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a b s t r a c tUrban areas, in particular, present unique challenges for the conservation of ecosystems. Allotment gardens (AGs) are an important greenspace feature of urban landscapes in Europe which have the potential to offer multiple social and bio-physical ecosystem services in addition to food production. This study is an attempt to assess and compare the ecosystem services provided by AGs in Manchester, UK, and Poznań, Poland as well as a comparison to city parks. The surveys included a detailed land cover characterisation and an assessment of cultivated and spontaneous plant species. There are differences in the land use characteristics in the two cities with a preference for vegetable growing and water recycling in Manchester, and a greater number of trees and a higher focus on recreation in Poznań. The consequences of these basic differences are discussed in terms of the ecosystem services that are provided by the two different AG types, and parks. In terms of ecology, there is higher species richness on AGs with a greater proportion of neophytes, which may potentially spread into cities. The species recorded in parks and AGs contained a lot of native characteristics of urban, ruderal plant communities.

Urban areas are characterised by large proportions of impervious surfaces which increases rainwater runoff and the potential for surface water flooding. Increased precipitation is predicted under current climate change projections, which will put further pressure on urban populations and infrastructure. Roof greening can be used within flood mitigation schemes to restore the urban hydrological balance of cities. Intensive green roofs, with their deeper substrates and higher plant biomass, are able to retain greater quantities of runoff, and there is a need for more studies on this less common type of green roof which also investigate the effect of factors such as age and vegetation composition. Runoff quantities from an aged intensive green roof in Manchester, UK, were analysed for 69 rainfall events, and compared to those on an adjacent paved roof. Average retention was 65.7% on the green roof and 33.6% on the bare roof. A comprehensive soil classification revealed the substrate, a mineral soil, to be in good general condition and also high in organic matter content which can increase the water holding capacity of soils. Large variation in the retention data made the use of predictive regression models unfeasible. This variation arose from complex interactions between Antecedant Dry Weather Period (ADWP), season, monthly weather trends, and rainfall duration, quantity and peak intensity. However, significantly lower retention was seen for high rainfall events, and in autumn, which had above average rainfall. The study period only covers one unusually wet year, so a longer study may uncover relationships to factors which can be applied to intensive roofs elsewhere. Annual rainfall retention for Manchester city centre could be increased by 2.3% by a 10% increase in intensive green roof construction. The results of this study will be of particular interest to practitioners implementing greenspace adaptation in temperate and cool maritime climates.

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Urban forest ecosystems confer multiple ecosystem services. There is therefore a need to quantify ecological characteristics in terms of community structure and composition so that benefits can be better understood in ecosystem service models. Efficient sampling and monitoring methods are crucial in this process. Full tree inventories are scarce due to time and financial constraints, thus a variety of sampling methods exist. Modern vegetation surveys increasingly use a stratified‐random plot‐based sampling to reduce the bias associated with convenience sampling, even though the latter can save time and increase species richness scores. The urban landscape, with a high degree of conspecific clustering and high species diversity, provides a unique biogeographical case for comparing these two methodological approaches. We use two spatially extensive convenience samples of the urban forest of Meran (Italy), and compare the community structure, tree characteristics and ecosystem service provision with 200 random circular plots. The convenience sampling resulted in a higher species diversity, incorporating more rare species. This is a result of covering more area per unit sampling time. Pseudorandom subplots were compared to the random plots revealing similar Shannon diversity and sampling comparability indices. Measured tree variables (diameter at breast height, height, tree‐crown width, height to crown base) were similar between the two methods, as were ecosystem service model outputs. Synthesis and applications. Our results suggest that convenience sampling may be a time and money saving alternative to random sampling as long as stratification by land‐use type is incorporated into the design. The higher species richness can potentially improve the accuracy of urban ecological models, which rely on species‐specific functional traits.

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Green roofs are increasingly being utilised as urban climate adaptation measures given good evidence of their passive cooling effects. Shading of conventional building surfaces, higher albedo and latent cooling from evapotranspiration mean that vegetated surfaces can be used to significantly lower surface and air temperatures in cities. The extent to which cooling properties may be affected by poor maintenance, green roof damage and the general health of the vegetation is not as well known. This study investigates the ability of an intensive green roof in Manchester, UK, to cool the air above it relative to an adjacent conventional, concrete roof. The monthly median air temperature was found to be 1.06°C lower at 300 mm over the green roof. Diurnal trends were apparent, with strongest cooling of 1.58°C, occurring at night when Urban Heat Islands are most common. A section of green roof was damaged by mismanagement in a drought period, which allowed an investigation into the impairment to the cooling effect when large areas of bare substrate are present. Daytime temperatures were higher over this section of the roof than over an adjacent healthy green roof, being a maximum 0.63°C warmer than the bare roof on average, in the late morning. Cooling still occurred at night, albeit with a lower maximum average relative cooling of 0.78°C. Implications of the spatial influence of green roof cooling are discussed along with the need to undertake careful maintenance and irrigation of the roofs for the benefits to be maintained.

Runoff and rainfall quality was compared between an aged intensive green roof and an adjacent conventional roof surface. Nutrient concentrations in the runoff were generally below Environmental Quality Standard (EQS) values and the green roof exhibited NO3(-) retention. Cu, Pb and Zn concentrations were in excess of EQS values for the protection of surface water. Green roof runoff was also significantly higher in Fe and Pb than on the bare roof and in rainfall. Input-output fluxes revealed the green roof to be a potential source of Pb. High concentrations of Pb within the green roof soil and bare roof dusts provide a potential source of Pb in runoff. The origin of the Pb is likely from historic urban atmospheric deposition. Aged green roofs may therefore act as a source of legacy metal pollution. This needs to be considered when constructing green roofs with the aim of improving pollution remediation.