Assessment of a constructed community of native geophytes and sedum species as a habitat analog for extensive green roofs in an urban East Mediterranean environment

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Talhouk This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4690744/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 03 Feb, 2025 Read the published version in Urban Ecosystems → Version 1 posted 4 You are reading this latest preprint version Abstract Extensive green roof research has primarily focused on cooler, wetter climates, resulting in a lack of knowledge of Mediterranean conditions. This long-term study addresses this gap by assessing a constructed plant community of native Mediterranean geophytes and Sedum species. While both are individually recognized for their resilience to prolonged dry periods, their combined performance has been underreported. We studied the performance of 15 Mediterranean geophytes combined with one native sedum on an unirrigated extensive green roof for four years. Data collection included plant survival, number of plants, spread, flowering, and new species recruitment. Throughout the study, eight geophytes did not survive, five increased in number, one remained stable, and two declined. Five geophytes readily spread, one occupied the same space, and one decreased. Most surviving geophytes flowered. Sedum spread vegetatively and flowered consistently. Seven native species were recruited. By the end of the experiment, vegetation cover was 100% (47% Sedum,44% geophytes,12% overlapping vegetation,21% new native species). The findings underscore the importance of long-term studies to observe plant dynamics and reveal the possibility of constructing new urban habitats thus contributing valuable insights for green roof development in Mediterranean cities. Extensive green roof geophytes Mediterranean sedum habitat analogs urban environment Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 INTRODUCTION Extensive green roofs can be adopted broadly in Mediterranean cities, turning barren roofs into green spaces because they need low physical, operational, and financial input. However, the successful implementation of extensive green roofs in cities around the Mediterranean depends on finding suitable plant species and plant compositions that will survive shallow substrate depth and withstand hot dry climates. (Azeñas et al 2018; Dunnett and Kingsbury 2008; Esfahani et al. 2022; Kotsiris et al.2012; Nektarios et al. 2021; Papafotiou et al. 2013a). The number of plant species that can tolerate such conditions is limited (Filazzola et al. 2019; Oberndorfer et al. 2007; Zhang et al. 2021; Zhang et al. 2021; Wooster et al. 2022) and includes mainly low-growing forbes, sedums, and grasses (Nagase and Dunnett, 2013). Sourcing plant species suitable for extensive green roofs is typically achieved by relying on a combined search for species from analogous ground-level habitats (habitat template approach) and species with traits suitable for green roof environments (trait approach). The Mediterranean region is rich in floristic diversity and offers the potential for finding new species suitable for extensive green roofs. The habitat template approach alone may not be sufficient, as plants from the same habitat may react differently to extreme extensive green roof conditions. In contrast, the plant trait-based approach, which focuses on drought tolerance and other key traits, better supports species survival and growth (Schrieke and Farrell 2021; Van Mechelen et al.2014). The most commonly used species on extensive green roofs, regardless of climate conditions, are the succulent Sedum spp. due to their wide range tolerance to extreme temperatures, high winds, low fertility, and limited water supplies (Benvenuti and Bacci 2010; Durhman et al. 2006; Durhman et al. 2007; Nektarios et al. 2015; Perez et al. 2020; Tran et al. 2019; Van Woert et al. 2005). With respect to the Mediterranean climate, some studies show that, in addition to Sedum species, several native species can be considered in the implementation of extensive green roofs (Azeñas et al. 2018; Varela-Stasinopoulou et al. 2023). Geophytes were proposed as a suitable plant form because the species are tolerant to harsh environments due to their storage organs, such as true bulbs, corms, tubers, and rhizomes, that allow plants to retreat underground for long periods of dormancy during hot dry summers with a swollen storage organ (Garrett and Dusoir 2004; Mathew and Swindells 1994; Raunkiaer 1934). In addition to their tolerance, geophytes may add aesthetic value and enhance biodiversity but they should be combined with other plant species such as succulents (Nagase and Dunnett 2013; Zhang et al. 2021) to avoid a ‘brown’ roof phase during the hot dry summer, when they go dormant, which may not be desirable aesthetically (Simmons 2015). For this reason, Sedum species together with geophytes offer possibilities to provide a continuous green cover for extensive green roof design in Mediterranean regions with hot dry summers, irregular precipitation, and regions facing climate change (Rayner et al. 2016; Van Mechelen et al. 2015). Sedum species, when planted alongside other native species, not only help keep green cover but also serve as beneficial companion plants, enhancing the health of neighboring plants. (Butler and Orians 2011; Macvlor et al. 2013; Matsuoka et al. 2020). The combination of species selected based on their adaptation to extensive green roofs results in novel habitats that may support biodiversity in urban environments. These novel green roof habitats are not only the result of constructed plant assemblages but, over time, also include colonizing native species (Ksiazek-Mikenas et al. 2021). While the use of plant communities, rather than a single species, improves aesthetic effects and plant survival, only experimental trials in representative contexts can provide conclusive information to understand whether these choices are functional (Leotta et al. 2023). Furthermore, the observed plant dynamic should be evaluated through long-term studies to accurately evaluate plant communities especially when species use different strategies to survive extreme conditions (Vandegrift et al. 2019). According to long-term extensive green roof studies, plant dynamics change over the years and are affected by seasonal changes and local environmental conditions. Over time, while plant cover is increasing, plant succession and species diversity decreases or does not change (Köhler 2006; Ksiazek-Mikenas et al. 2018; Zhang et al. 2021; Van Mechelen et al. 2015; (van der Kolk et al. 2020). Few long-term studies on unirrigated extensive green roofs have been conducted in Mediterranean climate regions, while most research has focused on cooler and wetter climates, making these studies less relevant to Mediterranean conditions (Nektarios et al. 2021). This study aims to address the gap in research on extensive non-irrigated green roofs in East Mediterranean climates by providing a long-term assessment of a constructed habitat featuring a plant community of native Mediterranean geophytes and Sedum species. MATERIALS AND METHODS Study location: The study was conducted on the roof of a four-floor building at the American University of Beirut which overlooks the east Mediterranean Sea shore (33° 53' N, 35° 29' E). The Lebanese coast has a typical East Mediterranean climate, characterized by hot dry summers (May to late September or October), with temperatures between 23–31°C, and mild winters with temperatures ranging from 5–12°C. The average rainfall is between 650–850 mm/ year. Table 1 summarizes climate conditions during the experimental period between 2015 and 2019. Table 1 . Table 1 Climate summary in the study location (Beirut) during the experimental period 2015–2019 ( www.weatherspark.com ) Winter average temperature (°C) Summer average temperature (°C) Highest summer temperature (°C) Average Yearly precipitation 2015 7.7 31 40 653 mm 2016 7.7 31.9 36.6 626 mm 2017 8.3 30 35 360 mm 2018 7.7 31.9 34.8 735 mm 2019 7.7 30 33.3 796 mm Plant species and extensive green roof set up: The experimental species mix used in the study included 15 Mediterranean geophytes and one native sedum ( Sedum sediforme ) (Table 2 ). Geophytes were bought (Bulb Argence, France) as bulbs or rhizomes. Rooted cuttings of Sedum sediforme were produced from mother plants which were transplanted from semi-natural urban areas near campus and established in a greenhouse. The unirrigated experimental green roof area consisted of a 19.8 m2 roof space framed by 20 cm high waterproofed edges (250 cm x 800 cm) and two drainage outlets one at each end. The experimental green roof was lined with geotextile and filled with growing media (10% organic matter, 60% peat moss and 30% local sandy clay soil) to a 10 cm depth. Planting was completed in October 2015. The planting layout focused on creating a plant community by distributing bulbs, rhizomes, and rooted cutting to accommodate plant growth and spread at maturity while looking to achieve a natural appearance. Table 2 . Table 2 Plant species used in the experiment (Polunin et al 1965.;* Ouasti et. al. 2023) Scientific name Typical habitat Life form Allium ampeloprasum Hedges, banks, and arid places Bulb Allium nigrum Cultivated ground Bulb Anemone coronaria Fields, olive groves, vineyards Tuber Asphodelus aestivus Syn: Asphodelus microcarpus Rocky places, hills, and dry places Tuber Arum dioscoridis Hedges, track sides Rhizome Arum hygrophilum Garigue and Maquis near water Rhizome Colchicum lusitanum Brot. * Stony and grassy places Corm Crocus cartwrightianus Stony and grassy places Corm Crocus ochroleucus Fertile Soil Corm Cyclamen persicum Rocks, walls. Edges of thickets Tuber Gladiolus segetum Cultivated ground Corm Narcissus tazetta Field, meadow, and garigue, especially in damp places Bulb Oxalis pes-capre Cultivated ground Bulb Pancratium maritimum Maritime sand Bulb Scilla hyacinthoides Hedge, rocky places and fields Bulb Sedum sediforme (Jacq.) Rocks, walls, and stony places largely on calcareous soil and clay Succulent perennial Data collection: Data was collected over four years (2016–2019) between February and March to capture maximum plant growth and flowering. Data was recorded and a photo taken of the whole experimental roof area to confirm and review the collected field data. Collected data included plant survival (dead/alive), number of plants/clumps, plant spread (m 2 ), number of flowers per plant, and newly recruited species. RESULTS Eight out of 15 Mediterranean geophytes did not survive the first year under extensive green roof conditions in our study location. These are Allium nigrum , Arum hygrophilum, Arum dioscoridis, Crocus hadriatus, Crocus ochroleucus, Colchicum byzantinum, Cyclamen persicum , and Oxalis per- capre. The number of plants varied with species that survived as follows (Table 3): Asphodelus aestivus,, Narcissus tazetta , Scilla hyacinthoides and Allium ampeloprasum increased in numbers. A. aestivus doubled every two years starting with five plants and ending with 17 plants. A.ampeloprasum doubled the first year and the fourth year resulting in 4 times more plants at the end of the experiment. N. tazetta . and S. hyacinthoide grew steadily, their numbers doubled by the third year, and increased threefold and fourfold respectively, by the end of the experiment. The number of Pancratium maritimum stayed the same throughout the four years. Gladiolus segetum declined after the first year and remained stable thereafter with only 20 percent of the plants still alive. Anemone coronaria declined throughout and by the end of the experiment none of the plants survived. S. sediforme started propagating vegetatively from the first year through tip rooting and by the fourth-year individual plants were no longer visible as they coalesced into clumps. Table 3. Number of Mediterranean geophytes and native sedum plants on an extensive green roof in Beirut. *The number of Sedum plants did not increase but the plants started propagating vegetatively through tip rooting until year four when the number of individual plants was no longer visible as individual plants coalesced into clumps Number of clumps Name of plants 2015 2016 2017 2018 2019 Allium ampeloprasum 4 7 4 26 17 Allium nigrum 5 0 0 0 0 Anemone coronaria 84 17 5 9 1 Arum dioscoridis 2 0 0 0 0 Arum hygrophilum 2 0 0 0 0 Asphodelus aestivus 5 9 9 13 17 Colchicum byzantinum 5 0 0 0 0 Crocus hadriatus 4 0 0 0 0 Crocus ochroleucus 4 0 0 0 0 Cyclamen persicum 5 0 0 0 0 Gladiolus segetum 84 12 25 17 16 Narcissus tazetta 4 7 9 9 12 Oxalis per- capre 14 0 0 0 0 Pancratium maritimum 4 2 2 2 2 Scilla hyacinthoides 4 9 12 10 15 Sedum sediforme 25 25 27 25 25+ * TABLE 3. The speed of plants spread throughout the four years varied with species (Table 4 and Fig. 1 a and 1 b). Plant spread is a visual sign of plant performance under extensive green roof conditions. The information is useful for selecting plant species that have a rapid establishment rate and can achieve maximum cover. Plant spread increased six-fold for A. aestivus , five-fold for S.sediforme , threefold for A.ampeloprasum , N.tazetta , and S. hyacinthoides , and two fold for G.segetum , while P.maritimum did not spread, and A. coronaria declined. Table 4 Plant spread (m 2 ) of Mediterranean geophytes and native sedum on an extensive green roof at the American University of Beirut, Lebanon Plant spread in m 2 Name of the plant 2016 2017 2018 2019 Allium ampeloprasum 0.6 0.4 1.7 1.5 Anemone coronaria 1.3 0.4 0.8 0.02 Asphodelus aestivus 0.6 0.8 2.0 3.9 Gladiolus segetum 0.3 0.7 0.6 0.7 Narcissus tazetta 0.3 0.5 0.6 1 Pancratium maritimum 0.04 0.04 0.04 0.04 Scilla hyacinthoides 0.4 0.7 1.2 1.3 Sedum sediforme 2.4 3.4 5.5 9.3 Table 4. Figure 1 All surviving geophytes flowered, except P. maritimum , during the experimental period producing a range of 0.5 to 2.7 flowers per plant (Table 5 and Fig. 2 a, b, c). S. sediforme flowered throughout the study producing many flower heads which were not possible to count without destructive sampling. Table 5 Number of flowers and number of flowers per plant (in parenthesis) of Mediterranean geophytes and native sedum on an extensive green roof at the American University of Beirut, Lebanon Total number of flowers and (number of flowers/plant) Name of plants` 2016 2017 2018 2019 Allium ampeloprasum 7 (1) 4 (1) 26 (1) 17 (1) Anemone coronaria 22 (1.3) 9 (1.8) 12 (1.3) 1 (1) Asphodelus aestivus 3 (0.3) 6 (0.7) 7 (0.5) 18 (1.1) Gladiolus segetum 7 (0.6) 28 (1.1) 9 (0.5) 27 (1.7) Narcissus tazetta 6 (0.9) 24 (2.7) 14 (1.6) 32 (2.7) Pancratium maritimum 0 0 0 0 Scilla hyacinthoides 0 6 (0.5) 0 2 (0.1) Table 5. The appearance of new species recorded during regular monitoring revealed the recruitment of seven native species that colonized the experimental green roof. In the first year, Ainsworthia trachycarpa appeared and persisted until the end of the experiment while Lavatera cretica was recorded in the first year only. No new species were recorded in the second year. In the third year, four native species, Trifolium repens , Melilotus officinalis , Misopates orontium , and Dittrichia viscosa , appeared and persisted until the end of the experiment. In the fourth year, an new species, Lophochloa phleoides , appeared (Fig. 3 a, b). Figure 3 . By the end of the 4 years, the surface of the experimental roof was fully covered with noticeable flowers (Fig. 4 a,b). The planting layout included 230 bulbs and rhizomes belonging to 15 geophytes and 25 sedum plants belonging to one Sedum species. After four years, plants covered the whole green roof area (100%) as follows: 47% covered by sedum, 44% cover by geophytes, 12% overlapping vegetation, and 21% newly recruited native plant species. In the spring of the last experimental year the roof presented 97 flowers contributing 5 flowers / square meter. In the summer blooming Sedum contributed to the aesthetic of the roof. Figure 4 . DISCUSSION This study confirmed that a combined selection of suitable species for extensive green roofs in the Mediterranean based on both natural growing conditions and plant traits serves only as a framework. Our findings showed varying behaviors among the geophytes although they are all native to the Mediterranean. Out of the fifteen geophytes used in the study, 50% died directly after the first year. Of the survivors, two-thirds increased in biomass and flowering, while the remaining third stagnated and declined. Thus, only five out of fifteen (33%) geophytes thrived and performed well under extensive green roof conditions. These findings confirm the statement by Caneva et al. (2015) who showed that the production of possible species lists based on phytosociological and ecological criteria for extensive green roofs serve only as a framework for setting up field studies to identify the exact species suitable for this purpose. In their study, Caneva et al. (2015) created a database of 471 taxa, of which 146 were identified as potentially suitable for green roofs in the Mediterranean, including 26 geophytes. When comparing the two geophytes, Allium and Gladiolus , listed as potentially suitable in their study, we found that A. ampeloprasum performed well, consistent with their findings. However, G.segetum exhibited stagnant behavior throughout the four years, indicating it was surviving but not thriving. It is worth noting that the authors did not specify whether their focus was on extensive or intensive Mediterranean green roofs; if it was the latter, we would expect Gladiolus species to perform equally well. Our findings also support Van Mechelen et al. (2014), who focused on plant trait analysis rather than habitat to help green roof companies find species suitable for extensive green roofs in the Mediterranean. The authors rated 309 species, including 41 geophytes, using correlation analysis. In their final list, sixty-one species scored higher than 10, indicating potential for green roof application. Among these, the two geophyte genera common to both their study and ours, Allium and Anemone , performed as predicted. Allium ranked high in their analysis and performed well throughout our study, while they gave a low score for A. coronaria which declined in our study until it disappeared by year four. Our results show that conducting short term experiments may not fully describe the performance of species. While in the first year we found species that are unsuited to Mediterranean extensive green roof conditions, subsequent years revealed fluctuations in growth and success rates among remaining species with some stagnating or declining and others thriving throughout the four years. This finding is in line with Rowe et al. (2012) who showed that long-term extensive green roof research can provide more accurate information on community succession and performance of species. The authors described how plants that initially survived eventually experienced reduced coverage or disappeared completely. They indicated that such information is valuable for the design and maintenance of green roofs, while research of short duration is likely to result in premature conclusions and misleading recommendations (Rowe and Durham 2012). Similar conclusions were made by Zhang et al. (2021) who indicated that long term variability reveals actual survival of species often preceded by several years of decline. The authors, who conducted an 8-year study in Beijing, reported species decline at various times after planting, with six out of ten succulent species showing signs of decline starting no earlier than the third year. Ultimately, after 8 years, only two species remained viable, irrespective of substrate depth. To the best of our knowledge, few extensive green roof studies longer than three years have been published in the past decade. Using the key words ‘extensive green roof’ and ‘long term’ we found a total of eighteen long term extensive green roof studies of which five were conducted in a Mediterranean / dry climate (Bates et al 2013; Cao et al. 2019; Giorgioni and Grandi 2021; Heim and Lundholm 2022; Nektarios et al.2021; Paço et al. 2019; Salman and Blaustein 2018; Salih et al. 2021; Thuring and Dunnett 2019; Todorov et al. 2018; Tran et al. 2019; Zhang et al. 2018; Zhang et al. 2021; Zhang et al.2021;Zheng et al. 2022; Vannucchi et al.2022; Vandegrift et al.2019; van der Kolk et al. 2020; Vidaller et al. 2023) Long-term studies also reveal the link between plant performance and local weather patterns. For example, van der Kolk et al. (2020) who conducted an eight-year study were able to detect fluctuations in plant performance which appear to be linked to local weather patterns. They noted a decline in species richness between years 2 and 7, followed by an increase by year eight. The authors attributed this fluctuation to an exceptionally dry summer, which reduced grass cover and allowed other species to colonize the roof surface in the later year. In our study, observation of flowering of two species ( G.segetum and N. tazetta ) after the first year of planting (years 2, 3, and 4) seem to be linked to average rainfall preceding bloom (Fig. 5 ) The importance of long-term studies is also clear in revealing when and how spontaneous vegetation colonizes extensive green roofs. In our study, regular monitoring revealed the recruitment of seven native species that colonized the experimental green roof. Two species A. trachycarpa and L.cretica appeared in the first year however only the former persisted throughout the four years while the latter appeared only in year one. No new species were recorded in the second year, however, starting with year 3, four native species, T. repens, M. officinalis, M. orontium , and D. viscosa , appeared and persisted until the end of the experiment. An additional species, L.phleoides , appeared in the last experimental year i.e. year 4. All the recruited species were ruderal East Mediterranean native annual species that typically grow along roadsides, wastelands, and sea sides (Polunin et al. 1965; Tohmé and Tohme 2014). The observed facilitated recruitment of native species by perennial geophyte and sedum is in support with Vidaller et al. (2023) who indicated that the planting of perennial species followed by spontaneous colonization of species present in the vicinity of the roof would then represent a more efficient strategy for the persistence of extensive non-irrigated green roofs in Mediterranean environments than sowing a species-rich local Mediterranean seed mixture dominated by annual species. Our findings regarding the appearance of spontaneous species a few years after green roof establishment are in line with Vidaller et al. (2023) who identified 34 spontaneous species in a long-term experiment indicating a sharp increase after two years. Our findings which suggest that colonizing species are mostly ruderal are also in line with Vanstockem et al. (2019) who indicated that ruderal species were the most common colonizers following a survey of 129 green roofs in Belgium (Vanstockem et al. 2019). These species may have benefited from the absence of interspecific competition that normally occurs in later successional stages and colonize bare and disturbed land (Itani et al. 2020). We found that combinations of plant communities consisting of mixed geophyte species and succulents are suitable to create new urban habitats on extensive green roofs in urban Mediterranean environments. The suitability of geophytes for use in unirrigated extensive green roofs has been reported by Benvenuti and Bacci (2014) and Zhang et al (2021) who explained that geophytes require no management and could survive unfavorable conditions. Similarly, the adaptability of Sedum species to extensive green roof conditions has been reported for more than 20 years. Our selection of the plant species was based on habitat template where natural habitats shared similar climate characteristics to inform the potential species pool (Ksiazek-Mikenas et al. 2021) while the Sedum geophyte combination was based on plant trait synergy (Nagase A and Dunnett N. 2013) The identity of the new urban plant community in our study was not evident until the end of the four-year experiment. This was because almost half of the native geophyte species planted did not survive beyond the second or third year. While the use of plant communities, rather than a single species, may contribute to plant survival only experimental trials in representative contexts can provide conclusive information to understand whether these choices are functional (Leotta L et al. 2023). Our findings suggest that although habitat template approaches can serve to guide plant choices, long term roof experiments are essential to unveil actual plant tolerance to restrictive extensive green roofs and trait synergies. As such, this study is in line with Lundholm and Walker (2018) and Chell et al. (2022) who indicated the habitat-template approach is probably best used as a coarse filter for plant selection on green roofs. Through this study a new plant community was created from a mix of native geophyte and Sedum species. The mixture of geophytes and Sedum thrived over the four-year experiment and spread covering approximately two-thirds of the extensive green roof study area. The presence of Sedum species in mixed planting has been previously reported to be beneficial for the performance and survival of Mediterranean species (Azeñas et al. 2018; Becker and Bucholz 2016; Fournier et al. 2020; Ksiazek-Mikenas et al 2021; Van Mechelen et al. 2015; Vasl et al 2017). This new plant community offered a plant architecture typology that recruited new colonizing species and allowed them to establish, interjected in the remaining one-third thus serving as habitat analogue. As such physiognomy of constructed plant communities might be a useful tool in extensive green roofs that facilitates colonization by native species leading to unique species assemblages that do not resemble natural analogs (Aloisio et al. 2020, Itani et al. 2020). The process of colonization in such constructed communities is reportedly dynamic leading to continuous change in species composition and presenting an increase in the proportion of native species which could play a role in urban biodiversity if developed at large scales in cities (Madre et al. 2014; Thuring et al. 2019). However, with each green roof supporting novel habitat analogues, contribution to urban biodiversity depends on biotic and abiotic factors that are not consistent among extensive green roofs (Ksiazek-Mikenas et al. 2018; Martini et al. 2022). A limitation of our study is that although we recorded the native species that colonized the experimental extensive green roof, we did not record their number or spread. Similarly, during our study we observed birds and insect visitations but did not document species and frequency of visits. CONCLUSION Our long-term non-irrigated extensive green roof study allowed us to monitor the differing behaviors of geophytes native to the Mediterranean, confirmed the suitability of the native Sedum in combination species mix, and witnessed the recruitment of native annual and perennial herbaceous species. We created an extensive green roof habitat analogue which was adapted to East Mediterranean conditions thus contributing to literature that is lacking for this region (Vidaller at al. 2023). This study also showed how short term experiments may not reflect the dynamic changes that occur over the years in terms of the survival of planted species and the establishment of newly recruited ones. Finally, we demonstrated that a constructed community of mixed geophyte species and succulents are suitable to create new urban habitat analogues on extensive green roofs in urban Mediterranean cities. This type of knowledge can contribute to the development of guidelines for the urban environments in the Mediterranean region which according to Catalano et al. (2018) need to be widely refined considering the peculiarities of green roof design in the Mediterranean ecoregion. Declarations Competing Interests The authors have no relevant financial or non-financial interests to disclose. Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Author Contribution Both authors contributed to the study conception and design. Material preparation and data collection were performed by Monika Fabian. Data analysis was performed by Monika Fabian and Salma Talhouk. The manuscript was written by Monika Fabian and Salma Talhouk. Both authors read and approved the final manuscript. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 03 Feb, 2025 Read the published version in Urban Ecosystems → Version 1 posted Editorial decision: Revision requested 06 Aug, 2024 Editor assigned by journal 05 Jul, 2024 Submission checks completed at journal 05 Jul, 2024 First submitted to journal 05 Jul, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4690744","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":330999400,"identity":"b267ceff-550f-4bc1-951d-97feab3b55f3","order_by":0,"name":"Monika Fabian","email":"","orcid":"","institution":"American University of Beirut","correspondingAuthor":false,"prefix":"","firstName":"Monika","middleName":"","lastName":"Fabian","suffix":""},{"id":330999403,"identity":"f6ba8d9a-dd8f-4fd4-844a-f12607f7684e","order_by":1,"name":"Salma N. Talhouk","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYLCCBwwMcgwMPEAWGwMDnwQh5UBFDAkMDMZwLWzEaklsIFqLuXz7ww+JOXbp/TNyDzB8KDvMwCbdgF+LZRuPsUTituTcGTfyEhhnnANqkTmAX4vBMR4GoBbm3IYbOQbMvG1ALRIJhLSwP/6RuK0+XR6k5S9xWhjMgLYcTjAAaWEkTkuOmUXituOGG8+8SzjYcy6dh7BfDh9/fOPjtmp5ueO5Bx/8KLOW4ycUYigAZDwPCepHwSgYBaNgFOACAKRgQYRORw7fAAAAAElFTkSuQmCC","orcid":"","institution":"American University of Beirut","correspondingAuthor":true,"prefix":"","firstName":"Salma","middleName":"N.","lastName":"Talhouk","suffix":""}],"badges":[],"createdAt":"2024-07-05 08:22:56","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4690744/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4690744/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11252-025-01679-6","type":"published","date":"2025-02-03T15:57:18+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":61429115,"identity":"551b9fa4-4c75-4498-92f5-2021895d437d","added_by":"auto","created_at":"2024-07-30 15:29:33","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":886346,"visible":true,"origin":"","legend":"\u003cp\u003eSnapshot showing plant spread and plant distribution (1a) 2 months and (1b) 42 months after planting under extensive green roof conditions at the American University of Beirut, Lebanon\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4690744/v1/b1f56926169d393d53e53ad4.png"},{"id":61429734,"identity":"abf87109-528a-4064-980a-6b338b59fe6c","added_by":"auto","created_at":"2024-07-30 15:37:33","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1059452,"visible":true,"origin":"","legend":"\u003cp\u003e(2a) \u003cem\u003eNarcissus tazetta, (2b) Asphodelus aestivus\u003c/em\u003e and (2c) \u003cem\u003eGladiolus segetum\u003c/em\u003ein bloom 30 months after planting under extensive green roof conditions at the American University of Beirut, Lebanon\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4690744/v1/3330d27d4c7a23baa998b187.png"},{"id":61429113,"identity":"ab1c7722-43e7-400d-8872-72db1c009879","added_by":"auto","created_at":"2024-07-30 15:29:33","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1596843,"visible":true,"origin":"","legend":"\u003cp\u003eExamples of native plant species, \u003cem\u003eAinsworthia trachycarpa \u003c/em\u003e(3a)\u003cem\u003e \u003c/em\u003eand \u003cem\u003eTrifolium repens \u003c/em\u003e(3b), that colonized the experimental extensive green roof at the American University of Beirut, Lebanon\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4690744/v1/85946d3103f2f2fe91875575.png"},{"id":61429117,"identity":"59572080-bb64-4988-9d68-0b1e17cad90a","added_by":"auto","created_at":"2024-07-30 15:29:33","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1017429,"visible":true,"origin":"","legend":"\u003cp\u003eFlowering extensive green roof during spring (4a) and summer (4b) at the end of the four-year experiment\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4690744/v1/0e0642fbeded91fd28478291.png"},{"id":61429112,"identity":"d5477395-d1ae-42c5-9b66-67e16a229a51","added_by":"auto","created_at":"2024-07-30 15:29:33","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":31839,"visible":true,"origin":"","legend":"\u003cp\u003eNumber of flowers produced by \u003cem\u003eGladiolus segetum and Narcissus tazetta\u003c/em\u003e in different years under different rainfall patterns\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4690744/v1/0a56bb0ebe35faba28e40da3.png"},{"id":75931314,"identity":"f8ec7011-c54b-4aa3-a10f-73d29e41717b","added_by":"auto","created_at":"2025-02-10 16:14:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5570784,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4690744/v1/bc399f13-7111-4844-be24-f8626316d67e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Assessment of a constructed community of native geophytes and sedum species as a habitat analog for extensive green roofs in an urban East Mediterranean environment","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eExtensive green roofs can be adopted broadly in Mediterranean cities, turning barren roofs into green spaces because they need low physical, operational, and financial input. However, the successful implementation of extensive green roofs in cities around the Mediterranean depends on finding suitable plant species and plant compositions that will survive shallow substrate depth and withstand hot dry climates. (Aze\u0026ntilde;as et al 2018; Dunnett and Kingsbury 2008; Esfahani et al. 2022; Kotsiris et al.2012; Nektarios et al. 2021; Papafotiou et al. 2013a). The number of plant species that can tolerate such conditions is limited (Filazzola et al. 2019; Oberndorfer et al. 2007; Zhang et al. 2021; Zhang et al. 2021; Wooster et al. 2022) and includes mainly low-growing forbes, sedums, and grasses (Nagase and Dunnett, 2013).\u003c/p\u003e \u003cp\u003eSourcing plant species suitable for extensive green roofs is typically achieved by relying on a combined search for species from analogous ground-level habitats (habitat template approach) and species with traits suitable for green roof environments (trait approach). The Mediterranean region is rich in floristic diversity and offers the potential for finding new species suitable for extensive green roofs. The habitat template approach alone may not be sufficient, as plants from the same habitat may react differently to extreme extensive green roof conditions. In contrast, the plant trait-based approach, which focuses on drought tolerance and other key traits, better supports species survival and growth (Schrieke and Farrell 2021; Van Mechelen et al.2014).\u003c/p\u003e \u003cp\u003eThe most commonly used species on extensive green roofs, regardless of climate conditions, are the succulent \u003cem\u003eSedum spp.\u003c/em\u003e due to their wide range tolerance to extreme temperatures, high winds, low fertility, and limited water supplies (Benvenuti and Bacci 2010; Durhman et al. 2006; Durhman et al. 2007; Nektarios et al. 2015; Perez et al. 2020; Tran et al. 2019; Van Woert et al. 2005). With respect to the Mediterranean climate, some studies show that, in addition to \u003cem\u003eSedum\u003c/em\u003e species, several native species can be considered in the implementation of extensive green roofs (Aze\u0026ntilde;as et al. 2018; Varela-Stasinopoulou et al. 2023).\u003c/p\u003e \u003cp\u003eGeophytes were proposed as a suitable plant form because the species are tolerant to harsh environments due to their storage organs, such as true bulbs, corms, tubers, and rhizomes, that allow plants to retreat underground for long periods of dormancy during hot dry summers with a swollen storage organ (Garrett and Dusoir 2004; Mathew and Swindells 1994; Raunkiaer 1934). In addition to their tolerance, geophytes may add aesthetic value and enhance biodiversity but they should be combined with other plant species such as succulents (Nagase and Dunnett 2013; Zhang et al. 2021) to avoid a \u0026lsquo;brown\u0026rsquo; roof phase during the hot dry summer, when they go dormant, which may not be desirable aesthetically (Simmons 2015). For this reason, Sedum species together with geophytes offer possibilities to provide a continuous green cover for extensive green roof design in Mediterranean regions with hot dry summers, irregular precipitation, and regions facing climate change (Rayner et al. 2016; Van Mechelen et al. 2015). Sedum species, when planted alongside other native species, not only help keep green cover but also serve as beneficial companion plants, enhancing the health of neighboring plants. (Butler and Orians 2011; Macvlor et al. 2013; Matsuoka et al. 2020).\u003c/p\u003e \u003cp\u003eThe combination of species selected based on their adaptation to extensive green roofs results in novel habitats that may support biodiversity in urban environments. These novel green roof habitats are not only the result of constructed plant assemblages but, over time, also include colonizing native species (Ksiazek-Mikenas et al. 2021). While the use of plant communities, rather than a single species, improves aesthetic effects and plant survival, only experimental trials in representative contexts can provide conclusive information to understand whether these choices are functional (Leotta et al. 2023). Furthermore, the observed plant dynamic should be evaluated through long-term studies to accurately evaluate plant communities especially when species use different strategies to survive extreme conditions (Vandegrift et al. 2019). According to long-term extensive green roof studies, plant dynamics change over the years and are affected by seasonal changes and local environmental conditions. Over time, while plant cover is increasing, plant succession and species diversity decreases or does not change (K\u0026ouml;hler 2006; Ksiazek-Mikenas et al. 2018; Zhang et al. 2021; Van Mechelen et al. 2015; (van der Kolk et al. 2020).\u003c/p\u003e \u003cp\u003eFew long-term studies on unirrigated extensive green roofs have been conducted in Mediterranean climate regions, while most research has focused on cooler and wetter climates, making these studies less relevant to Mediterranean conditions (Nektarios et al. 2021). This study aims to address the gap in research on extensive non-irrigated green roofs in East Mediterranean climates by providing a long-term assessment of a constructed habitat featuring a plant community of native Mediterranean geophytes and Sedum species.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eStudy location:\u003c/h2\u003e\n \u003cp\u003eThe study was conducted on the roof of a four-floor building at the American University of Beirut which overlooks the east Mediterranean Sea shore (33\u0026deg; 53\u0026apos; N, 35\u0026deg; 29\u0026apos; E). The Lebanese coast has a typical East Mediterranean climate, characterized by hot dry summers (May to late September or October), with temperatures between 23\u0026ndash;31\u0026deg;C, and mild winters with temperatures ranging from 5\u0026ndash;12\u0026deg;C. The average rainfall is between 650\u0026ndash;850 mm/ year. Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes climate conditions during the experimental period between 2015 and 2019.\u003c/p\u003e\n \u003cp\u003eTable\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eClimate summary in the study location (Beirut) during the experimental period 2015\u0026ndash;2019 (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ewww.weatherspark.com\u003c/span\u003e\u003c/span\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e)\u003c/span\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eWinter average temperature\u0026nbsp;(\u0026deg;C)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSummer average temperature (\u0026deg;C)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHighest summer temperature (\u0026deg;C)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAverage Yearly precipitation\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e653 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e626 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e360 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e735 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e796 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003ePlant species and extensive green roof set up:\u003c/h2\u003e\n \u003cp\u003eThe experimental species mix used in the study included 15 Mediterranean geophytes and one native sedum (\u003cem\u003eSedum sediforme\u003c/em\u003e) (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). Geophytes were bought (Bulb Argence, France) as bulbs or rhizomes. Rooted cuttings of \u003cem\u003eSedum sediforme\u003c/em\u003e were produced from mother plants which were transplanted from semi-natural urban areas near campus and established in a greenhouse.\u003c/p\u003e\n \u003cp\u003eThe unirrigated experimental green roof area consisted of a 19.8 m2 roof space framed by 20 cm high waterproofed edges (250 cm x 800 cm) and two drainage outlets one at each end. The experimental green roof was lined with geotextile and filled with growing media (10% organic matter, 60% peat moss and 30% local sandy clay soil) to a 10 cm depth. Planting was completed in October 2015. The planting layout focused on creating a plant community by distributing bulbs, rhizomes, and rooted cutting to accommodate plant growth and spread at maturity while looking to achieve a natural appearance.\u003c/p\u003e\n \u003cp\u003eTable \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePlant species used in the experiment (Polunin et al 1965.;* Ouasti et. al. 2023)\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"3\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eScientific name\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTypical habitat\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLife form\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAllium ampeloprasum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHedges, banks, and arid places\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBulb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAllium nigrum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCultivated ground\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBulb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAnemone coronaria\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFields, olive groves, vineyards\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTuber\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAsphodelus aestivus Syn: Asphodelus microcarpus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRocky places, hills, and dry places\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTuber\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eArum dioscoridis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHedges, track sides\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRhizome\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eArum hygrophilum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGarigue and Maquis near water\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRhizome\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eColchicum lusitanum Brot. *\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStony and grassy places\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCorm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCrocus cartwrightianus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStony and grassy places\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCorm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCrocus ochroleucus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFertile Soil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCorm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCyclamen persicum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRocks, walls. Edges of thickets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTuber\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eGladiolus segetum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCultivated ground\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCorm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eNarcissus tazetta\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eField, meadow, and garigue, especially in damp places\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBulb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eOxalis pes-capre\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCultivated ground\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBulb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePancratium maritimum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaritime sand\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBulb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eScilla hyacinthoides\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHedge, rocky places and fields\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBulb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eSedum sediforme (Jacq.)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRocks, walls, and stony places largely on calcareous soil and clay\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSucculent perennial\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eData collection:\u003c/p\u003e\n \u003cp\u003eData was collected over four years (2016\u0026ndash;2019) between February and March to capture maximum plant growth and flowering. Data was recorded and a photo taken of the whole experimental roof area to confirm and review the collected field data. Collected data included plant survival (dead/alive), number of plants/clumps, plant spread (m\u003csup\u003e2\u003c/sup\u003e), number of flowers per plant, and newly recruited species.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eEight out of 15 Mediterranean geophytes did not survive the first year under extensive green roof conditions in our study location. These are \u003cem\u003eAllium nigrum\u003c/em\u003e, \u003cem\u003eArum hygrophilum, Arum dioscoridis, Crocus hadriatus, Crocus ochroleucus, Colchicum byzantinum, Cyclamen persicum\u003c/em\u003e, and \u003cem\u003eOxalis per- capre.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe number of plants varied with species that survived as follows (Table 3): \u003cem\u003eAsphodelus aestivus,, Narcissus tazetta\u003c/em\u003e, \u003cem\u003eScilla hyacinthoides\u003c/em\u003e and \u003cem\u003eAllium ampeloprasum\u003c/em\u003e increased in numbers. \u003cem\u003eA. aestivus\u003c/em\u003e doubled every two years starting with five plants and ending with 17 plants. \u003cem\u003eA.ampeloprasum\u003c/em\u003e doubled the first year and the fourth year resulting in 4 times more plants at the end of the experiment. \u003cem\u003eN. tazetta\u003c/em\u003e. and \u003cem\u003eS. hyacinthoide\u003c/em\u003e grew steadily, their numbers doubled by the third year, and increased threefold and fourfold respectively, by the end of the experiment. The number of \u003cem\u003ePancratium maritimum\u003c/em\u003e stayed the same throughout the four years. \u003cem\u003eGladiolus segetum\u003c/em\u003e declined after the first year and remained stable thereafter with only 20 percent of the plants still alive. \u003cem\u003eAnemone coronaria\u003c/em\u003e declined throughout and by the end of the experiment none of the plants survived.\u0026nbsp;\u003cem\u003eS. sediforme\u003c/em\u003e started propagating vegetatively from the first year through tip rooting and by the fourth-year individual plants were no longer visible as they coalesced into clumps.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cp\u003eTable 3. Number of Mediterranean geophytes and native sedum plants on an extensive green roof in Beirut. *The number of \u003cem\u003eSedum\u003c/em\u003e plants did not increase but the plants started propagating vegetatively through tip rooting until year four when the number of individual plants was no longer visible as individual plants coalesced into clumps\u0026nbsp;\u003c/p\u003e\u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003ccolgroup cols=\"6\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003eNumber of clumps\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eName of plants\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAllium ampeloprasum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAllium nigrum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAnemone coronaria\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eArum dioscoridis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eArum hygrophilum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAsphodelus aestivus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eColchicum byzantinum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCrocus hadriatus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCrocus ochroleucus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCyclamen persicum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eGladiolus segetum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eNarcissus tazetta\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eOxalis per- capre\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePancratium maritimum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eScilla hyacinthoides\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eSedum sediforme\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25+ *\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cdiv align=\"left\"\u003e\u003cstrong\u003eTABLE 3.\u003c/strong\u003e\u003c/div\u003e\n\u003cp\u003eThe speed of plants spread throughout the four years varied with species (Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e and Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea and \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb). Plant spread is a visual sign of plant performance under extensive green roof conditions. The information is useful for selecting plant species that have a rapid establishment rate and can achieve maximum cover. Plant spread increased six-fold for \u003cem\u003eA. aestivus\u003c/em\u003e, five-fold for \u003cem\u003eS.sediforme\u003c/em\u003e, threefold for \u003cem\u003eA.ampeloprasum\u003c/em\u003e, \u003cem\u003eN.tazetta\u003c/em\u003e, and \u003cem\u003eS. hyacinthoides\u003c/em\u003e, and two fold for \u003cem\u003eG.segetum\u003c/em\u003e, while \u003cem\u003eP.maritimum\u003c/em\u003e did not spread, and \u003cem\u003eA. coronaria\u003c/em\u003e declined.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePlant spread (m\u003csup\u003e2\u003c/sup\u003e) of Mediterranean geophytes and native sedum on an extensive green roof at the American University of Beirut, Lebanon\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003ePlant spread in m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eName of the plant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAllium ampeloprasum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAnemone coronaria\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAsphodelus aestivus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eGladiolus segetum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eNarcissus tazetta\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePancratium maritimum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eScilla hyacinthoides\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eSedum sediforme\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eTable 4.\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eAll surviving geophytes flowered, except \u003cem\u003eP. maritimum\u003c/em\u003e, during the experimental period producing a range of 0.5 to 2.7 flowers per plant (Table \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e and Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ea, b, c). \u003cem\u003eS. sediforme\u003c/em\u003e flowered throughout the study producing many flower heads which were not possible to count without destructive sampling.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eNumber of flowers and number of flowers per plant (in parenthesis) of Mediterranean geophytes and native sedum on an extensive green roof at the American University of Beirut, Lebanon\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eTotal number of flowers and (number of flowers/plant)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eName of plants`\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAllium ampeloprasum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAnemone coronaria\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eAsphodelus aestivus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 (0.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7 (0.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18 (1.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eGladiolus segetum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7 (0.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28 (1.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 (0.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eNarcissus tazetta\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 (0.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14 (1.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ePancratium maritimum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eScilla hyacinthoides\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 (0.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (0.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eTable 5.\u003c/p\u003e\n\u003cp\u003eThe appearance of new species recorded during regular monitoring revealed the recruitment of seven native species that colonized the experimental green roof. In the first year, \u003cem\u003eAinsworthia trachycarpa\u003c/em\u003e appeared and persisted until the end of the experiment while \u003cem\u003eLavatera cretica\u003c/em\u003e was recorded in the first year only. No new species were recorded in the second year. In the third year, four native species, \u003cem\u003eTrifolium repens\u003c/em\u003e, \u003cem\u003eMelilotus officinalis\u003c/em\u003e, \u003cem\u003eMisopates orontium\u003c/em\u003e, and \u003cem\u003eDittrichia viscosa\u003c/em\u003e, appeared and persisted until the end of the experiment. In the fourth year, an new species, \u003cem\u003eLophochloa phleoides\u003c/em\u003e, appeared (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea, b).\u003c/p\u003e\n\u003cp\u003eFigure\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eBy the end of the 4 years, the surface of the experimental roof was fully covered with noticeable flowers (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ea,b). The planting layout included 230 bulbs and rhizomes belonging to 15 geophytes and 25 sedum plants belonging to one Sedum species. After four years, plants covered the whole green roof area (100%) as follows: 47% covered by sedum, 44% cover by geophytes, 12% overlapping vegetation, and 21% newly recruited native plant species. In the spring of the last experimental year the roof presented 97 flowers contributing 5 flowers / square meter. In the summer blooming Sedum contributed to the aesthetic of the roof.\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis study confirmed that a combined selection of suitable species for extensive green roofs in the Mediterranean based on both natural growing conditions and plant traits serves only as a framework. Our findings showed varying behaviors among the geophytes although they are all native to the Mediterranean. Out of the fifteen geophytes used in the study, 50% died directly after the first year. Of the survivors, two-thirds increased in biomass and flowering, while the remaining third stagnated and declined. Thus, only five out of fifteen (33%) geophytes thrived and performed well under extensive green roof conditions. These findings confirm the statement by Caneva et al. (2015) who showed that the production of possible species lists based on phytosociological and ecological criteria for extensive green roofs serve only as a framework for setting up field studies to identify the exact species suitable for this purpose. In their study, Caneva et al. (2015) created a database of 471 taxa, of which 146 were identified as potentially suitable for green roofs in the Mediterranean, including 26 geophytes. When comparing the two geophytes, \u003cem\u003eAllium\u003c/em\u003e and \u003cem\u003eGladiolus\u003c/em\u003e, listed as potentially suitable in their study, we found that \u003cem\u003eA. ampeloprasum\u003c/em\u003e performed well, consistent with their findings. However, \u003cem\u003eG.segetum\u003c/em\u003e exhibited stagnant behavior throughout the four years, indicating it was surviving but not thriving. It is worth noting that the authors did not specify whether their focus was on extensive or intensive Mediterranean green roofs; if it was the latter, we would expect \u003cem\u003eGladiolus\u003c/em\u003e species to perform equally well. Our findings also support Van Mechelen et al. (2014), who focused on plant trait analysis rather than habitat to help green roof companies find species suitable for extensive green roofs in the Mediterranean. The authors rated 309 species, including 41 geophytes, using correlation analysis. In their final list, sixty-one species scored higher than 10, indicating potential for green roof application. Among these, the two geophyte genera common to both their study and ours, \u003cem\u003eAllium\u003c/em\u003e and \u003cem\u003eAnemone\u003c/em\u003e, performed as predicted. \u003cem\u003eAllium\u003c/em\u003e ranked high in their analysis and performed well throughout our study, while they gave a low score for \u003cem\u003eA. coronaria\u003c/em\u003e which declined in our study until it disappeared by year four.\u003c/p\u003e \u003cp\u003eOur results show that conducting short term experiments may not fully describe the performance of species. While in the first year we found species that are unsuited to Mediterranean extensive green roof conditions, subsequent years revealed fluctuations in growth and success rates among remaining species with some stagnating or declining and others thriving throughout the four years. This finding is in line with Rowe et al. (2012) who showed that long-term extensive green roof research can provide more accurate information on community succession and performance of species. The authors described how plants that initially survived eventually experienced reduced coverage or disappeared completely. They indicated that such information is valuable for the design and maintenance of green roofs, while research of short duration is likely to result in premature conclusions and misleading recommendations (Rowe and Durham 2012). Similar conclusions were made by Zhang et al. (2021) who indicated that long term variability reveals actual survival of species often preceded by several years of decline. The authors, who conducted an 8-year study in Beijing, reported species decline at various times after planting, with six out of ten succulent species showing signs of decline starting no earlier than the third year. Ultimately, after 8 years, only two species remained viable, irrespective of substrate depth. To the best of our knowledge, few extensive green roof studies longer than three years have been published in the past decade. Using the key words \u0026lsquo;extensive green roof\u0026rsquo; and \u0026lsquo;long term\u0026rsquo; we found a total of eighteen long term extensive green roof studies of which five were conducted in a Mediterranean / dry climate (Bates et al 2013; Cao et al. 2019; Giorgioni and Grandi 2021; Heim and Lundholm 2022; Nektarios et al.2021; Pa\u0026ccedil;o et al. 2019; Salman and Blaustein 2018; Salih et al. 2021; Thuring and Dunnett 2019; Todorov et al. 2018; Tran et al. 2019; Zhang et al. 2018; Zhang et al. 2021; Zhang et al.2021;Zheng et al. 2022; Vannucchi et al.2022; Vandegrift et al.2019; van der Kolk et al. 2020; Vidaller et al. 2023)\u003c/p\u003e \u003cp\u003eLong-term studies also reveal the link between plant performance and local weather patterns. For example, van der Kolk et al. (2020) who conducted an eight-year study were able to detect fluctuations in plant performance which appear to be linked to local weather patterns. They noted a decline in species richness between years 2 and 7, followed by an increase by year eight. The authors attributed this fluctuation to an exceptionally dry summer, which reduced grass cover and allowed other species to colonize the roof surface in the later year. In our study, observation of flowering of two species (\u003cem\u003eG.segetum and N. tazetta\u003c/em\u003e) after the first year of planting (years 2, 3, and 4) seem to be linked to average rainfall preceding bloom (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe importance of long-term studies is also clear in revealing when and how spontaneous vegetation colonizes extensive green roofs. In our study, regular monitoring revealed the recruitment of seven native species that colonized the experimental green roof. Two species \u003cem\u003eA. trachycarpa\u003c/em\u003e and \u003cem\u003eL.cretica\u003c/em\u003e appeared in the first year however only the former persisted throughout the four years while the latter appeared only in year one. No new species were recorded in the second year, however, starting with year 3, four native species, \u003cem\u003eT. repens, M. officinalis, M. orontium\u003c/em\u003e, and \u003cem\u003eD. viscosa\u003c/em\u003e, appeared and persisted until the end of the experiment. An additional species, \u003cem\u003eL.phleoides\u003c/em\u003e, appeared in the last experimental year i.e. year 4. All the recruited species were ruderal East Mediterranean native annual species that typically grow along roadsides, wastelands, and sea sides (Polunin et al. 1965; Tohm\u0026eacute; and Tohme 2014). The observed facilitated recruitment of native species by perennial geophyte and sedum is in support with Vidaller et al. (2023) who indicated that the planting of perennial species followed by spontaneous colonization of species present in the vicinity of the roof would then represent a more efficient strategy for the persistence of extensive non-irrigated green roofs in Mediterranean environments than sowing a species-rich local Mediterranean seed mixture dominated by annual species.\u003c/p\u003e \u003cp\u003eOur findings regarding the appearance of spontaneous species a few years after green roof establishment are in line with Vidaller et al. (2023) who identified 34 spontaneous species in a long-term experiment indicating a sharp increase after two years. Our findings which suggest that colonizing species are mostly ruderal are also in line with Vanstockem et al. (2019) who indicated that ruderal species were the most common colonizers following a survey of 129 green roofs in Belgium (Vanstockem et al. 2019). These species may have benefited from the absence of interspecific competition that normally occurs in later successional stages and colonize bare and disturbed land (Itani et al. 2020).\u003c/p\u003e \u003cp\u003eWe found that combinations of plant communities consisting of mixed geophyte species and succulents are suitable to create new urban habitats on extensive green roofs in urban Mediterranean environments. The suitability of geophytes for use in unirrigated extensive green roofs has been reported by Benvenuti and Bacci (2014) and Zhang et al (2021) who explained that geophytes require no management and could survive unfavorable conditions. Similarly, the adaptability of Sedum species to extensive green roof conditions has been reported for more than 20 years. Our selection of the plant species was based on habitat template where natural habitats shared similar climate characteristics to inform the potential species pool (Ksiazek-Mikenas et al. 2021) while the \u003cem\u003eSedum\u003c/em\u003e geophyte combination was based on plant trait synergy (Nagase A and Dunnett N. 2013)\u003c/p\u003e \u003cp\u003eThe identity of the new urban plant community in our study was not evident until the end of the four-year experiment. This was because almost half of the native geophyte species planted did not survive beyond the second or third year. While the use of plant communities, rather than a single species, may contribute to plant survival only experimental trials in representative contexts can provide conclusive information to understand whether these choices are functional (Leotta L et al. 2023). Our findings suggest that although habitat template approaches can serve to guide plant choices, long term roof experiments are essential to unveil actual plant tolerance to restrictive extensive green roofs and trait synergies. As such, this study is in line with Lundholm and Walker (2018) and Chell et al. (2022) who indicated the habitat-template approach is probably best used as a coarse filter for plant selection on green roofs.\u003c/p\u003e \u003cp\u003eThrough this study a new plant community was created from a mix of native geophyte and Sedum species. The mixture of geophytes and Sedum thrived over the four-year experiment and spread covering approximately two-thirds of the extensive green roof study area. The presence of Sedum species in mixed planting has been previously reported to be beneficial for the performance and survival of Mediterranean species (Aze\u0026ntilde;as et al. 2018; Becker and Bucholz 2016; Fournier et al. 2020; Ksiazek-Mikenas et al 2021; Van Mechelen et al. 2015; Vasl et al 2017). This new plant community offered a plant architecture typology that recruited new colonizing species and allowed them to establish, interjected in the remaining one-third thus serving as habitat analogue. As such physiognomy of constructed plant communities might be a useful tool in extensive green roofs that facilitates colonization by native species leading to unique species assemblages that do not resemble natural analogs (Aloisio et al. 2020, Itani et al. 2020). The process of colonization in such constructed communities is reportedly dynamic leading to continuous change in species composition and presenting an increase in the proportion of native species which could play a role in urban biodiversity if developed at large scales in cities (Madre et al. 2014; Thuring et al. 2019). However, with each green roof supporting novel habitat analogues, contribution to urban biodiversity depends on biotic and abiotic factors that are not consistent among extensive green roofs (Ksiazek-Mikenas et al. 2018; Martini et al. 2022). A limitation of our study is that although we recorded the native species that colonized the experimental extensive green roof, we did not record their number or spread. Similarly, during our study we observed birds and insect visitations but did not document species and frequency of visits.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eOur long-term non-irrigated extensive green roof study allowed us to monitor the differing behaviors of geophytes native to the Mediterranean, confirmed the suitability of the native Sedum in combination species mix, and witnessed the recruitment of native annual and perennial herbaceous species. We created an extensive green roof habitat analogue which was adapted to East Mediterranean conditions thus contributing to literature that is lacking for this region (Vidaller at al. 2023). This study also showed how short term experiments may not reflect the dynamic changes that occur over the years in terms of the survival of planted species and the establishment of newly recruited ones. Finally, we demonstrated that a constructed community of mixed geophyte species and succulents are suitable to create new urban habitat analogues on extensive green roofs in urban Mediterranean cities. This type of knowledge can contribute to the development of guidelines for the urban environments in the Mediterranean region which according to Catalano et al. (2018) need to be widely refined considering the peculiarities of green roof design in the Mediterranean ecoregion.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting Interests\u003c/h2\u003e \u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eBoth authors contributed to the study conception and design. Material preparation and data collection were performed by Monika Fabian. Data analysis was performed by Monika Fabian and Salma Talhouk. The manuscript was written by Monika Fabian and Salma Talhouk. Both authors read and approved the final manuscript.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"urban-ecosystems","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ueco","sideBox":"Learn more about [Urban Ecosystems](https://www.springer.com/journal/11252)","snPcode":"11252","submissionUrl":"https://submission.nature.com/new-submission/11252/3","title":"Urban Ecosystems","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Extensive green roof, geophytes, Mediterranean, sedum, habitat analogs, urban environment","lastPublishedDoi":"10.21203/rs.3.rs-4690744/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4690744/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eExtensive green roof research has primarily focused on cooler, wetter climates, resulting in a lack of knowledge of Mediterranean conditions. This long-term study addresses this gap by assessing a constructed plant community of native Mediterranean geophytes and Sedum species. While both are individually recognized for their resilience to prolonged dry periods, their combined performance has been underreported. We studied the performance of 15 Mediterranean geophytes combined with one native sedum on an unirrigated extensive green roof for four years. Data collection included plant survival, number of plants, spread, flowering, and new species recruitment. Throughout the study, eight geophytes did not survive, five increased in number, one remained stable, and two declined. Five geophytes readily spread, one occupied the same space, and one decreased. Most surviving geophytes flowered. Sedum spread vegetatively and flowered consistently. Seven native species were recruited. By the end of the experiment, vegetation cover was 100% (47% Sedum,44% geophytes,12% overlapping vegetation,21% new native species). The findings underscore the importance of long-term studies to observe plant dynamics and reveal the possibility of constructing new urban habitats thus contributing valuable insights for green roof development in Mediterranean cities.\u003c/p\u003e","manuscriptTitle":"Assessment of a constructed community of native geophytes and sedum species as a habitat analog for extensive green roofs in an urban East Mediterranean environment","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-30 15:29:28","doi":"10.21203/rs.3.rs-4690744/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-08-06T22:01:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-07-05T14:21:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-07-05T13:50:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"Urban Ecosystems","date":"2024-07-05T08:21:36+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"urban-ecosystems","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ueco","sideBox":"Learn more about [Urban Ecosystems](https://www.springer.com/journal/11252)","snPcode":"11252","submissionUrl":"https://submission.nature.com/new-submission/11252/3","title":"Urban Ecosystems","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"9528bcc9-211a-4638-87d6-9f91f5531db6","owner":[],"postedDate":"July 30th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-02-10T16:10:21+00:00","versionOfRecord":{"articleIdentity":"rs-4690744","link":"https://doi.org/10.1007/s11252-025-01679-6","journal":{"identity":"urban-ecosystems","isVorOnly":false,"title":"Urban Ecosystems"},"publishedOn":"2025-02-03 15:57:18","publishedOnDateReadable":"February 3rd, 2025"},"versionCreatedAt":"2024-07-30 15:29:28","video":"","vorDoi":"10.1007/s11252-025-01679-6","vorDoiUrl":"https://doi.org/10.1007/s11252-025-01679-6","workflowStages":[]},"version":"v1","identity":"rs-4690744","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4690744","identity":"rs-4690744","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}