MedMossRoofs: Urban green covers based on mosses with no irrigation requirements under Mediterranean climate

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Using chlorophyll a fluorescence imaging to select desiccation-tolerant native moss species for water-sustainable green roofs

Publication . Carvalho, Ricardo Cruz; Paço, Teresa; Branquinho, Cristina; Silva, Jorge Marques

Green roofs have been more thoroughly investigated in the last few years due to the potential benefits they o er to ecosystems in urban areas (e.g., carbon sequestration, particle retention, heat island e ect attenuation). However, current climate change models predict an increase in desertification, with an increase in temperature and decrease in rainfall, which means there is an increasing demand for green roofs with lower water consumption. Vegetation with very little water requirements, such as desiccation-tolerant mosses, has shown a potential to complement or substitute for vascular species, increasing the sustainability of lower water use in green roofs. In this study, we use chlorophyll a fluorescence imaging to screen for bryophytes with adequate physiology to be used in green roofs placed in at-risk areas with prolonged drought episodes. Apart from Hypnum cupressiforme, all selected species presented a high potential for use in those conditions, particularly Didymodon fallax, Grimmia lisae, Pleurochaete squarrosa, and Targionia hypophylla. Chlorophyll a fluorescence imaging technology proved to be a simple and non-invasive tool for a fast screening of these poikilohydric organisms, to be used in future studies of bryophyte biology, but more importantly in the green roof industry

2020Journal article

Open access

Are Biocrusts and Xerophytic Vegetation a Viable Green Roof Typology in a Mediterranean Climate? A Comparison between Differently Vegetated Green Roofs in Water Runoff and Water Quality

Publication . Rocha, Bernardo; Paço, Teresa A.; Luz, Ana Catarina; Palha, Paulo; Milliken, Sarah; Kotzen, Benzion; Branquinho, Cristina; Pinho, Pedro; Cruz De Carvalho, Ricardo

Green roofs can be an innovative and effective way of mitigating the environmental impact of urbanization by providing several important ecosystem services. However, it is known that the performance of green roofs varies depending on the type of vegetation and, in drier climates, without resorting to irrigation, these are limited to xerophytic plant species and biocrusts. The aim of this research was therefore to compare differently vegetated green roofs planted with this type of vegetation. A particular focus was their ability to hold water during intense stormwater events and also the quality of the harvested rainwater. Six test beds with different vegetation compositions were used on the roof of a building in Lisbon. Regarding stormwater retention, the results varied depending on the composition of the vegetation and the season. As for water quality, almost all the parameters tested were higher than the Drinking Water Directive from the European Union (EU) andWord Health Organization (WHO) guidelines for drinking-water quality standards for potable water. Based on our results, biocrusts and xerophytic vegetation are a viable green roof typology for slowing runoff during stormwater events.

2021-01Journal article

Open access