Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services

Abstract

Green roofs (roofs with a vegetated surface and substrate) provide ecosystem services in urban areas, including improved storm-water management, better regulation of building temperatures, reduced urban heat-island effects, and increased urban wildlife habitat. This article reviews the evidence for these benefits and examines the biotic and abiotic components that contribute to overall ecosystem services. We emphasize the potential for improving green-roof function by understanding the interactions between its ecosystem elements, especially the relationships among growing media, soil biota, and vegetation, and the interactions between community structure and ecosystem functioning. Further research into green-roof technology should assess the efficacy of green roofs compared to other technologies with similar ends, and ultimately focus on estimates of aggregate benefits at landscape scales and on more holistic cost-benefit analyses.

A Global Geospatial Ecosystem Services Estimate of Urban Agriculture

“…), growth of agricultural crops is constrained, but not precluded, by the rooftop environment. As stated in Oberndorfer et al (2007), "In theory, almost any plant taxon could be used for green-roof applications, assuming it is suited to the climatic region, grown in appropriate substrate at an adequate depth, and given adequate irrigation … many possibilities have yet to be realized. "…”

“…UA offers potential to ameliorate a host of urban environmental problems by increasing vegetation cover and therefore contributing to a decrease in the urban heat island (UHI) intensity (Susca et al, 2011), improving the livability of cities (Frumkin, 2003;Turner et al, 2004) and providing enhanced food security to over half of Earth's population (de Bon et al, 2009;Pearson et al, 2010). UA is connected to multiple metabolic pathways in the urban ecosystem including food provisioning (Zezza & Tasciotti, 2010), regulation of local microclimate and hydrology (Oberndorfer et al, 2007), consumption of nutrient rich "waste" water and biosolids/organic matter (Armstrong, 2009;de Zeeuw et al, 2011;Smit & Nasr, 1992), and fixation of atmospheric nitrogen (Herridge et al, 2008) and carbon (Beniston & Lal, 2012). For pollinators and other wildlife, habitat is created in the city (Goddard et al, 2010).…”

Urban vegetable for food security in cities. A review

“…However, due to the high cost of installation, significant ongoing maintenance, and building weight restrictions, so far, most green roofs are extensive, cultivating drought-tolerant and shallow-rooted plants (Getter and Rowe 2006;Oberndorfer et al 2007;Mok et al 2014) whereas implementing intensive horticultural plants on roofs is becoming difficult (Mok et al 2014). …”

The potential of building envelope greening to achieve quietness

“…In densely built-up city centers, building envelope greening is often the only possibility to meet this demand. These measures have many ecological advantages too, ranging from increasing the thermal insulation of the building envelope and reduction of urban heat island effects [1]- [9], acting as a buffer for storm water [9]- [14], improving air quality and increased carbon dioxide uptake [15]- [17], increasing urban biodiversity [18]- [22], providing a visually pleasant environment [23], to even crop harvesting. In addition, also from an economical point of view, building greening seem interesting [24]- [27].…”