleoptera and Hemiptera (larvae and adults) species in 30 ponds in Stockholm, Sweden, in 2014 and 2019. Past species richness was the best predictor of current species richness, whereas temporal changes in land cover and pond environment were not significantly related to current species richness. No correlations between temporal beta diversity and land cover or pond environmental changes were detected. However, ponds showed large changes in their temporal beta diversity, with equal contributions from species gains and losses. The probability of species colonizing and going extinct from ponds revealed that more common species were more likely to colonize a pond, while uncommon species were more likely to go extinct in a pond. Within our 5-year study, we found (i) highly similar spatial and temporal beta diversity, (ii) that past species richness is a good predictor of current species richness; however, the same does not hold true for species composition. The high dynamics of urban pond communities suggest that a large number of ponds are required to maintain high species richness at a landscape level.

Abstract

The rapid expansion of urban areas and intense human activities have exerted serious impacts on the structure and service functions of ecosystems. A clear understanding of the interaction between urbanization (UI) and ecosystem service (ES) is of great significance for formulating regulations of future urban development and environment protection. In this study, we analyzed the impacts of urbanization on ecosystem services from 2000 to 2020 in the Central China (CC) urban in China. The results show that the urbanization process in the CC evolves from a rapidly growing state to a steady state with a slower rise. The ESV in CC increased from 2.75 trillion yuan in 2000 to 5.07 trillion yuan in 2020. There is an inverted U-shaped curve relationship between UI and ESV, the ESV sharply decrease when the urbanization index exceeded 0.5. Land urbanization and social urbanization has the greatest impact on ESV. There was an spatial heterogeneity in the hotspots of ecosystem services. The hot spots of ecosystem products services are distributed in the northeast of the study area, while regulation services and cultural services are distributed in the southwest of CC. The results can provide insights for enhancing urban sustainability in the CC region, as well other urban megaregion with similar characteristics throughout the world.

Initiatives to repurpose vacant lots to improve people’s well-being are increasing worldwide. Still, little is known about how distinct plant communities influence the provision of ecosystem services in vacant lots. To bridge this gap, we investigated associations in vacant lots between land-cover type, plant diversity (both taxonomic and functional), and composition with soil organic carbon and hydraulic conductivity which are indicators of carbon storage and stormwater runoff control. We sampled plant communities, soil organic carbon, and hydraulic conductivity across 50 sites, three plots per site, in the Greater Quebec City Area, Canada. The sites comprised five land-cover types: lawn, bare soil, low- and high-density herbaceous vegetation, and sparse trees. Soil organic carbon was lowest in bare soil lots, while the lowest hydraulic conductivity was found in lots with sparse trees and high-density herbaceous vegetation. Soil organic carbon was positively correlated with forb and total plant cover, but negatively correlated with functional dispersion. Hydraulic conductivity was positively correlated with taproot frequency and functional dispersion of three traits (lifespan, specific leaf area, and reproductive modes), but negatively correlated with grass and total plant cover. This research highlights the associations between plant functional traits and groups with soil characteristics, uncovering patterns that might be overlooked if only land-cover was considered, such as higher carbon storage and hydraulic conductivity associated with forb-rich meadows with high taproot frequency. We advocate for a trait-focused approach in vacant lot revitalization, particularly when the goal is to enhance local levels of soil-based ecosystem services.

Abstract

Urban greenspaces, including green roofs and ground-level urban habitats provide habitat for insect communities in cities. However, beneficial insect communities likely differ between human-managed habitats because of varying provision of resources and connectivity in these greenspaces. This study examined the insect communities in four extensive green roofs and three non-adjacent, similarly structured, managed ground-level habitats. We detected a high degree of overlap in insect taxa but found moderate differences in overall insect community composition between the green roof and ground-level habitats. While there was no difference in Shannon diversity between green roofs and ground-level habitats, the ground-level habitat had greater insect taxa richness. Green roof and ground-level habitats supported pollinators and natural enemies, while ground-level had greater mean pollinator and natural enemy richness and Shannon diversity. Green roofs intentionally designed for biodiversity using native plants for habitat did not differ from those designed for stormwater management and energy reduction using non-native plants in insect community metrics used in this study. These findings suggest that urban greenspaces continue to provide valuable habitat while connectivity and structure play a role in shaping urban insect communities.

As urbanization expands, so does the presence of anthropogenic materials within bird’s nests. However, our understanding of this phenomenon remains limited, particularly in terrestrial birds. This study describes and compares the use of anthropogenic materials in great tit (Parus major) and blue tit (Cyanistes caeruleus) nests in relation to the intensity of anthropogenic activities, distance to contamination sources and reproductive metrics, in nest boxes in a suburban wood in Coimbra, Portugal, during the breeding seasons of 2020 and 2021. Nests were collected after fledging and sorted to remove anthropogenic materials. From a total of 9.71% anthropogenic materials in great tit nests we observed an abundance of uncoloured tangles of mixed fibres, representing 78% of the total weight of the anthropogenic materials in great tit nests in 2021. The chemical composition of these mixtures was determined by spectroscopy analysis, using Fourier transform infrared spectroscopy (FTIR), and 56% of the nests (16/25) contained fibres from synthetic origin. The percentage of anthropogenic materials was higher in great tit than in blue tit nests and increased in 2021, comparatively to 2020. The proximity to potential contamination sources influenced positively the percentage of anthropogenic materials in nests, as those closer to areas with more intense anthropogenic activities (the bar/tennis court and the wastewater treatment plant) had a higher percentage of these materials. No effects on productivity were detected. Our results suggest that the use of these materials is probably related to the intensity of anthropogenic activities.