The effect of drainage height on plant-species composition on a semi-arid green roof system

Har'el Agra, Hadar Shalom, Omar Bawab, Gyongyver J. Kadas, Leon Blaustein

Research output: Contribution to journalArticlepeer-review


Green roofs are expected to contribute to higher biodiversity in urban surroundings. Typically, green roofs have been designed with low plant diversity. However, plant diversity can be enhanced by controlling resource availability and creating distinct niches. Here we hypothesize that by using different drainage heights during the short plant-growing season in a semi-arid green roof system we can create distinct niches and plant communities. Our experiment took place at the University of Haifa, north Israel. We tested three different heights of drainage outlet: 10 cm under the surface of the substrate (Low), 1 cm under the surface of the substrate (Medium) and 3 cm above the surface of the substrate (High) on plant species-composition in green-roof gardens. Grasses cover was higher in High and Medium drainages while forbs cover was higher in Low drainage. Species richness was the highest in Low drainage while diversity indices showed the opposite trend. We conclude that by changing the height of the drainage we can create different niches and change species composition in a short time period of one growing season. This way we can create more diverse green roof communities and enhance biodiversity in urban areas, particularly in semi-arid regions.

Original languageEnglish
Pages (from-to)149-155
Number of pages7
JournalIsrael Journal of Ecology and Evolution
Issue number3-4
StatePublished - 2021

Bibliographical note

Publisher Copyright:
© Koninklijke Brill NV, Leiden, 2021


  • Annual plants
  • Living roofs
  • Substrate moisture
  • Urban biodiversity

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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