Local scale prioritisation of green infrastructure for enhancing biodiversity in peri-urban agroecosystems. A multi-step process applied in the Metropolitan City of Rome (Italy)

Urban-rural interfaces represent complex systems that require complex solutions for sustainable development and resilience against pollution, habitat fragmentation, biodiversity loss and impaired flux of ecosystem services (ES). Green infrastructure (GI) is increasingly recognised as an effective tool for addressing such a complexity, but needs priority setting to maximise benefits and minimise drawbacks of implementation. Therefore, a prioritisation approach focused on biodiversity and ES in peri-urban areas is required. In the present work, a systematic and hierarchical framework is proposed for setting priority GI objectives, location and actions aimed at enhancing local biodiversity, ES flux and farming sustainability in urban peripheries. By means of a case study in the Metropolitan City of Rome, the framework allowed identification of the main demand for ES and biodiversity; the most suitable location for GI implementation; and the best cost-effective actions. The GI implementation showed an improvement in terms of wooded hedgerow density, an increase regarding the ecological connectivity of riparian ecosystems, and an increment of agroecosystems designated to enhance the ecological network and wildlife support. Finally, the prioritisation framework contributes to fostering environmental benefits while complying with regulations and management practices from the regional to the farm/field decision level

Modelling the response of urban lichens to broad-scale changes in air pollution and climate

To create more resilient cities, it is important that we understand the effects of the global change drivers in cities. Biodiversity-based ecological indicators (EIs) can be used for this, as biodiversity is the basis of ecosystem structure, composition, and function. In previous studies, lichens have been used as EIs to monitor the effects of global change drivers in an urban context, but only in single-city studies. Thus, we currently do not understand how lichens are affected by drivers that work on a broader scale. Therefore, our aim was to quantify the variance in lichen biodiversity-based metrics (taxonomic and trait-based) that can be explained by environmental drivers working on a broad spatial scale, in an urban context where local drivers are superimposed. To this end, we performed an unprecedented effort to sample epiphytic lichens in 219 green spaces across a continental gradient from Portugal to Estonia. Twenty-six broad-scale drivers were retrieved, including air pollution and bio-climatic variables, and their dimensionality reduced by means of a principal component analysis (PCA). Thirty-eight lichen metrics were then modelled against the scores of the first two axes of each PCA, and their variance partitioned into pollution and climate components. For the first time, we determined that 15% of the metric variance was explained by broad-scale drivers, with broad-scale air pollution showing more importance than climate across the majority of metrics. Taxonomic metrics were better explained by air pollution, as expected, while climate did not surpass air pollution in any of the trait-based metric groups. Consequently, 85% of the metric variance was shown to occur at the local scale. This suggests that further work is necessary to decipher the effects of climate change. Furthermore, although drivers working within cities are prevailing, both spatial scales must be considered simultaneously if we are to use lichens as EIs in cities at continental to global scales.info:eu-repo/semantics/publishedVersio

Biodiversity and ecosystem services in urban green infrastructure planning. A case study from the metropolitan area of Rome (Italy)

Target 2 of the European Biodiversity Strategy promotes the maintenance and enhancement of ecosystem services <(ES) as well as the restoration of at least 15% of degraded ecosystems by creating green infrastructure (GI). The purpose of the this research is to present a GI proposal that combines the delivery of regulating services with the restoration and ecological reconnection of urban forests and trees in a densely urbanised context. The project area covers about 3 000 ha in the urban sector of the metropolitan area of Rome and the GI components consist of 533 ha of areal green spaces and of more than 500 km of road verges. Planned interventions include forest restoration and tree plantations, with a varying service supply according to type and condition of the different components. Potential natural vegetation (PNV) models and dispersal potential of representative forest species, together with structural and functional vegetation models for the enhancement of air pollutants removal, guided the selection of the species to be promoted and of the planting pattern. Environmental benefits of the proposal include more than 30 ha of restored urban forests, about 15 000 planted individuals of native oaks, a sevenfold improvement in ecological connectivity and halved isolation between green spaces. On the other hand, the expected socio-economic benefits include almost 300 000 potential beneficiaries of the improved air quality and avoided costs for damages to human health that range between 40 700 and 130 200 EUR per year. Notwithstanding their preliminary character, these estimates allowed the proposal to highlight the relationship between GI and public health. Moreover, they showed the economic and social effectiveness of nature-based solutions in comparison with further development of grey infrastructure. These results promote the definition of a national GI strategy in Italy

Biodiversity and ecosystem services in urban green infrastructure planning. A case study from the metropolitan area of Rome (Italy)

Target 2 of the European Biodiversity Strategy promotes the maintenance and enhancement of ecosystem services <(ES) as well as the restoration of at least 15% of degraded ecosystems by creating green infrastructure (GI). The purpose of the this research is to present a GI proposal that combines the delivery of regulating services with the restoration and ecological reconnection of urban forests and trees in a densely urbanised context. The project area covers about 3 000 ha in the urban sector of the metropolitan area of Rome and the GI components consist of 533 ha of areal green spaces and of more than 500 km of road verges. Planned interventions include forest restoration and tree plantations, with a varying service supply according to type and condition of the different components. Potential natural vegetation (PNV) models and dispersal potential of representative forest species, together with structural and functional vegetation models for the enhancement of air pollutants removal, guided the selection of the species to be promoted and of the planting pattern. Environmental benefits of the proposal include more than 30 ha of restored urban forests, about 15 000 planted individuals of native oaks, a sevenfold improvement in ecological connectivity and halved isolation between green spaces. On the other hand, the expected socio-economic benefits include almost 300 000 potential beneficiaries of the improved air quality and avoided costs for damages to human health that range between 40 700 and 130 200 EUR per year. Notwithstanding their preliminary character, these estimates allowed the proposal to highlight the relationship between GI and public health. Moreover, they showed the economic and social effectiveness of nature-based solutions in comparison with further development of grey infrastructure. These results promote the definition of a national GI strategy in Italy

A dataset of the flowering plants (Angiospermae) in urban green areas in five European cities

This article summarizes the data of a survey of flowering plants in 80 sites in five European cities and urban agglomerations (Antwerp, Belgium; greater Paris, France; Poznan, Poland; Tartu, Estonia; and Zurich, Switzerland). Sampling sites were selected based on a double orthogonal gradient of size and connectivity and were urban green areas (e.g. parks, cemeteries). To characterize the flowering plants, two sampling methodologies were applied between April and July 2018. First, a floristic inventory of the occurrence of all flowering plants in the five cities. Second, flower counts in sampling plots of standardized size (1 m2) only in Zurich. We sampled 2146 plant species (contained in 824 genera and 137 families) and across the five cities. For each plant species, we provide its origin status (i.e. whether the plants are native from Europe or not) and 11 functional traits potentially important for plant-pollinator interactions. For each study site, we provide the number of species, genera, and families recorded, the Shannon diversity as well as the proportion of exotic species, herbs, shrubs and trees. In addition, we provide information on the patch size, connectivity, and urban intensity, using four remote sensing-based proxies measured at 100- and 800-m radii.ISSN:2352-340

Modelling the response of urban lichens to broad-scale changes in air pollution and climate

To create more resilient cities, it is important that we understand the effects of the global change drivers in cities. Biodiversity-based ecological indicators (EIs) can be used for this, as biodiversity is the basis of ecosystem structure, composition, and function. In previous studies, lichens have been used as EIs to monitor the effects of global change drivers in an urban context, but only in single-city studies. Thus, we currently do not understand how lichens are affected by drivers that work on a broader scale. Therefore, our aim was to quantify the variance in lichen biodiversity-based metrics (taxonomic and trait-based) that can be explained by environmental drivers working on a broad spatial scale, in an urban context where local drivers are superimposed. To this end, we performed an unprecedented effort to sample epiphytic lichens in 219 green spaces across a continental gradient from Portugal to Estonia. Twenty-six broad-scale drivers were retrieved, including air pollution and bio-climatic variables, and their dimensionality reduced by means of a principal component analysis (PCA). Thirty-eight lichen metrics were then modelled against the scores of the first two axes of each PCA, and their variance partitioned into pollution and climate components. For the first time, we determined that 15% of the metric variance was explained by broad-scale drivers, with broad-scale air pollution showing more importance than climate across the majority of metrics. Taxonomic metrics were better explained by air pollution, as expected, while climate did not surpass air pollution in any of the trait-based metric groups. Consequently, 85% of the metric variance was shown to occur at the local scale. This suggests that further work is necessary to decipher the effects of climate change. Furthermore, although drivers working within cities are prevailing, both spatial scales must be considered simultaneously if we are to use lichens as EIs in cities at continental to global scales.ISSN:0269-7491ISSN:1878-2450ISSN:1873-642

How wild bees find a way in European cities: Pollen metabarcoding unravels multiple feeding strategies and their effects on distribution patterns in four wild bee species

1. Urban ecosystems can sustain populations of wild bees, partly because of their rich native and exotic floral resources. A better understanding of the urban bee diet, particularly at the larval stage, is necessary to understand biotic interactions and feeding behaviour in urban ecosystems, and to promote bees by improving the management of urban floral resources. 2. We investigated the larval diet and distribution patterns of four solitary wild bee species with different diet specialization (i.e. Chelostoma florisomne, Osmia bicornis, Osmia cornuta and Hylaeus communis) along urban intensity gradients in five European cities (Antwerp, Paris, Poznan, Tartu and Zurich) using two complementary analyses. Specifically, using trap-nests and pollen metabarcoding techniques, we characterized the species' larval diet, assessed diet consistency across cities and modelled the distribution of wild bees using species distribution models (SDMs). 3. Our results demonstrate that urban wild bees display different successful strategies to exploit existing urban floral resources: not only broad generalism (i.e. H. communis) but also intermediate generalism, with some degree of diet conservatism at the plant family or genus level (i.e. O. cornuta and O. bicornis), or even strict specialization on widely available urban pollen hosts (i.e. C. florisomne). Furthermore, we detected important diet variation in H. communis, with a switch from an herbaceous pollen diet to a tree pollen diet with increasing urban intensity. 4. Species distribution modelling indicated that wild bee distribution ranges inside urban ecosystems ultimately depend on their degree of specialization, and that broader diets result in less sensitivity to urban intensity. 5. Policy implications. Satisfying larval dietary requirements is critical to preserving and enhancing wild bee distributions within urban gradients. For high to intermediate levels of feeding specialization, we found considerable consistency in the preferred plant families or genera across the studied cities, which could be generalized to other cities where these bees occur. Identifying larval floral preferences (e.g. using pollen metabarcoding) could be helpful for identifying key plant taxa and traits for bee survival and for improving strategies to develop bee-friendly cities.ISSN:0021-8901ISSN:1365-266

Urban intensity gradients shape community structure, life-history traits and performance in a multitrophic system

Urban ecosystems are formed by pronounced socio-ecological gradients, which are distinct from other ecosystems and can simultaneously filter and promote taxa, ultimately affecting their interactions. However, the strength of the effect of filtering and facilitation across the different trophic levels could vary among biotic and abiotic factors. Here, we investigate the effects of habitat amount, temperature and host-enemy biotic interactions in shaping communities of cavity-nesting bees and wasps and their natural enemies. We installed trap-nests in 80 sites distributed along urban intensity gradients in five European cities (Antwerp, Paris, Poznan, Tartu and Zurich). We quantified the species richness and abundance of hosts and their natural enemies, as well as two performance traits (survival and parasitism) and two life-history traits (sex ratio and number of offspring per nest for the hosts). We analysed the importance of the abiotic and biotic variables using generalised linear models and multi-model inference. We found that habitat amount was the main driver of multiple host responses, with larger habitat amounts resulting in higher species richness and abundance for hosts and natural enemies, as well as a larger probability of survival and a larger number of brood cells for hosts. Local resources proxies shaped both bees and wasps and indicate different uses of existing vegetation between bees and wasps. Temperature proxies had a minor role in shaping host and natural enemies. Biotic interactions were a main driver of host and enemy community structure, with natural enemies being strongly affected by host availability, that is, with direct density-dependence between hosts and their natural enemies. Overall, our study highlights the importance of habitat amount and temperature in shaping urban food webs, as well as on biotic interactions through direct effects on hosts responses and the subsequent consequences for their natural enemies. As cities prepare to tackle the consequences of global change, strategies that make it possible to maintain habitat and mitigate urban overheating emerge as a key urban adaptation for biodiversity conservation.ISSN:1752-458XISSN:1752-459

Research agenda on biodiversity and ecosystem functions and services in European cities

Cities are challenging environments for human life, because of multiple environmental issues driven by urbanization. These can sometimes be mitigated through ecosystem services provided by different functions supported by biodiversity. However, biodiversity in cities is affected by numerous factors, namely habitat loss, degradation, and fragmentation, as well as pollution, altered climate, and new biotic challenges. To better understand the link between biodiversity and ecosystem functions and services, we need to improve our mechanistic knowledge of these relationships. Trait-based ecology is a promising approach for unravelling the causes and consequences of biodiversity filtering on ecosystem processes and underlying services, but large gaps remain unexplored. Here, we present a series of research directions that are aimed at extending the current knowledge of the relationship between trait-based biodiversity and ecosystem functions and services in cities. These directions are based on: (1) improving urban habitat mapping; (2) considering often neglected urban habitats and ecological niches; (3) integrating multiple urban gradients; (4) using trait-based approaches to improve our mechanistic understanding of the relationships between biodiversity and ecosystem functions and services; and (5) extending the involvement of citizens. Pursuing these research directions may support the sustainable management of urban ecosystems and the long-term provision of ecosystem services, ultimately enhancing the well-being of urban populations.info:eu-repo/semantics/publishedVersio