Effects of heterogeneity in solar exposure and soil moisture on the distribution of green roof plant functional groups

Abstract

Green roofs often have heterogeneous microclimates due to variation in surrounding conditions, for example shading from adjacent trees or buildings. However, little is known of the effects of fine-scale variation in microclimate on green roof plant community composition. This is important to understand because green roof ecosystem services are supported by the productivity, diversity, and functionality of the plants. We conducted a spatial survey of plant species distribution relative to solar exposure and soil moisture, on a 50 m2 sloped extensive green roof originally established with nine Sedum species evenly distributed on the roof. After seven years in the presence of partial shading from adjacent trees, the number of plant species had increased to 28, with the new species mostly volunteer graminoids and forbs. Solar exposure strongly shaped plant species distribution on the roof along a gradient (high to low): succulents - graminoids - forbs. Plant species richness was highest in the transition zone between the sunny/dry and shady/moist parts of the roof. Our results demonstrate that spatial variation in microclimate can influence green roof plant communities over time. Thus, an awareness of microclimate variation should be incorporated into managing green roof plant communities to optimize ecosystem services.

Keywords

microclimate; species richness; plant communities; green roof management

Published in

Journal of living architecture
2020, volume: 7, number: 2, pages: 40-61

SLU Authors

• Buffam, Ishi

  • University of Cincinnati

UKÄ Subject classification

Ecology
Architecture

Publication identifier

• DOI: https://doi.org/10.46534/jliv.2020.07.02.040

Permanent link to this page (URI)

https://res.slu.se/id/publ/109549