Urban Ecosystems最新文献

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

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

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

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

Abstract

Urban trees offer many ecosystem services which can be affected by pathogens, including phytoplasmas. Phytoplasmas cause regulator growth imbalances in infected plants, which produce deviations from the normal plant architecture, among other symptoms. In Bogotá, Colombia, ‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma fraxini’ infect at least 11 species of urban trees, including Andean oak. This tree species is endemic to Colombia and Panama, and it plays an important ecologic role in the Colombian Andes wild forests. In Bogotá, knowledge about the insect vectors associated with the transmission of phytoplasmas to Andean oak is scarce. In this work we sampled the entomofauna of Andean oaks and evaluated the role of Cicadellidae and Psylloidea taxa as potential vectors of phytoplasmas in Bogotá. Insects were captured using direct and indirect sampling methods from Andean oaks at three contrasting sites in Bogotá, and also from neighbouring trees. The insects were identified by morphological and molecular methods and tested for phytoplasmas. In total, 510 Cicadellidae members of 13 taxa and 129 Psylloidea of 8 taxa were captured; richness and abundance depended on the type and sampling site. The most abundant species were Scaphytopius (Convelinus) sp. (Cicadellidae) and Acizzia uncatoides (Psylloidea). Leafhoppers positive for phytoplasmas were Chiasmodolini, Dikrella (Readionia) sp., Empoasca sp. and Scaphytopius sp. taxa. Our results suggest that several potential species of phytoplasmas may be dispersing phytoplasmas to Andean oaks and other urban tree species. It is necessary to conduct transmission tests to evaluate the transmission capacity of the potential vectors.

Abstract

Private gardens comprise a large component of greenspace in cities and can offer substantial conservation opportunities. There has been strong advocacy from researchers, policymakers, and conservation practitioners to engage householders in wildlife-friendly gardening practices to increase the quantity, quality and connection of habitat resources for urban wildlife. Despite this call to action, there remains limited knowledge on the use and benefit of some wildlife-friendly structures within gardens, such as artificial refuges and water sources. In collaboration with 131 citizen scientists in southwestern Australia, we examined the use of seven wildlife-friendly structure types by four vertebrate taxa groups. Following 2841 wildlife surveys undertaken between 31 July 2022 and 22 February 2023, we found that all structures were used primarily by target taxa, water sources were often used by relatively common species, certain structures such as possum shelters were used by rare and threatened species (e.g. western ringtail possum), and that there was evidence of animals making use of the wildlife-friendly structures for reproduction (e.g. bird eggs in nest boxes and tadpoles in water sources). Water sources were used more frequently and by a greater diversity of wildlife than artificial refuges. In particular, bird baths were used by the highest number of species (mainly birds) while ponds were used by the greatest variety of taxa (birds, reptiles, frogs, mammals). Our findings provide evidence-based support for the advocacy of wildlife-friendly gardening practices and further highlight the role of residential gardens for biodiversity conservation.

Urban beaver and stormwater ponds provide hydrologic retention in the landscape while collecting dissolved organic matter (DOM)-rich runoff that can promote primary productivity. Our objective was to determine how the quantity, source, and bioavailability of DOM changed across urban stormwater and beaver pond systems, then compare the two pond types to each other. We measured dissolved organic carbon (DOC) and specific ultraviolet absorbance at 254 nm (SUVA₂₅₄) from upstream, within, and downstream of seven ponds in Atlanta, GA, USA, biweekly from March to December 2021. Additionally, we completed 28-day laboratory microcosm incubations of pond in- and out-flow during summer and autumn of 2021. We found higher concentrations of DOC in the pond and outflows of stormwater ponds, whereas beaver ponds did not cause any change. Effects of pond type (beaver vs. stormwater) were greater than other controls on concentration, including flow and season. In contrast, SUVA₂₅₄ showed a shift toward more aromatic carbon below both systems without a clear difference between pond types. Beaver and stormwater pond outflows had similar ranges of DOM bioavailability in summer, but during autumn bioavailability at both sites declined to near zero. Overall, we found that stormwater ponds and beaver ponds had similar impacts on aromaticity and bioavailability, however stormwater ponds increased the quantity of DOC while beaver ponds did not. This suggests that in addition to increasing hydrologic residence times in urbanized systems, urban beaver ponds may limit the export of bioavailable carbon and reduce microbial processing downstream.