Potential of Rooftop and Vertical Gardens in Promoting Urban Plant Diversity and Ecosystem Services

Abstract

Rapid urban growth poses significant risks to urban biodiversity and ecosystem health, making the need for innovative green infrastructure solutions essential. This research evaluates the potential of rooftop and vertical gardens in providing ecosystem services and promoting urban plant diversity. From 2015 to 2025, 15 peer-reviewed studies published and systematically analyzed by using a pragmatism-oriented qualitative review. Using Taguette, the data were extracted and coded across categories system type, substrate depth, irrigation, plant functional groups, origin, and ecological outcomes, following thematic analysis principles. Results indicate that rooftop gardens predominantly support pollinators, stormwater retention, thermal regulation and spontaneous colonizers, fostering horizontal habitat connectivity and supporting succulents, graminoids, herbaceous forbs. Although they contain fewer species, vertical gardens deliver essential vertical stratification, shade micro-niches, and air filtration, enhancing multi-dimensional habitat diversity. Complementary ecological pathways like rooftops increase species richness and horizontal network connectivity, while vertical systems expand niche differentiation and microclimatic benefits are revealed in comparative synthesis. The design and management factors strongly influenced the ecological outcomes including substrate depth, irrigation regime, species selection, and maintenance intensity. Regulating services were followed by supporting, provisioning, and cultural services depending on species composition and most consistently delivered. This research indicates that the strategic integration of rooftop and vertical gardens can enhance ecosystem resilience, mitigate environmental stressors, and restore urban plant diversity, offering evidence-based recommendations for architects, urban planners, and policymakers.