Small urban woodlands as biodiversity conservation hot-spot: a multi-taxon approach

To evaluate the importance of urban woodlands to serve as potential sites for biodiversity conservation, we analysed bird, carabid beetle and small mammal community responses to urbanisation at different spatial scales. We analysed the relationships between the variations of the structure (species richness S, diversity H′ and dominance D) of animal communities of woodlands distributed along a rural–urban gradient, and the variations along this same gradient of (1) the vegetation within woodlands, (2) the landscape at 100 m and (3) 600 m around the woodlands. We identified the spatial scales whose variations along the gradient most affected each animal community structure, and characterised community responses to these variations. Our results showed that urbanisation affected taxa differently according to their dispersal ability. Carabid beetles, less mobile, seem to be sensitive to increasing fragmentation and built surfaces from periurban to town centre which could make their movement within the urban landscape difficult. Birds, mobile species, seem to be more sensitive to variations of the vegetation structure within woodlands from periurban to town centre that could affect their capacity to maintain in habitat patches. Although our study did not allow relating the small mammal community structure to urbanisation, it suggests that this taxa is sensitive to urban local disturbances. A relevant management scale of woodlands can be specified for each taxa conservation. Urban woodlands accommodate over 50% of the species present in periurban woodlands, and effective management could enhance this number. Woodlands seem to be a good choice for promoting biodiversity conservation in towns.     

Community structure of dung beetles in Amazonian savannas: role of fire disturbance,vegetation and landscape structure

Understanding the relative influence of environmental and spatial variables in driving variation in species diversity and composition is an important and growing area of ecological research. We examined how fire, local vegetation structure and landscape configuration interact to influence dung beetle communities in Amazonian savannas, using both hierarchical partitioning and variance partitioning techniques to quantify independent effects. We captured a total of 3,334 dung beetles from 15 species at 22 savanna plots in 2003. The species accumulation curve was close to reaching an asymptote at a regional scale, but curves were variable at the plot level where total abundance ranged from 17 to 410 individuals. Most plots were dominated by just three species that accounted for 87.7% of all individuals sampled. Hierarchical partitioning revealed the strong independent and positive effect of percentage forest cover in the surrounding landscape on total dung beetle abundance and species richness, and richness of uncommon species and the tunneler guild. Forest cover also had a negative effect on community evenness. None of the variables that related to fire affected community metrics. The minimal direct influence of fire was supported by variance partitioning: partialling out the influence of spatial position and vegetation removed all of the individual explanation attributable to fire, whereas 8% of the variance was explained by vegetation and 28% was explained by spatial variables (when partialling out effects of the other two variables). Space-fire and vegetation-fire joint effects explained 14 and 10% of the dung beetle community variability, respectively. These results suggest that much of the variation in dung beetle assemblages in savannas can be attributed to the spatial location of sites, forest cover (which increased the occurrence of uncommon species), and the indirect effects of fires on vegetation (that was also dependent on spatial location). Our study also highlights the utility of partitioning techniques for examining the importance of environment variables such as fire that can be strongly influenced by spatial location.     

Using superpixel- or pixel-based segmentation for efficient green roof digital image classification and rapid estimation of plant species cover

Green roofs are “nature-based solutions” that provide numerous ecosystem services in the context of urban green infrastructures. Plant species diversity and the associated vegetation communities, in strong interactions with green roof substrate, play a central role in the green infrastructure functioning. In order to better understand the influence of vegetation in relation with the co-benefits provided by green roofs as well as to select suitable species for these usually harsh environments, it is essential to be able to achieve accurate and long-term monitoring of plant communities. In this short communication, two free plugins recently developed for the open-source image analysis software Fiji (a distribution of the freely available ImageJ platform, initially dedicated to biological image analysis) were investigated for their capacity to rapidly and efficiently perform supervised machine-learning for the classification of green roof vegetation photographs, with the aim of estimating individual plant species abundance. Two simple methods are thus described using the Trainable Weka Pixel Segmentation (Arganda-Carreras et al., 2017) or the Trainable Superpixel Segmentation (Salinas Colina et al., 2018), which allowed for rapid, efficient and reproducible classification and estimation of multispecies colonized green roof regardless the color or shape similarities among species or ground cover materials. Finally, recommendations are made for the use of the Trainable Superpixel Segmentation which is particularly convenient for quick and efficient green roof image analysis.     

Local and landscape effects of agricultural intensification on Carabid community structure and weed seed predation in a perennial cropping system

Context

The effects of agricultural intensification on service-providing communities remain poorly studied in perennial cropping systems. However, such systems differ greatly from annual cropping systems in terms of spatio-temporal dynamics and levels of disturbance. Identifying how land use changes at different scales affect communities and ecosystem services in those habitats is of major importance.

Objectives

Our objectives were to examine the effects of local and landscape agricultural intensification on ground beetle community structure and weed seed predation services.

Methods

We examined the effects of local vegetation management and landscape context on ground beetle community structure and weed seed predation in 20 vineyards of southwestern France in 2013 and 2014. Vineyards were selected along a landscape complexity gradient and experienced different management of local vegetation.

Results

The activity-density of ground beetles decreased with increasing landscape complexity while species richness and evenness remained unchanged. Phytophagous and macropterous species dominated ground beetle communities. Seed predation was positively related to the activity-density of one species, Harpalus dimidiatus, and was not affected by local management or landscape context. We found that within-year temporal diversity in ground beetle assemblages increased with landscape complexity.

Conclusions

Our study shows that increasing the proportion of semi-natural habitats in vineyard landscapes enhances the temporal diversity of ground beetles. However, we also found that measures targeting specific species delivering biological control services are a reasonable strategy if we are to maximize natural pest control services such as weed seed regulation to support crop production and reduce agrochemical use.

     

Semi-natural vegetation and its relationship to designated urban green space at the landscape scale in Leeds, UK

The species composition of semi-natural vegetation in urban areas is influenced by a diversity of factors operating at a variety of spatial scales. This study investigates relationships at the landscape scale between species numbers of semi-natural plant communities and variations in the nature of designated urban green space. Species’ records were obtained from a survey of tetrads (2 km × 2 km) across a contiguous central area of built-up landscape and nearby satellite settlements in the metropolitan borough of Leeds, northern England. Plant species were categorised into natives, archaeophytes, neophytes, casuals and conservation-designated species. The type and extent of designated urban green space within a tetrad was determined using GIS. There was more built-up and designated green space area in the central urban area than in the satellite settlements. However, this difference was not reflected statistically significantly in plant category species’ numbers. Numbers of native species correlated positively with areas of green space designated for relatively high nature conservation value. Neophytes and casuals correlated positively with semi-natural green space lacking rare native species or high native species richness but designated principally for local community accessibility. The value of such spaces and the importance of their appropriate management, not only for community benefits like individual physical health and mental well-being, but also for overall urban plant biodiversity, is highlighted.     

Native plants on experimental urban green roofs support higher community-level insect abundance than exotics

Urbanization is one of the multiple factors leading to global insect declines. As urbanization grows, green roofs represent a nature-based solution that could provide habitat for plants and animals within cities. Several characteristics of green roofs could enhance insect biodiversity. Nevertheless, little is known about the effects of plant origin on insect abundance from a multi-taxa perspective. Thus, our main goal was to evaluate the effects of plant origin, local resources, and urbanization level on green roofs’ overall insect abundance, the abundance of different taxonomic orders, and community composition. Using experimental green roofs, we compared insect communities between native and exotic plants across an urbanization gradient, in Córdoba city, central Argentina. On the roofs of 30 houses, we installed two blocks of a modular extensive green roof system, with either native or exotic plant species (6 species each). In March 2019, we used yellow pan traps and pitfall traps (N = 360) to sample insects and measured flower abundance and plant cover at each plant treatment. The urbanization level of each house was estimated by the Normalized Difference Vegetation Index (NDVI), the Normalized Difference Built-up Index (NDBI), and the Land Surface Temperature (LST). A total of 35,257 insects from 12 orders were registered, with Diptera, Hymenoptera, and Hemiptera as the dominant groups. Native plants supported significantly higher total insect abundance on both types of traps, independently from the urbanization level, flower abundance, or plant cover of each roof. The abundance of most of the taxonomic orders was higher in natives as well, but particular effects of the covariables were detected for certain groups. In addition, plant origin was an important factor for insect composition. Our results highlight that green roof design should prioritize native plants to enhance insect conservation while achieving more sustainable cities.     

Assessing the potential of strategic green roof implementation for green infrastructure: Insights from Sumida ward,Tokyo

Urban green spaces, and green infrastructure more generally, provide multiple benefits that can enhance urban livability and sustainability. These range from the mitigation of air pollution and urban heat island (UHI) effect, to multi-dimensional benefits to human wellbeing and biodiversity. However, the expansion of urban green spaces is not always feasible in many cities. In such urban contexts, there have been proposals to utilize rooftops as green roofs in order to gain some of these benefits. This study spatially identifies areas where roofs have the potential to provide different types of benefits associated with urban green spaces if they are retrofitted with green roofs. Through a GIS-based approach we catalogue available roof space in Sumida ward in Tokyo for green roof implementation, and subsequenlty evaluate the potential of each roof patch to offer four types of benefits if retrofitted with a green roof, namely UHI effect mitigation, air pollution mitigation, and benefits to subjective wellbeing and biodiversity. Approximately 25% of the total roof surface in Sumida ward can potentially be used for green roof implementation. Furthermore, about 5.2% and 59% of this area has a respectively high and moderate potential to provide all four benefits if retrofitted with green roofs. This could increase the extent of green spaces by 10% and 120% respectively across the Sumida ward. In this sense, green roofs can become a major element of green infrastructure with ripple positive effects for urban livability and sustainability through the provision of UHI effect and air pollution mitigation, and benefits to subjective wellbeing and biodiversity.     

Functional beetle diversity in managed grasslands: effects of region,landscape context and land use intensity

Current biodiversity conservation policies have so far had limited success because they are mainly targeted to the scale of individual fields with little concern on different responses of organism groups at larger spatial scales. We investigated the relative impacts of multi-scale factors, including local land use intensity, landscape context and region, on functional groups of beetles (Coleoptera). In 2008, beetles were suction-sampled from 95 managed grasslands in three regions, ranging from Southern to Northern Germany. The results showed that region was the most important factor affecting the abundance of herbivores and the abundance and species composition of predators and decomposers. Herbivores were not affected by landscape context and land use intensity. The species composition of the predator communities changed with land use intensity, but only in interaction with landscape context. Interestingly, decomposer abundance was negatively related to land use intensity in low-diversity landscapes, whereas in high-diversity landscapes the relation was positive, possibly due to enhanced spillover effects in complex landscapes. We conclude that (i) management at multiple scales, from local sites to landscapes and regions, is essential for managing biodiversity, (ii) beetle predators and decomposers are more affected than herbivores, supporting the hypothesis that higher trophic levels are more sensitive to environmental change, and (iii) sustaining biological control and decomposition services in managed grassland needs a diverse landscape, while effects of local land use intensity may depend on landscape context.     

Taxonomic diversity,functional diversity and evolutionary uniqueness in bird communities of Beijing's urban parks: Effects of land use and vegetation structure

The importance of biodiversity conservation is well recognized, and the loss of biodiversity is particularly evident in highly urbanized areas. On the other hand, green spaces inside cities, as parks, can provide a resource for maintaining and increasing biodiversity, especially for bird species. However, only a few studies have addressed the effects of vegetation structure and land use composition on different components of biodiversity.Here, we explored the response of bird community composition to environmental differences related to land use composition and vegetation structure in green spaces in the city of Beijing, China. We compared the values of taxonomic diversity, functional diversity and community evolutionary distinctiveness in breeding bird communities, among ten urban parks of the world's third most populous city. Variation partitioning analysis and generalized linear mixed models were used to explore the unique and shared effects of land use composition and vegetation structure on each biodiversity metric.Park size was not associated with the diversity of bird communities in Beijing. Land use composition was the best predictor of change in bird community composition, followed by vegetation structure at ground level and the intersection between land use and vegetation structure at tree level. Water coverage increased bird species richness, while the presence of large trees increased both taxonomic diversity and bird functional richness in urban parks. Finally, the presence of patches of deciduous trees showed a positive effect on the average score of evolutionary distinctiveness of bird communities. In conclusion, we highlight that different elements of the environment are supporting different components of bird community diversity.     

Can microbial inoculants boost soil food webs and vegetation development on newly constructed extensive green roofs?

Green roofs are a key to providing nature-based solutions in cities. However, most green roofs installed in the Northern hemisphere are shallow, stonecrop planted systems (“extensive” green roofs), which have been shown to support limited biodiversity and could be more effective at providing ecosystem services. One issue with this type of extensive green roof is that rootzones are almost sterile on construction, relying on natural colonisation to provide a soil food web. This is a slow process, meaning plant growth can also be slow. Our aim was to determine if a soil food web could be introduced when the green roof is built. We applied microbial inoculants (mycorrhizal fungi and bacteria (Bacillus spp.)) to a new green roof and monitored plant growth and the soil food web (bacteria, mycorrhizal fungi and microarthropods). Different inoculants altered the composition of microarthropod communities, potentially impacting later succession. In particular, bacterial inoculants increased microarthropod populations. This is one of the first studies to demonstrate that the addition of microbial inoculants impacts not only plant growth, but also faunal components of the soil food web, which could have implications for long-term resilience. Bacteria were effective at aiding mycorrhizal colonisation of plants roots, but this colonisation had no impact on the growth of our selected stonecrops, Sedum album, Petrosedum reflexum and Phedimus spurius. We suggest that if a beneficial mycorrhiza could be found to promote the growth of these specific species on green roofs, bacteria could be effective “helper” species to aid colonisation. This study enables green roof researchers and the industry to justify further exploration of the impact of microbial inoculants on green roofs.     

Understanding spontaneous biodiversity in informal urban green spaces: A local-landscape filtering framework with a test on wall plants

In densely urbanized areas, small pockets of vegetated areas such as street verges, vacant lots, and walls can be rich in biodiversity. In spite of their small size, these ‘informal urban greenspaces’ can provide critical ecosystem services to urban residents. Maintaining and enhancing the provisioning of ecosystem services requires a systematic understanding of biodiversity patterns and drivers in informal urban green spaces. The ‘environmental filtering’ (a process of certain species selected by specific environmental conditions) concept in community ecology theory may serve as a useful tool for this goal. We tested a multi-scale filtering framework by examining the spontaneous plant diversity patterns (from 83 surveyed sites) on the vertical surfaces of the ancient city wall of Nanjing, China. We found that the variables representing local-habitat filtering (e.g., wall substrates and aspect) and landscape filtering (including spatial configuration of urban land cover, and nighttime light intensity surrounding the local habitats) can jointly explain substantial fractions of variations in taxonomic diversity (up to ca. 60%) and functional diversity (up to ca. 40%). The explanatory power was stronger in the repaired wall habitats than in the unrepaired counterparts, in line with the prediction that environmental filtering is more pronounced during the early stages of community assembly. While the strength of landscape filtering showed clear scale-dependency, its relative importance consistently outweighs local-habitat filtering across all study scales of 200–1600 m, suggesting that configuration of neighboring landscape context can play an important role in shaping local-scale biodiversity of informal urban green spaces. Our results have useful implications for the study, design, and management of informal urban green spaces. Well-tailored multi-scale filtering frameworks may contribute to understanding urban biodiversity patterns in a systematic way.     

Role of green roofs in urban connectivity,an exploratory approach using landscape graphs in the city of Paris,France

Green roofs provide many ecosystem services, but little is known about the way they contribute to urban functional connectivity. This paper has the following four objectives: (1) to compare the potential green roofs’ role to connectivity in relation to other urban green spaces, (2) to specify the green roofs contribution’s type, (3) to explore the influence of building height integration method and finally (4) to assess the impact on connectivity of simulated greening new roofs. Using a landscape graph approach, we modeled ecological networks of three species groups with different dispersion capacities in the Paris region (France). Then, we computed several connectivity metrics to assess the potential contribution of green roofs to functional connectivity. At a large scale (metropole scale), our results show that green roofs can slightly improve the global connectivity largely through the connections rather than the addition of habitat area. More than a stepping stone function, green roofs would have a dispersion flux function at a local scale. Furthermore, when the difficulty of crossing movement is exponential to the height of buildings, green roofs over 20 m high are mostly disconnected from the ecological networks. In addition to the green roof’s height, our analysis highlights the very strong role played by buildings’ configuration. This study raises promising directions for the integration of building height into the analysis of urban connectivity. Detailed research and long-term biological data from green roofs and green spaces are needed to confirm our results.     

A GIS-based mapping methodology of urban green roof ecosystem services applied to a Central European city

Green roofs provide a number of different urban ecosystem services (UESS), e.g. regulation of microclimate, support of air quality improvement, or stormwater retention. To estimate the spatial variation of green roof UESS across an urban area, a GIS-based mapping and spatial analysis methodology was established and applied to the city of Braunschweig, Germany. Based on the analysis of available geodata, in a first step, a quantity of 14,138 rooftops in the study area (14% of all buildings) was found to be generally suitable for greening. This resulted in a green roof area of 3 km². Based on criteria such as roof slope and minimum roof size, nearly two-thirds of these buildings (8596 buildings, 8.6% of total number of buildings) were categorised ‘appropriate’ for greening and subject to green roof UESS analysis.The spatial distribution of green roof UESS was estimated based on the categories thermal urban climate, air quality, stormwater retention and biodiversity. Due to their potential benefits in the four UESS categories an overall assessment resulted in a number of 867 roofs (0.9% of total number of buildings) categorised as ‘high benefit’ from rooftop greening. Another 3550 buildings (3.5%) and 4179 buildings (4.2%) were defined as ‘moderate benefit’ and ‘low benefit’, respectively. The inner city area of Braunschweig appears as a hot-spot of green roof UESS, i.e. higher percentage of ‘high benefit’ green roofs in comparison to residential areas. The proposed method is a simple but straightforward approach to analyse urban green roof UESS and their spatial distribution across a city but it is sensitive to the quality of the available input geodata.     

Is colourful self-sustaining forb vegetation mere fantasy?

Biodiversity in urban and suburban environments can be supported through establishment of low maintenance-requiring herbaceous vegetation types. Here, we attempt to provide a perspective on the possibilities and limitations of establishing forb-dominated vegetation to support local biodiversity and contribute to changing public aesthetics concerning green spaces. Plant ecological theories, methods and experiences are the foundation for the design and establishment of such vegetation types. We emphasise the importance of high plant density and recurrent disturbance for the maintenance of forb communities. Well-established ecological theory tells us that totally self-sustaining herbaceous vegetation is not a realistic possibility. Without intervention, herbaceous vegetation will change over time and eventually be colonized by woody species through the process of succession. However, by applying a creative and strategic approach to establishment and subsequent management involving small scale disturbances, rather than solely a uniform maintenance regime, it may be possible to maintain a colourful, aesthetically appealing and species-rich forb dominated community that will support biodiversity and increase public acceptance of alternatives to conventional lawns in urban and suburban environments.     

An initial experimental assessment of the influence of substrate depth on floral assemblage for extensive green roofs

Extensive green roofs have the potential to be used as mitigation tools to compensate for urban habitat loss, but there is little information about how closely these systems emulate ground-based habitats. This study investigated the effect of limited substrate depth on plant assemblages in the initial phase of growth in extensive green roof substrates. Five replicate mesocosms (1 m²) for each of three design treatments: (A) 10 cm aggregate depth with green roof drainage and solid floor, (B) 15 cm aggregate depth with green roof drainage and solid floor, and (C) 15 cm aggregate depth on top of bare earth; were positioned at ground level. Each mesocosm had an identical growth substrate and was seeded with the same seed mix. Plant assemblages were analysed using point-quadrat methods. Significant differences in species composition were observed between treatments that seemed to be related to water availability. Even the deep (15 cm) solid floor green roof treatment showed many significant differences in floral assemblage compared to the identical treatment (C) where plants had access to water in the soil profile. Therefore, it is not possible to exactly recreate most ground-based urban habitats on roofs by simply copying the soil characteristics and floral composition found on the ground. Like for mitigation for habitat loss using extensive green roofs requires the careful manipulation of design elements in order to counteract the limited water availability on green roofs.     

Cityscape quality and resource manipulation affect natural enemy biodiversity in and fidelity to urban agroecosystems

Context

Complex landscapes with high resource availability can support more diverse natural enemy communities and better natural pest control by providing resources and facilitating organism dispersal. Moreover, in agricultural landscapes, local agroecosystem management can support biodiversity maintenance and pest control by adding resources in less complex landscapes with fewer resources. However, we lack an understanding of how local and landscape factors interact to affect natural enemy communities and their site fidelity to agroecosystems in urban landscapes (i.e., cityscapes).

Objective

To better understand how local and landscape factors influence natural enemies in urban agroecosystems, we used urban community gardens as a model system to test if and how local resource manipulation and differences in cityscape quality affect natural enemy (ladybird beetles, parasitoid wasps) communities and their fidelity to urban habitats.

Methods

We performed two manipulations. First, we added local floral resources in 6 of 12 gardens situated in different cityscapes to measure differences in natural enemy biodiversity. Second, in those 12 gardens, with and without resource additions, we manipulated populations of a common natural enemy, Hippodamia convergens, to assess fidelity to the gardens.

Results

Floral resource additions increased parasitoid abundance and changed community composition, but had little effect on ladybeetle abundance, richness or site fidelity. Rather, ladybeetle fidelity to gardens was lower in gardens in low quality cityscapes with high impervious cover.

Conclusions

Cityscape quality influences natural enemies in and fidelity to gardens. Landscape-moderated biodiversity patterns observed in rural landscapes likely differ from urban contexts with implications for pest control.

     

Taxon-dependent Scaling: Beetles,Birds, and Vegetation at Four North American Grassland Sites

Because organisms respond to the environment at different scales, it is important to develop ways of determining the appropriate scales for a specific ecological process and organism. We consider whether the relative importance of different scales is associated with organism mobility, and whether this relationship is independent of landscape characteristics. We observed abundances of particular species for vascular plants, ground-dwelling beetles and breeding birds along eight 2-km transects of 40 sampling stations each, distributed over four sites along the regional gradient from shortgrass steppe in central Colorado to tallgrass prairie in central Kansas. For each transect and taxonomic group, the relative importance of factors measured at the trap scale (1 m; soil texture and hardness, vegetation height, bare ground), at the local scale (10 m; density of shrubs and cacti) and at the landscape scale (30 m; Landsat 7 TM spectral bands, slope and elevation) was assessed using hierarchical canonical variance partitioning with forward selection of explanatory variables. Plant, beetle and bird community composition was explained by environmental factors measured at all three scales. Factor influence was more consistent between transects and between plants and beetles for the more homogeneous landscapes of the shortgrass steppe than for the more heterogeneous landscapes of the tallgrass prairie. We conclude that, independent of the mobility of a taxonomic group, factors at several scales are important in explaining community composition. The importance of different scales shifts along a regional gradient, and the variability between sites is high even for nearby sites.     

Green roof vegetation type affects germination and initial survival of colonizing woody species

Green roofs provide a number of valuable ecosystem services compared to conventional roofs, but may require yearly maintenance. Trees and other woody plants that persist on the roof may damage or overload shallow-substrate green roofs and their removal is a standard maintenance procedure. The germination potential of colonizing species may differ depending on the vegetation surrounding them. The aim of this study was to determine whether the germination of colonizing tree species (Picea glauca and Ulmus glabra) will vary depending on which plant species form the established vegetation seeds land in. To determine germination success, survival, and seed capture ability of the plant canopy, tree seeds were added either directly to the growing medium or atop the plant canopy, in replicated monocultures of 14 species native to Nova Scotia. When seeds were added directly to the soil, no significant difference was detected between the monocultures for germination success or survival for U. glabra or P. glauca. However, when the seeds were added atop the plant canopy, percent germination of U. glabra was significantly higher in Carex argyrantha green roof modules. Overall, sod forming graminoids showed higher germination of U. glabra. The number of seeds reaching the soil was typically lower in vegetation with a denser canopy. This study demonstrates that some vegetation repels colonizing tree species by reducing ground contact. Although these effects differed according to tree species, non-vegetated substrates enhanced seedling persistence. Additionally, the majority of tree seeds that germinated failed to survive a single growing-season on shallow-substrate green roofs.     

Urban parks can maintain minimal resilience for Neotropical bird communities

Birds may use urban parks as shelter and refuge, contributing with numerous ecosystem services upon which humans and other organisms depend on. To safeguard these services, it is important that bird communities of urban environments hold some degree of resilience, which refers to the capacity of a system to absorb disturbances and changes, while maintaining its functions and structures. Here we assessed the resilience of the bird community inhabiting an urban park in the Southeast region of Brazil. We classified birds in feeding guilds and identified discontinuities and aggregations of body masses (i.e., scales) using hierarchical cluster analysis. We then calculated five resilience indices for our urban park and for a preserved continuous forest (reference area): the average richness of functions, diversity of functions, evenness of functions, and redundancy of functions within- and cross-scale. The urban park had less species, lower feeding guild richness, and lower within-scale redundancy than the reference area. However, they had similar proportion of species in each function, diversity of functions, evenness of functions, and cross-scale redundancy. The lower species richness and, consequently, the lack of some species performing some ecological functions may be responsible for the overall lower resilience in the urban park. Our results suggest that the bird community of the urban park is in part resilient, as it maintained many biological functions, indicating some environmental quality despite the high anthropogenic impacts of this area. We believe that urban forest remnants with more complex and diverse vegetation are possibly more likely to maintain higher resilience in the landscape than open field parks or parks with suppressed or altered vegetation. We propose that raising resilience in the urban park would possibly involve increasing vegetation complexity and heterogeneity, which could increase biodiversity in a large scale.     

Can green roofs help with stormwater floods? A geospatial planning approach

Increasing urbanization, impervious space, and the impact of climate change are threatening the future of cities. Nature-based solutions, specifically urban green infrastructures, are seen as a sustainable strategy to increase resilience against extreme weather events, including the escalating occurrence of stormwater runoff flooding. Consequently, urban planners and decision-makers have pushed their efforts toward implementing green infrastructure solutions to reduce the impact of stormwater floods. Among others, green roofs help store water and decrease stormwater runoff impacts on a local scale. This research aims to investigate the effect of surface permeability and green roof implementation on reducing stormwater flooding and subsequently provide urban planners with evidence-based geospatial planning recommendations to improve urban resilience in Helsinki. First, we modeled the current impact of stormwater flooding using the Arc-Malstrom model in Helsinki. The model was used to identify districts under high stormwater flood risk. Then, we zoomed in to a focus area and tested a combination of scenarios representing four levels of green roof implementation, two levels of green roof infiltration rates under 40-, 60-, 80-, 100 mm precipitation events on the available rooftops. We utilized open geographic data and geospatial data science principles implemented in the GIS environment to conduct this study. Our results showed that low-level implementation of green roofs with low retention rates reduces the average flood depth by only 1 %. In contrast, the maximum green roof scenario decreased most of the average flood depth (13 %) and reduced the number of vulnerable sites. The proposed methodology can be used for other cities to develop evidence-based plans for green roof implementations.