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Vegetated roofs are hoped to benefit urban wildlife, yet there are few empirical results regarding the conservation potential of such roofs. In this paper, we focus on arthropods on vegetated roofs. We vacuum sampled 17 succulent, meadow or succulent-meadow roofs, in Helsinki, Finland, and used order to species level information together with trait data to describe the communities. We evaluated the importance of biophysical roof characteristics on shaping arthropod assemblages to provide information concerning roof designs that promote rich arthropod fauna. Arthropod communities differed between the three roof types and the influence of roof variables varied between and within arthropod orders. The main local drivers of arthropod abundance across the individually analysed taxa were roof height and vegetation, with mainly positive effects of height (up to 11 m) and litter cover, and mainly negative effects of grass cover. Based on trait data from true bugs, spiders and ants, the roofs consisted mainly of common dispersive species that are generalist feeders and associated with dry open habitats or have wide habitat tolerance. We found one true bug species new to the country and assume that it arrived with imported vegetation. Based on these findings, vegetated roofs of varying height and size benefit common generalists and fauna of open dry habitats, but seem to lack rare native specialists and may introduce non-natives if imported plant material is used. Because the responses to vegetation characteristics are taxon-specific, high diversity of roof vegetation types would benefit arthropod conservation. [ABSTRACT FROM AUTHOR]

Green (i.e. vegetated) roofs are an increasingly popular measure to improve climate regulation in residential areas. However, there is limited knowledge on the effect of green roof characteristics (e.g. substrate depth and roof age, size and height), especially in northern climates, on plant species composition of the roofs, even though roof performance is mediated through the plants. We hypothesized that substrate depth and roof age, size and height shape the vegetation on green roofs. We inventoried vegetation on 51 green roofs in the metropolitan area of Helsinki in 2011 and found 230 plant species, of which seven are red-listed. We showed that substrate depth and roof age were predominant in structuring plant communities on green roofs. Thin substrates and young roofs maintained sedum and moss species, while thick substrates and older green roofs supported meadow plants. Roof size and height had variable effects on the vegetation. Our results provide knowledge on the dependence of plant species on roof parameters, which is useful in the planning for particular vegetation on roofs taking into account, e.g. load capacity and substrate depth, the wanted functional properties of the roof, and maintenance. [ABSTRACT FROM AUTHOR]

Some golf courses start off as half-size, 9-hole courses and, if successful, expand in area to full-size courses, thus converting more land to highly managed greenspace. We investigated carabid beetle assemblages in three established and newly created suburban golf courses in Helsinki, southern Finland., Beetles were collected from similar habitat types on established courses, newly created courses and nearby reference areas., Seventy-one carabid beetle species were collected and the beetle assemblages were dominated by open habitat and generalist species., Assemblages differed considerably between the three golf courses studied and between the habitat types sampled, but not between course development stages (established vs. newly created) or reference areas., We argue that some carabid beetle species in the urban landscape in Helsinki are resilient and capable of rapidly colonising these modified environments., Under current management regimes, these golf courses in Helsinki, Finland, do not host carabid beetles of conservation concern, yet are rich in generalist and open habitat species. [ABSTRACT FROM AUTHOR]

Abstract: We studied the restorative potential of fragmented urban forests in Helsinki, Finland. Our aim was to explore how perceived restorativeness (PR) in urban forests changes when exposed to different levels of urbanity observed through the forest vegetation from the viewpoint of the forest interior. The level of PR was measured in forests that bordered either housing or a road. Three sampling points were selected within each forest, which included (1) an open view (at the edge), (2) a semi-closed view (at the edge zone), and (3) a closed view (in the forest interior) to the urban matrix. We hypothesized that the less urban matrix is observed through the forest vegetation from within the forest, the higher PR would be, and that PR is higher in forests bordering housing than in forests bordering roads. Results supported our hypotheses, as PR was higher inside forests with a closed view to the urban matrix compared to semi-closed and open views. PR was also higher in forests bordering housing than forests bordering a road, albeit not statistically significantly so. We conclude that in order to enhance the restorative potential of an urban forest, planners and managers should preserve sufficiently large forest patches with forest interior habitats, or promote the growth of dense and multilayered vegetation to restrict visibility to the urban matrix. [Copyright &y& Elsevier]

Question: How do habitat edges and trampling affect mesic (Myrtillus type) understorey vegetation in fragmented urban forests, and what are the relative strengths and spatial extent of these effects? Location: The city of Helsinki, southern Finland. Methods: Vegetation sample plots were placed at different distances from the forest edge. At each distance we selected plots on, next to and away from paths of different levels of wear, and the covers and frequencies of plant species were sampled. We used generalized linear mixed models and ordination techniques to test our hypotheses. Results: The effect of the edge penetrated up to 50 m into the forest interior. Only light effects of trampling were found in seemingly untrampled areas, in addition to the direct effects of trampling on the paths. Both trampling and edge effects changed the forest understorey species composition. Trampling changed plant species composition locally on paths, and provided opportunities for new species to establish in previously unbroken forest vegetation. Urban forest edges were characterised by species better adapted to sunny, warm and dry conditions. These species, such as grasses, replaced more sensitive forest species, such as dwarf shrubs and mosses. We observed a large number of light demanding deciduous trees at the edges, which may be one of the factors increasing soil fertility and consequently promoting the high abundance of fast growing species, such as grasses and herbs related to more fertile site types. Conclusions: We recommend that urban forest fragments left within urban development should be at least 2-3 ha in size and that the shape of the patch and the number of potential recreational users should be taken into account when preserving true forest understorey vegetation from the effects of edges and trampling. [ABSTRACT FROM AUTHOR]

We studied the effects of fragmentation (edge effects and patch size) and trampling (path cover) on carabid beetle assemblages in urban woodland patches in Helsinki, Finland. We expected that (1) open habitat and generalist species would benefit and forest species would suffer from increased woodland fragmentation, and (2) most carabid species would respond negatively to increased levels of trampling. A total of 2088 carabid individuals representing 37 species were collected. A cluster analysis distinguished sites in the interior of large woodland patches, with low or moderate path cover, from the other sites. The other sites did not cluster meaningfully, suggesting increased variation in the carabid fauna with increasing human impact. All species and ecological species-groups decreased with increasing distance from the edge toward the woodland interior and with increasing patch size. This pattern is in accordance with our expectation for open habitat and generalist species but opposite to what we expected for forest species. The reason for these surprising results may be that (1) the species we collected are not true forest interior species, (2) urban woodland edges are optimal habitats for many forest carabids, or (3) edges are actually sub-optimal, and high catches simply reflect increased activity of beetles moving away from the edge. Trampling did not have an overall negative effect on carabids as hypothesized. Species associated with moist forest habitat responded as predicted: they decreased in abundance with increasing path cover. Furthermore, open habitat species decreased with increasing path cover but more straightforward than we had predicted. Model elaboration, by dropping the highly trampled sites from the analyses, suggested that our data of high trampling may be too scarce: the results without these sites were more in accordance with our predictions than with the full dataset. [ABSTRACT FROM AUTHOR]

To investigate the effects of urbanization on carabid beetles (Carabidae) and ground dwelling spiders (Araneae) a study was completed along a 20 km urban–rural forest gradient in the Helsinki–Espoo area of southern Finland. To study changes in assemblage structure, abundance and species richness, these taxa were collected in the year 2000 using pitfall traps, which had been placed in four forest sites within each of the urban, suburban and rural zones. We expected to find changes in the abundances and species richnesses in the two taxa across the urban–rural gradient, but did not find any. Our second and third hypotheses, stating that generalist species and small-bodied species should gain dominance along the gradient from rural to urban sites, were partly supported as carabid specialists were more characteristic of suburban and rural environments whereas generalists were more likely to be collected from rural areas compared to suburban or urban sites. Furthermore, medium to large-sized carabid individuals were more likely to be collected in the rural sites compared to urban forests. We found no evidence for significant changes in spider abundance or species richness across the urban–rural gradient in relation to body size or habitat specialization. We suggest that urbanization does not have significant effects on the total abundances and species richnesses in these two taxa. However, individual species responded differently to urbanization, and there were significant differences in the specialization and body sizes of carabids across the gradient. [ABSTRACT FROM AUTHOR]

• Urban park age and plant type influence soil characteristics. • Urban greenspaces provide important ecosystem services similarly to non-urban ones. • High soil C content is associated with higher microbial and earthworm biomass. • Path analysis linked OM accumulation with evergreen trees. As cities grow, urban greenspace assumes a more central role in the provision of ecosystem services (ESS). Many ecosystem services depend on the interactions of soil-plant systems, with the quantity and quality of services affected by plant type and age. The question, however, remains whether urban greenspace can be included in the same ecological framework as non-urban greenspace. Our previous studies have contributed towards filling this knowledge gap by investigating the effects of plant functional type (evergreen trees, deciduous trees and lawn) and plant age on soil characteristics and functionality in urban greenspace, offering also a comparison with non-urban greenspace. A total of 41 urban parks and five non-urban forest sites within and adjacent to the cities of Helsinki and Lahti (Finland) were included in this project. Path analyses presented in this contribution, combined with a synthesis of previous findings, offer strong evidence that urban greenspace functions similarly to non-urban greenspace. In particular, plant functional types lead to soil environmental modifications similar to those in non-urban ecosystems. Therefore, vegetation choice upon park construction/implementation can improve the quality and quantity of ESS provided by urban greenspace. However, although vegetation modifies urban greenspace soils with time in a fashion similar to non-urban greenspace, the vegetation type effect is greater in non-urban greenspaces. To conclude, our synthesis of previous studies provides science-based guidance for urban planners who aim to optimize ESS in urban greenspaces. [ABSTRACT FROM AUTHOR]

Although it is commonly believed that trees can improve air quality, recent studies have shown that such pollution mitigation can be negligible – or that tree canopies can even increase pollutant concentrations near their sources compared to adjacent treeless areas. We explored the impacts of urban roadside forest patches on the concentrations of nitrogen dioxide in summer and winter in the Helsinki Metropolitan Area, Finland, and especially investigated if canopy cover can result in increased concentrations of NO 2 below the canopy. Our results, however, did not show significantly higher – or lower – NO 2 concentrations underneath tree canopies compared to levels above canopies. Neither did NO 2 levels at the below-canopy sampling height differ significantly between forest patches and adjacent open, treeless areas. The lack of a canopy effect may derive from the rather small size of the forest patches, and – compared to previous studies with similar design – divergent tree species composition forming a dense canopy structure. Our results corroborate previous studies that the potential ecosystem services offered by urban near-road forests are more likely due to benefits other than those related to the removal of air pollutants. • We studied if tree canopy cover can increase NO 2 levels below the canopy. • Tree canopies did not cause higher or lower NO 2 levels underneath canopies. • NO 2 levels at the below-canopy height did not differ from adjacent treeless areas. • This may be due to the tree species and the small forest patch size in the study. [ABSTRACT FROM AUTHOR]